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PLS-CADD
PLS-CADD – Version 16.0 © Power Line Systems, 2019
2
PLS-CADD – Version 16.0 © Power Line Systems, 2019
Table of Contents
(Printing date: June 2019)
1.
2.
3.
FOREWORD .....................................................................................................................17
DISCLAIMER, WARRANTY AND LICENSES ...................................................................18
HARDWARE REQUIREMENTS AND INSTALLATION .....................................................21
3.1
Upgrade Installation (via email) ...................................................................................21
3.1.1
Requesting an Upgrade .....................................................................................21
3.1.1.1
Downloading Upgrade ..................................................................................21
3.2
CD Installation ............................................................................................................24
3.3
Troubleshooting the Hardware Key .............................................................................25
3.4
Electronic Manual and Online Help .............................................................................25
4. OVERVIEW .......................................................................................................................27
5. LOADING AND VIEWING AN EXISTING MODEL ............................................................29
5.1
Loading a Line Model ..................................................................................................30
5.2
Preferences ................................................................................................................33
5.3
Saving, Backing up or Moving a Model .......................................................................37
5.3.1
Backing up a Model ...........................................................................................37
5.3.2
Moving a Model and Associated Libraries without Using "Backup" ....................38
5.4
Viewing Functions .......................................................................................................39
5.4.1
Windows and Toolbars.......................................................................................39
5.4.2
Graphics Commands Available in all Views .......................................................42
5.4.3
Graphics Command Only Available in Profile Views ..........................................45
5.4.4
Graphics Commands Only Available in 3-D Views .............................................45
5.4.4.1
Graphics Commands Only Available in Plan Views ......................................46
5.4.4.2
Structure View Graphics Commands Only ....................................................46
5.4.5
Miscellaneous Display Options ..........................................................................47
5.4.6
Display Options for Line and Tension Sections ..................................................53
5.4.6.1
Colors for Line, Tension Sections, Structures and Insulators ........................53
5.4.6.2
Phases Displayed .........................................................................................56
5.4.6.3
Weather Case, Cable Condition and Wind Direction .....................................56
5.4.6.3.1 As Surveyed Temperature .........................................................................57
5.4.6.4
Multiple Lines ................................................................................................58
5.4.6.5
Effect of Line Angle on Sags .........................................................................60
5.4.7
Terrain Display Options......................................................................................60
5.4.8
Cross-section Views ..........................................................................................61
5.4.9
Exporting to Google Earth™ ..............................................................................63
5.4.10
Additional Text and Lines ...................................................................................63
5.4.11
View Location in Bing Maps™............................................................................64
5.4.12
Virtual Profile .....................................................................................................64
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5.5
Latticed Towers Line ...................................................................................................65
5.6
Entity Info....................................................................................................................67
5.7
Merging Projects .........................................................................................................69
5.8
Web Download Files ...................................................................................................70
6. TERRAIN ..........................................................................................................................72
6.1
General - Use of Feature Codes .................................................................................72
6.1.1
Checking of Required Clearances ......................................................................75
6.2
XYZ Terrain Model ......................................................................................................82
6.2.1
XYZ Coordinate System Selection .....................................................................83
6.2.1.1 Coordinate System Reprojection .......................................................................84
6.2.2
GPS Tracking ....................................................................................................84
6.3
Alignment....................................................................................................................85
6.3.1
Defining or Editing Alignments on Terrain without Existing Line .........................85
6.3.1.1
Defining or Editing a Single Alignment ..........................................................85
6.3.1.2
Defining or Editing Additional Alignments......................................................88
6.3.1.3
Display Options for PI, Alignment, Right of Way ...........................................93
6.3.2
Maximum Offsets and Center Line Profile ..........................................................95
6.3.3
Editing Alignment when there is a Line on the Terrain .......................................98
6.3.3.1 Alignment Survey Point Snap ........................................................................101
6.4
Triangulating XYZ terrain - TIN model .......................................................................102
6.4.1
Triangulated Irregular Network (TIN) ................................................................102
6.4.2
Creating, Saving, Loading or Deleting a TIN Model..........................................102
6.4.3
Displaying TIN Model .......................................................................................104
6.4.4
Creating Interpolated Ground Points ................................................................107
6.4.5
Adding XYZ Points ...........................................................................................107
6.4.6
TIN Interpolation of Z .......................................................................................108
6.5
Break Lines ...............................................................................................................109
6.5.1
Using Break Lines to Enhance XYZ Terrain Models .........................................110
6.5.2
Using Break Lines to Describe Existing or Planned Facilities ...........................111
6.6
Terrain Attachments..................................................................................................112
6.6.1
DXF Drawings..................................................................................................115
6.6.2
Raster Images .................................................................................................118
6.6.2.1
Draping of Raster Images on Top of TIN Model ..........................................121
6.6.3
Shapefiles ........................................................................................................122
6.6.4
Miscellaneous Attachment Options ..................................................................123
6.6.4.1 Drafting/ Attachments/ Find Text .....................................................................123
6.6.4.2 Drafting/ Attachments/ Associate Structure Photos .........................................123
6.6.5
Web Mapping Services (WMS) ........................................................................124
6.7
PFL Terrain Model ....................................................................................................126
6.8
Using Scanned Raster Drawings to Create PFL Terrain Model .................................127
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6.8.1
Opening a Profile View ....................................................................................128
6.8.2
Attaching Scanned Drawing to Profile ..............................................................128
6.8.3
Scaling and Orienting Scanned Drawing ..........................................................129
6.8.4
Sliding Scaled Attachment ...............................................................................129
6.8.5
Creating PFL Points .........................................................................................129
6.8.6
Creating Line Model .........................................................................................130
6.9
XYZ or PFL? .............................................................................................................130
6.9.1
XYZ to PFL Conversion ...................................................................................131
6.9.2
PFL to XYZ conversion ....................................................................................131
6.10
Side Profiles, Clearance Lines, Prohibited Zones and Special Cost Zones............132
6.10.1
Side Profiles.....................................................................................................132
6.10.2
Ground Clearance Line ....................................................................................132
6.10.2.1 Wire Clearance Line ...................................................................................133
6.10.3
Spotting Constraints.........................................................................................133
6.11
Equation Stations ..................................................................................................138
6.12
LiDAR Tools ..........................................................................................................139
7. DESIGN CRITERIA .........................................................................................................145
7.1
General .....................................................................................................................145
7.1.1
Modeling of Wire System .................................................................................145
7.1.1.1
Level 1 Modeling - Ruling Span Method (RS) .............................................146
7.1.1.2
Level 2 modeling - Finite Element (FE) Modeling Ignoring Interaction between
Wires
...................................................................................................................147
7.1.1.3
Level 3 Modeling - Finite Element (FE) Modeling Accounting for Interaction
between Wires.............................................................................................................149
7.1.1.4
Level 4 Modeling - Full System Analysis .....................................................150
7.2
Wind and Ice Models ................................................................................................153
7.2.1
Wind Model ......................................................................................................155
7.2.1.1
Reference Wind and Escalation with Height ...............................................155
7.2.1.1.1 Effective Height for Structures or Portions of Structures ..........................157
7.2.1.1.2 Effective Height for all Wires of a Tension Section (for purpose of displaying
tension section and making clearance calculations) ..................................................157
7.2.1.1.3 Effective Height for a Single Wire in a Single Span (for purpose of
determining design wind reactions at ends of span) ..................................................158
7.2.1.2
Wind Load per Unit Length of Wire .............................................................158
7.2.1.2.1 Assumptions for Calculating Wind Load on all the Spans of a wire in a
single tension section, UHTS , for purpose of displaying the tension section and making
clearance calculations...............................................................................................159
7.2.1.2.2 Assumptions for Calculating Wind Load on a Wire for Purpose of
Determining the Contribution to Load on Supporting Structure..................................160
7.2.1.3
Wind Load on Supporting Structure ............................................................161
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7.2.2
Ice Model .........................................................................................................163
7.2.2.1
Ice on Wires ................................................................................................163
7.2.2.2
Ice on Structures.........................................................................................164
7.2.3
Load per Unit Length of Wire ...........................................................................164
7.2.3.1
NESC District Case ....................................................................................164
7.3
Detailed Design Criteria ............................................................................................166
7.3.1
Notes ...............................................................................................................166
7.3.2
Weather Cases ................................................................................................167
7.3.3
Code Specific Wind and Terrain Parameters ...................................................169
7.3.4
Conditions for Cable Creep and Permanent Stretch .........................................169
7.3.5
Bimetallic Conductor Model .............................................................................170
7.3.6
Cable Tensions ................................................................................................171
7.3.7
Automatic Sagging ...........................................................................................171
7.3.8
Maximum Tension............................................................................................172
7.3.9
Weight Span Model ..........................................................................................172
7.3.10
Conditions for Checking Weight Spans of Method 1 Structures .......................172
7.3.11
Conditions for Checking Method 2 Structures ..................................................173
7.3.12
Load Trees for Method 3 and Method 4 Structures ..........................................173
7.3.12.1 Structure Axes and Orientation Relative to Line ..........................................173
7.3.12.2 Wind Direction ............................................................................................174
7.3.12.2.1 Wind Direction XYZ Structures ..............................................................176
7.3.12.3 Reactions at Ends of Span (in span coordinate system) .............................177
7.3.12.4 Design Loads at Structure Attachment Points .............................................179
7.3.12.5 Design Pressures on Structure Faces .........................................................181
7.3.12.6 Load and Strength Factors..........................................................................182
7.3.12.7 Unbalanced Loading ...................................................................................185
7.3.12.7.1 Adjust Percent of Horizontal Tension .....................................................186
7.3.12.7.2 Specify Number of Broken Subconductors ............................................186
7.3.12.7.3 Add a Concentrated Vertical Load .........................................................187
7.3.12.7.4 Add a Concentrated Transverse Load ...................................................187
7.3.12.7.5 Add a Concentrated Longitudinal Load ..................................................187
7.3.12.7.7 Adjust Vertical (or Transverse or Longitudinal) Load ..............................187
7.3.12.7.8 Adjust Ice Prior to Sag and Tension Calculation ....................................188
7.3.12.7.9 Adjust Wind Pressure Prior to Sag and Tension Calculation ..................188
7.3.12.7.10 Adjust Wire Dead Weight Prior to Sag and Tension Calculation ..........188
7.3.12.7.11 Rotate Wire Coord. System Clockwise After Sag-Tension ...................188
7.3.12.8
7.3.12.9
6
Structure Loads Criteria Table ....................................................................189
Structure Groups ........................................................................................194
PLS-CADD – Version 16.0 © Power Line Systems, 2019
7.3.13 Conditions for Checking Survey Points Clearances ..............................................197
7.3.14
Conditions for Checking Clearances between Cables .....................................199
7.3.15
Conditions for Drawing Galloping Ellipses ........................................................199
7.3.16 Conditions for Checking Suspension Insulator Swings and Load Inclinations on
2-part Insulators ..............................................................................................................202
7.3.16.1 Structures with Suspension Insulators at Line Angles .................................204
7.3.16.2 Conditions For Checking Insulator Uplift .....................................................206
7.3.17
Wind & Weight Spans Report...........................................................................206
7.3.18
Blowout and Departure Angles Report .............................................................207
7.3.19
Default Wire Temperature and Condition, Section Sort Order ..........................207
7.3.20
Finite Element Modeling Data ..........................................................................207
8. STRUCTURES ................................................................................................................208
8.1
General .....................................................................................................................208
8.2
Structure Top Geometry............................................................................................208
8.2.1
Cable Sets .......................................................................................................209
8.2.2
Clamps and Insulators .....................................................................................210
8.2.3
Tension Sections .............................................................................................210
8.3
Structure Strength .....................................................................................................211
8.3.1
Method 1 - Basic Allowable Spans Method ......................................................211
8.3.2
Method 2 - Allowable Spans Interaction Diagram Method ................................213
8.3.3
Method 3 - Critical Components Method ..........................................................214
8.3.4
Method 4 - Detailed Structural Analysis Method ...............................................215
8.4
Structure Display ......................................................................................................217
8.4.1
Method 1, 2 and 3 Structure Files Generated Directly ......................................218
8.4.2
Method 1, 2 and 3 Structure Files Created by PLS-POLE or TOWER..............219
8.4.3
Method 4 Structures.........................................................................................219
8.5
Parts and Assemblies ...............................................................................................220
8.5.1
Parts Table ......................................................................................................221
8.5.2
Assemblies List ................................................................................................224
8.5.3
Material Setup ..................................................................................................226
8.5.4
Material Population ..........................................................................................228
8.5.4.1
Structure Specific Material ..........................................................................228
8.5.4.2
Line Specific Material ..................................................................................229
8.5.4.3
Conductor Specific Parts ............................................................................230
8.5.5
Item Status (New, Existing, Transferred, Retired) ............................................231
8.5.5.1
Global Change Item Status .........................................................................232
8.5.5.2
Specific Change Item Status .......................................................................233
8.5.5.3
Global Dismiss Items with Status ................................................................234
8.5.5.4
Global As-Built ............................................................................................234
8.5.6
Material Reporting............................................................................................236
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8.5.6.1
Bill of Material Report..................................................................................236
8.5.6.2
Bill of Material by Structure Location Report ...............................................237
8.5.6.3
Bill of Material Delta Report ........................................................................237
8.6
Creating, Editing or Customizing Structure File .........................................................238
8.7
Summary of the Advantages of Using Method 4 Structures ......................................238
9. GROUND WIRES AND CONDUCTORS .........................................................................241
9.1
Mechanical Model .....................................................................................................241
9.1.1
Initial Behavior - Elastic vs. Nonlinear ..............................................................241
9.1.2
Final Behavior after Creep ...............................................................................244
9.1.3
Final Behavior after Stretching from Severe Load ............................................247
9.1.4
Thermal Properties ..........................................................................................248
9.2
Creating or Editing Cable Files..................................................................................249
9.2.1
Cables in Bundles ............................................................................................257
9.2.1.1
Twisted Pairs (Fig. 9.2-5a) ..........................................................................258
9.2.1.2
Lashed Cable onto a Messenger (Fig. 9.2-5b) ............................................258
9.2.1.3
Conductor Bundles (Fig. 9.2-5c and d) .......................................................259
9.2.1.4
Spaced Conductors Supported by Messenger (Fig. 9.2-5e) ........................260
9.2.2
GAP-type Conductor ........................................................................................261
9.2.3
Create Bundled Cable ......................................................................................262
9.3
High or Extremely High Temperature Considerations ...............................................263
9.3.1
Additional Creep from Using Conductors at Extremely High Temperatures......263
9.3.2
Aluminum in Compression ...............................................................................263
9.3.3
Steady State and Transient Thermal Ratings ...................................................264
9.4. PLS-CADD Circuits and phase labels .......................................................................264
9.4.1
Defining Circuit and Phase Labels ...................................................................264
9.4.2
Assigning Circuit and Phase Labels .................................................................265
10.
CREATING OR EDITING LINE MODEL ......................................................................268
10.1
Loading Terrain Data and Defining the Alignment .................................................269
10.1.1
When a Project.xyz File is Available................................................................269
10.1.2
When a Project.pfl File is Available ..................................................................270
10.1.3
When No Project.xyz or Project.pfl Terrain File is Available .............................270
10.2
Interactive Structure Spotting ................................................................................271
10.2.1
Spotting Structures at Line Angles ..................................................................272
10.2.1.1 Terrain Points at Line Angles Have Unique Feature Codes ........................272
10.2.1.2 Locating One Structure Type at all Line Angles ..........................................272
10.2.1.3 Snapping Structure to Line Angle Location .................................................272
10.2.2
Spotting Tangent Structures ...........................................................................273
10.2.3
Spotting Short Cuts ..........................................................................................275
10.2.3.1 Structure Copy/ Paste .................................................................................276
10.2.3.2 Structure Copy/ N-Paste .............................................................................276
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10.2.4
Effects of Spotting (Adding) New Structures in Existing Line Model .................276
10.2.5
Moving Structures ...........................................................................................277
10.2.5.1 Dragging Structure with the Mouse .............................................................277
10.2.5.2 Snapping Structure to Designated Point .....................................................277
10.2.6
Brief Discussion of Automatic Optimum Spotting ............................................279
10.2.7
Customizing Structures ....................................................................................279
10.2.8
XYZ Based Structures .....................................................................................279
10.2.8.1 Adding XYZ Based Structures ....................................................................279
10.2.8.2 Moving XYZ Based Structures ....................................................................283
10.2.8.3 XYZ Based Structures in Profile and Sheets View ......................................283
10.2.8.4 XYZ Based Structures Stationing ................................................................283
10.2.8.5 XYZ Based Structures Line Angles .............................................................284
10.2.8.6 Stringing to XYZ Based Structures and Structure Orientation .....................285
10.2.8.7 Convert Station Based Structure to XYZ Based Structure ...........................287
10.2.8.8 Rotate XYZ Based Structures .....................................................................287
10.3
Ground Wires and Conductors Installation ............................................................288
10.3.1
Stringing of Tension Section ............................................................................288
10.3.1.2 Automatic Stringing .....................................................................................291
10.3.1.3 Graphical Stringing .....................................................................................292
10.3.2
Sagging Tension Section ................................................................................303
10.3.2.1 Sagging for Uniform Tension Throughout Tension Section at Reference
Condition ...................................................................................................................303
10.3.2.1.1 Sagging by Tension ...............................................................................304
10.3.2.1.2 Sagging by Catenary Constant ..............................................................304
10.3.2.1.3 Automatic Sagging.................................................................................304
10.3.2.1.4 Graphical Sagging .................................................................................305
10.3.2.2 Sagging to Match Non-uniform Tensions in Spans of Tension Section .......308
10.3.2.3 Additional Comments Regarding the Effect of Clipping Insulators ...............309
10.3.3
Displaying Tension Section .............................................................................311
10.3.3.1 Displaying a Tension Section for a Given Catenary Constant and Swing
Angle
...................................................................................................................311
10.3.3.2 Displaying a Tension Section for a Given Weather Case and Cable
Condition ...................................................................................................................311
10.3.4
Reusing Tension Section Sagging Parameters ...............................................311
10.3.5
Section Table ...................................................................................................312
10.3.6
Modifying Tension Section after Insulators are Clipped ....................................314
10.3.7
Swap Attachments ........................................................................................315
10.3.8
Jumpers ...........................................................................................................315
11.
ENGINEERING CALCULATIONS ...............................................................................318
11.1
Structures ..............................................................................................................318
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11.1.1
Wind and Weight Spans...................................................................................318
11.1.2
Loading Trees .................................................................................................319
11.1.3
Strength Checking ..........................................................................................321
11.1.3.1 Strength Check Report for Method 1 Structures..........................................321
11.1.3.2 Strength Check Report for Method 2 structures ..........................................323
11.1.3.3 Strength Check Report for Method 3 Structures..........................................323
11.1.3.4 Strength Check Report for Method 4 Structures..........................................324
11.1.4
Leg Extensions and Guy Lengths in Sloping Terrain .......................................325
11.2
Tension Sections ...................................................................................................327
11.2.1
Sags and Tensions ..........................................................................................327
11.2.2
Design Limits Checking....................................................................................330
11.2.3
Clearances.......................................................................................................330
11.2.3.1 Clearances from Survey Points to Phases ..................................................330
11.2.3.2 Clearances between Cables .......................................................................337
11.2.3.2.1 Basic Clearance Check .........................................................................337
11.2.3.2.2 Multiple Spans Clearance Checks .........................................................339
11.2.3.2.3 Clearances between Galloping Ellipses .................................................342
11.2.3.3 Clearance between Wires and Structures - Departure Angles ....................342
11.2.3.3.1 Departure Angles ...................................................................................345
11.2.3.4 Clearance to TIN and Isoclearance Contours .............................................346
11.2.4
Construction Stringing Charts .........................................................................349
11.2.5
Construction Offsets .......................................................................................352
11.2.6
Thermal Ratings ..............................................................................................354
11.2.6.1 Steady-state Thermal Rating ......................................................................355
11.2.6.2 Transient Thermal Rating ...........................................................................360
11.2.6.3 Batch Thermal Calculator ...........................................................................362
11.2.7
Conductor Loss of Strength at High Temperature ............................................364
11.2.8
Electro-Magnetic Field Calculations .................................................................364
11.2.9
Clearance to Vegetation and Falling Trees (Vegetation Management) ............366
11.2.10 Line Constants Calculator ................................................................................373
11.2.11 Full Line Constants Calculator .........................................................................374
11.2.11.1 Full Line Constant Matrix Calculations ......................................................377
11.2.12 Lightning Protection Calculator ........................................................................379
11.2.13 Elevated Temperature Creep ...........................................................................382
12.
REPORTS AND SUMMARY TABLES .........................................................................383
12.1
Reports .................................................................................................................383
12.1.1
Viewing and Editing Reports ............................................................................383
12.2
Summary Tables ...................................................................................................385
12.2.1
Structures Staking Table .................................................................................385
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12.2.2
Bill of Material by Structure Location ...............................................................387
12.2.3
Bill of Material .................................................................................................388
12.2.4
Table Functions ..............................................................................................388
12.3
XML Exports ..........................................................................................................389
13.
PLAN & PROFILE DRAWINGS ...................................................................................390
13.1
Overview ...............................................................................................................390
13.2
Sheets Layout .......................................................................................................393
13.2.1
Page Size ........................................................................................................394
13.2.2
Page and Sheet Layout....................................................................................394
13.2.2.1 Pages and Station Range ...........................................................................398
13.2.3
Scales and Plan Display Type.........................................................................399
13.2.4
Detailed Text and Lines Appearances..............................................................401
13.2.5
Saving Drawing Parameters ............................................................................401
13.3
Lines and Annotation .............................................................................................401
13.3.1
Interactive Drawing of Arrow, Line, Polygon or Text .........................................401
13.3.1.1 Adding New Arrow, Line or Text .................................................................401
13.3.1.2 Editing Existing Line or Text........................................................................404
13.3.1.3 Moving, Rotating or Deleting Lines, Polygons or Text .................................404
13.3.2
Editing Drawing of Line or Text in Table ...........................................................404
13.3.3
Re-using Lines and Text in Different Projects ..................................................408
13.4
Direct Printing of P&P Sheets or Exporting DXF or PDF Files ...............................409
13.5
Inset Plan Detail or Sheet Index Map in the Sheets View ......................................411
13.6
Inset Report Views ................................................................................................414
13.6.1 Adding Inset Report Views................................................................................414
13.6.2 Moving, Editing, & Deleting Inset Report Views ....................................................415
13.6.3 Updating Inset Report Views ................................................................................415
13.6.4 Splitting Inset Report Views ..................................................................................415
13.6.5 Locking Inset Report Views ..................................................................................415
13.6.6 Building Inset Report Views ..................................................................................415
13.6.7 Empty Inset Views ................................................................................................416
13.6.8 Display Order of Inset Views.................................................................................416
13.6.9 Pan, Rotate, or Zoom Inset Views ........................................................................416
13.7
Inset Structure Views.............................................................................................417
13.8
Inset Phasing Diagram ..........................................................................................418
14.
OPTIMUM STRUCTURE SPOTTING & OPTIMUM POLE SELECTOR ......................418
14.1
Automatic Optimum Structure Spotting ..................................................................418
14.1.1
Terrain Constraints and Design Criteria ..........................................................419
14.1.2
Basic Spotting Algorithm ..................................................................................421
14.1.3
Simplified Line Model .......................................................................................422
14.1.4
Editing of Terrain and Required Structures Constraints ...................................423
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14.1.5
Editing of Structures Available for Optimization ................................................425
14.1.6
Running the Optimization .................................................................................427
14.1.7
Accepting Automated Spotting .........................................................................434
14.2
Automatic Optimum Pole Selector .........................................................................435
14.3
Optimum Body and Leg Extension Selection .........................................................436
14.3.1
TOWER Model Requirements for Optimum BLE .............................................436
14.3.2
Optimum Body and Leg Extension settings .....................................................436
15.
PLS-CADD/ LITE ........................................................................................................440
15.1
Installing and Sagging Wires .................................................................................442
15.1.1
Data Needed Regardless of Selection of Installation and Sagging Methods ...443
15.1.2
Defining Attachment at Structure ....................................................................445
15.1.2.1 With Global Coordinates of Attachment Points............................................445
15.1.2.2 By Importing a Structure Model with Already Defined Attachment Points ....445
15.1.3
Defining End of Each Span .............................................................................446
15.1.3.1 With Global Coordinates of End Point .........................................................446
15.1.3.2 With Azimuth, Span Length and Vertical Projection ....................................446
15.1.3.3 With Wind Span and Weight Span ..............................................................446
15.1.4
Sagging Wires ................................................................................................447
15.1.4.1 Specifying the Horizontal Component of Tension for Given Temperature and
Cable Condition ...........................................................................................................447
15.1.4.2 Specifying the Catenary Constant for Given Temperature and Cable
Condition ...................................................................................................................447
15.1.4.3 Specifying Mid Span Sag for Given Temperature and Cable Condition ......447
15.1.4.4 Specifying Coordinates of One Point Surveyed Along Wire for Given
Temperature and Cable Condition ...............................................................................447
15.1.4.5 Using the Autosag Function ........................................................................448
15.1.5
Starting New Project .......................................................................................448
15.2
Viewing PLS-CADD/ LITE Model ...........................................................................449
15.3
Engineering Calculations and Reports...................................................................450
16.
PLS-CADD/ ULTRALITE ............................................................................................454
16.1
PLS-CADD/ ULTRALITE Project ...........................................................................454
17.
DISTRIBUTION LINE MODELING WITH PLS-CADD & PLS-POLE ...........................459
17.1
PLS-CADD/DISTRIBUTION ..................................................................................459
17.1.1
Opening and creating new projects .................................................................460
17.1.2
Creating a criteria file for PLS-CADD/Distribution............................................461
17.1.2.1 Distribution Toolbar .....................................................................................462
17.1.2
Terrain Functionality .......................................................................................462
17.1.2.1 Coordinate System Definition......................................................................463
17.1.2.2 Loading Survey Data ..................................................................................463
17.1.2.3 Survey Symbols and Clearances ................................................................463
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PLS-CADD – Version 16.0 © Power Line Systems, 2019
17.1.2.4 Surface Modeling ........................................................................................463
17.1.3
Structure Functionality ....................................................................................464
17.1.3.1 Adding and Deleting Structures ..................................................................464
17.1.3.2 Modifying Structures ...................................................................................464
17.1.3.3 Structure Staking Table ..............................................................................465
17.1.3.4 Checking Structures....................................................................................465
17.1.3.5 Customizing Structures ...............................................................................465
17.1.4
Wire Functionality ...........................................................................................465
17.1.4.1 Adding and Deleting Wires .........................................................................466
17.1.4.2 Modifying Wires ..........................................................................................466
17.1.4.3 Relocating Wires.........................................................................................466
17.1.4.4 Sagging Wires ............................................................................................466
17.1.4.5 Wire Table ..................................................................................................466
17.1.4.6 Checking Wires...........................................................................................467
17.1.4.6 Checking Wire Clearances..........................................................................467
17.1.4.7 Stringing Chart ............................................................................................467
17.1.4
Reports and Design Checks............................................................................467
APPE7NDIX A. NOTATION .................................................................................................469
APPENDIX B.
REFERENCES ...........................................................................................472
APPENDIX C.
FEATURE CODES FILE .............................................................................477
APPENDIX D.
XYZ TERRAIN FILE....................................................................................478
D.1 XYZ File Format ........................................................................................................478
D.2 XYZ Terrain Editor ....................................................................................................479
D.3 Importing and Translating .........................................................................................480
D.3.1
Importing XYZ data from the Internet ..............................................................483
D.3.1.1 Organizing User LiDAR for use with Importing XYZ data from the Internet .484
D.4 Importing and Filtering ..............................................................................................485
D.5 Deactivating, Reactivating or Deleting Points ............................................................487
D.6 Break Lines File Format ............................................................................................489
D.7 Import of .LAS Files ..................................................................................................490
D.8 Creation of XYZ or PFL Points from DXF or Shapefile Attachment ...........................491
D.9 Creation of XYZ Point Data from KML or KMZ files ...................................................492
D.10
Merge Points from Raster Attachments .................................................................492
APPENDIX E.
PFL TERRAIN FILE ....................................................................................493
E.1 PFL File Format ........................................................................................................493
E.2 PFL Terrain Editor.....................................................................................................494
APPENDIX F.
STRUCTURE FILE .....................................................................................496
F.1 Method 1, 2 or 3 Structures - Direct Editing...............................................................496
F.1.1
Top Geometry Information ...............................................................................498
F.1.2
Data Needed Only for Suspension and 2-Part Insulators ................................500
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F.1.3
Data Needed Only for 2-Part Insulators ...........................................................501
F.1.4
Creating or Editing Structure Strength..............................................................503
F.1.4.1
Strength by Method 1..................................................................................503
F.1.4.2
Strength by Method 2..................................................................................505
F.1.4.3
Strength by Method 3..................................................................................507
F.1.5
Assigning Structure Material ............................................................................508
F.1.6
Batch saving multiple structures.......................................................................509
F.2
Method 1 or 2 Structures - Using Structure Programs ......................................509
F.3 Method 4 Structures..................................................................................................510
F.3.1
Linear vs. nonlinear analysis ...........................................................................511
APPENDIX G.
GROUND WIRE OR CONDUCTOR FILE ...................................................512
G.1
Stress-elongation and Creep-elongation Coefficients from Test Data ......................512
G.2 Linear Conductor Example........................................................................................516
G.3 Improved Linear Conductor Example ........................................................................518
APPENDIX H.
DEMO LINE EXAMPLE ..............................................................................520
APPENDIX I. CONCEPTS OF RULING, WIND AND WEIGHT SPANS ..............................522
I.1 Ruling Span .................................................................................................................522
I.1.1
Limits of Validity of the Ruling Span Concept ...................................................524
I.1.1.1
Situations Where the Ruling Span Concept Works Well .............................524
I.1.1.2
Situations Where the Ruling Span Concept Does Not Work Well ...............525
I.2 Wind Span ...................................................................................................................528
I.3 Weight span ................................................................................................................529
APPENDIX J.
SPAN END REACTIONS ............................................................................532
J.1
Level 1 Modeling - Ruling Span Method....................................................................532
J.1.1
Cable in its Plane .............................................................................................532
J.1.2
Swung-out Catenary ........................................................................................534
J.2
Levels 2, 3 and 4 Modeling - Finite Element Method .................................................535
APPENDIX K.
FILES OVERVIEW .....................................................................................536
K.1 Project View ..............................................................................................................536
K.2 Files and Directories .................................................................................................538
K.3 Project back-up .........................................................................................................541
APPENDIX L.
PLS-CADD AND STRUCTURE PROGRAMS LINKAGES ..........................543
APPENDIX M.
MATERIAL HANDLING ..............................................................................544
M.1
Linking Parts List to Commercial Databases ............................................................544
M.1.1
Create a Parts Table in PLS-CADD ................................................................544
M.1.2
Identify or Create a Corresponding Table in Database ....................................544
M.1.3
Create an ODBC Data Source ........................................................................545
M.1.4 Create the Link Between the ODBC Data Source and PLS-CADD ........................545
M.2 Linking Assemblies List to Commercial Databases ...................................................546
M.3 Exporting Staking and Material Tables to Commercial Databases ............................547
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PLS-CADD – Version 16.0 © Power Line Systems, 2019
M.4 To Learn More About Links Between PLS-CADD, GIS and Databases.....................547
M.5 Project Lifecycle and Material Status ........................................................................548
M.6 Project Estimator ......................................................................................................565
APPENDIX N.
FINITE ELEMENT ANALYSIS OF WIRE SYSTEM .....................................567
N.1 General Considerations ............................................................................................567
N.1.1
Major Differences Between the Ruling Span Assumption and a Finite Element
Analysis ........................................................................................................................567
N.1.2
Nonlinear Cable Model for Conductors and Ground Wires ...............................569
N.1.2.1 Linearized Cable Model Used in Stand-alone SAPS Program ....................569
N.1.2.2 Nonlinear Cable Model when SAPS is used as the analysis engine of PLSCADD
...................................................................................................................570
N.1.3
Insulator Modeling............................................................................................571
N.2 Selecting Finite Element for Display and for Calculating Structure Loads .................572
N.3 Selection of Level and Default Stiffness Parameters .................................................573
N.4 Unstressed Cable Lengths ........................................................................................577
N.5 In-span Concentrated Loads and Partial Ice .............................................................580
N.5.1
Concentrated Loads Automatic Placement ......................................................584
N.6 Sag-tension calculations ...........................................................................................587
N.7 Illustrative Example Showing Different Behaviors with Level 1, 2, 3 or 4 ...................588
N.7.1
Level 1 .............................................................................................................588
N.7.2
Level 2 with Infinitely Stiff Springs at Supports ................................................589
N.7.3
Level 2 with Extremely Flexible Springs at Supports ........................................589
N.7.4
Level 3 .............................................................................................................590
N.7.5
Level 4 .............................................................................................................590
N.7.6
Discussion .......................................................................................................591
N.8 Graphical Sag of Finite Element Model .....................................................................593
N.8.1
First FE Graphical Sag Option .........................................................................593
N.8.2
Second FE Graphical Sag Option ....................................................................593
N.8.3
Third FE Graphical Sag Option ........................................................................594
N.8.4
Fourth FE Graphical Sag Option ......................................................................596
N.8.5
Fifth FE Graphical Sag Option .........................................................................596
N.9 Display finite element model for given load case .......................................................597
APPENDIX O. CUSTOMIZING MENUS, DIALOGS, TOOLBARS, TABLES & REPORTS .....598
O.1 Customizing Menus ..................................................................................................598
O.2 Customizing dialog boxes .........................................................................................599
O.3 Customizing Tables and Reports ..............................................................................600
O.3.1
"C" Format Notation .........................................................................................601
O.4 Customizing Toolbars ...............................................................................................603
O.5 Keyboard Shortcut Keys ...........................................................................................604
APPENDIX P.
SITE-SPECIFIC STRUCTURE MODELS ...................................................605
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15
P.1 Making Site-specific Structure Models ......................................................................605
P.2 Interactive Insulator Change at a Site-specific Structure ...........................................606
P.3 Interactive Adjustment of Height of Insulator or Arm Attachment to Pole...................606
P.4 Interactive Adjustment of Guy Geometry...................................................................606
P.5 Comparing customized structures to original standard designs .................................607
P.6 Interactive Adjustment of Structure Attachment Points ..............................................607
P.7 Interactive Adjustment of Pole Inclination..................................................................608
P.8 Interactive Adjustment of Guy Strain Insulators .........................................................609
APPENDIX R.
Reports .......................................................................................................610
R.1 Summary Report .......................................................................................................610
R.2
Structure Longitude, Latitude, and Height Report ..................................................612
R.3
Construction Staking Report ..................................................................................613
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PLS-CADD – Version 16.0 © Power Line Systems, 2019
1.
FOREWORD
This manual describes the capabilities of PLS-CADD (Version 12.5 and newer) and shows how
to use the program.
PLS-CADD is the most powerful and comprehensive program available anywhere for the
structural and geometric design of overhead lines. It integrates in a seamless environment all
aspects of transmission line design, including terrain modeling and rendering, route selection,
manual or automatic minimum cost spotting, sag-tension, clearance and strength checks,
electric and magnetic field calculations, material list generation, plan & profile drafting, and
much more.
For new transmission lines, assessment or refurbishing projects, PLS-CADD will significantly
increase your capabilities and productivity.
We support our software by telephone, fax, email and/or training seminars. Augmenting our own
software development staff, we have alliances with some of the best transmission line design
professionals and engineering firms to help us provide support and training worldwide.
In addition to PLS-CADD, Power Line Systems offers a full line of Microsoft Windows based
software for the analysis and design of transmission structures. Our programs are used by
hundreds of fabricators, utilities and engineering organizations throughout the world.
If you have any questions about PLS-CADD or any other Power Line Systems program, please
call us or visit our web site.
The distribution and maintenance of PLS-CADD as well as its technical support are provided
by:
Power Line Systems, LLC
610 North Whitney Way, Suite 160
Madison, WI 53705 USA
Tel: 608 238 2171
Fax: 608 238 9241
Email:
[email protected]
Web site:
https://www.powerlinesystems.com
PLS-CADD - Version 16.0 © Power Line Systems, 2019
17
2.
DISCLAIMER, WARRANTY AND LICENSES
This License Agreement ("Agreement") is a binding agreement between you (the "Licensee")
and Power Line Systems, LLC ("Power Line Systems"). By accepting a Power Line Systems
quotation or invoice (each a "Quote") or downloading, accessing or using the Power Line
Systems software (the "Software"), Licensee unconditionally agrees to be bound by all of the
terms and conditions of this Agreement. By entering into this Agreement on behalf of a company
or other legal entity, Licensee represents that it has the authority to bind such entity and its
affiliates to the terms of this Agreement, and, accordingly, the terms "Licensee" shall refer to
such entity and its affiliates. If Licensee does not have such authority, or Licensee does not
agree to all of the terms of this Agreement, Licensee may not use the Software.
Subject to the terms and conditions of this Agreement, Power Line Systems grants Licensee a
nonexclusive, non-sublicensable, non-transferable right to use the Power Line Systems
Software solely during the Term (as defined in the applicable Quote) so long as Licensee
complies with the terms of this Agreement.
This Agreement (and the license granted herein) will continue in effect for the Term specified in
the Quote. At its sole discretion, Power Line Systems may terminate this Agreement and
Licensee's license if the Licensee fails to comply with any of the terms and conditions of this
Agreement. In the event of such termination all copies of the Software and all of its component
parts must be destroyed or returned to Power Line Systems in its sole discretion, and all
hardware keys and media returned to Power Line Systems, LLC within three (3) business days
of notification of such termination. No refund or other reimbursement shall be made in such
event and any amounts due shall immediately become due and payable. Upon any expiration or
termination of this Agreement, all rights and licenses granted to Licensee shall immediately
terminate and Licensee shall immediately cease all use of the Software.
The Software is protected by both the United States copyright law and international copyright
treaty provisions. Licensee may copy this Software onto one or more of its computers so long as
no more than the licensed number of copies is in simultaneous use. Licensee may also make
archival copies of the Software for the sole purpose of backing up the Software and protecting
its investment from loss. Licensee is responsible for ensuring that the number of concurrent
instances of the application executing do not exceed the number of copies licensed.
The Software is provided "as is." Power Line Systems expressly disclaims express or implied
warranties of any kind, including without limitation warranties of merchantability, noninfringement, or fitness for a particular purpose. Power Line Systems does not warrant the
accuracy or completeness of any information, text, graphics, links or other items contained
within the Software; that the Software is error-free; or that designs generated by it will be
acceptable. Power Line Systems further expressly disclaims any warranty to Licensee's
authorized users or to any third party. The Software should only be used by an experienced
engineer, and Licensee assumes all responsibility for the design assumptions and results. The
18
PLS-CADD – Version 16.0 © Power Line Systems, 2019
only warranty made is that the media on which the Software is recorded (if applicable) or keys
enabling the Software will be replaced without charge if determined to be defective during the
support period.
Notwithstanding anything to the contrary, the liability of Power Line Systems for direct damages
arising from or relating to this Agreement, under any legal or equitable theory, shall be limited to
the refund of the purchase price of the Software. Further, notwithstanding anything to the
contrary, Power Line Systems shall not be liable, under any legal or equitable theory, for any
indirect, punitive, exemplary, special, incidental, or consequential damages, including without
limitation damages for lost profits, business interruption, personal injury, property damage, loss
of data or the disclosure of confidential information, or for errors or omissions contained within
the Software, even if Power Line Systems has been advised of the possibility of such damages.
This Agreement (and the license granted herein) is not assignable or transferable by Licensee
without Power Line Systems' prior written consent, and Power Line Systems reserves the right
to refuse to permit the transfer or assignment of this Agreement (or the Software license) to any
party other than the original purchaser.
Licensee acknowledges and agrees that the structure, sequence, features, functionality and
organization of the Software are the valuable trade secrets of Power Line Systems. Licensee
agrees to hold such trade secrets in confidence, not to disclose such trade secrets to any other
party and to only use the Software as expressly permitted herein. Licensee further
acknowledges and agrees that ownership of, and all right, title and interest (including all
intellectual property rights) in and to, the Software and all derivatives, enhancements and copies
thereof regardless of the form or media, and the associated protection devices, are held by
Power Line Systems, and that this agreement in no way transfers any ownership rights in the
Software.
Licensee shall not (and shall not permit any other party to) (i) reverse engineer, disassemble,
decompile, modify or otherwise attempt to discover any underlying ideas or algorithms of the
Software, except and only to the extent that such restrictions are expressly prohibited by
applicable law notwithstanding this limitation, (ii) provide, lease, lend, use for timesharing or
service bureau purposes or otherwise use or allow others to use the Software for the benefit of
any third party, or (iii) use the Software, or allow the transfer, transmission, export, or re-export
of any Software or portion thereof in violation of any applicable export control laws or
regulations. All limitations and restrictions on Software in this Agreement also apply to
documentation. Removal, emulation or reverse-engineering of all or any part of the Software or
protection device constitutes unauthorized activity with respect to the Software and is
specifically prohibited.
The Licensee represents and warrants that it is not now developing a competing product to the
Software and agrees not to develop or participate in the development of any such competing
product while this agreement is in force. Without limiting the foregoing, the Licensee specifically
PLS-CADD - Version 16.0 © Power Line Systems, 2019
19
agrees not to use the binary executables, its algorithms, file formats, manuals or any information
derived from the Software in any manner, directly or indirectly, to develop or derive any
competing product or service. The Licensee shall take reasonable measures to protect Power
Line System's Software and intellectual property by limiting disclosure to or access by any other
party (including, without limitation, any competing organizations).
Power Line Systems reserves the right to include, and Licensee acknowledges that the
Software may contain anti-piracy monitoring functionality. Licensee expressly agrees that the
software may contact Power Line Systems in the event it determines that the Licensee is not in
compliance with the terms of this Agreement.
In the event any provision of this agreement is found to be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in any way be affected or
impaired and a valid, legal and enforceable provision of similar intent and economic impact shall
be substituted therefore. This agreement will be governed by the laws in force in the State of
Wisconsin, without regard to its choice of law rules. Licensee expressly agrees to submit to the
jurisdiction of any state or federal court sitting in Dane County, Wisconsin, and agrees that
venue is proper in Dane County, Wisconsin.
This Agreement, along with the relevant sales document, represents the entire agreement
between the parties, and it supersedes any prior proposal, representation or understanding
between the parties. Power Line Systems expressly rejects the terms of any purchase order or
other document prepared by Licensee.






TIFF support is Copyright (c) 1988-1997 Sam Leffler and Copyright (c) 1991-1997
Silicon Graphics, Inc.
This software is based in part on the work of the Independent JPEG Group.
Zlib compression courtesy and Copyright of (c) 1995-2002 Jean-loup Gailly and Mark
Adler.
Coordinate system projections courtesy of Gerald Evenden and Copyright (c) 2000
Frank Warmerdam.
Shapefile support courtesy of and Copyright (c) 2001 Frank Warmerdam.
LAS support courtesy LASlib with LASzip Copyright (c) 2015 rapidlasso GmbH,
GERMANY. All rights reserved.
This computer program is protected by copyright law and international treaties. Unauthorized
reproduction or distribution of this program, or any portion of it, may result in severe civil and
criminal penalties, and will be prosecuted to the maximum extent possible under the law.
20
PLS-CADD – Version 16.0 © Power Line Systems, 2019
3.
HARDWARE REQUIREMENTS AND INSTALLATION
You will need Microsoft Windows Vista, 7, 8, 8.1, 10 or newer (x64 edition recommended)
running on a computer with a minimum of 512 MB of RAM and 100 MB of disk drive space. The
digital terrain modeling and bitmap features (aerial photos and digitized drawings) will require
additional memory. For more detailed hardware requirements please review the following
document available on the Internet: http://powline.com/presales.pdf.
PLS-CADD is initially shipped on one CD but upgrades are only provided electronically. The
program and files can be installed in any directory. The software may be installed on a file
server, but the hardware key driver will need to be installed on each individual workstation.
3.1
Upgrade Installation (via email)
3.1.1 Requesting an Upgrade
Software upgrades are provided exclusively by electronic means. They can be downloaded
manually or directly from within the software. In either case, you should use the Help/
Download Upgrade command described in
Section 3.1.1.1 to request an upgrade.
3.1.1.1
Downloading Upgrade
If you select Help/ Download Upgrade from
PLS-CADD, the dialog box of Fig. 3.1-1 will
open. You will first need to request an
upgrade code by clicking on the “Email
Upgrade Request” button or “Web Upgrade
Request” button. A code should be emailed to
you within one business day. You can then
enter the code into the "I have an upgrade
code" dialog and the program will download
the upgrade automatically. Please note that
all upgrade codes expire within one to two
weeks so you should promptly download your
upgrade after receiving the code.
Fig. 3.1-1 Internet Upgrade
PLS-CADD - Version 16.0 © Power Line Systems, 2019
21
If you should have difficulty downloading the upgrade
from within the software, you may download it
manually by following the instructions in the upgrade
email. In this case, you should use the third option “I
have an upgrade code and upgrade file” to install the
upgrade.
It may take several minutes before the upgrades you
are asking for are downloaded. Once they are
downloaded, you will be presented with the same
installation dialog box as you do with a CD installation
as described in Section 3.2. See Section 3.2 for
instructions to complete the installation.
Notes for systems administrators and advanced
users:
Your upgrade is stored in a sub-directory of the PLS
temporary directory named “SETUP”. The PLS
temporary directory is defined in File/ Preferences
and defaults to " C:\PLS\TEMP ". So, if you
Fig. 3.1-2 About Dialog
downloaded an upgrade of PLS-CADD it would be
stored in “C:\PLS\TEMP\SETUP”. If you need to install the upgrade on multiple computers you
may skip the above steps and merely need to copy this directory to the target computer and run
the “SETUP.EXE” program. The Internet Upgrade feature uses either FTP or HTTP, and will
use the proxy settings defined in Internet Explorer. These proxy settings can also be set in the
Settings section of the File/ Preferences dialog. You can verify that you have access to our
server by using the Help/ Check for Updated Manual command. If this command completes
without errors you will know that you can access our servers even before you request the
upgrade code. If for some reason you cannot access our servers, you may manually download
the upgrade or try modifying your Internet Setting using the “Edit Internet Settings” button in the
Help/ Download Upgrade dialog.
In Windows Vista each user now has their own PLS temporary folder:
C:\Users\<user_name>\Appdata\Roaming\PLS\Temp. The SETUP.EXE located in this folder
will work in the same manner as mentioned above.
Starting with version 10.60 the program will automatically check to make sure the latest version
of the software is installed on the machine. The results of this check will be shown in the About
dialog that appears when you run the program or when you visit Help/About. As demonstrated
in Figure 3.1-2, the About dialog shows the current version of the program being executed and
the registered company name for the software. It also shows the key number that is detected
as well as a statement whether the software is up to date or not. The program will compare the
version being executed to the current version listed on the Power Line Systems, Inc. website or
if you prefer to a version stored on a network share at your company. If the version being
22
PLS-CADD – Version 16.0 © Power Line Systems, 2019
executed is not the latest version then the user may click the message in the About dialog to
download the latest version of the software so long as the software is currently within its
technical support and upgrade period. The user can change the location of the network share
that the software checks for the latest version using File/Preferences and changing the path to
check for upgrades in the Settings portion of the dialog box. You may disable the check by
deleting the path from the settings box altogether.
The setup program has command line arguments that allow for a silent install to enable scripting
of installs. Contact [email protected] for more information.
For more information on running PLS Software on Windows Vista , 7 and 8 see the following
link: http://www.powline.com/products/vista.html
PLS-CADD - Version 16.0 © Power Line Systems, 2019
23
3.2
CD Installation
During CD installation,
you will have the
opportunity to install not
only PLS-CADD, but
also the demo versions
of all our programs or
the
commercial
versions of all the
programs for which you
hold valid licenses. The
CD installation dialog
box (see Fig. 0-2)
should open after you
insert the CD in its
drive. If it does not
open, click on the Start
button, then Run. When
prompted for a file
name, select your CD
drive
and
type
"setup.exe"
Fig. 3.2-1 Setup Dialog from CD
The following options are available when installing from a CD:
Full installation or Upgrade: Select the Full Installation if the program has not yet been installed
or if you want to upgrade the program and it's example files. Select Upgrade if you are reinstalling over an existing version. You will be prompted "File Already Exists. OK to overwrite ?"
for each existing file. Respond by clicking on "Always".
Install hardware key driver: This option will check itself automatically as needed. Unless you
know that you need or do not need the driver, you should leave this option alone.
Install online documentation (PDF format): This option will check itself if the CD has manuals on
it. We strongly recommend that you allow the program to install the electronic manuals. The
manuals are in the Adobe ® Portable Document Format (PDF) which can be viewed using the
Adobe Acrobat Reader. If manuals are installed and the Reader is not yet on your system, setup
will prompt you after installation to install the Acrobat Reader software. We provide a 32 bit
English language version of the Reader. If you want a different language or version you should
visit http://www.adobe.com to download it.
24
PLS-CADD – Version 16.0 © Power Line Systems, 2019
Allow application directory override: This option is provided for advanced users to customize the
particular directories that each application will be placed in. It is useful for those who wish to
maintain multiple versions of our applications on a computer at once. During the install the
program will allow you to type in a directory name other than the default one for each application
installed. Unless you feel you have a strong need to do this we suggest you leave it unchecked.
Once you have selected the options above and checked the applications and demos you want
installed you may click on Install and the program will install all the software.
3.3
Troubleshooting the Hardware Key
If your program is displaying a "Can't Find Hardware Key" error message, you should consult
the following technical note on our web site:
http://www.powline.com/products/ntdriver.html
3.4
Electronic Manual and Online Help
If you have installed the electronic version of the manual (PDF format) by checking Install online
documentation in Fig. 3.2-1, you will have access to online help in any dialog box. All you need
to do is to click on the "?" button at the top right of the box and you will be taken to the relevant
section of the electronic version of the manual where you will find the appropriate information.
Updates to the manual are periodically made available via our Internet site. You should use the
Help/Check for Updated Manual command to discover if they are available and download
them. They are also advertised in our Newsletter which you can read and subscribe to on our
web site.
PLS-CADD - Version 16.0 © Power Line Systems, 2019
25
A Quick Search Toolbar is available when the View/ Toolbars/ Quick Search Toolbar is
selected. You may enter text in the quick search menu which will search all items in the menu
of the program, sections of the manual, online technotes, File/ Preferences Settings, and online
videos for the keyword entered in the search box. If you click on any of these items then it will
take your to that particular selection whether it is a menu command, section in the manual,
preference setting, video, or technote. Figure 3.4-1 shows the resulting menu items and help
topics in the manual with the word “Sections” as the search string. You can limit your search to
certain sections by prefixing your search term with ‘m’ for menu item, ‘h’ for help topics in the
manual, ‘t’ for technotes, and ‘v’ for videos. The search dialog can also be used as a calculator
by prefixing your calculation with the ‘=’ sign. If you enter the “=help” expression the program
will display a list of available functions. This also works in many of the input dialogs in the
program where a number can be input.
Two functions that are handy are the
“=RSC(HorizProj1,HorizProj2…)” that will calculate the classical ruling span for the comma
separated list of spans and the “RSI(HorizProj1,Chord1,HorizProj2,Chord2…)” which will
calculated the improved ruling span for the list of horizontal spans and chord lengths between
attachments. This command may be especially useful when entering ruling span information in
the Line/ Setup table in PLS-CADD/Lite.
Figure 3.4-1 Quick Search Toolbar
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4.
OVERVIEW
Power Line Systems Computer Aided Design and Drafting (PLS-CADD) is an MS-WINDOWS
program for the analysis and design of overhead electric power lines. It integrates into a single
computer environment all the data and algorithms necessary for the geometric and structural
design of a line. It enables surveyors, line layout designers, structural/ geotechnical engineers
and drafters to better work together and thus increase productivity and reduce the chance of
errors. It supports the entire design process, from the selection of a line route all the way to the
production of construction documents and drawings. It is also a line rating and a management
tool.
PLS-CADD seamlessly integrates many programs developed over the years by Power Line
Systems. These programs have handled such varied tasks as line routing and design, structural
design of latticed towers, poles and frames of different materials, sag and tension calculations,
optimum structure spotting, automatic production of plan and profile sheets, etc.
Most data files in PLS-CADD are ASCII files. The use of ASCII files allows you to easily write
software that integrates PLS-CADD with your enterprise databases. Power Line Systems has
developed and will continue to develop file translator modules so that prior users of other line
design packages can easily switch to PLS-CADD.
The overall guiding concept
behind PLS-CADD is its use of
a detailed
3-dimensional
model of a line and its
components to enable Power
Line Information Management
(PLIM). This is illustrated in
Fig. 4.1-1. The 3-D model
includes
the
terrain,
all
structures, all insulators, and
all
cables.
Building
and
modifying the model is done
through interactive graphics
and/or optimum spotting or
sagging algorithms. The line
model
requires
careful
management of a considerable
amount of data in library files.
These libraries of terrain,
structure, cable, and design
Input
Processing
3-D Terrain
Corridor Terrain
Survey Data
Feature Codes
Ground + Obstacles
3-D Model of
Line in Corridor
Libraries
Design Criteria
Geometry
Strength
Cables
All Properties
Reports
Material List
Specification
Etc.
Drawings
Plan & Profile
exported to
CAD system
Loads
Clearances
Structures
Output
Installation
Calculations
Archiving
Spotting
- Automatic
- Manual
Stringing
Sagging
Etc.
Sag Tension
Clearances
Struct-Strength
Swings
Etc.
Line
Management
Future
Modifications
Fig. 4.1-1 PLS-CADD Overall Organization for PLIM
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27
criteria data are fully described in this manual. Once a line model is constructed, all engineering
calculations normally performed to produce or validate a design are available at the click of the
mouse.
PLS-CADD is not only an invaluable tool for the engineering of new lines, but it is also a very
powerful tool for the assessment of existing lines (Peyrot, 1991; Kluge, 1994). The capabilities
provided by PLS-CADD greatly increase the productivity of all professionals involved in a line
design. PLS-CADD allows designers to quickly evaluate alternate design solutions. It is also an
ideal "teaching tool" with which design concepts can be clearly illustrated.
This manual is both a user's manual and a theoretical manual. The assumptions behind all
models and calculations are fully described. PLS-CADD was developed to support not only
prevailing US design practice but also other international methods (IEC, 2003; CENELEC, 2001;
etc.).
PLS-CADD is available in several versions:
The basic or standard version, PLS-CADD, includes all the capabilities described in this manual
except optimum structure spotting. The optional optimum structure spotting capability is
described in Section 14.
The demo version is identical to the PLS-CADD version with optimum spotting, except that it
can only be used with the terrain models which are provided as examples on the distribution CD
and it does not allow saving.
The PLS-CADD/ LITE version can only be used to perform sag, tension and structure load tree
calculations. It does not include the terrain modeling, material or drafting functions of the basic
version and is based on the ruling span concept. It is described in Section 15. The features
described in Section 15 are also available in the standard edition of PLS-CADD.
The PLS-CADD/ SURVEY version provides terrain modeling and drafting capabilities, but not
structure spotting, loads, clearances, or sag-tension. It is generally used by surveyors to check
terrain data prior to delivering them to transmission line designers.
Originally, all wire tension calculations in PLS-CADD were made using the ruling span
assumption. While this is still the method of choice for the great majority of applications, PLSCADD now provides you with the option to determine all wire tensions by an exact finite element
analysis. Finite element sag-tension is discussed in Section 7.1.1 and in Appendix N.
PLS-CADD lets you customize menus, dialog boxes, tips and a certain number of tables and
reports, thus giving you complete flexibility to translate them into the language of your choice.
This is fully described in Appendix O.
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5.
LOADING AND VIEWING AN EXISTING MODEL
This section describes how to load, view and check an existing line model. It is assumed that
you are familiar with the basic MS-WINDOWS commands and terminology. Start the PLSCADD program (for example by double-clicking on the PLS-CADD icon). You will be taken to
the PLS-CADD Project Wizard shown in Figure 5.0-1. If you click on the OK button in the
wizard you will be taken to the File/ Open dialog shown in Figure 5.1-1. If you hit the Cancel
button in the File/ Open dialog the main PLS-CADD window with the File menu at the upper left
corner will be shown which is similar to the ‘Classic’ interface.
Fig. 5.0-1 PLS-CADD Project Wizard
Many of the normal loading and creating of projects can be accomplished in the PLS-CADD
Project Wizard. At the top of the dialog you can click on one of the recently saved projects
which will automatically open the project. If you select the Create a New Project option you
can create either a PLS-CADD/Standard (.xyz or .pfl) project, a PLS-CADD/Lite (.loa) project, or
a PLS-CADD/Ultralite project (.ult). The PLS-CADD/Lite project is discussed in Section 15 of
the manual and the PLS-CADD/Ultralite project is discussed in Section 16 of the manual. The
next option is to Restore Project from PLS-CADD Backup (BAK) file which is discussed in
section 5.3. If you have an upgrade code you can select the Install PLS-CADD Upgrade
option. If the upgrade code is copied to your clipboard before launching PLS-CADD the
program will recognize this and offer to go straight to the upgrade dialog. The last option is to
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Switch to ‘Classic’ interface (menus instead of this Wizard dialog) which will bring up the
Menu view of PLS-CADD on the next instance similar to older versions of the program. If you
wish to show the Project Wizard in the future after deactivating it you can go to File/
Preferences and change it in the Settings.
Throughout the manual it may reference opening or creating a new project with the ‘Classic’
method or with the Project Wizard.
Another option to open files is the jump list which is available in the program’s taskbar icon in
Windows 7/ 8/ 10 by right clicking on the icon. The jump list contains your most frequently used
and most recently used models. You can also choose to pin any model you would like to
access to the jump list for easy access.
5.1
Loading a Line Model
In this section, we will look mostly at
the Demo line, a fictitious model
with fictitious design criteria and
properties. The Demo line even (see
Appendix H for details) violates
some of its own design criteria, but
do not worry about that, since the
example is there for illustration
purposes only.
To load a line model, first click on
File/ Open or select the OK button
in the Project Wizard. You can also double click
on the file in Windows Explorer or on one of the
projects ancillary files to open the project. The
dialog of Fig. 5.1-1 will open. The dialog displays
the terrain files of existing models in the default
Projects directory. As explained in Section 6,
terrain models can be of the *.xyz or *.pfl types.
A simplified *.loa terrain type is also available if
you want to run in PLS-CADD/ LITE mode as
described in Section 15.
Fig. 5.1-1 Files Dialog
Once you are in the Open PLS-CADD Project
dialog, double-click on the Demo.xyz icon to load
Fig. 5.1-2 Demo Line
the Demo line. If you wished to open the project
in read only mode you can check the option at the bottom of the dialog box for Read-only. After
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opening your screen will look like Fig. 5.1-2 with the Demo line fully visible in a Profile window,
while four other windows are minimized and shown as icons above the lower status bars. The
minimized windows include a Plan view, a 3-dimensional view, a Plan & Profile sheets view
and a Project window.
Profile, Plan, 3-D, and Sheets views are just different ways to display the same model. In fact,
you can display all views simultaneously as shown in Fig. 5.1-3. As you will see later, most
engineering functions can be performed in any of the graphical views. For example you will be
able to modify or move a structure directly on a P&P sheet if you so desire. With PLS-CADD,
P&P sheets are no longer the result of an additional drafting process at the end of the
Figure
5.1-3Views
View Display
Fig. 5.1-3
Various
of Demo Line
engineering phase of the project. They interactively display the current state of the line. Since
PLS-CADD automatically updates your P&P sheets while you design, you will find that you can
save from 90 to 100 percent of your traditional drafting costs.
The display of Fig. 5.1-3 was obtained by maximizing all the views listed at the bottom of Fig.
5.1-2 and using the Window/ Tile command. Some additional rotating and zooming was done
to the 3-D window as described in Section 5.4.4. You will note that, as you move the mouse
cursor in any view, a red ball appears simultaneously in all views tracking the closest terrain
point. Information about that point is displayed in the lower status bar. Similar information can
be displayed in the Terrain Info box which you open with Terrain/ Info or when you click on a
terrain point.
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If you were building a new line model instead of opening an existing one, you would click on
File/ New instead of File/ Open or select Create New Project in the Project Wizard, and you
would follow the steps described in Section 10. But do not attempt to build a new model until
you are familiar with all the material in Sections 5 to 9.
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5.2
Preferences
Fig. 5.2-1 Preference Dialog Box
If you click on File/ Preferences, you are taken to the Preferences dialog (Fig. 5.2-1) where you
can select the following:
Unit system:
This is where you specify which unit system to use. With PLS-CADD you
can work with US customary units, SI (metric) units with forces in Newton
(N), or SI (metric) units with forces in decaNewton (1 daN = 10 N). You
can change units in the middle of working on a project. All data files in
PLS-CADD have a header indicating the units of the data which they
contain. Internally PLS-CADD stores all data and does all calculations in
the SI units system. Whenever PLS-CADD reads or writes a data file, it
identifies the file units and makes the appropriate unit conversion. The
examples which we provide with the program were generated in US
Units. However, you can see these examples in SI units by switching the
units preference.
Sag with:
In the Section Modify dialog box described in Section 10.3.2, you will see
that sagging can be done by specifying either a Catenary Constant or an
Horizontal Component of Tension at a given temperature. The "Sag with"
preference lets you specify which of the two methods is enabled in the
Section Modify box.
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Stations displayed:
As described in Section 6.11, stations can be described as True Stations,
i.e. stations measured from the start of the alignment, or as Equation
Stations, i.e. stations renumbered arbitrarily from any point along the
alignment. The "Station displayed" preference lets you select which
station is displayed in the Profile view or the profile portion of the Sheets
views
Report font:
Font to be used in all report windows
Table font:
Font to be used in all input tables
Table header font:
Font to be used in header of tables
Graphics font:
Font to be used in all Plan, Profile, 3-D and Sheets views.
View font:
Font to be used in individual structure views opened by the Structure
programs (TOWER, PLS-POLE, etc.). Only applies to Method 4
structures (see Section 8.3.4)
View background color:
The background color of all views can be selected in the color
palette which appears when you click on this button
The Settings portion of the dialog contains user defined settings for many items throughout the
program that the user may wish to customize such as the MRU list and file compression
settings. If a setting in this section has been changed then it will be shown in black text. If it is
default value then it will be shown in grey. There is also a Search box at the top of the settings
section that will filter the settings options based on the entered search criteria.
One of these options in the Settings portion of the dialog box is to “Prompt for permission before
saving projects in new versions” setting which if enabled will cause the issuance of a warning
when you are above to save a project in a newer version of PLS-CADD than the one that last
saved the project.
Two other settings that are useful are the Export KML during each save and Export project XML
during each save which will write either a KML or XML of the details of the entire project and
save in the same directory as the project .xyz file. These two commands can be useful when
linking data to other programs such as GIS databases. Please note that when these are
enabled it will increase the save time of the project.
Next in the Preferences dialog box of Fig. 5.2-1 you can specify the default directories and files
for new projects in the Default for New Projects column of the table at the bottom of the box.
These are the directories and files which will be used after you select the File/ New command.
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Application directory:
Directory where the PLS-CADD program is installed
Temporary directory:
Directory where all temporary files are written.
Important note: the Temporary Directory should be specified on
your local computer, even if you are working with files on a
network. This will prevent lost time accessing the network and the
possibility of collisions with others trying to access the same
directory
Project directory:
Directory where the model and some of associated files reside
Structure directory:
Default starting directory for the Open Structure File dialog (see
Appendix F)
Cable... directory:
Default starting directory for the Open Cable File dialog (see
Section 9.2) or Edit Concentrated Load File dialog (see Section
N.5)
Part/ assembly library:
Name of the Material list file (master parts list which include part
numbers, prices, etc. for all structural components potentially used
in the line). The material list file is the one operated upon by the
Structures/ Material menus (see Section 8.5)
Schema File :
Name of customization file which controls the text of your various
menus, dialog boxes, etc. (see Appendix O)
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Finally, you can specify the default directories and material file for the current project. The
default structure and cable directories as well as the material file and schema file are usually the
same as those selected for new projects, but they need not be. They are specified in the
Setting for Project column. Note that this column is only available when you have a project
loaded. To clear any file name from the File/Preferences table you can press the delete key
while in any of the file name buttons.
When you OK the Preferences dialog, all the preference settings, except those in the Setting
for Project column, are automatically saved in a file named PLS_CADD.INI which is located in
your WINDOWS directory or in C:\Users\<user name>\Appdata\Roaming\PLS\pls_cadd.ini if
you are using WINDOWS VISTA. The file name may vary based on the WINDOWS installation.
These preferences remain in effect until changed. The preferences in the Setting for Project
column are saved together with the project information.
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5.3
Saving, Backing up or Moving a Model
A line model (or project) is made up of a terrain, structures, cables, design criteria as well as
parameters for generating reports and P&P sheets. It may also include maps and photographs.
Some of the line model data are included in specialized files with strict naming conventions. For
example, if Project is the name of a model, files named Project.xyz, Project.fea, Project.brk,
Project.num, Project.cri, Project.don, Project.pps, Project.dbc, and Project.str include
information related to the terrain point coordinates, terrain feature codes, terrain break lines,
alignment, design criteria, structures spotting and wires stringing, P&P sheets formats, parts
data base and available structures list, respectively. Appendix K describes these files in more
detail. When selecting File/ Save after building or modifying a model, you are saving the current
versions of all the Project.* files.
In addition to the project-specific data stored in the Project.* files, a model refers to files in
Libraries of structures, cables and parts. These Libraries, which are generally shared by several
projects, are not affected by a File/ Save. Since the Project.* files refer to files in the Libraries,
the model is therefore not complete without the relevant Library files.
5.3.1 Backing up a Model
When selecting File/ Save, you are saving the model currently residing in memory to
designated Project.* files. File/ Save has no effect on the contents of the Libraries which the
model refers to. The files in the Libraries only get saved when you edit them.
Occasionally, you might want to save in a single file, say Project.bak, the model (i.e. all the
Project.* files) as well as the relevant structure, cable and parts Library files. Therefore,
Project.bak is a complete record of the information available at the time a model is backed-up.
Project.bak is created with File/ Backup. It can be restored on the same or another computer
with File/ Restore Backup. Project.bak includes not only files but their complete directory
structure. Section K.3 includes additional information regarding the backup command. Using
File/ Backup and File/ Restore Backup is the best way to archive or transfer a PLS-CADD
project from one computer to another.
When you use File/ Restore Backup, you are given the opportunity to change the name of the
directories in which the various files are kept. You also have the option to use the Quick
Restore button which will restore all the files to one directory. The Change Common Directory
Path button will use a search and replace through the directories noted for the project and
replace the common string in each directory path for the files to maintain folder architecture
while restoring the project. Note that when restoring, if you choose to overwrite an older
existing component library with a new one you may corrupt all your existing models that refer to
that database. Restore Backup is a disk function only which does not open the restored model
automatically.
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The Restore backup function allows you to multi-select .bak files so you can choose to restore
more than one backup file with a single command.
File/ Backup also includes reference to any files that have been excluded from the backup (but
not the file itself) so that File/ Restore Backup can be used to remap any folders that do not
exist on the destination systems. This enables the WMS functionality discussed in Section 6.6.5
to download any files that are not included in the backup file.
We strongly encourage you to create a backup file of your project whenever it is significantly
revised or completed.
When requesting technical support from Power Line Systems regarding a specific model, you
MUST send us a backup file of that model.
5.3.2 Moving a Model and Associated Libraries without Using "Backup"
As mentioned previously, a single PLS-CADD model (complete project) is stored in Project.*
files which include pointers to other Library files. In order to move a complete project and its
associated Library files from one computer to another or even to a different directory on the
same computer you may use the File/Backup and File/ Restore Backup commands as
described in Section 5.3.1.
However, there is an alternate simpler way to move one or more than one PLS-CADD projects
and their associated Libraries with the WINDOWS EXPLORER so long (THIS IS ESSENTIAL)
as all the files share a common base directory and were saved in Version 4.80 or newer. For
example, assume that your single project files (Project.*) or all the files of several of your
projects (for example Project1.*, Project2.*, etc.) are stored on a network drive, say in the
F:\engr\pls\pls_cadd directory or one of its subdirectories and that all of the Library files to which
these projects refer to are included in the F:\engr\pls\libraries directory or one of its
subdirectories. The directory F:\engr\pls, which is the longest string common to all the Project*.*
files and all the associated Library files, is called the common base directory. Now assume that
you wish to move all your PLS-CADD projects and associated Library files to your local drive to
work on them in the directory C:\models. All you need to do is to simply copy (using the
WINDOWS EXPLORER) the entire content of the common base directory F:\engr\pls to your
C:\models directory. Then you can run any PLS-CADD model in the C:\models directory and its
pointers to the needed Library file will automatically be changed to their new locations in the
C:\models directory.
If the files do not share a common base directory, for example if a PLS-CADD model is in
F:\engr\pls\pls_cadd but the associated structure, cable or parts files are stored on a different
network drive, say G:\components, then the above procedure which globally moves a model
and its associated files cannot be used.
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To summarize, if PLS-CADD models and all their associated Library files share a common base
directory they can be moved around freely so long as their relative positions do not change
when moved to a new directory or drive
5.4
Viewing Functions
PLS-CADD has extremely powerful graphics capabilities. You can view a line in its entirety
(even if hundreds of kilometers long) or you can zoom-in on a single swung-out insulator.
5.4.1 Windows and Toolbars
As shown in Fig. 5.1-3, several views of your model can be displayed simultaneously. These
views are displayed in Profile, Plan, 3-D, and Sheets windows which can selectively be opened
with the Windows/ New Window/ ... commands. The windows can be tiled, moved, sized or
closed following standard WINDOWS conventions. When several windows are opened
simultaneously, the active window, i.e. that in which the various functions apply, is indicated by
a solid blue header. As you will discover, some graphics commands work in all windows while
others only work in specific views.
While inside the application window any of the view windows can be detached outside the
application window by middle clicking and choosing the Detach Window command. These view
windows can be reattached within the application window again by middle clicking within the
window and choosing the option to Attach Window to Application. These commands are very
useful when working on multiple monitors.
Any of the display views can be dragged to the upper edge of the application window to have it
maximize across the application window or to either side to have the display window size to half
the application window.
The window views of the project including the project view, profile view, plan view, 3D view,
sheets view, and any other reports that are currently shown in the project are shown as tabs in
the main window of the application. The File/ Preferences settings has a “Tab location for
open windows” where you can set the tabs to be at the top or bottom of the main application
window or off for the legacy behavior of older versions. If you right click on any of the Window
Tabs that are related to reports, graphs, or deformed geometry views you have the option to
close all of these tabs without having to close them individually.
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Fig. 5.4-0 Window Tabs
Below the menu bar, you will note a line of toolbars. These can be turned on or off with View/
Toolbars. Fig. 5.4-1a shows most of the available tool bars. Shown from left to right are the
Standard Toolbar with 6 buttons, the 3D Toolbar with 12 buttons, the Alignment Toolbar with 4
buttons, the Structures Toolbar with 5 buttons, the Sections Toolbar with 4 buttons and the
Applications Toolbar that lets you start our optional transmission structures programs. The
Annotation toolbar is not shown. Momentarily positioning the mouse cursor over a toolbar icon
will display a descriptive "tooltip" in a little window. Positioning the cursor over a menu item or
toolbar icon will display a related "toolhint" in the status bar.
Figure 5.4-1a Toolbars
The status bar is the informational bar at the bottom of the application window. As different
tools or items are selected in the project the information in the status bar will change to be
sensitive to the currently selected mode. Background process information activity is also shown
in the right side of the status bar. The size of the text displayed in the status bar can be altered
by going to File/ Preferences/ Font size for status bar text. If the length of the information
outgrows a single line then the status bar will become multi-line and grow to accommodate the
text.
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Various input tables in PLS-CADD default to
a horizontal type of table with each entry
occupying a single row of the table when
accessed through the menu items. When
accessing items through entity info it may
default to a vertical table. For example the
Sheet Inset Plan View is a horizontal table
such as Fig. 5.4-1c when accessed through
the menu. But when it is edited using Entity
Info commands it will default to a vertical
table dialog such as Fig. 5.4-1b. However
this view can be changed to either table
option by hitting the Transpose Table option
in the upper right corner of the table dialog.
Fig. 5.4-1b Vertical Table Dialog
Fig. 5.4-1c Horizontal Table Dialog
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5.4.2 Graphics Commands Available in all Views
The view in any window can be modified through the use of the following commands. The
commands are available under the View menu and/or by pressing the appropriate function key,
and/ or by clicking on the appropriate buttons in the 3D toolbar. Unless you like using function
keys, using the buttons is recommended. The graphics commands only affect the currently
active window. You also have the option of navigating the various geometry views using a 3-D
Connexion input device (3D Mouse) such as the SpaceNavigator (R).
Important note: When you select a particular graphics mode or other engineering function, you
will generally stay in that mode or function (for example zoom rectangle function) until you select
another function or right-click the mouse. The mouse cursor will often change to let you know
what mode or function you are in. There will also be some information in the lower status bar as
to what you should do. Remember that the quickest way to get out of a mode or function is to
right-click.
Zooming or Inverse Zooming
In
Out
Window
Click the + button on the toolbar or press the "+" key on the keyboard
Click the - button on the toolbar or press the "-" key on the keyboard
Select View/ Zoom Rect and drag a window over the part of the view you wish to
zoom on. This is done by bringing the mouse cursor to the desired location of the
upper left corner of the window and dragging the cursor to the lower right corner.
A magnifying glass will remind you that you are in zoom mode. To get out of the
zoom mode or any other viewing mode just right-click the mouse. The Zoom In
toolbar button is a short cut to View/ Zoom Rect.
Panning
Press the Left, Right, Up or Down arrow keys on keyboard or click the arrows of the window
scroll bars.
Restoring Original View
To restore the original view, select View/ Initial from the main menu or click on Init button.
Restoring Previous View
To redraw the previously drawn view, select View/ Previous.
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Miscellaneous
Drafting/ Line Width Multiplier from the main menu lets you change the thickness of all lines
by specifying the number of pixels used in their representation. Clicking on the View
Background Color button in the Preferences dialog box of Fig. 5.2-1 lets you select the
background color for all graphics windows. View/ Redraw refreshes the view when deleted
items are still showing.
Printing, Saving or Exporting View in Graphics Window
Use File/Print from the main menu to print the view in the active window. You can use File/
Print preview to preview individual pages before they are printed. Use File/ Export DXF to
export the view in DXF format.
When you check a Method 4 structure, the structure program (TOWER or PLS-POLE) which
automatically makes that check (see Section 11.1.3.4) can open a new window displaying the
structure deformed geometry and the associated percent strength uses of its components. You
can save the view in this window as a ".plt" file by clicking on Save as in the menu that appears
when you right click anywhere in the window (do not use the File/ Save from the main menu for
this purpose as it will save the entire project rather than the graphics view). An individual
structure view in a ".plt" file can be read by any one of our programs using Window/ New View.
Unlike structure deformed geometry views, Profile, Plan, 3-D or Sheets views cannot be saved
as ".plt" files.
Measuring Distance Between Points
In Plan, Profile, Sheets, and 3D views you can measure the distance between any two points
on the screen with View/ Measure Distance/ Between Points. You click on the first point, then
drag (rubber band) the mouse to the second point. The distance and its projections are
displayed in the bottom status bar. The View/ Measure Distance/ Between Points command
also works in 3-D views provided that the latitude and longitude of your line of sight are a
multiple of 90 degrees. If you hit enter in this mode it will drop a marker as a red line to show
you the distance just measured.
You can also use the View/ Measure Distance/ Between Entities and it will bring up the
Distance Between Points Snap Modes dialog box. This allows you to snap distances between
different entities. You can snap the ends of your measurement to items such as survey points,
wires, dxf and shapefiles, structure joints, etc. The entities highlighted in blue in the dialog box
will be the items the Distance Between Entities command will snap to. If you hit the enter key
when using this command you will get a context menu that gives you the option to add
annotation or a marker to the project with information on the distance between the entities. You
also have the option to define whether the distance being measured is a 3D distance based on
the location of the elements selected or a 2D distance based on the view selected.
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You can also create XYZ Points at regular intervals along the line segment defined by the View/
Measure Distance/ Between Entities command. After selecting the first entity, hover the
mouse over the second entity and press the middle mouse key or the Enter key. This will bring
up a context menu which contains the option to Create Survey Points Along Line Segment.
Once this option is selected you will be prompted to identify the feature code for the newly
created points as well as the interval along segment at which points will be created.
Copy of Graphic View
You can go to Edit/ Copy and make a copy of the current window selected as a bitmap on the
clipboard to be used in other programs. You can also save the window as an image file in either
.tiff or .bmp format. If you are in the plan view the image saved from PLS-CADD will contain the
georeferencing information.
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5.4.3 Graphics Command Only Available in Profile Views
Changing Aspect Ratio of Profile View
You can change the ratio of vertical to horizontal scales in a profile view by changing the Station
Scale Factor and Elevation Scale Factor in the Drafting/ Profile View Aspect Ratio menu.
Default values of 1 and 10 give you the aspect ratio of 10. Values of 1 and 20 will give you an
aspect ratio of 20.
5.4.4 Graphics Commands Only Available in 3-D Views
When you are in 3-D views, you can view the entire line or any portion of it and zoom-in on any
component from any vantage point. You must first define a line of sight (see Fig. 5.4-1) and then
select its longitude and latitude rotations.
Z
Origin of Line of Sight
The origin of your line of sight, which can be an
Y
existing terrain point, is determined as follows. First
LAT.
click the View Rotation Origin button on the
X
toolbar. You will see a red circle snap to the closest
O
terrain point as you move the mouse in the 3-D
view. Once the red circle is on top of the point that
LONGIT.
you want to select as your rotation origin, click the
left mouse button. The selected point will remain as
the rotation origin until changed by going through
Fig. 5.4-1 Line of Sight
the rotation origin selection procedure again. You
can also set the origin by going to the View/ Pan, Zoom & Rotate/ Set Rotation Origin and
snap to one of the items when Entity Info mode is active. These can be terrain points, wires,
attachment points, structures, etc.
Longitude and Latitude Rotations
Changing the latitude or longitude of your line of sight is done by clicking on the Lat+, Lat-,
Long+ and Long- buttons on the toolbar, pressing the Pg Up, Pg Dn, End and Home keys, or
entering desired values in the 3-D Controls dialog box opened by clicking on the Set Rotations
and Scales button or going to View/ Pan, Zoom & Rotate/ Set Rotations and Scale factors.
The amount of change effected by each click of the Lat. or Long. buttons is defined in the
Rotation Increment field of the 3-D Controls box.
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Eliminating Portion of Line from View
When you are in any view or an unrotated 3-D view, you can hide from view any portion of the
line that is outside a "clip area". To define a clip area, click on the View clip button and drag the
clip area over the region which you want to keep. Click on View/ Initial to bring the entire model
back into view.
5.4.4.1
Graphics Commands Only Available in Plan Views
Calculation of Area
While in the plan view you can use the View/ Calculate Area or Angle to get the area of a
defined polygon or the angle defined by the last three selected vertices. Once enabled you can
define the vertices of the polygon and close the polygon by middle clicking or hitting the Enter
key. The angle of the last three selected vertices is reported in the status bar as you are
selecting points.
5.4.4.2
Structure View Graphics Commands Only
Eliminating portion of structure from structure view
You can eliminate from view any portion of the model inside a "cut rectangle" in a structure view
such as the Deformed Geometry view after running a Structure Check. To define a cut
rectangle, click on the Cut button or go to the View/ Display Options/ Cut command and drag
the cut window over the region which you want to eliminate. Click on Uncut to bring back all
members into view. The Cut command gives three options for selecting the members to be cut
which can be toggled by hitting the R, S, or B keys when the command is active. The R option
requires one end of a member to be in the rectangle in order to be removed from the view. The
B option requires both ends of the member to be in the rectangle to be removed from the view.
The S option allows you to select the member to be removed from the view.
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5.4.5 Miscellaneous Display Options
A large number of options exist for displaying various graphical or text items in the different
views. The best way for you to learn the effect of these options is to experiment with them. Most
display options are available under the View/ menu or can be found in the Drafting/ menu and
are self-explanatory. Following are some comments regarding the less obvious display options.
View/ Markers/ Clear markers lets you clear the temporary red markers left to identify TIN
triangles selected to create terrain points at given X,Y locations (Section 6.4.5) or to show
locations of the shortest distances between cables or between cables and structures as
determined by the clearance commands (Sections 11.2.3.2 and 11.2.3.3).
Drafting/ Structure and Section Labeling/ Structure Numbers lets you display as Structure
Number, either the True structure number (consecutive integers starting with 1 at the line
origin), or the text contained in any one of the fifty comment fields of the Structures/ Modify
dialog box.
Drafting/ Structure and Section Labeling/ has the option for labeling of structures and
sections in the Profile, Plan, Sheet Profile, and Sheet Plan views. Fig. 5.4-2a below is for the
Profile View and contains 4 tabs for display of the Structure Labels, Wire Labels, Span Length,
and Inset Views. The Plan and Sheet Plan views only contain the Structure Labels tab and the
Sheet Profile view contains the same 4 tabs as the Profile view below but also has a Section
Labels tab. At the top of the structure labels tab you can pick whether you wish the orientation
of the label to be horizontal or vertical. In the second section of the structure labels tab you can
pick what to include in the label from a list of predetermined items such as station, structure
description, height and elevation, material items associated with the structure etc. as well as the
50 possible structure comments. You can also check the option to suppress structure program
file extensions if displaying the structure file name. The Move Up and Move Down button allow
you to customize the order in which the items appear and the Customize button allows you to
input a user defined prefix and suffix for the item in the label. For example by default the Station
has a prefix of “sta=” and you may wish to change this to “Station=”. The default button allows
you to get the default values back for the labels. Another feature of using the prefix is that you
can insert certain keywords in the structure comments fields for wind and weight spans for
designated weather cases and conditions. For example you may want the weight span shown
in the label for 60F weather case under Initial RS with the units displayed so you could input
“Weight Span is (%WeightSpan(wc=’60F’,cc=’Initial RS’,units=’Yes’)” and the structure may
have a label like “Weight Span is 500 (ft)” on the drawing. These options allow for you to report
the wind and weight span for the total structure or just the wind and weight span for the ahead
and back span. You can right click in the prefix and suffix edit controls to get a popup menu for
inserting keywords and automatically selecting the weather case and condition wanted for the
command.
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Fig. 5.4-2a Profile View Structure and Section Labels
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The Wire Labels tab gives you the option to draw a tick mark at the lowest point on the
displayed wire as well as option to label the wire with their cable names, sags, or surveyed
temperature. The Span Length tab gives the option on whether to display the span length in the
profile view and options for rounding of the span length. The Inset Views tab allows you to pick
the location of an inset view to be drawn at ground level or below ground level and whether to
show the structure geometry and any imagery attached to the structure file. You can also pick
to show a cross section view below ground with the structure outline and ground profile. A scale
factor gives control of the height of the inset views. The Section Labels tab is only available in
the Profile View tab and gives you options to position the section label text within the sheet
profile view. Within the labels to display a portion of the section labels tab the user can pick
what to include in the label from a list of predetermined items such as structure range, circuit
label, voltage, cable file, design tension, etc.
Drafting/ Show Structure Compass will display the structure compass at the base of Method 4
structures which visually displays the structure coordinate system. This can be useful when
looking at loading configurations. It can also be shown in Structure Inset Views and controlled
through the table.
Fig. 5.4-2b Structure Compass
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Drafting/ Text Size, Line Width, Style, Color and Layer is used if you want to control text and
Fig. 5.4-3 Controlling Pen Styles, Colors and Thicknesses, etc.
line characteristics (primarily in P&P sheets) or export P&P sheets drawings to a CAD system in
DXF format. Fig. 5.4-3 shows some of the choices you have. You can assign the pen thickness,
color, style and CAD layer in which various items (ground line, catenaries, structures, sheet
index map, etc.) will appear in the CAD systems.
Line thickness for 3D view Used to make structures and sections dominate over a cluttered
structures
and
sections background in a 3D view
(pixels):
Symbol Size
display::
for
screen Used to set size of survey points in the Plan, Profile, and 3D
views. The sheets view is controlled in the table
settings.
Automatically select text and Computes largest text size that allows for the station and
symbol size for sheet view:
elevation labels to fit within the constraints of the major grid
lines.
Automatically select text and Computes largest text size that allows for the station and
symbol size for sheet view:
elevation labels to fit within the constraints of the major grid
lines.
Use PI and alignment display Overrides the settings in the table for the alignment and PI
settings defined in the table:
symbols with those selected in the Terrain/ Alignment/ Display
Options for PI, Alignment, Right of Way table.
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Drawing Entity:
Items being drawn in the plan and profile view.
Prof. Text Height:
Height of text in profile part of sheet view. Set to 0 to suppress text
Prof. Symbol Height:
Height of symbol to draw in the profile part of sheet view
Prof. Line Thick.:
Thickness of pen used to draw lines in profile portion of sheet view.
Enter 0 for minimum line thickness possible.
Prof. Line Style:
Type of line to draw in the profile view. Select none to suppress.
Prof. Color:
Color for lines drawn in profile views
Plan Text Height:
Height of text in plan part of sheet view. Set to 0 to suppress text
Plan Symbol Height:
Height of symbol to draw in the plan part of sheet view
Plan Line Thick:
Thickness of pen used to draw lines in plan portion of sheet view.
Enter 0 for minimum line thickness possible.
Plan Line Style:
Type of line to draw in the plan view. Select none to suppress.
Plan Color:
Color for lines drawn in plan views
Prof. Line Layer:
Layer used for profile lines when exporting to DXF.
Prof. Text Layer:
Layer used for profile text when exporting to DXF.
Plan Line Layer:
Layer used for plan lines when exporting to DXF.
Plan Text Layer:
Layer used for plan text when exporting to DXF.
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Drafting/ Text Position, Orientation and Background gives you a menu of many options
regarding the way text is printed in various views. Opaque text background is selected to
highlight text displayed over a dark photograph or bitmap. One option is to limit the labeling of
the PI’s to minimum line angle. Any line angles below this would not be labeled.
Drafting/ Show cable attachment points is used to display each cable attachment point as a
solid square if that point is assumed to be fixed (i.e. deadend point at the end of a tension
section) or as an open circle if that point is assumed to be a suspension point or a point at the
tip of a flexible post insulator (i.e. a point on both sides of which the cable tensions are assumed
to be equal.
Drafting/ Show Stringing Direction places an arrow on the center of the span of wire showing
the direction that the conductor or jumper is strung. This is important to know as the direction
wire is strung decides what is considered an ahead or back span which is the basis of structure
load adjustments, wind direction, clearance reporting, etc.
Drafting/Show Set and Phase Labels in 3D Views command is used to display the set and
phase labels that are defined within structure files.
Drafting/Show Circuit and Phase Labels in 3D Views command is used to display the circuit
and phase labels that are defined within Sections/Electric/Define Circuits and
Phases/Table...
When Drafting/ Show Structure and Section Check Bitmaps is enabled, you will see green
G's (Good) or red N's (Not good) next to structures and cables. A "G" next to a structure
indicates that its strength and insulator swings are OK for the current location and design
criteria. A "N" indicates that there is a violation. Similarly, a "G" or "N" next to a cable indicates
that the conductor or ground wire in the corresponding tension section meets the cable design
criteria or not. When the check bitmap is enabled, the structure and section checking is done
dynamically, i.e. it is carried out continuously during idle computing cycles and does not
interfere with whatever else you are doing. Dynamic checking is only currently applied to
Method 1, Method 2 and Method 3 structures (see Section 8.3 for definitions of Methods 1, 2
and 3) for performance reasons.
Drafting/ Show Embedded Portions of Structures will display the portions of structures that
are underground in the 3D and structure views such as the embedded portion of a wood pole.
Drafting/ Show Insulator Counter Weights is used to display each attachment point on a
structure that has a counter weight attached. Counter weights show up as a black square.
Insulator counter weights are added to the structure in the Structures/ Modify dialog box.
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Drafting/Show PP Sheet Rectangles will display boxes that represent the extents of the plan &
profile sheets that have been defined within the menu options within Drafting/Plan Profile
Sheet Configuration.
5.4.6 Display Options for Line and Tension Sections
The colors, number of phases, weather case, wind direction and cable condition (initial, after
creep or after permanent stretch from heavy load) which are used to display the line in any view
depend on combinations of parameters selected in three dialog boxes. The Line Display
Options dialog box (Fig. 5.4-4a) is opened with Sections/ Display Options or with Lines/ Edit/
Info. The Section Modify dialog box (Fig. 5.4-5) is opened with Sections/ Modify. A table of all
sections within your model and their display conditions is also available to edit under
Sections/Table. This allows editing of the section display data for many sections at once.
5.4.6.1
Colors for Line, Tension Sections, Structures and Insulators
The colors used to display the wires, the structures and the insulators depend on your
selections in the Line Display Options dialog box (see Fig. 5.4-4a and Fig. 5.4-4b). There is a
common header section of the Line Display Options dialog box where you have information
concerning the line such as the number of structures and sections as well as the cost of the line.
Then below this you can pick the line type and curve type for the wires.
The Line Type portion of the box defines the lines used to display the wires. These lines can be
solid, dashed or dotted.
The Line Display Options dialog box contains two tabs. One tab contains options for displaying
sections (Fig. 5.4-4a) and the other contains options for displaying the structures (Fig. 5.4-4b).
Within the Section color portion of the box there are options to for the section color. If you select
Draw each section …, the wires of each tension section will be displayed for the color which you
specify in the Display portion of the Section Modify box shown in Fig. 5.4-5 or what is shown
in the last columns of the Section Table. If you select Draw all sections ..., all wires in the
entire line will be displayed with the color which you chose by clicking on the Sections Color
button. The third option is to display each section with the color specified in the cable file. The
bottom two options are used to display wires using the line style and color for either the
assigned circuit or the assigned phase.
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Fig. 5.4-4a Section Tab of Line Display Options
The Phases Displayed and Display Weather Case portions of the dialog box allow you to select
a global display option for the sections or to display the sections as selected in the Sections/
Modify dialog box of Fig. 5.4-5. The Show Cables portion allows you to select which views to
display the cables. You can turn them on or off by checking the corresponding box to the view
you wish to control.
In all views, all metallic structures are displayed in grey and all wood structures are displayed in
brown if you select Render Structures. Otherwise, the structures are displayed with the color
that you select by clicking on the Structures Color button. All insulators are displayed with the
color that you select by clicking on the Insulators Color button.
The structure symbols section allows you to select a symbol that is available in the Terrain/
Feature Code Date/ Edit table for the structure center, pole base, tower legs, guy anchors, and
M1/M2 Structures for each of the possible views including the plan and profile section of the
sheets view. If Default is selected then it will use the traditional symbol that had been used in
previous versions of the software.
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Fig. 5.4-4b
The Show Structure Geometry section of the dialog allows you to select which views to display
structure geometry. You can turn them on or off by checking the corresponding box to the view
you wish to control.
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5.4.6.2
Phases Displayed
If you select Draw all phases ... in the Phases Displayed area of the Line Display Options
box, all phases (all wires of the set - sets are defined in Section 8.2.1) will be displayed.
Otherwise (i.e. you select Draw only the phase ...), only one phase will be shown in each
tension section. The phase displayed is that which you select in the lower right portion of the
Section Modify box (Phase 1 is selected in the box of Fig. 5.4-5). The option to show only one
phase (usually the lower one) is only applicable in cases where you model more than one wire
per set. It is sometimes used when printing P&P sheets or to decrease clutter.
5.4.6.3
Weather Case, Cable Condition and Wind Direction
If you select Draw all sections for weather case below ... in the Display Weather Case area of
the Line Display Options box, all wires will be
displayed for the combination of Weather Case, Cable
Condition and Wind Direction which you select from
lists of available choices. A wind from the left is a
wind which blows towards the positive offset direction
of the line. A wind from both directions will show
simultaneously the positions of the wires with the wind
blowing from the left and from the right. This may be
used when looking at the line from the top (latitude of
line of sight = 90 degrees) in a 3-D window to see the
envelope of the wire blowouts. The option to display
all sections for the same weather case may be used if
you wish to see the entire line under some extreme
wind, extreme cold or everyday condition where all
wires are at about the same temperature and are
subjected to the same wind and ice conditions.
If you select Display each section as selected in
Section/ Modify ... , then all the wires (or the
Fig. 5.4-5 Section Modify Dialog Box
single wire designated by its Phase number) of
each individual tension section will be displayed for the condition which you specify for the
particular tension section in the Display area at the bottom of the Section Modify box (see Fig.
5.4-5). The wires are displayed for the wind direction which you specify in the Wind from field in
the lower right portion of the box. If you do not select Show selected weather case in the
Display area of the Section Modify box, you will have access to the Catenary constant and
Swing angle fields (they are grayed in Fig. 5.4-5). Then, all wires in the tension section will be
displayed for your selected combination of Catenary constant and Swing angle. On the other
hand, if you select Show selected weather case, you will be able to pick the combination of
available Weather Case and cable Condition for which the wires in the section should be
displayed. The option to display each tension section for its own weather case may be used to
show the relative position of two wires, for example a very hot conductor over a not so hot
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distribution underbuild, or an iced conductor above a non-iced conductor. For example, when
drawing P&P sheets, you may decide to display the conductors at maximum design operating
temperature while ground wires are displayed simultaneously for a cold condition. To display a
conductor at very high temperature, you will need to create a fictitious weather case which has
that high temperature, as it is assumed that (unless you are in a dynamic rating mode) the wire
temperature is that of the ambient weather case. You may also display your wires at any
temperature without creating a weather case by simply typing the temperature into the WC pull
down menu. For instance if you want to display the conductor at 212 degrees F then you would
need to type 212 into the WC pull down menu.
5.4.6.3.1
As Surveyed Temperature
An Ahead Span Surveyed Wire
Temperature can be input in the
Wire Lengths and Attachment
Stiffness table shown in Figure 5.45a which is accessed by hitting the
Edit Span Specific Wire Lengths
button of the Sections/ Modify
dialog box. This column in the table
allows for span specific temperatures
in a section and allows the user store
a specific temperature that was
caught during a field survey for each
span in the section. The user can
then use this value as a display
weather case in the Sections/
Modify, Sections/ Display Options,
and Sections/ Table by selecting
Fig. 5.4-5a Ahead Span Surveyed Wire Temperature
*** Surveyed Wire Temp. *** in the
display weather case. This display case is also supported in the Sections/ Sag Tension,
Lines/ Reports/ Summary/ Structure Attachment Coordinates reports as well as for use in
the Sections/ Graphical Sagging command. The surveyed temperature can be displayed
using the Drafting/ Structure & Section Labels/ Profile View or Sheet Profile View/ Wire
Labels and checking the label wires with their surveyed temperature option.
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5.4.6.4
Multiple Lines
In general, with PLS-CADD, you are normally only working with one line referenced to your
ground profile. If you use Lines/ Edit, you will be taken to the Line dialog box of Fig. 5.4-6. At
the top of the box is a project notes section where you can enter any notes you would like about
the selected line in the Project Lines section of the dialog box. The current design is highlighted
in the project lines section. The name of the line model (which you select in the Name field at
the top of the Line Display Options box of Fig. 5.4-4) as well as some summary information:
cost of all structures if such information exists in the Available Structures table (see Section
14.3), number of structures, etc. Even if you are not working with multiple line designs you can
access the Line Specific Material List, As Built…, and Project Estimator menu items in the Lines
dialog box.
Fig. 5.4-6 Line Dialog Box
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There are some situations
(see Fig. 5.4-7) where you will
build different line models on
the same alignment. For
example,
using
the
optimization
technique
described in Section 14, you
can
obtain
complete
competing designs made out
of wood, steel or concrete
poles on the same profile. Or,
you may be comparing the
design of a distribution line
before and after adding new
communication cables to it as
part of a joint-use study. In
these cases, you may wish to
superpose these designs for
Fig. 5.4-7 Two Line Designs on the Same Profile
comparison. Each individual
design is described internally by the type and location of its structures and cables, as well as the
sagging conditions of the cables. This information, for each individual design, is stored in a file
which has the .don extension. For example, if you click on the Copy button at the bottom of Fig.
5.4-6, you will create a second line, initially identical to the first one, on the same alignment. You
can modify this second line and view it on the same profile as the first one as shown in Fig. 5.47. If you have more than one line on one alignment, you can select the one you want to work on
(the active line) with the Select button and you can chose to display or hide any one of the lines.
Structures and Sections operations apply only to the currently active line. You can delete any
selected line with the Delete button.
Several line designs, for example variations of one currently saved in the Project.don file, could
be saved under different names, say Project1.don, Project2.don, etc. with the Lines/ Save DON
File command. Then, at any future time, they could be brought back in with the Lines/ Load
DON File or Merge Projects command. They would then all show up in the Line dialog box of
Fig. 5.4-6.
The designs in the Lines/ Edit dialog box can be sorted by cost if the Sort by Cost button is
selected. The order of the designs can be made user specific by using the Move Up button.
You can also reorder the designs by right clicking one of the designs which will highlight the
design in green and then dragging and dropping it in the place you would like in the list.
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5.4.6.5
Effect of Line Angle on Sags
Without access to
true
3-dimensional
line modeling such as
provided by PLSCADD, sags have
traditionally
been
calculated by using
for span length the
centerline
distance
between structures.
However,
the
difference in span
length
between
phases on different
sides of an angle
structure can lead to
visible differences in
sags. For example,
the ground wires (or
the conductors) on
either
side
of
Fig. 5.4-8 Plan & Profile of Struct. #6 Demo
Structure # 6 of the
Demo line have clearly different sags (Fig. 5.4-8), even though they are installed under the
same tension.
5.4.7 Terrain Display Options
There are many options affecting how some terrain features are displayed. Only some of the
options are discussed here. These options are included under the Terrain/ Survey Data
Display Options, Terrain/ Clearance Line and Terrain/ Side Profiles menus. For example,
vertical lines at each terrain point (vertical lines in the Profile view in the lower right quarter of
Fig. 5.4-9) can be shown or hidden by checking Display ground point lines or not. Side profiles
and required ground clearance lines can selectively be shown or hidden. They are shown in the
Profile view in the lower right quarter of Fig. 5.4-9.
In a 3-D view, the terrain can be displayed by: 1) dots representing surveyed terrain points
(lower left of Fig. 5.4-9), 2) TIN triangles representing a surface over the terrain points (upper
right of Fig. 5.4-9), 3) contour lines determined automatically (upper left of Fig. 5.4-9), 4) color
rendering showing elevations, hidden surfaces and light incidence (not shown), or 5) draped
photographs (as shown on the cover of this manual). Display options 2) to 5) are selected in the
TIN Display Options dialog box by: checking Unrendered triangle outlines for 2), entering
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Contour line interval of 5 ft for 3), selecting Render triangle, color by elevation, intensity by
incidence for 4) and selecting Render triangle, color from bitmap, intensity from bitmap for 5).
You should note in Fig 5.4-9 that three 3-D views have been opened simultaneously and the
same terrain point is tracked in all four views.
Fig. 5.4-9 Terrain Display Options for Demo Line
5.4.8 Cross-section Views
By selecting View/ Pan, Zoom & Rotate/ Cross Section or by pushing the C key you can
generate a cross section view (perpendicular or at an angle to the alignment or relative to an
XYZ point) of all items in your line model located within a certain distance from the reference
station of the cross section view. For the Demo line and the selections in Fig. 5.4-10 you can
generate the cross section view shown in Fig. 5.4-11.
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Fig. 5.4-10 Parameters for Cross Section View of Fig. 5.4-11
Fig 5.4-11 Cross Section View at Structure #5
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5.4.9 Exporting to Google Earth™
You can visualize your PLS-CADD model in Google Earth to take advantage of that program’s
popular graphical environment. This is described in detail in the following technical note:
http://www.powline.com/products/ge_tips.html
Fig. 5.4-12 shows two parallel PLS-CADD lines exported to Google Earth.
Fig. 5.4-12 PLS-CADD Exported to Google Earth
In addition, you may export many reports to Google Earth by right clicking the mouse within the
body of the report and then selecting KML export and selecting the particular report in question.
It will then prompt you to save the file. After naming the file and selecting Save the program will
prompt you to see if you would like to view the report in the default system KML viewer which
can be set to Google Earth. This will then automatically launch the Google Earth Viewer and
display the particular report selected.
5.4.10 Additional Text and Lines
In addition to what you can see in the various PLS-CADD views, which is derived from the 3-D
model itself and its attachments, you can add some graphics and annotations to any view. This
is described in Section 13.3. An example of lines and annotations can be seen in the lower left
block of Fig. 13.4-1
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5.4.11 View Location in Bing Maps™
If your project has a coordinate system defined under the Terrain/ Coordinate System/ Define
menu then any point in your project can be viewed in Bing Maps as long as you are connected
to the internet. If you have a point selected in your model you can right click or hit the Enter key
which will bring up the Entity Info view menu which contains the View this location in Bing Maps
command that will automatically launch Bing Maps and zoom to the point in question.
5.4.12 Virtual Profile
The View/ Pan, Zoom Rotate/ Virtual Profile opens the dialog of Figure 5.4-13 where you can
select two points along a line from either 2 structures, and existing alignment segment, or
between two XY coordinates to create a new 3D view oriented to look like a profile view of the
line segment. The options at the bottom of the dialog allow you to set profile view aspect ratio
for the view or offset from the selected line segment.
The context sensitive view menu (middle click or enter during View/ Entity Info and View
Measure Distance/ Between Entities) also has Show Virtual Profile for Selected Span,
Show Virtual Profile for Selected Alignment Segment, and Show Virtual Profile Along
Selected Line Segment options for providing the alternate entry points for the Virtual Profile
dialog box.
Fig. 5.4-13 Virtual Profile
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5.5
Latticed Towers Line
Fig. 5.5-1 Profile, Sheets and 3-D Views of WPLFULL Line
Fig. 5.5-1 shows the Profile, 3-D and Sheets views for a latticed tower line that you can load
from your PLS-CADD distribution CD as file Wplfullm.xyz. This line, originally built in the 1930's,
was recently reconductored and refurbished to almost double its current carrying capacity
(Kluge et. al., 1994). It includes 112 steel latticed towers, all modeled with the TOWER program.
If you want to check a particular tower along the profile, simply select Structures/ Check, click
on the tower, and watch the Strength Percent Usage appear in the Structure check dialog.
Click on the Analysis button of the Structure check box to get more detailed information or the
Summary and Standard button to get a condensed form of the structure check output. If you
select Geometry, you will get a deformed geometry window of the tower which you can
manipulate to obtain a great deal of graphical information (for example a view like that on the
left pane of Fig. 5.5-2). However, in order to manipulate the deformed geometry window and
interpret the results within, you should be familiar with the TOWER program.
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For example we clicked on the second tower of the WPLFULLM line in the right pane of Fig.
5.5-2 and got a picture of the percent use of each member of the tower for each load case in the
left pane.
Fig. 5.5-2 Interactive Tower Checking
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5.6
Entity Info
View/ Entity Info Snap Settings or hitting the “s” key allows the user to snap to certain entities
within a PLS-CADD or PLS-CADD/Lite model with the mouse. As shown in Figure 5.6-1 you
can pick from a list of items in the Entity Info Snap Modes dialog box. Once selected the mouse
will snap to these items in the model and show information concerning the item in the status bar.
For example if you select Wires as one of the items in the Entity Info Snap Modes dialog and
move the mouse near a wire in the model you will get information such as circuit label, section
number, phase label, voltage, conductor type, structure range, etc. in the status bar. If you have
a structure item selected in the list and move the mouse near a structure then information about
the structure such as structure number and station will appear in the status bar. The Entity Info
command also gives you context sensitive commands concerning the item you are snapped on
by left clicking on the entity. For example
Figure 5.6-2 below shows the different
commands available when you left click on a
wire section and Figure 5.6-3 shows the
different commands available when you left
click on a survey point.
Figure 5.6-1 Entity Info Snap Modes
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Figure 5.6-2
Figure 5.6-3
Other general commands are available by middle clicking when Entity Info is active There are
also shortcut keys for many of these commands that are documented in the menu that appears
when you click on the entity. The Entity Info Snap Modes dialog box also allows the user the
option to use either display horizontal or 3D distance between entities when placing annotation.
You can also toggle the section and structure displays off and on by middle clicking when the
Entity Info is snapped to a structure or section item.
If you select Grid you also have the option to set a grid spacing for the sheet view or plan view
of the model that you can snap to as you create views, spot structures, and annotation for your
model. If you select Show Grid you will be able to see the grid points.
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5.7
Merging Projects
PLS-CADD can merge .xyz projects together into one project using the Lines/ Load DON File
or Merge Projects command. This command merges in structures and sections from another
DON file or project. It also gives you the ability to merge in alignments, XYZ data, annotation,
attachments, project notes, and spotting constraints from that project. It does not merge any
other items (TIN, feature codes, criteria, etc.). If you wish to merge attachments from another
project and nothing else then you should use the Drafting/ Attachments/ Merge in
Attachments from Another Project command.
For this function to work correctly the alignments in each project need to be constructed such
that the stationing of each project is running in the same direction. If they are not running in the
same direction then you will need to use the Terrain/ Alignment/ Reverse Alignment
command to change one of the projects so the alignment’s direction matches. The projects
being merged should also be in the same coordinate system.
After starting the merge you will be prompted to pick a DON file from another project to merge
into the current project. Then you will tell the program whether the structures from this DON file
exist on the current projects alignment or if not then the program will attempt to add the
alignments associated with the DON. This will only work if there are no structures beyond your
last PI. Next you will be prompted whether you wish to merge in the XYZ data and spotting
constraints from the project. If you choose to do so you will be presented with the opportunity to
filter the data being brought into the model similar to the filter described in Appendix D.4.
Once you have completed the merge you will be left with a new design in the Lines/ Edit menu
described in Section 5.4.6.4. The structures and sections in this separate line can be merged
into the current design using the Lines/ Merge command. After merging the lines it may be
necessary to delete certain common structures or sections in order to tie the designs together.
You will also want to merge together any common PI’s in the project using the Terrain/
Alignment/ Multiple Alignment Options/ Join Alignments command. This command can be
done as long as the two PI’s being joined are in consecutive order. For example you could join
PI numbers 3 and 4 but could not join PI numbers 3 and 5 since they are not in consecutive
order. Joining PI’s and merging projects can be complex if using multiple alignments in the
projects you are merging. There may be situations where multiple alignments are present that
merging of projects may not be recommended or possible.
Important Note: Be sure to make a backup of each model before merging so if a mistake is
made you can quickly get back to your original project prior to the merge. Merging projects is
not undoable and once you save a model in a merged state you cannot revert back to the old
model.
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5.8
Web Download Files
PLS-CADD can now download many of the example and reference files directly from Power
Line Systems’ website by clicking on the Download From PLS button in the load file screen.
For example Figure 5.8-1 below shows the Load Criteria File dialog that is available when you
go to Criteria/ Load CRI File. At the bottom of the dialog box highlighted in yellow is the
Download From PLS button.
Fig. 5.8-1 Download From PLS
Once you hit this button the dialog will expand and you will see the criteria files that are
available on our website for download. By double clicking on one of these files you the program
will automatically download the file into your selected directory and then you can select it from
that folder. There is also a search option at the top left of the dialog that allows for the input of
comma separated search terms.
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Fig. 5.8-2 Download From PLS
This option is available in the Criteria/ Load CRI File, Sections/Cable and Concentrated
Loads Files/Edit Existing Cable File, the cable selection options in the Sections/ Table,
Sections/ Modify, and Sections/ Add Graphical dialog boxes, the applicable cable inputs of
the Criteria/ Automatic Sagging and Criteria/ Cable Tensions table, and for grid shift files in
the Terrain/Coordinate System/Define/ Select Grid Shift File command.
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6.
TERRAIN
A 3-dimensional GIS-type (Geographic Information System) terrain model was adopted in PLSCADD for its flexibility and compatibility with modern electronic surveying equipment and
mapping techniques. Terrain data are normally collected electronically (total station,
photogrammetry, LIDAR, etc.) and are subsequently downloaded into ASCII terrain files. In
PLS-CADD, a terrain model normally includes information about the location and type of a large
number of terrain or above-terrain points. Above-terrain points will be referred to as "obstacle"
points. There are two ways to describe an obstacle point. You can either: 1) describe the
obstacle by its height above a ground point and the coordinates of that ground point, or 2) locate
the top of the obstacle directly with its own coordinates. With the first option (Obstacle Option 1),
the locations of both the top of the obstacle and the underlying ground point are known. With the
second option (Obstacle Option 2), only the location of the top of the obstacle is known.
6.1
General - Use of Feature Codes
Before generating a terrain file, one should
decide on broad categories of terrain or
obstacle points which have unique
requirements. These requirements include
minimum code clearances to be met above
or to the side of the points as well as
symbols to be used to display these points
on the screen or on the final drawings. Code
clearances depend on the voltage of
particular conductors. A separate feature
code must be created for each category of
Fig. 6.1-1 Wires Voltages Used in Project
terrain or obstacle points. These feature
codes must be defined in the project feature code file before they can be used in a terrain file.
Feature code files use the .fea extension.
Even though feature code files are ASCII files, we recommend they be created/edited with the
Terrain/ Feature Code Data/ Edit command or loaded from existing feature code tables with
Terrain/ Feature Code Data/ Load FEA File. For example, after loading the demo.xyz project,
click on Terrain/ Feature Code Data/ Edit. You are first taken to the Required Clearance
Voltages dialog (Fig. 6.1-1) where you can select the voltages (maximum of twenty) for which
you will be able to assign required clearances above and laterally from any ground or obstacle
point. When you exit the Required Clearance Voltages dialog, you are taken to the Feature
Code Data Edit dialog (Fig. 6.1-2). At the top of the dialog, you will need to select one of two
clearance violation options: this is explained in more details in Section 6.1.1.
Then, for each feature code, you should enter values for the following:
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Feature Code:
Integer used to uniquely identify the type of feature
Feature
Description:
Text description of the feature.
Prof Symbol:
Symbol used for the display of the point in the profile view.
Plan Symbol:
Symbol used for the display of the point in the plan or 3D views.
Line From Feature
Top to Bottom:
Select Yes or No whether to display a line from the feature code bottom z
to the feature code top z + h
Aerial Obstacle:
Select Yes of No whether the point is an aerial obstacle which allows
your wires to not only pass over the point but also below the point as long
as the vertical clearance requirement is met.
Point is on Ground:
Select Yes or No whether the point is on the ground. If the point is on the
ground it will be used to draw a ground profile or create a TIN model.
Req Vert
Clear(RV):
Each voltage listed in the Required Clearance Voltages dialog will have a
required vertical clearance column which is the required vertical
clearance above a point (and below for aerial points). This column is
alos used for the required radial clearance check when radial clearances
are used. See Section 6.1.1 below for more details on how this
information is used.
Req Horiz
Clear(RH):
Each voltage listed in the Required Clearance Voltages dialog will have a
required horizontal clearance column which is the required horizontal
clearance from a point. See Section 6.1.1 below for more details on how
this information is used.
Required
Clearance Str.
Base/Guy to
Spotting Constraint:
Required clearance that must exist between a spotting constraint polygon
or polyline with this feature code and the fixed joints of a method 4
structure model or the base of a method 1 or 2 structure model. See
Section 6.10.3 for further description of spotting constraints.
Prof Label:
Labeling options for the feature code in the profile view. Choose to
display the feature code, description, station, offset, height, Easting (X),
Northing (Y), Ground elevation (Z), Elevation at top of obstacle (Z + H),
Survey point description, and/or Survey point comment.
Plan Label:
Labeling option for the feature code in the plan view. Choose to display
the same options as in the Profile Label above.
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The last two columns of the Feature Code Data Edit window shows the number of active and
inactive survey points in your model that have the specified feature code.
Note: Use the Tab or Arrow keys to move around the feature codes table.
When you click in the Profile or Plan Symbol column, you can choose from a list of pre-defined
symbols or you can create your own symbols.
Fig. 6.1-2 Feature Codes Table
The choice of feature code numbers and descriptions is completely up to the user. Terrain/
Feature Code Data/ Feature Code for Ground Clearance and Interpolated TIN Points lets
you designate: 1) a default feature code for ground which impacts the height above ground at
which a clearance line is drawn as defined in Terrain/ Clearance Line, and 2) a default feature
code for interpolated points from TIN as defined in Terrain/ TIN/ Interpolated Points.
A user generally maintains one or more master feature code files (say Master.fea) which are
reused on several projects. When starting a new project the Master.fea file can be loaded using
Terrain/ Feature Code Data/ Load FEA File. Upon exiting PLS-CADD and saving, the feature
codes file Project.fea will be created.
A user can change the feature codes of survey points using the Terrain/Info command and
using the inputs found in the Edit XYZ but this must be done one point at a time. You can also
use the Terrain/Edit/Change Feature Code commands to change the feature code of a group
of points by using the Search and Replace, Inside Fence, Inside DXF or SHP Polygon,
Inside Planar Feature or Inside Polygon options. If a user selects Inside Fence or Inside
Polygon then the program will change all feature codes within the fence or polygon created with
the mouse. If Search and Replace is chosen then a dialog box will prompt the user to replace
all feature codes in the project with ones selected in the dialog. Some additional options to
restrict the search and replace command to a specified range of height above ground or offset
from centerline are also available.
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The Terrain/ Edit/ Change Feature Code/ From Raster Attachment Values changes the
feature code of survey points if they lie within a raster image attached in the plan view that
contains a numeric value per each pixel. This can be used to classify feature code data based
on certain types of raster features such as NDVI data.
6.1.1 Checking of Required Clearances
Feature codes and the corresponding required clearances allow PLS-CADD to automatically
identify clearance violations between wires and survey points for any number of combinations of
weather and cable conditions (defined under Criteria/ Survey Point Clearance and Danger
Tree Locator). In making its checks, PLS-CADD takes into account the voltage of the wires and
the required clearances as defined in the Required Vertical Clearance (RV) and the Required
Horizontal Clearance (RH) columns of the Feature Code Data Edit dialog. The clearance
checked depends on whether you are checking a rectangular or radial clearance zone. If the
user is checking a rectangular clearance then the checking of the clearance is dependent on
whether RH is a non-zero value (or non-blank).
COK
COK
COK
E
F
If RH is non-zero, PLS-CADD
B
CNG
considers
a
prohibited
C??
C??
COK
RV
RV
rectangular clearance zone
P
P
(A-B-C-D) about each survey
C??
RVB
RVB
point P as illustrated in the
CNG
RH = 0 OR UNDEFINED
upper left part of Fig. 6.1-3. AC
D
G
H
COK
B-C-D is in the vertical plane
RH
RH
COK
P = SURVEY POINT
passing through P and
COK = CABLE POSITION WITHOUT ANY CLEARANCE PROBLEM
perpendicular to the alignment
CNG = CABLE POSITION WITH CLEARANCE VIOLATION
C?? = CABLE POSITION WITH POSSIBLE CLEARANCE PROBLEM
at that point. If the point is an
DEPENDING ON HORIZONTAL DISTANCE TO P
aerial obstacle, the lower edge
RH = REQUIRED HORIZONTAL CLEARANCE
of the rectangle (C-D) is
RV = REQUIRED VERTICAL CLEARANCE ABOVE POINT
RVB = REQUIRED VERTICAL CLEARANCE BELOW POINT
located a distance RV below
RVB = HEIGHT OF P ABOVE GROUND, OR EQUAL TO RV FOR AERIAL OBSTACLE
the survey point: otherwise it
is on the ground. Any wire that
CROSS SECTION VIEW THROUGH POINT P PERPENDICULAR TO ALIGNMENT
pierces the plan of A-B-C-D
Fig. 6.1-3 Checking Survey Point Clearances
inside the rectangle is
reported as a clearance violation (with red text in the reports and red markers in the various
views). When RH is non-zero, you normally select “Not a violation“ at the top of the Feature
Code Data Edit dialog of Fig. 6.1-2: this is done for the treatment of points that have insufficient
vertical clearance but adequate horizontal clearance.
A
If RH is zero (or blank), the width of the rectangular zone A-B-C-D is no longer defined. The
zone is now an horizontal band bounded by an upper line (E-F) and a lower line (G-H) as shown
in the upper right part of Fig. 6.1-3. Any wire that pierces the band is reported as a potential
clearance violation (with blue text in the reports and blue markers in the various views). Once
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your attention has been drawn to the potential violation, you will need to look at the situation in
more detail to determine if it is an actual violation or not. If RH is zero (or blank), you normally
select “Questionable violation ..“ at the top of the Feature Code Data Edit dialog of Fig. 6.1-2.
Checking clearances is done with the Terrain/ Clearance or Lines/ Reports/ Survey Point
Clearances or Lines/ Reports/ Danger Tree Locator commands. A strictly vertical clearance
check is used when running the Lines/ Reports/ Thermal Rating Report.
If the user decides to check clearances radially in any of the clearance reports then the
clearance is checked based on the three dimensional distance to the point in question and the
required clearance is the value input in the Required Vertical Clearance (RV) column in the
Feature Code Data Edit table. The Required Horizontal Clearance (RH) column is not used
when performing a radial clearance check. Below are several examples of various settings for a
point in the Terrain/ Feature Code Data/ Edit and its influence on the results of a clearance
check.
Figure 6.1-4 Rectangular Clearance Point on Ground
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Figure 6.1-5 Rectangular Clearance Encroachment Aerial Obstacle
Figure 6.1-6 Rectangular Clearance Aerial Obstacle with Line From Top to Bottom
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Figure 6.1-7 Rectangular Clearance Aerial Obstacle
Figure 6.1-8 Rectangular Clearance Encroachment Non-Aerial and Non-Ground Obstacle
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Figure 6.1-9 Rectangular Non-Aerial Obstacle with Line From Top to Bottom Clearance
Figure 6.1-10 Rectangular Aerial Obstacle with Continuous Range of Wind Encroachment
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Figure 6.1-11 Radial Aerial Obstacle Clearance
Figure 6.1-12 Radial Aerial Obstacle Clearance Encroachment
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Figure 6.1-13 Radial Non-Aerial and Non-Ground Obstacle Clearance
Figure 6.1-14 Radial Non-Aerial, Non-Ground, Line from Feature Top to Bottom Clearance
Encroachment
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6.2
XYZ Terrain Model
PLS-CADD uses two terrain models. The XYZ
model includes points described by their
global coordinates X,Y, and Z. The PFL model
includes points described by their Station
(cumulative distance from an arbitrary
reference point along the centerline of the
line), Offset (lateral distance from the
centerline) and elevation, Z. The PFL model is
described in Section 6.6. PLS-CADD can
create a PFL model from an XYZ input and a
defined alignment or an XYZ model from a
PFL input. Fig. 6.2-1 shows a typical ground
point "P" and the top of an obstacle "O" in an
XYZ model.
Z
Y
O
h
X
P
Z
Y
X
O = OBSTACLE POINT ABOVE GROUND
P = GROUND POINT
Fig. 6.2-1 XYZ Terrain Model
The data for a ground point in the XYZ model
include the feature code, an optional point label or description, the point global coordinates X, Y,
Z, and a zero obstacle height (h = 0).
For an obstacle described by its height above a ground point (Obstacle Option 1) the data
include the obstacle feature code, the optional obstacle label or description, the global
coordinates X, Y, Z of the ground point directly below the obstacle, and the height of the
obstacle top above the ground. When you use this option, make sure that "Yes" is checked in
the Point is on Ground column of the feature codes table in Fig 6.1-2.
For an obstacle described by its own coordinates (Obstacle Option 2) the data include the
obstacle feature code, its optional label or description, the global coordinates X, Y, Z of the top
of the obstacle, and a zero obstacle height. When you use this option, make sure that "No" is
checked in the Point is on Ground column, otherwise you might see the ground center line or
some side profiles go through the top of your obstacles in a profile view.
Also included for each ground or obstacle point are optional surveyor's notes to be displayed on
profile or plan views. These notes can be used for any manner of information and can be
displayed as part of the label of the point. If you place a complete file path for any type of file
you will have a survey point file reference menu item available when you middle click on the
point. The data for the XYZ model are contained in an ASCII file with a record for each point.
The file must have the extension ".xyz" to be recognized as relating to an XYZ model. The
details of the records and fields of an XYZ file are described in Appendix D.
An XYZ file can be prepared and edited with a text editor or word processor according to the
format described in Appendix D. It can also be edited with the Terrain/ Edit/ Edit XYZ
command also described in Appendix D, or better yet, it can be created by downloading survey
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data from an automatic instrument. There are many tools and techniques available in PLSCADD for importing and filtering XYZ terrain points data. See Sections D.3 and D.4 in Appendix
D for details. With these tools and techniques, you can process very large numbers of terrain
points.
6.2.1 XYZ Coordinate System Selection
You should read the following technical note to see how you can designate the coordinate
system used in your project for compatibility with other software:
http://www.powline.com/products/coordsys.pdf
The project coordinate system can
be defined in the Terrain/
Coordinate System/ Define dialog
shown in Figure 6.2-1a. You can
select the coordinate system
category, coordinate system, grid
shift file if necessary, and define
whether using international or US
Survey foot definition. You can
select the coordinate system to use
as the default coordinate system for
new or existing projects by selecting
the option at the bottom of the
dialog box. This default can be
removed from your project by
visiting the Settings section of the
File/ Preferences menu. The radio
button at the bottom of the dialog
allows you to choose whether
reports containing longitude and
latitude have their conversion based
on GPS and Google Earth datum
WGS84 or the project datum that is
selected in the dialog box.
Fig. 6.2-1a Coordinate System Selection
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6.2.1.1 Coordinate System Reprojection
If you have defined a project coordinate system in the Terrain/ Coordinate System/ Define
dialog then you can use the Terrain/ Coordinate System/ Reproject Project to convert your
entire project to a different coordinate system. You can also reproject other items in the
program such as attachments in the Drafting/ Attachments/ Attachment Manager to the
project coordinate system upon attachment by defining their specific coordinate system when
attaching the item.
Important Note: PLS-CADD performs all calculations in S.I. units even if you have selected
Imperial units in the File/ Preferences. PLS-CADD uses the international foot conversion to
make the conversion to and from Imperial and SI units if you change the selection in File/
Preferences. If you need to convert a project from international foot to survey foot or from SI
units to survey foot then you should use the Terrain/ Coordinate System/ Reproject Project
command to make the reprojection and not the File/ Preferences setting as this can cause the
wrong coordinates to be reported when US survey foot coordinates are used.
6.2.2 GPS Tracking
In version 10.30 and later of the software, Terrain/Enable GPS Tracking leverages the
Windows 7 Sensors and Location platform to integrate a GPS device with PLS-CADD for real
time tracking (panning of all view to the
current GPS position) and logging a
position(leaves a "breadcrumb" trail of XYZ
points). This command does not work in
any other Windows operating system and
the project must have a coordinate system
defined
in
the
Terrain/Coordinate
System/Define dialog box. It requires that
the user have a GPS device attached to the
machine executing the program and this
device support the Windows 7 Location API.
Once enabled the GPS Options dialog box
Figure 6.2-2 GPS Options
shown in Fig. 6.2-2 will appear. This allows
the user to enable different options for tracking and collecting data such as adding certain
feature codes for the xyz data positions and what height to use for the point. The user can use
the elevation from the receiver or use a TIN elevation or have the elevation adjusted for a height
above ground. Another feature is to have a line added along the route that is added to the
annotation in the PLS-CADD project. The last option in the dialog box is to limit the addition of
points or annotation so points are not added on top of one another if the receiver is stationary
over a period of time.
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6.3
Alignment
The alignment (or alignments) of a
project need to be defined before any
engineering can be performed. In the
plan view, the alignments consist of
straight line segments between PI
points (Points of Intersection). If you
start with a XYZ terrain model, the
alignments are defined in the plan view
by selecting the PI points (alignment
corners in Fig. 6.3-1). This is not
required when using a PFL terrain
model since the alignment is implied
(however, the PFL model is limited to a
Y
ALIGNMENT CORNER
SURVEYED POINTS
DISPLAY WIDTH
X
single
alignment).
All
functions
Fig. 6.3-1 Defining Alignment
necessary to create or edit an
alignment are available under the Terrain/ Alignment menu or by clicking on the appropriate
buttons in the toolbar.
In this section we will illustrate many concepts with a simple 13 point XYZ terrain model named
GRID. This example has the shape of a symmetrical pyramid as shown on the right portion of
Fig. 6.3-2. It is provided in the file Grid.xyz included as one of the PLS-CADD examples. Points
1, 2, 3, 4, 6, 7, 8 and 9 are at the base of the pyramid and have an elevation of 100 ft. Point 5 is
at the top with an elevation of 300 ft. Points 10, 11, 12, and 13 are at a 200 ft elevation.
6.3.1 Defining or Editing Alignments on Terrain without Existing Line
The alignment functions operate somewhat differently depending on whether there is already a
line on the terrain or not. In this section, we show how to create an alignment, or several
alignments including branches and loops, when no line exists.
6.3.1.1
Defining or Editing a Single Alignment
For example load the GRID terrain model. Because no alignment has yet been defined on the
GRID terrain, the profile view is not yet available. Therefore, the only window which includes
useful information is the plan view which shows 13 points. Information about the terrain point
closest to the mouse cursor can be seen in the lower status bar.
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Our goal is to create a single
alignment that starts at Point 1,
goes straight to Point 8 and
terminates at Point 6. We will
eventually generate a centerline
profile and four side profiles as
shown in the left portion of Fig. 6.32. The process shown below is
deliberately round-about to illustrate
the main P.I. editing commands
Fig. 6.3-2 Alignment 1-8-6 on GRID Terrain Model
Fig. 6.3-3 Add P.I. Dialog Box
First click on the Add P.I. button on the toolbar (the one with the red + sign) to start creating a
new alignment. Then click on Points 1, 2, 5, and 6 until you see the GRID Alignment 1-2-5-6 of
Fig. 6.3-4. Get out of the Add P.I. mode by clicking on the right mouse button. You now have a
plan view of your entire corridor with five blue lines following the corridor. The outer pair of blue
lines shows the Maximum offset for profile view and the inner pair shows the Maximum offset for
centerline ground profile. Both widths are selected in the Terrain/ Terrain widths menu and are
discussed in Section 6.3.2.
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You can modify your corridor by moving, inserting or deleting alignment points. For example,
click on the Move P.I. button,
click and hold the mouse button
on the third alignment point (Point
5) and drag it to Point 8. Get out
of Move P.I. mode by rightclicking the mouse. Now click on
the Delete P.I. button and click on
Point 2 to get the alignment
shown in Fig. 6.3-5. Click the right
mouse button to get out of Delete
P.I. mode.
Fig. 6.3-4 GRID Alignment 1-2-5-6
Now, click on the Add P.I. button
again. Note that this time, the
Add P.I. command brings up the
Add/ Insert P.I. dialog box shown
in Fig. 6.3-3. This is different from
when we clicked on Add P.I. the
first time because the existence
of an alignment gives us some
options we did not have before.
You can try adding or inserting a
P.I. with each of the options to
see the behavior. You can undo
the addition/ insertion by selecting
Edit/ Undo Terrain/ Alignment/
Add P.I. Again, click the right
mouse button to get out of Insert
P.I. mode.
Fig. 6.3-5 GRID Alignment 1-8-5
When you are done working with the GRID Example, make sure that you do not save it when
you quit PLS-CADD as we will re-use the virgin terrain (without any alignment) again with the
examples of Section 6.3.1.2.
As an alternate to the manual definition of an alignment using the alignment functions defined
above, you can automatically create an alignment through points having specified feature codes
with Terrain/ Alignment/ Automatic Alignment.
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You can reverse the direction of your alignment, that is flip the corresponding Profile view left to
right, with Terrain/ Alignment/ Reverse Alignment.
Whether you create an alignment manually or have one generated automatically through a list
of surveyed points, you have the ability to remove PI's with small angle values with Terrain/
Alignment/ Delete Small Angle PI. You enter the maximum angle value and the maximum
allowed distance for a structure to move.
6.3.1.2
Defining or Editing Additional Alignments
Once you have at least one alignment defined, you can create: 1) other independent
(unconnected) alignments, 2) alignment branches, or 3) alignment loops. These are discussed
in the following examples. When you have multiple alignments you can build lines on all of
them. These lines will be displayed simultaneously in the 3-D views. Structures at the junctions
of several lines will be loaded by all wires attached to them. Additionally, clearances can be
measured between all wires regardless of the alignment they are on.
To create an independent alignment, branches or loops, click on the New Alignment button or
go the Terrain/Alignment/New Alignment to take you to the New Alignment dialog box of Fig.
6.3-6.
Fig. 6.3-6 New Alignments Box
Independent Alignment:
For example, load again the GRID terrain model: make sure it is the original terrain model
without any alignment on it. Create first the alignment 1-2-5-9 following the procedure described
in Section 6.3.1.1. That alignment will be shown in the Plan window (see right of Fig. 6.3-7).
Then click on the New Alignment button and select Independent and Add to End of Profile in
the New Alignment dialog box. Then create the alignment 4-12-8 following the procedure
described in Section 6.3.1.1. This will result in the view on the right of Fig. 6.3-7.
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Once you have defined at least one
alignment, you can open a Profile
window with Windows/ New Window/
Profile View. You can center the
profiles in that view by clicking on the
Init button in the tool bar. You will be
able to see both the Profile and the
Plan windows as displayed in Fig. 6.37 with Windows/ Tile Vertical.
You will note in the Profile window that
the profile of the original alignment (12-5-9) is shown first. After a short gap,
it is followed by the profile of the
second independent alignment (4-128). The length of the gap between the
two profiles is the Station Gap to Insert
Fig. 6.3-7 Unconnected Segments
Between Alignments selected in the
dialog box reached with Terrain/ Alignment/ Multiple Alignment Options.
Open Branch:
For this example, load again the
GRID terrain model (without any
alignment on it). Create first the
main
alignment
1-2-5-13-9
following the procedure described
in Section 6.3.1.1 (make sure you
click on Point 13 this time). That
alignment will appear as shown in
the Plan window at the right of Fig.
6.3-8. Then click on the New
Alignment button and select
Branch and Add to End of Profile
in the New Alignment dialog box.
Clicking consecutively on points 5
and 8 will create the additional
branch 5-8.
Fig. 6.3-8 Open Branch
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After you open a Profile window, you will note that the profile for the additional branch follows,
after the specified gap, that of the original alignment because you had selected Add to End of
Profile in the New Alignment dialog box.
Loop:
Now continue with the open branch
example, click on the Add P.I.
button, select Insert After in the
Add/ Insert P.I. dialog box, click
sequentially on Points 8 and 13, and
OK snapping on the existing P.I. at
Point 13. You have effectively
closed the branch and made a loop
out of it. This is shown in Fig. 6.3-9.
You will note that the Profile window
in Fig. 6.3-9 is identical to that in Fig.
6.3-8, except that you have added
one straight line segment 8-13 to the
profile of the branch. Actually, the
profile continues in a straight line
Fig. 6.3-9 Making a Loop Out of Branch in Fig. 6.3-8
beyond Point 13. Profiles are always
extended for some distance beyond
the last alignment point if terrain points exist in that region.
However, for reasons which will be explained later in this Section, creating a loop by closing an
open branch at the end of the profile should be avoided as it may cause some stringing
problems. Instead, the entire loop should be created from its departure point on an existing
alignment to its reconnecting point using the procedure described in the following example.
Load again the GRID terrain model (making sure again that there is no alignment on it). Create
first the main alignment 1-2-5-13-9 following the procedure described in Section 6.3.1.1 (make
sure you also click on Point 13 this time). That alignment will appear as shown in the Plan
window at the right of Fig. 6.3-10. Then click on the New Alignment button and select Branch
and Insert After Selected Structure or PI in the New Alignment dialog box. Clicking
consecutively on points 5, 8 and 13, and OK'ing snapping on the existing P.I. at Point 13 will
create the loop 5-8-13. This is shown in Fig. 6.3-10.
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If you compare the Plan windows in Figs.
6.3-9 and 6.3-10, they are identical.
However, the Profile windows are quite
different. In Fig. 6.3-9, the profile of Loop
5-8-13 is displayed entirely after the gap
that follows the profile of the main
alignment. In Fig. 6.3-10, the profile of
Loop 5-8-13 taken over the position of the
profile of the main alignment between
Points 5 and 13, and the profile of the
main alignment after Point 5 has been
moved over to the end of the Profile
window. This is because of one
imperative rule that you will need to
observe for loops because of the way you
Fig. 6.3-10 Creating a Complete Loop
will string cables to structures in the
Profile window (stringing is discussed in Section 10.3).
The rule is: when a loop rejoins an existing alignment at a particular P.I., the profiles of all the
paths leading to that P.I. must be displayed before continuing with the display of any profile
beyond the P.I. (remember that alignments are directional, i.e. they have stations that increase
in the direction in which you have created them). For example, in Fig. 6.3-9, the profile of
Segment 13-9 is displayed before the profile of the Loop 5-8-13, which is unacceptable and will
cause stringing problems later on. However, in Fig. 6.3-10, the profile of Segment 13-9 is shown
at the end of the Profile window following all branches leading to P.I. 13, which is necessary to
avoid future stringing problems.
You will understand the need for the rule once you will have learned that structures are spotted
in the Profile window and then cables are attached (strung) to the appropriate structures in that
Profile window. You always string a tension section by starting at a dead end structure and then
you move progressively to the right (you cannot move to the left) in the Profile window in search
of intermediate supports, eventually terminating the stringing at another dead end structure.
When you have a single alignment, the profile displayed in the Profile window is that of that
alignment. When you have more than one alignment, the profiles of all created alignments are
displayed in the Profile window as the profile of a single virtual alignment which is used for
spotting and stringing structures. In Fig. 6.3-7, the virtual alignment is 1-2-5-9-gap-4-12-8 (the
portion 9-4 is not real and is represented by a gap). In Fig. 6.3-8, the virtual alignment is 1-2-513-9-gap-5-8 (with a gap between points 9 and 5). In Fig. 6.3-9, the virtual alignment is 1-2-513-9-gap-5-8-13. Finally, in Fig. 6.3-10, the virtual alignment is 1-2-5-8-13-gap-5-13-9.
To summarize what we have learned about branches and loops, we will look at three more
examples in Fig. 6.3-11. The squares (or pairs of squares) in the figure represent structures at
the end of tension sections (dead ends) and the open circles represent intermediate structures
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(not dead ends). The numbers
shown (ignore the numbers in
parentheses at this time) are
the internal structure numbers,
numbers automatically assigned
by PLS-CADD in the order in
which the structures appear in
the Profile window, i.e on the
profile of the virtual alignment.
The sketch at the top of Fig.
6.3-11 represents a main line
with two taps. The alignment of
the main line was created first
(initial alignment), and then two
open branches were added
(and displayed at the end of the
main line profile) as was done
with the example of Fig. 6.3-8.
12
11
1
2
3
4
INITIAL
ALIGNMENT
BRANCH OR
LOOP
2
1
9
10
(4)8
3
PROFILES OF TWO OPEN BRANCHES ARE
DISPLAYED AT END OF MAIN PROFILE
(5)9
( 6 ) 10 ( 7 ) 11
( 8 ) 12
4
DEAD END
8
7
6
5
5
6
( 9 ) 13 ( 10 ) 14
7
LOOP INSERTED AFTER STUCTURE # 3
NOT DEAD END
1
2
( ) STRUCTURE NUMBER
BEFORE STRUCTURES
ARE ADDED IN LOOP
3
(3)5
(4)6
(5)7
4
LOOP INSERTED AFTER STRUCTURE # 2
Fig. 6.3-11 Spotted Structures on Various Alignments
The sketch in the middle of Fig. 6.3-11 represents a double circuit line with its circuits split on
separate alignments at Structure # 3 and then rejoined them again at Structure # 12 (in the
following discussion we will use the notation # i to denote Structure # i). A main alignment was
created first (following the top branch). In this example, ten structures (# ' s 1, 2, 3, (4), (5), (6),
(7), (8), (9), and (10) ) were first spotted on that main alignment before the bottom loop was
added. Then the alignment for the bottom loop was created as was illustrated with the example
of Fig. 6.3-10. This bottom loop was automatically inserted before the top branch in the virtual
alignment. Therefore, as structures were added to the bottom loop, their numbering system
started with the number 4. Each time one structure was added to that bottom loop, the internal
number of the structures in the top branch and all the structures to the end of the line were
automatically incremented by one. Once all four structures were spotted in the bottom loop, the
numbering scheme for all structures in the tension sections became those shown without
parentheses in the figure. It was then possible to string each circuit separately. For example, the
top circuit was strung from # 1, attaching at # 2 and #3 , passing over # 4 to # 7, attaching at # 8
to # 13 and ending at # 14. The bottom circuit was started at #1, attaching at # 2 to # 7, passing
over # 8 to # 11, attaching at # 12 to 13 and ending at # 14. Note that the sequence of
structures which are attached or by-passed is complete and in ascending order.
The sketch in the bottom part of Fig. 6.3-11 represents a tension section in a main line initially
defined along the alignment following # ' s 1, 2, (3), (4) and (5). A distribution tension section
that starts on a different alignment somewhere to the left of # (3) and joins the main line as
underbuild at # (3) needs to be strung. If the distribution circuit were dead-ended at # (3), then
we could simply create an open branch to the left of # (3) and string one tension section along
that branch through structures that would be numbered 6 and 7. Another tension section would
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be strung from # 3 to # (5). However, because the distribution is not dead ended at # (3), it is
necessary to make the distribution branch part of a loop that starts somewhere before # (3). We
arbitrarily started the loop at # 2 and closed it at # (3). As the two distribution structures # 3 and
# 4 were added, the structures in the main line were renumbered 5 to 7 as shown. Then the
distribution could be strung from # 3, attaching to # 4, #6, # 7 and ending at # 7.
Multiple Alignment Display Options:
You have several display options for multiple alignments that can be selected in the Multiple
Alignment Options dialog box that you reach with Terrain/ Alignment/ Multiple Alignment
Options.
6.3.1.3
Display Options for PI, Alignment, Right of Way
You can control the color and appearance in the Plan view of the different sections of an
alignment using the Terrain/ Alignment/ Display Options for PI, Alignment, Right of Way
table shown in Figure 6.3-11a below. This table includes twelve columns in the table and view
controls for the items in the table. The items in the table are as follows:
X, Y, Z:
X, Y, Z coordinates of the PI
Station:
Station of PI
Alignment Number:
Number of the alignment. If you have multiple alignments the
number will increment depending on the order you entered the
alignments.
Line Angle:
Angle of the PI
Closest Structure:
Structure number of the closest structure to the PI
Stationing to Closest Str.:
Station Distance to the Closest Structure. Should be zero if the
structure is located on the PI
Label:
Descriptive label for the ahead section of the alignment from the
PI Symbol/Leader Line
Color:
Self Explanatory
PI Leader Line Style:
Self Explanatory
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Ahead Segment Line
Color:
Self Explanatory
Ahead Segment Line
Style:
Self Explanatory
Right of Way Left Offset:
Distance left of centerline in the direction of negative offset to draw
a parallel line to represent the right of way.
Right of Way Right
Offset:
Distance right of centerline in the direction of positive offset to draw
a parallel line to represent the right of way
Right of Way Line Color:
Self Explanatory
Right of Way Line Style:
Self Explanatory
This table gives a list of each segment of an alignment from PI to PI. You can choose the color
and line style for these segments and PI’s and also a user defined label. The label will then
appear in certain reports such as the Terrain/ Alignment/ PI Report. A new project will default
to a blue solid line with no labels in the Plan view with Pink PI’s. A right of way line can also be
displayed that is parallel to the centerline of the alignment. The views in which the alignment is
seen is controlled by checking on or off the options at the bottom of the dialog box. This tool
can be useful when working with multiple alignments.
Figure 6.3-11a Display Options for PI, Alignment, Right of Way
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6.3.2 Maximum Offsets and Center Line Profile
Values for the Maximum Offset for Profile View (MOPV) and the Maximum Offset for Centerline
Ground Profile (MOCGP) are selected with Terrain/ Terrain Widths.
All ground or obstacle points within
the MOPV (measured from the
center-line) are displayed with the
GROUND
appropriate symbols in the various
PROFILE
WIDTH
profile views, whether on screen or
PLAN VIEW OF THEORETICAL GROUND PROFILE LINE
on a sheet of paper. Points outside
the MOPV are not displayed in the
Profile views. In addition, any
SMALL
structure or wire with an offset
PLAN VIEW OF SELECTED GROUND PROFILE LINE
greater than MOPV will not be
shown in the profile view. Once
you have an alignment defined on
LARGE
an XYZ terrain model, you can
create an equivalent PFL model by
Fig. 6.3-12 Definition of Centerline Ground Profile
using the File/ Save as command
and specifying a .pfl extension that tells the program that model should be saved as a PFL file. If
you create a PFL model this way, points that cannot be projected on the alignment will be lost.
These points are located outside the angle formed by the two lines perpendicular to the
alignment at a P.I. and on one side of the alignment. We generally do not recommend that you
save an XYZ file with its alignment as a PFL file.
The center-line is defined in the plan view as the collection of straight line segments connecting
alignment corners. The center-line ground profile is theoretically the intersection of vertical
planes going through the center-line and the ground. However, because the terrain data are
only defined at discrete points within the line corridor, there is a need for rules to define how the
profile is displayed on the screen and on drawings. The ground profile line displayed by PLSCADD is a line that joins all ground points within a specified offset from the center-line. That
offset (MOCGP), is shown in Fig. 6.3-12 for two widths. The points are joined in ascending order
of stations. For example, if one selects a MOCGP of 10 ft, then the profile line will pass through
all the points within 10 ft of the center-line. If there is significant side slope (perpendicular to the
line) the line profile may look jagged when it joins points of significantly different elevations on
alternate sides of the center-line. If the jaggedness of the profile line is objectionable, one may
draw separate side profiles as described later in this section. Or better, one may generate
additional interpolated center line and side profile points using the Triangulated Irregular
Network (TIN) model of the terrain as described in Section 6.4.
To illustrate the effect of selecting various MOPV and MOCGP values on the profile line
corresponding to the alignment in Fig. 6.3-5, open a profile view with Window/ New Window/
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Fig. 6.3-13 Small MOGCP and MOPV Widths
Profile View and tile both the plan and profile windows using Window/ Tile Vertical. Your
screen should look like Fig. 6.3-13 for a MOPV of 50 ft and a MOCGP of 10 ft (the default
values). The profile on the left of Fig. 6.3-13 is for an aspect ratio of 10. The aspect ratio of an
active profile view can be changed with Drafting/ Profile View Aspect Ratio. Note that this
command is only available if the Profile view is your active window. You will note that the profile
is flat between Points 1 and 8 because there is no intermediate point within an offset of MOPV
between these two points. The profile is obviously not correct but it is consistent with the
scarcity of ground points in the XYZ model. You will also note that nearby points (Points 10 and
12) are not visible in the profile view because they are outside the MOPV.
To get the views of Fig. 6.3-14,
change the MOPV to 300 ft and the
MOCGP to 200 ft in Terrain/ Terrain
Widths. The profile line is no longer
flat between points 1 and 8 and some
distant points (Points 4 and 5) are
now visible. However, the profile line
is still far from correct. As will be
shown in Section 6.4, a TIN model of
the terrain will be used to produce the
best possible profile for the given data
as shown on the left portion of Fig.
6.3-2.
Fig. 6.3-14 Large MOGCP and MOPV Widths
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Figure 6.3-15 below shows a transverse cross-section of an alignment and the different values
that can define how the profile view will appear.
Figure 6.3-15 Transverse Cross Section of Alignment Looking in Direction of Increasing Stationing
*
The centerline of the defined alignment. The centerline of the structures can differ when
using offset adjustments at structure locations.
A
Maximum Offset For Profile View (MOPV). Any points outside of this distance will not be
visible in the profile view.
B
Negative Offset for Side Profile. Defined in the Terrain/ Side Profiles table.
C
Positive Offset for Side Profiles. Defined in the Terrain/ Side Profiles table.
D,F
Offset tolerance for side profile. Only ground points with a plan distance less than the
“max separation” defined in the Terrain/ Side Profiles table will be joined together in the
profile view when the display is turned on.
E
Maximum Offset for Centerline Ground Profile (MOCGP). Similar to D and F for side
profiles. If this value is too large a saw tooth like profile will be produced and if set too
small the profile may omit vital features.
For the best results the values for D, E, and F should be set small and create interpolated points
based on the TIN surface.
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6.3.3 Editing Alignment when there is a Line on the Terrain
If a line model already exists, you
should be careful when Inserting
NEW POSITION FOR
an alignment point off the current
STRUCTURE # 4
centerline, as you will no longer
have a structure at that alignment
point and you will no longer have
#4
the same span lengths between
#6
the two alignment points on either
#3
#5
sides of the one you inserted.
TANGENT STRUCTURE
However, you can select any
#1
structure, move it and make an
alignment point out of it. You can
#2
AFTER STRUCTURE MOVE
also add an alignment point at the
BEFORE STRUCTURE MOVE
end of the line. Whether you insert
a new alignment point or make an
alignment point out of a moved
Fig. 6.3-15 Moving a P.I.
structure, the connectivity between
cables and structures of the present design is preserved, but not the span lengths. The
connectivity can only be changed with the Sections/ Modify command. With the Move P.I.
command, you are able to select an existing structure and drag it to a new location that
becomes a new alignment point. For example, in Fig. 6.3-15, Structure #4 was selected and
moved to a new location. The center-line between the start of the line and Structure #2, and
between Structure #5 and the end of the line are not affected by the move. However, the centerline between Structure #2 and Structure #5 is changed. Structure #3 (a tangent structure)
follows the move of Structure #4 in such a way that its distances to the alignment points at
Structures #2 and #4 remain in the same proportion before and after the move. After a structure
is moved, you should check your design in a profile view.
With the Delete P.I. command, you can click on a structure at an existing alignment point and
remove it from the alignment, i.e. make it a tangent structure on a straight line between the
previous and next alignment corners. The command Terrain/Alignment/Delete P.I. Range...
can delete a P.I. range as long as the alignment segments don't have structures spotted. The
feature will also delete all P.I. points that are shared between different lines within Lines/Edit....
For example, load the Demo line by selecting the Demo.xyz file. Tile the plan and profile views
as shown in Fig. 6.3-16. Small squares show where existing structures in the line are located.
Larger squares indicate current alignment points. You should be able to see six grid points in
the quadrant to the right and above Structure # 6. Any one of these six points can be snapped
onto in order to relocate the line in the quadrant.
If you want to re-route the line so that the alignment passes through point FICT6 (top right
point), select Move P.I., click on Structure # 6 and drag it to ground point FICT6 (Fig. 6.3-17)
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and then release the mouse button Because the demo.xyz terrain does not have any point
within the MOCGP along the new corridor between Structures # 3 and # 10, the profile along
that new corridor is made up of long straight line segments.
You will note that the number of structures and spans between Structure # 3 and Structure # 10
is preserved. If you were to use File/ Save (don't do this or you will need to re-install the
examples), the Demo line design would be updated in such a way that the terrain and design
are unchanged before Structure # 3, but the terrain and spans between Structures # 3 and 10
would be new. Remember: Do not save any of the changes you make to the Demo example or
any other example or you will need to re-install them if they are to appear as described in this
manual.
You can use Edit/ Undo Terrain Alignment/ Move P.I. to bring back the Demo line from its
state in Fig. 6.3-17 to that in Fig. 6.3-16.
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Figure 6.3-16 DEMO Line before Re-routing
Figure 6.3-17 DEMO Line after Re-routing
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6.3.3.1 Alignment Survey Point Snap
Figure 6.3-18 shows the Terrain/ Alignment/ Survey Point Snap dialog that allows the user to
select a Snap Mode as well as a Structure Position Lock when creating or editing alignment. In
the Snap Mode section you can choose to only create or move PI’s on existing survey points by
selecting the Snap to survey point option. You can also limit the feature code you will allow the
PI to snap to by checking the Limit snap feature. If you want to place PI’s freely without
snapping to existing XYZ points you can select the Do not snap option. When you select the Do
not snap option the program will create a xyz point at the selected XY location you select with
the mouse with the feature code you identify in the dialog box. You can either edit the point
prior to accepting the point or you can also interpolate the z of the point via either a TIN model
or from the closest XYZ point to the point selected.
In the Structure Position Lock section of the dialog you can choose whether or not moving a PI
with a structure influences adjacent tangent structures between the PI being moved and the
other PI’s. If you choose the locked option the adjacent structures will remain in their current
position after moving the PI in question by inserting new PI’s at the adjacent structures’
locations. If you choose unlocked then the tangent structures will move to stay in line with the
new PI’s location with the two adjacent PI’s. The change in distance between the PI’s and their
new locations will be distributed equally among all of the tangent structures. When working in
the Plan view and using the Move PI command you will see rubber band lines showing the
proposed alignment location with the options selected in this dialog. You can toggle between
the locked and unlocked options while in the Move PI command by hitting the “L” key and you
will see the rubber band lines automatically update as you change this setting.
Figure 6.3-18 Alignment Survey Point Snap
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6.4
Triangulating XYZ terrain - TIN model
6.4.1 Triangulated Irregular Network (TIN)
The XYZ terrain model
used
by
PLS-CADD
consists of individual
points
with
their
coordinates and feature
codes. The Triangulated
Irregular Network (or TIN)
model of the XYZ terrain
is a surface made up of
triangles
having
the
terrain points at their
apexes. PLS-CADD can
automatically create the
TIN model of an XYZ
terrain using Delauney
triangles. For example,
Fig. 6.4-1 shows the TIN
model of the XYZ terrain
Fig. 6.4-1 TIN Model of Demo Line Near Towers #5 and #6
of the Demo line near
Structures # 5 and 6. The primary advantage of a TIN model over the basic XYZ model is that it
is a surface and not a collection of points. That surface can be used to generate accurate center
line and side profiles, to find the elevations of arbitrary points or to locate points at the
intersection of latticed tower legs or guys with the ground. The TIN surface can be rendered in
different colors to give a more realistic display of the ground, including elevations and light
incidence (Fig. 6.4-3). Bitmaps (aerial photographs) can be projected onto it to give an even
more realistic appearance of the terrain (Fig. 6.4-3).
6.4.2 Creating, Saving, Loading or Deleting a TIN Model
The TIN model shown in Fig. 6.4-1 was created by first opening the demo.xyz file, maximizing a
Plan or 3-D view to be able to see the triangulation process, and going to the Create Tin Model
dialog box with Terrain/ TIN/ Create TIN. In the Create Tin Model box we chose to visualize
the progress of the triangulation and to exclude points with zero elevation, and we selected 300
ft for both the maximum offset and the maximum triangle edge width. The triangulation proceeds
as soon as you click on OK at the bottom of the Create Tin Model box. In order to see the final
result of the triangulation you must be in a Plan or 3-D window and check the Unrendered
triangle outline option under Terrain/ TIN/ Display options. Displaying TIN triangles or
rendering the TIN model is specific to a particular window. For example, the TIN triangles can
be displayed in one window (see right of Fig. 6.4-2) and not displayed in another window (left of
Fig. 6.4-2).
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Fig. 6.4-2 Plan Views W/WO Display of TIN Terrain Triangles
Once you have created a TIN model, you can optionally save it in the Project.tin file using the
Terrain/ TIN/ Save TIN and reload it in memory at a later time with Terrain/ TIN/ Load TIN.
You can use Terrain/ TIN/ Delete TIN to remove the TIN model from memory. When working
on a slow computer with insufficient memory it may be advantageous to delete the TIN model
once it is no longer required (when TIN display and cutting new profiles are no longer needed)
but this is rarely necessary with modern computers.
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6.4.3 Displaying TIN Model
Fig. 6.4-3 Various Renderings of a TIN Model
Using the Terrain/ TIN/ Display options menu, you can select several options for visualizing
the TIN model. To use this feature your display should be set for at least 16 bit color (65536
simultaneous colors) and 24 bit color (16777216 simultaneous colors) is recommended
Fig. 6.4-3 shows the effect of choosing certain options in the TIN Display Options box:
1)
2)
3)
4)
Unrendered triangle outlines (upper left corner)
Contour lines interval of 5 ft (upper right corner)
Rendered triangles - Color by elevation, intensity by incidence (lower left corner - original
is in color even though Fig. 6.4-3 is black & white)
Rendered triangles - Color by bitmap, intensity by bitmap (lower right corner – this
requires that a bitmap be attached to the plan view as described in Section 6.5)
Fig. 6.4-4 shows the dialog box for the Ground TIN Display Options.
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Figure 6.4-4 Ground TIN Display Options
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Unrendered Triangle Outline: shows the TIN triangles by drawing them with thin green lines
Render Triangles: Draws the terrain as realistically as possible based on the selections in the
Rendering Options section of the dialog box
Show Break Lines: Shows the break lines by drawing them as thick green lines
Show triangle vertices: Shows the vertices of the triangles in the TIN
Rendering Options: Options for colors or bitmaps when the render triangles option is checked.
If one of the color by slope options are selected then you can choose the color and
range for the different slope intervals. You can also choose the option to report the
horizontal triangle area in each slope category if you have the Generate report option
selected. You can also select the opacity level of the TIN when rendered. The opacity
is most useful with the wire surface TIN that is created for clearances as discussed in
section 11.2.3.1.
Show contour lines: Displays lines of constant elevation using the options selected below the
check box including the contour interval, label, and station interval for labels. You can
check the box to draw tick marks on the low side of the contour which makes it easier to
see which side of contour is higher.
Z value adjustment: Allows you to shift the display of the TIN display up or down by the input
value. This can be used to visually detect areas where a structure or wires are a certain
distance above the ground. This shift does not influence any of the calculations such as
clearance to the TIN. It is only a visual shift.
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6.4.4 Creating Interpolated Ground Points
One of the powerful uses of a TIN model is the generation of terrain points which are located on
the center line and side profiles. For example, open the grid.xyz file, define a 1-8-6 alignment as
described in Fig. 6.3-5, and create a TIN model excluding points with offsets larger than 1000 ft
and deleting triangles with sides longer than 1000 ft. If you chose to display the unrendered
triangles, they will appear as 16 green triangles as seen on the right side of Fig. 6.3-2. At this
point, your XYZ terrain consists of only 13 terrain points and the associated TIN model consists
of 16 triangles.
Now click on Terrain/ TIN/ Create interpolated points, select 200 (typical ground point) for the
feature code of the new interpolated points, ask to create interpolated points at offsets of -40 ft, 20 ft, 0 ft, 20 ft and 40 ft, and ask to create these interpolated points only on triangle legs shorter
than 1000 ft and with an elevation change of less than 1000 ft. You will note that 57 new points
are added to the XYZ model. You can track these points with the mouse or see them with
Terrain/ Edit/ Edit XYZ. These so called TIN points, with the description TINPT, are located at
the intersections of the sides of the triangles and vertical planes passing through the center line
and at offsets of -40, -20 , +20 and +40 ft from the center line. Now your XYZ terrain consists of
70 points, the original 13 plus the additional 57 located within 40 ft of the centerline.
Now go to the Terrain/ Terrain Widths dialog
and set MOCGP to 1 ft and MOPV to 50 ft. Go
to the Terrain/ Side Profiles table and set the
values as shown in Fig. 6.4-5.
If you open a Profile window using Window/
New window/ Profile, you will see color-coded
center line and side profiles as displayed on
the left side of Fig. 6.3-2. These are accurate
centerline and side profiles for the grid.xyz
terrain. They are certainly better than those
shown in Figs. 6.3-13 and 6.3-14.
Fig. 6.4-5 Side Profiles Table
6.4.5 Adding XYZ Points
The TIN model can be used to create XYZ terrain points with selected combinations of X and Y
coordinates. For example, select Terrain/ TIN/ Add point at X,Y and click on the location in the
plan view where you want the point to be created. A dialog box will let you edit the X and Y
coordinates of the point which you have selected, its feature code and the height of the obstacle
(if any is located at the point). The created point will be on the surface of the TIN model, i.e. its
elevation will be computed at the intersection of the vertical line at the X, Y location with the TIN
triangle (shown in red) at that location. If there is no TIN available you will be prompted for the
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Z value.
You can turn off the red highlighting of the triangle with View/ Markers/ Clear
Markers or the F5 key.
6.4.6 TIN Interpolation of Z
The TIN model can be used to convert above ground points like wire and vegetation shots
specified with X,Y,Z into points specifed as X,Y,Z (of TIN ground), H (height above ground)
using the Terrain/ TIN/ TIN Interpolation of Z and H for Non Ground Survey Points
command. This can be helpful when sorting points by height.
The TIN model can also be used to interpolate ground elevation for items that have a Z value of
0. The Terrain/ TIN/ TIN Z Interpolation for Z=0 Survey Points, PIs, Polygonal Constraints
or XY Based Structures command will do just as stated in the command and interpolate the
TIN value of Z for any of the items that have a value of 0 for Z.
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6.5
Break Lines
Break lines (or break line segments) can be used to enhance XYZ terrain models. While break
lines can be defined and displayed entirely by themselves, they are most useful in conjunction
with XYZ terrain points and TIN models.
A break line or break line string consists of break line segments. Each segment is a straight line
with known origin and end points. The location of each segment in 3-Dimensions is fully known
from the global coordinates X, Y and Z of its two end points. All break line data associated with
a given project are included in an ASCII file with a record for each break line segment as
described in Appendix D. The file must have the extension ".brk" to be recognized as containing
break line information. A break line file is referred to herein as a BRK file. Break line segments
which have one end in common are said to be part of the same break line string. Upon saving a
project model, all break lines associated with the project are saved in the file named Project.brk.
Several options are available for defining/editing break lines:
1)
Use Terrain/ Break Lines/ Import Break Lines from DXF Attachment to create break
lines from line and polyline entities in an attached DXF file. Since most commercial
terrain modeling packages can export their break lines to DXF this is a very quick and
easy way to import their break lines.
2)
Use Terrain/ Break Lines/ Import Break Lines from SiteWorks File to read points in
from a SiteWorks® file. The format of this file is described in the dialog box which
appears when this option is selected from the menu.
3)
Use Terrain/ Break Lines/ Load BRK File to load an externally created break line file.
See Appendix D for details on the file format.
4)
Use the Add or Delete Break Line commands under the Terrain/ Break Lines menu to
interactively add or delete break lines. The Add Break Line command will automatically
snap to the closest XYZ point so you will need to create XYZ points for your break line
end points if they don’t already exist. To create a string of break lines you need only click
on XYZ points in the order you want to connect them. To terminate a string and start a
new one simply press the Enter key. For example, to create two strings use Add as
follows. Click on the origin of the first break line string, click successively on each end of
its adjacent segments, and terminate the sequence by pressing the Enter key. Then
click on the origin of the second string, click successively on the ends of each of its
contributing segments and press Enter. Then right click the mouse to get out of the Add
Break Line function.
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6.5.1 Using Break Lines to Enhance XYZ Terrain Models
To illustrate the interactive use of
break lines to enhance an XYZ
terrain model, we will work with the
simple 14 point terrain (called
BREAK.XYZ) provided on the
Examples diskette. The model
describes a highway embankment
built above the original ground.
Points A, B, E, F, AM, AT, BT, ET
and FT are on the original ground
and points C, D, CM, CT, and DT
are surveyed points along the
edges of the highway embankment.
Using the functions described in
Fig. 6.5-1 Original TIN Model without Break Lines
Section 6.4.2 and deleting only
triangles with legs larger than 10,000 ft, we get the TIN model shown in Fig. 6.5-1. Contour lines
displayed at 2 ft intervals show that the various TIN triangles do not provide a realistic
representation of the highway embankment. This is because there are not enough surveyed
points along the base and top edges of the embankment. A profile cut across the triangles of
Fig. 6.5-1 will not be correct.
But if we now create: 1) a break line
segment between B and BT, 2) a
break line string between C, CM
and CT, 3) a break line segment
between D and DT, and 4) a break
line segment between E and ET,
then the TIN model is enhanced as
shown in Fig. 6-19, with 2 ft contour
lines displayed parallel to the
embankment edges. Profiles cut
across the triangles of Fig. 6.5-2 will
be correct.
Once the break lines are defined,
PLS-CADD can re-triangulate the
Fig. 6.5-2 Enhanced TIN with Break Lines
terrain in their vicinity so that
triangle edges always coincide with the break lines. This is done as if new XYZ points were
added at selected locations along the break lines.
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6.5.2 Using Break Lines to Describe Existing or Planned Facilities
Fig. 6.5-3 shows a
portion of a larger
terrain described by
over 80,000 break
line segments and
an
even
larger
number
of
XYZ
points. Some of the
break
lines
correspond to yet
un-built but planned
road improvements.
Fig. 6.5-3 Break Lines and Terrain Points
Fig. 6.5-4 shows the
TIN model of the
terrain in Fig. 6.5-3,
from
which
the
detailed center line
and side profiles
were generated.
Fig. 6.5-4 TIN Model of Terrain in Fig 6.5-3
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6.6
Terrain Attachments
Vector drawings and raster images can be overlaid on PLS-CADD views. These overlays can
be attached to a Plan view (Fig. 6.6-1), a 3D view, a Profile view (Fig. 6.10-1), a Plan & Profile
(P&P) sheet view (Fig. 13.1-4) or named Inset View. Attachments to a Plan or Profile view also
appear in the corresponding plan and profile sections of the P&P sheets. The following file
formats are supported as attachments.
Vector
drawings
Raster
images
.dxf - Drawing eXchange Format
.shp - Shapefile format
.bmp - Windows Bitmap format
.tiff - Tagged Image File Format
.jpg - Joint Photographic Experts Group (JPEG)
.j2k, .jp2,.j2c, jpc - JPEC 2000
.ecw - Enhanced Compressed Wavelet
.pgn - Portable Network Graphics
This section primarily discusses attachments to Plan views. Attachments to Profile and P&P
sheets views are discussed in more detail in Sections 6.8 and 13.2.2.
Fig. 6.6-1 DXF and Raster Plan Attachments
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Typical uses of the attachments are:
Plan View attachments:
Aerial photographs, planimetric maps
Profile View attachments:
Phasing diagrams, scanned drawings of existing line
Sheets View attachments:
Drawing borders, title block, company logo,
representations of older drawings
Inset View attachments:
Standard Drawings or Details
scanned
Because they generally do not include elevation information, DXF or raster images overlays do
not appear correctly in 3-D views. For example, the DXF drawing in Fig. 6.6-2 is displayed at
zero elevation while the line itself is shown at the correct elevation. If the DXF file contained
elevation information, then it would be displayed at the correct elevation.
The Attachment Manager dialog box accessed through the Drafting/ Attachments/
Attachment Manager and shown in Figure 6.6-1a gives the user access to the commands to
Attach a file, Detach the file, Show the attachment in the project, Hide the attachment in the
project, Options for each attachment discussed below, Order which allows you to reorder the
Figure 6.6-1a Attachment Manager
files in the attachment manager, Report which will generate a report of all the attachments in
the project, Open command which will open the attachment using the default program in
Windows Explorer, WMS which opens the web mapping services import dialog discussed in
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section 6.6.5, and Refresh which reimports the files that were downloaded previously using the
WMS capabilities, Compress raster files to .ecw files and OK will accept and close the dialog.
You can also reorder the attachments in the dialog box by right clicking on the file which will
highlight the selected file green and then you can drag and drop it to the location you would like.
There is also a Select portion that allows you to select all the attachments or select the
attachments based on whether they are vector or raster attachments. If you have downloaded
attachments using the WMS capabilities you will be able to select the WMS images based on
the time the images were downloaded.
Many of the button commands are also available by right clicking on the particular attachment in
the list. One such command that is not represented by a button is the Relocate command
which moves the attached file to a new location of your choosing.
Fig. 6.6-2 Zero Elevation DXF Overlay
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6.6.1 DXF Drawings
DXF drawings, with the .dxf file extension, are
normally generated in a CAD or mapping
system. They can be attached and overlaid to
plan or profile views using Drafting/
Attachments/ Attachment manager which
opens the File Attachments box shown in Fig.
6.6-3. When attached to a plan view, the X,Y
coordinate system (Z is elevation) used to
describe the DXF drawing should be the same
as that used to describe the PLS-CADD XYZ
terrain points. When attached to a profile view,
the X and Y coordinates of the DXF drawing
should be the same as the stations and
elevations of the PLS-CADD alignment. When
attached to a P&P sheets view, the X,Y DXF
Fig. 6.6-3 Overlays
coordinates should coincide with the local x
and y coordinates of a single page (zero at lower left corner of page, x to right and y up). Once a
drawing is attached, you can show it or hide it by clicking on the appropriate button at the
bottom of the File Attachments box. When you Save a project, all attachment information is
saved in the Project.don file. Therefore, when you re-open an existing project, it appears with all
its attachments.
Once a DXF drawing is attached for the first time, you are taken directly to the DXF Overlay
Options dialog box shown in figure 6.6-3a. If a DXF has already been attached, you can get to
the DXF Overlay Options box by clicking on the Options button at the bottom of the File
Attachments box (Fig. 6.6-3).
Figure 6.6-3a DXF Overlay Options
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At the top of the DXF Overlay Options dialog box you are able to see the location of the file
that is being attached. Below this you can choose which view you wish to attach the DXF. You
can choose whether the file is attached to the Plan View, Profile View, P&P View, Inset View,
or for the North Arrow in the P&P View. Each of these options allow you to pick whether the
file is in feet or meters except for the sheets view which are based on paper space so the units
are in cm or inches.
If the Plan View is selected you will be able to define the following information:
- The option to display the attachment in the Plan View, Plan Sheets and Inset Views,
and/or Sheet Index Map
- Various options for the display of the DXF relating to text size, colors, line styles, paper
space, etc.
- If the apply additional scale factors and rotations is checked you will be able to input
items shown in Fig. 6.6-4 below for DXF Advanced Transformations.
- Choose whether the attachment should be included in the extents of the view when
doing a view initial.
- The attachment coordinate system. If it is different than the project coordinate system it
will automatically be reprojected to fit the defined project coordinate system.
- At the bottom of the dialog will be a table of the layers in the dxf file with the type of
elements contained in the layer as well as the color of the layer. You can use the
Display column to turn on or off the display of the layer in the attachment.
If, when you OK the DXF Overlay Options box, the Advanced transformation check box is
checked, you are taken to the DXF Advanced Transformations table shown in Fig. 6.6-4.
Fig. 6.6-4 DXF Advanced Transformations Table
In most cases you should simply exit the DXF Advanced Transformations table by clicking on
OK. In some cases you might find the need to translate the DXF drawing parallel to the X, Y or
Z directions, rotate it about the X,Y, or Z axes, or expand or contract it in any of the three
directions. You can enter a series of translations, rotations and scales in the table.
However, rather than using the DXF Advanced Transformations table, the most common
adjustments to a DXF can easily be accomplished with the following two commands:
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Drafting/ Attachments/ Move lets you slide the entire DXF drawing without any rotation so that
the first point which you select on the DXF coincides with a second point which you select on
the plan view.
Drafting/ Attachments/ Stretch lets you adjust the entire DXF drawing so that two selected
points on the DXF coincide with two corresponding points on the plan view. This should only be
made for slight stretching adjustments. If the CTRL key is held down the stretch will preserve
the aspect ratio of the original attachment when stretched.
If the Profile View is selected you will be able to define most of the same information as the
Plan view except Plan specific items that are no longer selectable including the coordinate
system.
If the P&P View is selected you will be able to make the same selections as the plan view
except for the coordinate system and you will also be able to select whether to attach the image
to All Sheets, a Single Sheet, All Title Sheets, All Note Sheets, All Drawing Sheets, or All
Appendix Sheets. If a Single Sheet is selected you will be able to choose which specific sheet
to attach it to which also identifies which subsection (Title, Notes, Drawing, Appendix) that this
sheet is related to.
If the P&P North Arrow View is selected you will be able to define most of the same
information as the Plan view except Plan specific items that are no longer selectable including
the coordinate system.
If the Inset View is selected you will select the name Inset View in which the vector drawing will
appear. The DXF file is automatically centered and scaled to fil the inset view while preserving
the aspect ratio.
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6.6.2 Raster Images
Like DXF files, raster images or bitmaps in BMP,
TIFF, JP2, JPG, ECW or PNG formats can also be
attached to a Plan, Profile, 3D, Inset, or Sheet
View. Raster images in other formats such as SID
and others can be converted to one of the
supported formats using inexpensive paint
programs such as Paint Shop Pro. Additional
information regarding working with image
attachments can be found in our technical note:
http://www.powline.com/products/photos.html
The bitmap (BMP) format is the standard
WINDOWS representation of a raster image. It
supports only minimal compression (lossless) and
will result in very large file sizes. However, almost
all WINDOWS programs can read and write BMP
files. TIFF (Tagged Image File Format) is an
alternate raster format that has wide acceptance
and substantially better compression (typically
lossless) than BMP files as well as much more
flexibility in terms of the bit depth that the images
may be saved in. Therefore, TIFF files can be
much smaller than the equivalent BMP file. PLSCADD also supports the GeoTIFF variant of the
Fig. 6.6-5 Raster Image Parameters
TIFF format. ECW is a proprietary image file
format developed by ERMapper (http://www.ermapper.com). ECW offers extraordinary
compression frequently achieving compression ratios of 25:1 or even greater. This compression
is lossy; however, image degradation can be controlled by the user and is normally insignificant.
The JP2 format is discussed in the above-mentioned technical note. Portable Network Graphics,
PNG is a lossless file format designed to handle detailed, high-contrast images well. PLSCADD can convert a TIFF or BMP file to an ECW or JP2 file using the Compress button in the
Attachment Manager in Fig. 6.6-3.
Regardless of which format is used, PLS-CADD will internally need to convert the image to a
bitmap in order to draw it, so your computer should have as much RAM as you can afford. If you
have a large quantity of aerial imagery, PLS-CADD will be most efficient if that imagery is stored
in ECW or JP2 files.
When attached to Plan views, raster images are attached in the same manner as DXF files
except that you will be taken to the Bitmap Options dialog box (Fig. 6.6-5). The Bitmap
Options box lets you select: 1) whether to overlay the raster image on top of Plan, Profile,
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P&P, Background Plan, Background 3D, Background Profile, Inset View, or Plan View
Vertical Plane views.
If the Plan View is selected you will be able to define the following information:
- The attachments coordinate system. If it is different than the project coordinate system it
will automatically be reprojected to fit the defined project coordinate system.
- The option to display the image in the plan views of the Plan View, Plan Sheets and
Inset Views, and/or Sheet Index Map
- The transparency options allow you to make the image opaque, transparent (see
through pixels approximating the background color), or transluscent by setting the
degree of translucency between 0 (fully transparent) and 255 (opaque).
- The bottom section allows you to set the X, Y and Z coordinates of the upper left corner
of the image, the image width and height, and rotation angle.
If the Profile View is selected you will be able to set the transparency options as mentioned
above and the coordinates of the upper left and size of the image.
If P&P view is selected you will be able to select whether to attach the image to All Sheets, a
Single Sheet, All Title Sheets, All Note Sheets, All Drawing Sheets, or All Appendix Sheets. If a
Single Sheet is selected you will be able to choose which specific sheet to attach it to which also
identifies which subsection (Title, Notes, Drawing, Appendix) that this sheet is related to.
If one of the Background options is selected you will be able to set the transparency options of
the background image as well as its location specifics in the view based on the % of the view
width and height.
If the Plan View Vertical Plan is selected you will be able to input the same information as the
Plan View above plus the azimuth angle of the image which identifies the direction the image
was taken from. This will orient the image in the 3D view in the direction at which the image
was taken.
If the Inset View is selected you will be able to select the named Inset View you would like the
image attached to as well as the coordinates of the upper left and size of the image. These
coordinates are based on 0,0,0 being in the upper left of the Inset View. This is similar to how
an image is placed in the P&P View.
In some cases the values of the coordinates of the upper left corner of the bitmap, the bitmap
height and width, as well as the bitmap rotation angle can be determined automatically. One
such case is when you are attaching a scanned Plan & Profile sheet for digitizing purposes as
described in Section 6.8. In such a case the required values are calculated automatically as part
of the calibration process. Another case where PLS-CADD fills-in the values automatically is
when you are working with aerial photography and have a world reference file such as a TIFF
World File. These files contain georeferencing information such as the resolution and location of
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the image. PLS-CADD identifies a World File by its file extension. The World File must have the
same base name as the image and one of the following extensions: ".TFW", ".BFW", ".JDW" or
".SDW". Whenever an image is attached, PLS-CADD will look for a World File with the same
base name and in the same directory as the image. If PLS-CADD finds a World File, it will
attempt to read it and fill-in the values automatically. PLS-CADD does support the GeoTIFF
standard and will read georeferencing information directly from a GeoTIFF.
By default (can be overridden in F1 menu) raster images are not shown in 3-D views since they
are inherently 2-dimensional with the Z coordinate of each pixel unknown. However if plan view
vertical plan is selected as the attach to view then the program will read the azimuth angle from
the Bitmap Options dialog box and place the raster image in the 3D view oriented about the
vertical axis. The azimuth angle allows you to identify the direction the camera was taking the
image from. If you rotate the 3D view of the model and get to the back of the image that has an
azimuth angle entered you will not see the image when viewing from behind the image. Instead
you will only see a frame of the image. Many new GPS enabled cameras as well as
smartphone cameras have the ability to include an azimuth angle when the picture is taken.
If the Hide option in Fig. 6.6-3 is selected for a bitmap when the project is saved, that hidden
bitmap will not be loaded in memory when the project is re-opened, even though it will still be
listed in the Attachment Manager dialog. The bitmap will only be loaded in memory once you
change the option to Show.
Important note: Because bitmaps occupy large amounts of memory, judicious use of the Hide
and Show options lets you handle cases where it is not feasible to have all attached bitmaps
resident in memory at the same time.
The Optimize image draw for text or line work rather than aerial photography option in the
Bitmap Options dialog box of Figure 6.6-will improve the fidelity of text or line items in images.
This is not appropriate for aerial imagery but for items such as street map images or
topographic maps it can clarify the text. The appropriate setting is selected automatically for
images that are downloaded from the built in WMS servers.
You can use Drafting/ Attachments/ Image Drawing Options shown in Figure 6.6-5a below
to control the appearance of your images. You can change the brightness of your attached
raster images using the image brightness setting in the dialog box shown in Figure 6.6-5a
below. You can also check the option in the collar suppression and video driver issues section
of the dialog box to remove areas of the raster where the pixels match the background color.
Image printing options should be left alone unless there are problems printing.
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You can use the Drafting/ Attachments/ Image Info command to graphically select the raster
images in a project. The bounds of the image will be highlighted and when moving the mouse
cursor over the image you can hit the H, S or D keys to (H)ide, (S)how or (D)etach the image.
The O key will bring you to the Bitmap Options dialog box of Fig. 6.6-5. The C key allows you to
crop the image and the I key presents information about the image. If you hit the W key, PLSCADD will write a world file for that particular image. If you select the P key it will open the
selected attachment with the default program used when double clicking the file in Windows
Explorer.
Figure 6.6-5a Image Drawing Options
6.6.2.1
Draping of Raster Images on Top of TIN Model
If a digital terrain model (TIN) is available, the program can compute the Z coordinate of each
pixel and drape the image over the terrain as shown in the lower right corner of Fig. 6.4-3. This
is done using the Terrain/ TIN/ Display Options dialog by choosing to Render triangles and
then choosing one of the Color from bitmap options in the rendering options section of the
dialog box.
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6.6.3 Shapefiles
Shapefiles, with the .shp file extension, are normally generated in some type of GIS or mapping
system.
They can be attached and overlaid to plan and profile views using the
Drafting/Attachments/Attachment Manager which opens the File Attachment box shown in
Fig. 6.6-3. When attached to a plan view, the X,Y coordinate system (Z is elevation) used to
describe the shapefile should be the same as that used to describe the PLS-CADD XYZ terrain
points; However, the shapefile coordinate system does not have to match the program
coordinate system. PLS-CADD can do an automatic conversion to the project coordinate
system defined in Terrain/Coordinate System/Define if the shapefile coordinate system is one
available in the list of coordinate systems in PLS-CADD.
Once a shapefile is attached for the first time, you are taken directly to the Shape File Display
Options dialog box shown in Figure 6.6-6 below. If a shapefile has already been attached, you
can get to the Shapefile Display Options box by clicking on the Options button at the bottom of
the File Attachments box (Fig. 6.6-3)
The Shapefile Display Options dialog box lets you select which units have been used to
generate the shapefile data, how to display the geometry and attributes of the file, and which
attributes to display. The coordinate system can also be selected if it is different from the
project coordinate system defined in Terrain/Coordinate System/Define.
Figure 6.6-6 Shapefile Display Options
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The same commands that work for a DXF file can also be used on shapefiles. For example the
Drafting/Attachments/Move and Drafting/Attachments/Stretch work in the same way as they
do on the DXF files as described in section 6.6.1.
6.6.4 Miscellaneous Attachment Options
There are several options under the Drafting/ Attachments menu that allow you to download
imagery from other sources and to control the appearance of the attached pictures. You should
consult our technical notes on our web site for additional useful information. For example, to
import imagery into PLS-CADD you can consult the following technical note:
http://www.powline.com/products/usgs2.html
6.6.4.1 Drafting/ Attachments/ Find Text
The Drafting/Attachments/Find Text command searches for a text string in a selected
DXF/SHP file and zooms in on its location. The user first chooses the particular attachment to
be searched and then types the text to be searched in the dialog box which returns a list of all
matches. Double clicking on the text string in the list zooms the view to this particular instance
of text.
6.6.4.2 Drafting/ Attachments/ Associate Structure Photos
The Drafting/ Attachments/ Associate Structure Photos command will allow you to pick a
folder that contains multiple structure photos with built in GPS coordinates or an associated
world file and then automatically place a reference to that file in the Structure Comment for the
closest structure. These files can then be viewed by hitting the View button in the Structures/
Modify dialog box. After initiating the association command a report will be generated listing
any errors and the distance of the photo from any associated structure.
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6.6.5 Web Mapping Services (WMS)
When in the Attachment Manager you can select the WMS button at the bottom of the dialog
as shown in Figure 6.6-1a, which launches the WMS Import dialog box shown in Figure 6.6-7.
The WMS Import allows you to import imagery from pre-determined WMS (Web Mapping
Services) or WMTS (Web Map Tile Service) servers in the program or you can use a custom
server. The custom server must either be a WMS or WMTS server to be compatible with the
WMS functions.
Figure 6.6-7 WMS Import
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In order to use the WMS Import features you must first have a project coordinate system
defined in the Terrain/ Coordinate System/ Define dialog box as described in section 6.2.1. If
you do not have a coordinate system defined and you select the WMS button the program will
prompt you to define the coordinate system before proceeding. At the top of the WMS Import
dialog box you would first need to pick either one of the predefined servers or check the option
to user a custom server and define its address. If it is a custom server that requires “Basic
Access Authentication” you can enter the User Name and Password below the URL entry. The
program will remember the last 10 custom server settings (name, URL, and type) and allows
you to pick them from the server name combobox in future program sessions. After selecting
the server you would then hit the Query Server button which populates the Map Data and
Layers sections with the information from the server. You can pick which layers you would like
to download by highlighting them in the Layers section.
At the bottom of the dialog you can pick the information about which image format you would
like to download, resolution, and information about where to download the imagery in the
project. You can choose between JPEG, JPEG 2000, and ECW formats in the Image Format
drop down dialog.
The Import Project Extents allows you to define where the images should be downloaded by
four methods.
1. Wherever intersects project option will download imagery for the entire project
based on a rectangle that encompasses the entire plan view.
2. You can choose to download imagery within a user specified distance of the
alignment.
3. The current plan view extents.
4. Inside a rectangle defined by the longitude and latitude in decimal degrees of the
lower left and upper right corners of the rectangle.
The user can define the resolution of the imagery to bring in. If you leave the desired resolution
blank the program will use the default resolution or you can change this to a larger number to
decrease size of the file being downloaded. The desired tile size is the number of pixels on one
side of an image that is to be downloaded. This will default to 16384 for most WMTS servers
and 4096 for most WMS servers.
Once the Import button is selected the program will download the images in the background.
You will be able to continue working on your project as the images are downloaded. The
images being downloaded will appear as a translucent grey tile with the text “Load Pending”
appearing until they have downloaded.
After the images have been downloaded they will appear in the Attachment Manager with a
WMTS or WMS prefix and information about the downloaded image. You will also be able to
select these downloaded images in the Attachment Manager based on the time of the request
or server used for the download using the Select drop down menu.
Important Note: Power Line Systems does not administer any of the servers. Any server may
be unavailable or slow at any time and there is nothing Power Line Systems can do if that is the
case.
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6.7
PFL Terrain Model
The PFL terrain model requires that the
Y
center-line of the power line be defined
LINE ANGLE
PI2
first. The locations of terrain or obstacle
LA +
points are then described relative to that
Station
PI3
center-line. This is shown in Fig. 6.7-1.
The station of a point is the cumulative
P
PI1
X
distance from an arbitrary reference point
on the center-line to the projection of the
Z
point on the center-line and its offset is its
O
lateral distance to the center-line. In PLSh
CADD, positive offsets and positive line
P
angles are defined as follows. If one
Z
X
travels the line in the direction of
increasing stations, positive offsets are to
PI1
PI2
the right and positive line angles are
P[Desc., Sta., Off., Z, Angle, Feature Code, h]
clockwise. This is illustrated in Fig. 6.7-1.
Fig. 6.7-1 PFL Terrain Model
Prior to the days of electronic surveying
and computers, the PFL terrain representation was used almost exclusively in power line work.
Therefore, by tradition, many of the early line design programs used that representation.
However the XYZ model is more powerful as it allows the designer to easily change a line route
and to move a structure in the plan view without being constrained by the existing center-line.
Therefore, we discourage the use of the PFL representation. It is included in PLS-CADD solely
to support legacy data, including digitizing of old P&P sheets.
The data for a ground point in a PFL model include the feature code, an optional label or
description, the point station, its offset and elevation, the line angle at the location of the point (if
the point is on the center-line) and a zero obstacle height.
For an obstacle described by its height above a ground point (Obstacle Option 1) the data
include the obstacle feature code, an optional label or description, the station, offset and
elevation of the ground point directly below the obstacle, the line angle at the ground point (if on
center-line), and the height of the obstacle above the ground. When you use this option, make
sure that "Yes" is checked in the Point is on Ground column of the feature codes table in Fig
6.1-2.
For an obstacle described by its own coordinates (Obstacle Option 2) the data include the
obstacle feature code, an optional label or description, the station, offset and elevation of the top
of the obstacle, a zero line angle and a zero obstacle height. When you use this option, make
sure that "No" is checked in the Point is on Ground column of the feature codes table in Fig.
6.1-2, otherwise you might see the ground center line and some side profiles go through the top
of your obstacles in the profile views.
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Also included for each ground or obstacle point are optional surveyor's notes to be displayed on
profile or plan views. The data for the PFL model are contained in an ASCII file with a record for
each point. This file must have the extension ".pfl" to be recognized as relating to a PFL model.
The details of the records and fields of a PFL file are described in Appendix E. The records in
an XYZ file can be input in random order. However, in a PFL file, the records should be
arranged in ascending order of stations.
A PFL file can be prepared with a word processor according to the format described in Appendix
E, edited with the Terrain/ Edit/ Edit PFL command also described in Appendix E, or created
automatically after defining an alignment as described in Section 6.3.2.
Stations in a PFL file should be "true stations". They cannot be "equation stations" as defined in
Section 6.10.
6.8
Using Scanned Raster Drawings to Create PFL Terrain Model
There are basically two approaches to building models of existing lines in PLS-CADD. The
better approach is to resurvey the terrain, the structure locations and the positions of the
conductors with modern equipment, i.e. to create a XYZ terrain model. A limited and less
accurate alternative is to get the locations of terrain, structure and conductor points from
existing drawings or from scanned images of these drawings. These drawings can be displayed
in the background of the profile view. Once the drawings are properly positioned in the profile
view you need only click the mouse at locations where you wish to create PFL points.
It is generally not recommended to use existing drawings as templates for building models of
older lines because of the potential accumulation of errors at each step of the process. The
original survey may have been inaccurate. The nature of the terrain below and in the vicinity of
the line may have changed over the years. The as-built locations of the conductor attachment
points may not be well reflected by the drawing. The catenary curves showing the positions of
the conductors at some temperature may have been based on crude assumptions not reflecting
actual sagging conditions and creep effects. These curves may have been drawn with templates
not adjusted to the actual ruling spans in the lines. The digitizing process itself, through scaling
and clicking on lines of finite thicknesses, will also add errors.
However, there are cases where one would want to quickly build a line model on top of a raster
drawing. This can be done using the steps described in Sections 6.8.3 to 6.8.5. You should
make sure that the scanned drawing clearly shows labeled station and elevation axes, with the
station axis ideally labeled with true stations (true and equation stations are discussed in
Section 6.11), as well as line angle locations. This can be done before scanning by overwriting
the axes with a dark pen. True stations, that is stations measured from a point near the origin of
the line can easily be calculated and marked with a pen, if they are not already shown.
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When scanning your images for use with PLS-CADD we recommend that you use the lowest
resolution that yields a legible image. The lower the resolution, the smaller and more
manageable your scanned drawings will be. The drawings can either be saved as Windows
bitmaps (.bmp files) or as a TIFF (.tif files). TIFF files typically use compression and will be
substantially smaller than an equivalent Windows bitmap. However, aside from file size the two
are functionally equivalent and we will hereafter refer to bitmaps images to mean either a bitmap
or a TIFF. Unless your images have color on them, we recommend that you save them as a
1bpp (bit per pixel) blank and white image. Should you need to edit the image after the scan,
you can do so with whatever image editor you prefer; however, all editing should be done prior
to attaching the image in PLS-CADD. Changing the image after it has been attached to your
profile may result in the image "shifting" on the profile and inaccurate digitizing. Note that while
you can crop the plan portion of the sheet out many clients elect to leave it in so that they have
access to line angle and other information that may reside in the plan view.
A full digitization process example is available at:
http://www.powline.com/products/ppdigitizing.html
Please pay special attention to Note 14 in the Technical Note that gives information for
calibrating sheets that have stationing going from right to left.
6.8.1 Opening a Profile View
Importing and displaying a scanned profile drawing should be done in a Profile view. If this is a
new project, use File/ New to name the project file, say Project.pfl, create or import some
existing feature codes with Terrain/ Feature Code Data/ Load FEA File, open a profile view
with Window/ New Window/ Profile. You will get a blank Profile view. If there are already
some data in the Project.pfl file, open it and display the Profile view.
6.8.2 Attaching Scanned Drawing to Profile
This is done with the Drafting/ Attachments/
Attachment manager where you specify that
the bitmap should be attached to the profile
view (not the plan view) and you select the
approximate station and elevation of the top
left corner of the bitmap (Point A in Fig. 6.81), the approximate bitmap width, BW, in
station units, and the approximate bitmap
height, BH, in elevation units. At this stage
(Fig. 6.8-1), the horizontal axis of the profile
drawing may not coincide with the horizontal
edge of the bitmap due to poor positioning of
the drawing when it was scanned. Also, at
this stage you do not worry about exactly
matching the scales of the drawing and those
128
A
BITMAP WIDTH , BW
Figure 6.8-1 Scanned Drawing
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inherent in your current profile view. If you do not see the bitmap, it may be outside your current
viewing area. Click on View/ Initial to get a complete view of your project from which you can
zoom-in on the particular bitmap.
6.8.3 Scaling and Orienting Scanned Drawing
This is done with the Drafting/ Attachments/ Calibrate Profile Sheet or Plan Sheet menu.
You will be asked first to click on the left and on the right of a station line (Points B and C in Fig.
6.8-1) and input the true stations of these two points if True Stations is selected in the Stations
Displayed part of the Preferences dialog box of Fig. 5-4. You can input the equation stations of
the two points if: 1) Equations Stations is selected in the Preferences dialog box, and 2)
unambiguous relationships between true stations and equation stations have already been
defined in the Station Equations table (see Section 6.11). A station line is any line parallel to
the station axis of the drawing, i.e. points B and C should have the same elevation. The station
line does not have to physically coincide with the line labeled with stations. To improve
accuracy, points B and C should be selected as far away from each other as possible. The
program will use the information you input for points B and C to: 1) rotate the drawing so that
line BC is parallel to the station axis in the profile view and 2) scale the drawing to match the
scales used to display terrain points in the profile view. If the required rotation is small, you will
be given the choice of neglecting it to reduce redraw time.
Next you will be asked to click on the lower end and on the upper end of an elevation line
(Points D and E in Fig 6.8-1) and input the elevations of these two points. An elevation line is
any line parallel to the elevation axis of the drawing, i.e. points D and E should have the same
station. To improve accuracy, select points D and E as far apart as possible. The elevation
information at points D and E will be used to match the vertical scales of the scanned drawing
and the profile view.
6.8.4 Sliding Scaled Attachment
Once a drawing is properly scaled, you can always slide it with the Drafting/ Attachments/
Move command. You will be asked to click on any reference point on the attached drawing and
then click on where this point should be in the profile view. For example, you can slide the
drawing so that a particular point near the left edge of that drawing matches a selected point in
the profile view, for example the same point near the right edge of the previously attached
scanned drawing.
6.8.5 Creating PFL Points
Once a drawing is scaled and accurately positioned in the profile view, you can click on desired
terrain, structure and conductor points to create PFL terrain points at these locations. This is
done with the Terrain/ Edit/ Add PFL Points command. A small box appears at the top left of
the screen (see Fig. 6.8-2) where you select the feature code, description, offset, line angle and
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a profile comment for the point being created. If you make a mistake, you can always remove a
point with the Terrain/ Edit/ Delete PFL Points.
6.8.6 Creating Line Model
Once you have PFL
ground, structure or
conductor points on the
screen (visible with the
appropriate
feature
code
symbols
at
positions indicated by
vertical lines in Fig.
6.8-2 you can use the
standard PLS-CADD
commands to build the
line
by
adding
structures,
stringing
and sagging cables
(see Section 10).
You can automatically
spot structures and
Fig. 6.8-2 PFL Points Created on a Scanned Drawing
snap their conductor
attachment points to designated PFL points as described in Section 10.2.5.2.
You can sag sections to match catenary curves of the scanned drawings or to pass through
designated PFL points as described in Section 10.3.2.4.
6.9
XYZ or PFL?
Given the choice of working with an XYZ or a PFL terrain model, the XYZ model is much better.
The alignment can easily be changed on top of an XYZ terrain model. All you need to do is drag
a P.I. point to its new location and use Terrain/ TIN/ Create Interpolated Points to create new
centerline and side profile points. Your design will automatically be moved to the revised
centerline with the new centerline and side profiles displayed. There is no simple way to change
the alignment with a PFL terrain model as you do not have the ability to work in the plan view.
With an XYZ model you can better visualize the terrain. A terrain TIN surface can be developed
and used for color rendering and the automatic display of contour lines. Maps and raster images
can easily be superposed to the plan view. Raster images can be projected onto the TIN
surface for realistic 3-D photo rendering of the terrain.
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With an XYZ model, you can reference the locations of all your structures to the same
coordinate system used for the management of your line (GIS, databases, etc.). You can
integrate the PLS-CADD model with other management tools used by your company.
While we highly recommend the use of the XYZ model over that of the PFL, you should
understand that both models are just alternate ways to look at the same 3-dimensional terrain
and alignment information. In fact, you can convert an XYZ model to a PFL model or convert a
PFL model to an XYZ model as described below.
6.9.1 XYZ to PFL Conversion
Assume that you have defined an alignment on top
of a Project.xyz terrain. You can create the
equivalent PFL model by first going to the Terrain
Origin box (Fig. 6.9-1) with the Terrain/ Edit/ Edit
Origin command, where you will select the true
station of the first alignment point. Then use File/
Save As to save the project with the Project.pfl
name. The program will understand from the .pfl
extension that the terrain should be saved as a
PFL model.
6.9.2 PFL to XYZ conversion
Assume now that you have a PFL terrain model
Fig. 6.9-1 Terrain Origin Box
Project.pfl and want to create the equivalent XYZ
model. First you should provide the Azimuth of first point plus the X and Y coordinates of the
point with zero station in the Terrain Origin box. The azimuth (bearing) is the clockwise angle
of the first alignment leg measured from the Y axis. Then use File/ Save As to save the project
with the Project.xyz name. The program will understand from the .xyz extension that the terrain
should be saved as an XYZ model.
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6.10
Side Profiles, Clearance Lines, Prohibited Zones and Special Cost Zones
The collection of straight line segments making up the center line ground profile was defined in
Section 6.3.2 and displayed in Fig. 6.3-12.
6.10.1 Side Profiles
Similar to the center line ground profile, side profiles are defined by an Offset from the center
line and an Offset Tolerance as shown in Fig. 6.4-4 or Fig. 6.10-1. All adjacent points (in order
of increasing stations) within the Offset Tolerance distance from the Offset line which are not
separated by more than the Maximum Separation will be connected to form a side profile.
Side profiles are only shown where
there are terrain points within the
specified Offset Tolerance. For
example, the terrain of the Demo line
shown in Fig. 6.10-1 has survey
points within the range of side
profiles between Structures # 5 and #
6. There are significant side slopes in
that region. Side profiles are not
visible elsewhere because either: 1)
there are no survey points within the
designated offsets, or 2) the points
within the offsets are too far apart
(their distances exceed the Maximum
Separation).
6.10.2 Ground Clearance Line
Fig. 6.10-1 Demo Line Side Profiles
A required clearance line (or several clearance lines if there are side profiles) can be displayed
as a dotted line and dotted spikes above the profile (see Fig. 6.10-1). The line and spikes are
displayed for the voltage specified in the Terrain/ Clearance Line box. The voltages available
to select from are those previously established in the feature codes box of Fig. 6.1-1. The
clearance line consists of two parts. The first part is the basic ground clearance consisting of
copies of the centerline and side profiles shifted upward by a specified value. This value is the
required vertical clearance for the feature code selected in the Terrain/ Clearance Line. The
second part of the clearance line consists of vertical spikes indicating required vertical
clearances above (or below) specific terrain points or objects within the Maximum Offset for
Profile View (defined in Section 6.3.2). These spikes are only visible if the required clearances
are larger than the basic ground clearance.
If an obstacle is designated as an "Aerial Obstacle" in the Feature Codes table of Fig. 6.1-2,
the required vertical clearance is shown as two spikes, one above and one below the obstacle.
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6.10.2.1
Wire Clearance Line
Wire clearance lines are actual wire positions for selected weather cases with optional shifts up,
down, left, or right. In the bottom of the Terrain/Clearance Line table a user can specify the
clearance line type whether it is a clearance line projected from the wire position or from the
ground directly below the wire if a TIN is available. The user can choose which view to display
the clearance line. They can also limit which wires to draw the wire clearance based on the
placement of the wire in relation to the centerline or other wires or by voltage. The vertical shift
and horizontal shift can also be specified in the table.
The Terrain/ Update Wire Clearance Line or Profile Below Wire command will refresh any
Ground or Wire Clearance lines. This command can be added to a Custom Toolbar for easy
refresh of the clearance lines as changes are made to a project.
When selecting L3 or L4 Finite Element Analysis options wire clearance lines will be drawn
based on the position of the wire with structure deflections being taken into account. The
calculations to display the wire clearance lines can take significant time to complete for some
models. Within the menu command Criteria/SAPS Finite Element Sag-Tension... the setting
"Use Level 2 modeling for display and insulator swing calculations" within the L4 options also
applies to wire clearance lines. When this option is selected the wire clearance line will be
displayed using the wire position based on level 2 modeling.
6.10.3 Spotting Constraints
Prohibited and Extra Cost Zones can be defined in a project for use in the Optimum Spotting of
a line or also in the manual spotting of a line. A spotting constraint can be added and modified
in the Structures/ Automatic Spotting/ Spotting Constraint menu.
Fig. 6.10-2 Prohibited Zones near End of Demo Line
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Prohibited Zones and Extra Cost Zones can be defined along an alignment manually with the
Structures/ Automatic Spotting/ Spotting Constraints/ Edit (table based) command which
will bring up the table shown in Fig. 6.10-3 below. These zones are taken into account when
optimizing the spotting of a line with Structures/ Automatic Spotting/ Optimum Spotting (see
Section 14). They can also be used in limited form as a visual guide when manually spotting a
line and give the user feedback if they place a structure in a prohibited or extra cost zone. Fig.
6.10-2 shows three prohibited or extra cost zones near the end of the demo.xyz line. A
prohibited zone is indicated by a solid red rectangle at the bottom of the profile view and a red
line or polygon in the 3D and Plan views. An extra cost zone is indicated in green. The
constraints table contains 9 columns detailed below that relate to the different constraints that
can be placed in a model.
Description:
Description of the type of constraint whether it is station based xyz based.
Station is based on the alignment while a polygonal, line, or point based
constraint is based on xyz point data.
Type:
There are 4 types of constraints which are Extra Cost Zone, Prohibited
Zone, Required Structure, and Required Position. The extra cost zone is
just an area or station range that cost extra money in order to place a
structure. A prohibited zone is an area or station range in which a
structure is not permitted. A required position is a station that a structure
must be located. A required structure is a station that a particular
structure model must be located.
Start Station:
Station of the start of a station based zone. Also used as the station for
the required structure or the required position.
End Station:
Station at the end of a station based prohibited or extra cost zone. Not
used for the other types.
Extra Cost:
Cost used for the extra cost zone. Only used for extra cost zones.
Feature Code:
Feature code used in relation to a Prohibited Zone or Extra Cost Zone to
identify a buffer around the features identified. The value of the buffer is
taken from this feature code and is identified in the feature code table.
(See section 6.1)
Source:
Automatically generated information about how the constraint was
created. The source can be from a dxf or shapefile attachment, user
input, or an automatically generated constraint such as a required
position at a PI.
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Structure File:
The structure file that should be used when Required Structure is the
constraint type. Not used for the other types.
Comment:
User defined comment or information about the dxf or shapefile that was
used to create the constraint.
Fig. 6.10-3 Constraints Table
A constraint can be added manually in the table by entering the required information, graphically
by manually drawing the constraint, importing the geometry of the constraint from a dxf or
shapefile, or importing the constraint based on the slope of the TIN model. The manual addition
of constraint is accessed through the Structures/ Automatic Spotting/ Spotting Constraint/
Add Graphical menus and based on whether the constraint is a station based or polygonal
based constraint you will add it accordingly. If you select to add a station based constraint the
mouse will follow the centerline and the station being selected will be shown in the status bar. If
you select a polygonal based constraint you will be able to choose what type of constraint
whether it is polygonal, polyline, or point and whether to freehand the shape or snap to survey
points. Figure 6.10-4 below shows the Polygonal Extra Cost Zones dialog box where you can
pick how you wish to add the polygonal constraint. If you select one of the dxf based options
then you will be able to select which dxf to import the constraint data from. When adding
constraints graphically the dialog box will give you the opportunity to enter the data required for
the particular constraint selected.
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Figure 6.10-4 Add Graphical Constraint
The other option for adding a constraint is based on TIN slope which is accessed through the
Structures/ Automatic Spotting/ Spotting Constraints/ Add Prohibited or Extra Cost
Zones Based on TIN Slopes. This will bring up the dialog of Figure 6.10-5 which will allow you
to pick the slope limit of the zone based on the slope angle or percent. This feature will go
along the centerline looking at the sampling interval that is input in the dialog box and see if the
slope exceeds the limit that has been input based on the distance input for the centerline or
cross-section. For example if you select a sampling interval of 1m and a distance to check of
5m then it will check the slope at Station 0+01 as being the elevation difference between Station
0+01 and 0+06. If the slope exceeds the limit then the interval from Station 0+01 and 0+02 will
be considered a constraint. Then it will check the slope between Station 0+02 and 0+07 to see
if the limit is met in this interval and work its way along the alignment looking at the centerline
and cross-section if selected. If you have two slope constraints that are within the distance
specified in the dialog box then they will be combined into one slope constraint over the entire
distance. For example if you have a constraint that has been identified at Station 0+01 to 0+03
and another constraint from Station 0+06 to 0+10 and the distance within which adjacent zones
will be combined is set to 5 then the constraint will be joined to be one constraint from Station
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0+01 to 0+10 since the distance between the end of the first constraint at 0+03 and the start of
the second constraint at 0+06 is less than the 5m distance.
Fig. 6.10-5 Constraint Based on Slopes Dialog
The Structures/ Automatic Spotting/ Spotting Constraints/ menu items give you options to
be able to not only add constraints but also delete constraints, turn on or off the display, and
report on the constraints. The Structures/ Automatic Spotting/ Spotting Constraints/
Report will give you a report of all constraints in the model similar to the table in Figure 6.10-3
and also a list of all structures that fall inside one of the constraint zones.
Upon saving a project, spotting constraints and their stations are saved in the Project.con file. A
constraint file can be loaded into an existing project or saved to a .con file name of your choice
using the Structures/ Automatic Spotting/ Spotting Constraints/ Load or Save .CON File.
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6.11
Equation Stations
Once an alignment is defined, any terrain point has a station (distance along the alignment) and
an offset (distance from the center line).
"True station" is defined as the total distance measured from the first P.I. in the alignment to
which is added the designated station of that first P.I. The station of the first alignment point can
be changed from the default value of zero to any value with Terrain/ Edit/ Edit Origin.
Fig. 6.11-1 First P&P Sheet of Demo Line w/ Equation Stations
"Equation station" is defined as a relative distance measured either forward or backward along
the alignment from an arbitrary point along the alignment. Unlike "True stations", "Equation
stations" are not continuous. For example, open the Demo line and with Terrain/ Station
Equations enter the data shown in the insert box of Fig. 6.11-1. The "Equation stations" of the
points with "True stations" between 1000 and 2000 will decrease from 5000 to 4000 along the
alignment, and the "Equation stations" of the points with "True stations" larger than 2000 will
increase from 15000. The change will be effective instantly in all Profile views and in the profile
portion of P&P sheets (see Fig. 6.11-1). Red vertical lines extending from the bottom of the
screen to the ground line indicate station equation locations.
The stations which are displayed in the status bar, P&P sheets, the Terrain Info box or any
report can either be the "True station" or the "Equation station" depending on your selection in
the File/ Preferences menu.
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6.12
LiDAR Tools
There are several tools in the Terrain/ Edit/ LiDAR Tools menu to help with the classification of
LiDAR data for the purpose of building a PLS-CADD model. You may have a model with nonclassified or partially classified data that you can use these tools to classify the relative points.
The first command is the Terrain/ Edit/ LiDAR Tools/ Ground Point Classification which
brings up the dialog of Figure 6.12-1. This tool will classify the ground points from a selected
set of points by breaking the points into user defined tiles and identifying the lowest point in
each tile and creating a TIN model from these points. Further refinement of the surface can
identify if any of the undefined set of points fall below this TIN surface and can include them in a
new TIN model. This command can also be used on previously classified ground points to
intelligently thin the surface model.
Figure 6.12-1 Ground Point Classification
The first selection in the table is for mandatory feature codes. These are points that have been
previously classified as being on the ground and you would like included in the ground surface
model. The second selection is for the optional feature codes that may or may not be on the
ground. The Point Inclusion Criteria allows you to input a tile size for the grid to search for the
low points. The smaller the tile size, the more refined the surface and the more points that will
be included in the final surface model. You can also choose whether to include only the low
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point in the tile or to make further passes after identifying the low point in each tile to make sure
no points lie below the surface created from the low points. The Marker Options section allows
you to create markers for the points but this can be quite memory intensive. The last portion of
the dialog box allows you to change the feature codes of the points that are included in the TIN
model that is identified.
The next feature that is available is a tool to find possible wire points in the model. Figure 6.122 shows the Terrain/ Edit/ LiDAR Tools/ Find Wire Points dialog box which determines which
of the currently displayed survey data points are likely to belong to a wire catenary. It will assign
the feature code specified to the probable wire points that you have selected in the dialog box.
You can also use the bundle thickness and vertical spacing between phase inputs to help
identify the points. These options are included in the first tab of the dialog box labeled Wire
Feature Code. This feature works only on the displayed data points so it is best to use the Filter
Survey Data to remove any of the points from consideration for the wires as possible as it will
speed up the process. This is similar to the Terrain/ Survey Data Display Options and any
changes in this tab will be reflected in that dialog as well. It is good to limit the display the best
you can using limits of offset and height above TIN to properly identify the wire. It would be a
good idea to have a rough alignment prior to using this command to take advantage of using the
offset filter to limit points considered.
Figure 6.12-2 Find Wire Points
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The Terrain/ Edit/ LiDAR Tools/ Find Structure Points identifies possible structure points
using the currently displayed points which can be adjusted using the Filter Survey Data tab. It
uses an algorithm based on the wire points and the maximum structure radius and the highest
point within this radius to determine the probable structure points. In the Structure Feature
Codes tab you can pick what feature code you would like to use for the structure tops as well as
for the structure points. You also identify the feature code to be used for wire points, that you
may have identified using the Find Wire Points command, and also the radius to use for the
structures and the highest point for the structure. Figure 6.12-3 below shows the Find Structure
Points dialog box.
Figure 6.12-3 Find Structure Points
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The Terrain/ Edit/ LiDAR Tools/ Find Centroids of Structure Points can be used to create
survey points at the centroids of groups of points with the selected feature codes separated by
no more than a specified distance. The z value of the new centroid point can be set to a 0
elevation, Z of the centroid, or can be set to a Z value interpolated from the TIN at the centroid
point XY. Figure 6.12-4 shows the LiDAR Survey Point Centroid dialog box. The top of the
dialog box allows you to use a filter on the points considered including a list of feature codes to
include, restriction on height, and restriction on offset. The next section of the dialog box
dictates what feature code to use for the created centroid point, the maximum separation
distance between points in the group, and the maximum centroid size. You also have the option
to drop markers for the points included in the centroid calculation as well as a marker at the
centroid center. The last section gives you control on how to assign the z value for the centroid
point.
Figure 6.12-4 LiDAR Survey Point Centroid
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The next two commands in the LiDAR Tools are for the identification of catenaries and probable
attachment points. The catenaries are best fit lines fitting through the LiDAR data that are
closest to the shape of a catenary. In order to identify attachment points you must first identify
catenaries. The Terrain/ Edit/ LiDAR Tools/ Catenaries/ Fit Catenaries command attempts
to fit catenary curves to survey points with the wire point feature code identified in the dialog
box. After fitting these curves you can use the Terrain/ Edit/ LiDAR Tools/ Catenaries/
Toggle Catenaries to turn on and off catenaries identified in the models. Only the catenaries
which are On will be used to determine probable attachment points for structures. The LiDAR
Catenaries dialog box shown in Figure 6.12-5 allows you to select the feature codes to use for
the fit of the catenaries and also allows you to select an optional point for the location of a
structure. The structure location is not necessary if you have a PI already at every structure but
can be helpful to identify span ends if you don’t have them. The bundle thickness allows for the
width of the bundle and margin for data point accuracy when fitting the catenary. At the bottom
of the dialog box you can enter catenary filter parameters that automatically turn off catenaries
that do not fall in these parameters. This is useful to filter out bogus catenaries or other
catenaries from crossing or parallel lines. It also gives you the ability to eliminate catenaries
that are identified using short lengths, heights, or number of points which can rule out catenaries
not related to overhead line spans.
Figure 6.12-5 LiDAR Catenaries Identification
After the initial identification of the catenaries it may be necessary to turn off catenaries that
were misidentified or not related to the line you are wishing to model. This can be done with the
Terrain/Edit/LiDAR Tools/Catenaries/Toggle Catenaries On/Off command which will allow
you to manually turn them On or Off. A catenary that has been turned Off will be drawn with a
dashed line type while an On catenary will be a solid line.
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After creating catenaries and filtering out or turning off the unnecessary catenaries, you can use
the Terrain/ Edit/ LiDAR Tools/ Attachments/ Find Attachments command shown in Figure
6.12-6 to identify attachment points based on the intersection of the catenaries. You can
choose to assign xyz points with selected featured codes for deadend or suspension
attachments. You can use the Filter Survey Data tab to display only relevant points.
Figure 6.12-6 Find Attachment Points
After identifying attachment points, you can use the Terrain/ Edit/ LiDAR Tools/ Attachments/
Toggle Attachment Type to toggle the type of attachment from a deadend (marked as a green
square) or a suspension (marked as a hollow circle).
The Terrain/ Edit/ LiDAR Tools/
Attachments/ Move Attachments command can be used to move an attachment point location
along its related catenary which can be helpful for manual adjustment of the attachments. Also
the Terrain/ Edit/ LiDAR Tools/ Attachments/ Merge Catenaries command can be used to
merge adjacent catenaries into one catenary. This is useful when you may have data in only
partial segments of a span and the automatic identification algorithm labels the single span as
two catenaries due to missing data.
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7.
DESIGN CRITERIA
7.1
General
Design criteria for power lines are often not the same in various countries and in different
companies within the same country. These criteria also change over time. However, in spite of
differences in particular numerical values, there are many similarities. When we developed PLSCADD, we built into the program very general design check functions that could easily apply to
a wide variety of design practices, from very simple requirements for distribution lines to the
most highly engineered processes for extra high voltage lines. We also provided a framework
within which some recently published international design techniques (NESC 2012; ASCE 74,
1991 or newer; IEC 60826, 2003; CENELEC EN 50341-1, 2001; UK NNA, 2001; REE , 2001;
Portugal NNA, 2001; AS/NZS 7000:2016; French specifications of RTE-EDF; and more as
described
in
http://www.powline.com/products/version7_loads.pdf)
are
automatically
implemented in both PLS-CADD and our structure programs PLS-POLE and TOWER. An effort
has been made in this document to fully describe the assumptions behind the design
calculations, so that the user can determine whether these apply to a particular situation. Design
criteria must be defined before proceeding with the design of a project in PLS-CADD. This is
done by creating/editing the project criteria file Project.cri with the various criteria dialogs under
Criteria or loading an existing master criteria file, say Master1.cri, with Criteria/ Load CRI.
Whenever a PLS-CADD project is saved its criteria are saved in the file Project.cri (even if the
criteria initially came from some other loaded criteria file such as Master1.cri). Criteria files have
the ".cri" extension.
7.1.1 Modeling of Wire System
One of the most complex parts of a transmission line is the wire system (conductors and ground
wires) in a tension section (from one dead end structure to the next dead end structure).
Questions arise regarding: 1) the handling of wind load which may not be uniform over the
length of the section (wind on individual spans may be larger than the average wind over the
section because of varying gust response factors and different wind incidences), 2) the handling
of non-uniform ice loads, 3) the handling of the many phenomena that generate longitudinal
loads (broken wires, slack redistribution, etc.), and 4) the possibility of interaction between
flexible structures and all wires in the tension section. Therefore, for practical design reasons,
approximations and assumptions have to be made. In PLS-CADD, four modeling levels are
available to determine the response of the wire system to some loading criteria. These four
levels are summarized in Fig. 7.1-1.
The simplest modeling level (Level 1) is based on the concept of the Ruling Span (RS) and it is
sufficient in most cases. The most advanced modeling level (Level 4) is based on a full
structural analysis of the entire tension section, including detailed models of all supporting
structures and all cables. Because it is computer time intensive and is not justified in most
situations, Level 4 should only be used in special cases where a very accurate representation
of the interaction between the structures and the wires needs to be considered. You likely will
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never have the need for this advanced modeling capability (Level 4). Between Level 1 and
Level 4, there are two intermediate modeling levels (Level 2 and Level 3). Levels 2, 3 and 4
are defined herein as Real Span (because it works with actual real lengths of wires in each
span) or Finite Element (FE) modeling. The general assumptions used at these different levels
are discussed in this section.
In order to use Levels 2, 3
or 4, you must have a
license of our SAPS
program in addition to
PLS-CADD. You should
also become familiar
with the material in
Appendix N. Levels 2, 3
and 4 have not been
widely used due to their
perceived
complexity.
However, if you select one
of these methods in PLSCADD, the complexity is
hidden from you and you
seldom
realize
that
complex calculations are
made in the background.
7.1.1.1
WIRE SYSTEM MODELING LEVELS
RULING
SPAN
FINITE
ELEMENT
NO INTERACTION
LEVEL 1
BETWEEN WIRES
INTERACTION BETWEEN WIRES
( REQUIRES METHOD 4 STRUCTURES )
LEVEL 2
LEVEL 2
LEVEL 3
ATTACHMENT
SPRINGS AT
STRUCTURES
POINTS
ATTACHMENT
INFINITELY
POINTS
STIFF
( DEFAULT )
CONDENSED TO
FLEXIBILITY MATRIX
AT ATTACHMENT
POINTS
( EFFICIENT LINEAR
LEVEL 4
FULL METHOD 4
STRUCTURE MODELS
BECOME PIECES OF
HUGE MODEL OF
TENSION SECTION
( TIME CONSUMING )
APPROXIMATION )
STRUCT. ATTACHMENT POINT ( INFINITELY STIFF )
TOP SUSP. INSUL. OR TIP OF POST INSULATOR
Fig. 7.1-1 Wire Modeling Levels
Level 1 Modeling - Ruling Span Method (RS)
Usefulness and practicality of method:
This is by far the most practical method and it is applicable to the overwhelming majority of line
design situations. It should be used in all preliminary design situations. This is what you will use
most of the time. This method works well with legislated design loads which are generally
applied uniformly over a tension section. It should always be used at the preliminary design
stage.
Assumptions:
1) The analysis involves a single wire (cable), in one or more spans, between dead ends, i.e. it
is assumed that there is no interaction between the wire and other phases of the same electrical
circuit or wires in other circuits.
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2) The horizontal component of tension along the wire in all the spans of the tension section
between dead ends is constant, i.e. all intermediate supports are assumed to be perfectly
flexible in the longitudinal direction. This may not be very accurate in the case of rigid post
insulators and short suspension insulators subjected to large vertical loads. It is usually
considered sufficiently accurate in view of all the other uncertainties and approximations
associated with line design. A recent IEEE report entitled Limitations of the Ruling Span
Methods for Overhead Conductors at High Temperature provides some discussions on this
topic (IEEE, 1997). The IEEE Guide for Determining the Effects of High Temperature Operation
on Conductors (IEEE, 2002) also mentions potential problems with the ruling span assumption
when calculating sags at very high temperature.
3) Based on the horizontal component of its tension, the geometry of each span is determined
as discussed in Appendix J and the design loads are calculated as discussed in Section 7.3.12.
Limitations:
1) All the spans need to be subjected to the same loading, i.e. this level of modeling is not
capable of analyzing situations with different ice thicknesses in various spans.
2) There is no way to study the effect of slack re-allocation due to moving a conductor
attachment point or cutting/adding some wire length in a span.
3) There is no way to account for support displacements in a system where there is a fixed
length of wire, for example inserting or raising a structure to fix a clearance problem without
resagging the wires.
4) This level of modeling cannot be used to model an existing line where unequal tensions have
been surveyed in various spans of a given tension section.
7.1.1.2
Level 2 modeling - Finite Element (FE) Modeling Ignoring Interaction
between Wires
Usefulness and practicality of method:
With this method, all supports (towers, poles and frames) are assumed infinitely rigid unless you
chose to insert fictitious springs between the supports and the insulators).
For conductors supported by latticed towers with suspension insulators, Level 2 should give you
better sags at very high temperature than Level 1 and very good approximations of unbalanced
loading situations.
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Assumptions:
1) As with Level 1, the analysis involves a single wire at a time between dead ends, i.e. it is
assumed that there is no interaction between different wires (other phases).
2) An accurate finite element model of the wire in all the spans between dead ends is used. This
model is assumed in longitudinal equilibrium (i.e. the horizontal component of tension is
assumed to be the same in all the spans) for the sagging condition, i.e. for a specified weather
case and cable condition or unstressed lengths can be specified. Strain, suspension and 2parts insulators are modeled as structural
POLE
elements. Attachment points at the tips of
ARM
post insulators and at the structure ends
of strain, suspension and 2-parts
TOP VIEW
TOP VIEW
AO
PO
insulators are assumed fixed in the
TD
TD
vertical direction, but can optionally be
PD
AD
LD
LD
allowed to move in the transverse and
AD
longitudinal directions as shown in Fig.
PD
7.1-2. The transverse and longitudinal
ELEVATION
movements of the attachment points (TD
and LD in Fig. 7.1-2) depend on their
ELEVATION
assumed transverse and longitudinal
flexibilities (or stiffnesses). With zero
Fig. 7.1-2 Optional Springs for Level 2 Modeling
flexibilities, the supports are fixed. More
information on this subject is provided in Appendix N.
3) Once the tensions in all the spans of the tension section are determined (unlike with Level 1,
you will get different tensions in different spans), the corresponding design loads are calculated
using the same procedures as used with Level 1.
Limitations:
With Level 2, you can apply different loads in different spans (unbalanced ice, broken
conductor, etc.), you can reallocate slack between spans and you can move attachment points.
However:
1) There is still no accounting of the possible mechanical coupling between wires in different
phases.
2) In the case of post insulators, it is difficult to know what value of longitudinal stiffness should
be used.
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7.1.1.3
Level 3 Modeling - Finite Element (FE) Modeling Accounting for
Interaction between Wires
Level 3 modeling is similar to Level 2 modeling, except that all the wires between two limiting
infinitely rigid dead end structures (the ends of the model) are analyzed simultaneously, thus
accounting for the possibility of some longitudinal interaction between the phases. If a dead end
structure is being checked for strength with potentially different loads on each side, the limiting
dead end structures are at the ends of the tension sections to the left and to the right of the
structure being checked. If not a limiting dead end, a dead end structure is treated as any other
structure as far as its flexibility is concerned. The interaction between the wires is accounted for
through the flexibility matrices of the supporting structures between the limiting dead ends. With
Level 2, you do not consider structure flexibility (unless you specify two flexibility numbers at
each support as described in Section 7.1.1.2). With Level 3, PLS-CADD determines a flexibility
matrix at each structure. A flexibility matrix is just a device to represent the behavior of a flexible
structure without having to model it in its entirety when you connect it to supported wires (Peyrot
and Goulois, 1978).
Structure flexibility matrices are
G
G
determined automatically by our
F
F
PLS-POLE and TOWER programs
1
I,I
I,J
for Method 4 structures (Method
I
I
4 structures are discussed in
Section 8.3.4). Therefore, there is
no additional complexity required if
F
F
1
J,I
J,J
J
you are already using Method 4
J
structures. Flexibility matrices
include
flexibility
coefficients.
Consider two insulator attachment
points, I and J, as shown in Fig.
BASE
BASE
7.1-3. These points can arbitrarily
be located in space, for example
LONGITUDINAL DISPLACEMENTS OF INSULATOR ATTACHMENT POINTS
"I" could be a ground wire
NOT NECESSARILY IN SAME VERTICAL PLANE
attachment point and "J" the
structure attachment point of the
Fig. 7.1-3 Structure Flexibility Coefficients
insulator supporting the lower left
phase of a double circuit tower. If a single unit longitudinal load is applied at point I, the
corresponding longitudinal displacement at point J is the flexibility coefficient FJ,I. For a
transmission structure with N attachment points, the NxN symmetrical matrix that includes all
the coefficients FI,J is called the structure longitudinal flexibility matrix. If, instead of restricting
yourself to longitudinal loads and longitudinal displacements as shown in Fig. 7.1-3, you
consider both transverse and longitudinal unit loads and their corresponding displacements, you
get a flexibility matrix of size 2N x 2N. This is in fact the flexibility matrix used by PLS-CADD at
each structure location when the wire system is modeled at Level 3.
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Usefulness and practicality of method:
This method only works with Method 4 structures, as the flexibility matrices for all the structures
are automatically re-calculated by our PLS-POLE and TOWER programs when needed. Except
for some additional computer time, Level 3 has all the advantages of Level 2 without its
limitations: it accounts for the interaction between the wires and relieves you from having to
assume a flexibility value. However, expect approximately an order of magnitude more
computer time when you use Level 3 as compared to Level 2. Level 3 is the recommended
method when you have longitudinal load issues in lines supported by flexible poles and frames.
Assumptions and limitations:
If a deadend structure is being checked for loads or is part of a tension section for which
tensions are calculated, its flexibility matrix, if available, is taken into account.
1) Interaction between the wires is modeled through structure flexibility matrices which are
inherently linear. Thus the nonlinear effects of extremely flexible poles and frames (which may
account for 10 to 20 percent of the stresses) cannot be accounted for. Guyed structures, which
are also highly nonlinear, may not exhibit the correct behavior.
2) The effect on the equilibrium of the system of the wind load applied directly to the structures
cannot be taken into account.
7.1.1.4
Level 4 Modeling - Full System Analysis
At Level 4, PLS-CADD models all the wires and supporting structures of an entire range of
tension sections as a single gigantic structure. A gigantic finite element model is created
automatically from the individual finite element models of the individual supports and the
interconnected cables. This method requires that you use Method 4 structures. For example, a
single model of the first six spans of the line shown in Fig. 7.1.-4 included five accurate flexible
wood H-frame models. That model was used to study the system under high temperature and
unbalanced ice condition.
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Usefulness and practicality of method:
Due to the large number of nodes and elements in the gigantic finite element model that is used
internally, this method can be prohibitively computer intensive as it requires orders of magnitude
more computer time and memory than Level 3. However, you may be able to work around the
prohibitive time and memory demands by specifying that Level 4 only be used for guyed or
flexible structures, while all latticed towers are modeled at Level 3.
Fig. 7.1-4 Full System Analysis
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Assumptions:
A Level 4 model includes few limiting assumptions unless wind is involved. The finite element
model is as accurate a model of your physical line as you can hope to get. There is complete
interaction between the wires through accurate behavior of the supporting structures, including
their nonlinear behavior.
Limitations:
While the idea of accurately modeling an entire line segment by finite element is theoretically
attractive, its practicality is limited.
1) You will rarely be able to justify the extensive time needed to run a full system model. It may
take a very long time to analyze just one load case.
2) Some codes require that you apply load factors between the reactions at the ends of the
spans and the supporting structures (see Section 7.3.12.3). This is an impossible situation to
model with Level 4 (or Level 3 for that matter) since the structures will always respond to the
unfactored loads provided by the cables to which they are connected while your code may
dictate that you analyze and check the strength of these structures under factored loads.
3) While we can apply a uniform wind to an entire model (same velocity and global direction
blowing on each and every span of a multi-spans model), this is not realistic. In fact we will
never know what would be an appropriate wind or even a legislated wind with gust response
factors to apply simultaneously to all wires and structures.
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7.2
Wind and Ice Models
Wind and ice loads are the primary design loads on a transmission line. These sections
describe general concepts which are used by PLS-CADD for the calculation of wind and ice
loads on the wire system (conductors and ground wires) and on the supporting structures.
The currently supported structure wind and ice models and wind height adjust and gust
response factor (GRF) methods are listed below and can be selected in the Criteria/ Structure
Loads table or the Criteria/ Weather table for the models. For more on each of these
selections the user can see the Criteria/ Code Specific Wind and Terrain Parameters in the
program.
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Structure Wind/ Ice Models
ASCE 74-1991
Wind Height Adjust/ GRF Methods
ASCE 74-1991
ASCE 74-2009F
ASCE 74-2006
ASCE 74-2009M
ASCE 74-2009
NESC 2002, 2007, 2012, 2017
NESC 2002, 2007, 2012, 2017
IEC 60826: 2003 and 2017
Russia 7th Edition
EN50341-1: 2001
EN50341-1: 2012F
EN50341-1: 2012M
Russia 1
EN50341-3-9:2001 UK NNA
EN50341-3-17: 2001 Portugal NNA
UK NNA 2001, 2015
EN50341-1: 2001 CENELEC
Portugal NNA
EN50341-1: 2012 CENELEC
REE (Spain)
IEC 60826: 2003 and 2017
RTE-Hyp1
REE Spain
RTE Hyp2
REE Spain RD 223/2008
AS/NZS 7000: 2010 SF and DF
TPNZ
AS/NZS 7000: 2010 SM and DM
TPNZ 2008
AS/NZS 7000: 2016 SF and DF
ESAA C(b) 1-2003
AS/NZS 7000: 2016 SM and DM
STATNETT
TPNZ
British ENA Fixed Swing Angle
ESAA C(b)1
AS/NZS 7000: 2010 Synoptic
IS 802: 1995
AS/NZS 7000: 2010 Downdraft
SAPS
IS 802 1995
Wind on All
CAN/CSA-C22.3 No. 60826-10
Wind on Face
ISEC-NCR-83 (Israel)
th
154
Russia 7 Edition
EN50341-3-2:2012 Belgium NNA
ISEC-NCR-83 (Israel)
Russia 1
CAN/CSA-C22.3 No. 60826-10
EN50341-2-9:2015 UK NNA
EN50341-2-22:2016 Poland NNA
AS/NZS 7000: 2016 Synoptic
EN50341-2-22:2016 Poland NNA
AS/NZS 7000: 2016 Downdraft
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7.2.1 Wind Model
7.2.1.1
Reference Wind and Escalation with Height
A wind condition in PLS-CADD is described by a "reference wind" and various adjustments
which may be made for height above the ground (even elevation above sea level according to
some codes) and gustiness. The reference (or basic) wind velocity, W, is described by either
keying it directly in the Weather Cases table that you reach with Criteria/ Weather, or by
entering the corresponding reference pressure. It is the wind velocity at the reference height,
usually taken as 10 m (33 ft) above ground. Depending on the code that governs your design,
the reference wind can be a gust value (for example a 3-second gust) or a value with a longer
average (1-minute average, 10-minute average, fastest mile, etc.). The reference wind velocity
is related to the corresponding reference pressure by the following formula:
Reference pressure at reference height = Q x W
2
(7-1)
where the Air Density Factor Q is also entered in the Weather Cases table. Common values of
Q are:
US units:
SI units:
Q = .00256
Q = .6125
Pressure is in "psf"
Pressure is in "Pa"
The Air Density Factor Q may be changed
for extreme conditions of temperature and
elevation above sea level. While you can
specify either a reference wind or a
reference pressure (the other is calculated
automatically with Eq. 7-1), you should be
aware that in all cases, it is the displayed
reference pressure which is used as the
starting point of all wind load calculations.
W is in "mph"
W is in "m/s"
Z REF
10 m
HEIGHT
Z
33 FT
HEIGHT
Z
ASCE
WIND
STAIR
WIND
Z REF
Z REF
W
W
Many codes and criteria require that
the design wind velocity be increased
with height.
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W
Z
Z
W
Fig. 7.2-1 Wind Profiles
155
Therefore, at height "z" above the ground the design wind velocity, W Z, may be higher than the
reference value W. The increase may be specified by an equation (for example the profile
shown on the left part of Fig. 7.2-1) or in a table (for example the stair shown on the right part of
Fig. 7.2-1).
The increase of wind velocity with height, when required by a code, can be handled in two
different manners in PLS-CADD.
Manual increase of wind velocity with height: If the increase is not available as part of a
built-in PLS-CADD code option, you can take care of it manually and approximately by
increasing the input value for the reference wind. This works well for lines with relatively uniform
height, for example lines on flat terrain with similar structures and spans throughout. For
example, you could use one set of criteria for short 69 KV wood pole lines with a reference wind
velocity of 70 mph and another one for taller 138 KV steel pole lines with a reference wind of 90
mph.
Automatic increase of wind velocity with height: With each new version of PLS-CADD (and
the associated structure programs TOWER and PLS-POLE) we are increasing the number of
codes and specifications for which we are automating the increase of wind velocity with height
for the purpose of calculating wire loads and wind loads on structures. For wire loads, you select
the code in the Wire Wind Height Adjust column of the Weather Cases table. For wind loads on
structures, you select the code in the Structure Wind Load Model column of the Structure
Loads Criteria table. See http://www.powline.com/products/version7_loads.pdf for more
information regarding these codes and their implementations. For the automatic options, you
may have to provide some wind and terrain parameters as indicated in the Criteria/ Code
Specific Wind and Terrain Parameters dialog. If you click at the bottom of the Code Specific
Wind and Terrain Parameters dialog, you can visualize the different wind escalation functions
and gust response factors that are used for the selected code (for example NESC 2007 in Fig.
7.2-1a).
Fig. 7.2-1a Kz and Wire Gust Response Factor for NESC 2007
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The pressure due to the wind velocity at height z is calculated as:
2
2
Pressure at height z = Q x (W Z) or KZ x Q x W
(7-2)
where KZ is often referred to as the velocity pressure exposure coefficient. For example, the left
part of Fig. 7.2-1a shows KZ for the NESC 2002 code.
For the automatic adjustment of wind velocity with height, an effective height z has to be
assumed. The assumptions described in Sections 7.2.1.1.1 to 7.2.1.1.3 are used in PLS-CADD.
7.2.1.1.1
Effective Height for Structures or Portions of Structures
Prior to Version 7, when a code required an increase of wind velocity with height for the
calculation of wind pressures on structures, PLS-CADD determined the pressure at 2/3 of the
total height of the structure, multiplied it by a Structure Gust Response Factor if required, and
passed that pressure to TOWER and PLS-POLE as a uniform pressure to be applied over the
entire structure model. Therefore, prior to Version 7, structure design pressures reported by
PLS-CADD included the effect of increase of wind velocity with height and structure gust
response factors when required by a code. For compatibility purposes, we have provided “Pre
V7" structure wind load models in Version 7 that continue to do this.
Starting with Version 7, when using other than “Pre V7“ structure wind load models, PLS-CADD
only determines the pressure at the reference height (usually 33 ft or 10 m above the ground)
and passes that pressure to TOWER and PLS-POLE. Starting with Version 7, when using other
than “Pre V7“ structure wind load models, TOWER and PLS-POLE take as input the pressure at
the reference height and automatically increase it with height on various portions of the
structures and apply a structure gust response factor when required. Therefore, starting with
Version 7, structure design pressures reported by PLS-CADD are pressures at the reference
height and do not include the structure gust response factors.
7.2.1.1.2
Effective Height for all Wires of a Tension Section (for purpose of
displaying tension section and making clearance calculations)
With Level 1 modeling, the wind velocity which is used to determine the response of an entire
tension section (cable set between dead ends) is assumed uniform over the entire length of the
tension section and is based on the average height above the ground of all the structure
attachment points in the tension section. Therefore, for a set with three phases and twenty
spans, the effective height is the average height of sixty three attachment points. This wind
velocity is used to determine the 3-D position of the wires under wind conditions and all sagtension calculations.
With Level 2, Level 3 or Level 4 modeling, the wind velocity which is used to determine the
response of an entire tension section (cable set between dead ends) is calculated separately for
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each wire of each span and is based on the average height of its two end structure attachment
points.
7.2.1.1.3
Effective Height for a Single Wire in a Single Span (for purpose of
determining design wind reactions at ends of span)
For all modeling levels, the wind velocity blowing on a single wire in a span is based on the
average height above the ground of its two end structure attachment points (Some
specifications reduce that height by a fraction of the sag and suspension insulator length, but
PLS-CADD conservatively neglects that unnecessary complication). This wind velocity is used
to determine the loads at the structure attachment points and the insulator swing. This is
discussed in more details in the following sections.
7.2.1.2
Wind Load per Unit Length of Wire
The formula used in PLS-CADD for calculating the design wind load per unit length of wire, UH,
is:
𝑈𝐻 = 𝑊𝐿𝐹 ∗ 𝑄 ∗ 𝑊𝑧 2 ∗ 𝐺𝑅𝐹𝑐 ∗ 𝐶𝐷𝑐 ∗ (cos[𝑊𝐴])2 ∗ (𝐷 + 2𝑡𝑧)
(7-3)
where Q and W Z were defined previously and:
WLF
GRFC
CDC
WA
D
tZ
= Weather Load Factor
= Gust Response Factor for wire
= Drag coefficient of wire
= incidence angle between the wind direction and a perpendicular to the span
= wire diameter
= ice thickness at height z
The Weather Load Factor WLF is input in the Weather Cases table and is normally equal to
one.
The wire Gust Response Factor GRFC usually depends on the wire effective height, the span
length and the averaging period used in the definition of the reference wind. In PLS-CADD,
GRFC can be entered manually or it can be determined automatically.
Manual input of wire gust response factor: If you are not required to use a code that
specifies how the gust response factor is to be calculated, you can enter its value manually in
the Wire Gust Response Factor column of the Weather Cases table. If you do so, that value will
be applied to the calculation of UH in all the wires in your line, regardless of their effective height
and span length. For example, for a line on flat terrain with similar structures and spans
throughout, you might specify a single value GRFC = 1 if your reference wind is a fastest mile or
a 1-minute average wind. You might specify a smaller value, say GRFC = 0.8, if your reference
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wind is a 3-second gust wind. The manual option is also the one to use if your design
specification calls for simple nominal values of wind pressures, say 20 psf or 800 Pa to be
applied to all conductors. In these cases, the pressure is input and the gust response factor is
set equal to one.
Automatic calculation of wire gust response factor: If you want to have PLS-CADD
automatically calculate the wire gust response factor for a supported design code, you select
the code in the Wire Gust Response Factor column of the Weather Cases table. See
http://www.powline.com/products/version7_loads.pdf for more information regarding these
supported design codes and their implementations. For the automatic option, you may have to
provide some wind and terrain parameters as indicated in the Criteria/ Code Specific Wind
and Terrain Parameters menu. You can visualize the variation of the wire gust response factor
by clicking at the bottom of the Code Specific Wind and Terrain Parameters dialog (for
example see the right part of Fig. 7.2-1a for the NESC 2002).
The wire Drag Coefficient CDC is assumed by default to be equal to one for all wires. However,
if you select one of the supported design code (in the Wire Gust Response Factor column of the
Weather Cases table) the appropriate drag coefficient will be used automatically. This
coefficient may be a function of conductor diameter, ice deposit or Reynold’s Number. If you are
not using a supported design code and wish to use a drag coefficient different from one, you
can include its effect in your input value of wire gust response factor, GRFC.
The Wind Incidence Angle WA is automatically calculated based on your wind direction
selection in the Wind Direction column of the Structure Loads Criteria table.
7.2.1.2.1
Assumptions for Calculating Wind Load on all the Spans of a wire in a
single tension section, UHTS , for purpose of displaying the tension section
and making clearance calculations
With Level 1 modeling, when a tension section is displayed in 3-D for a particular weather case
or when basic geometric clearance calculations are made, the same load per unit length UHTS is
assumed on all the wires of all the spans which make up the tension section, regardless of their
lengths and orientations. For the calculation of UHTS, the wind is assumed perpendicular to each
span (i.e. WA = 0 or 180 degrees) and a single value of GRFC is used. GRFC is based on the
effective height described in Section 7.2.1.1.2 and the ruling span of the tension section (see
Section I.1 for the definition of ruling span). While there is no theoretical reason to chose the
ruling span for the calculation of GRFC, since the average effect of the wind takes place over the
entire length of the tension section, a conservative consistent assumption had to be made.
With Level 2, Level 3 or Level 4 modeling, a unique load per unit length, UHi, is applied to each
cable of each span. For the calculation of UHi, the wind is assumed perpendicular to the span
(i.e. WA = 0 or 180 degrees unless specified otherwise in a load case being displayed) and the
gust response factor is based on the effective height described in Section 7.2.1.1.3 and the
length of the span.
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7.2.1.2.2
Assumptions for Calculating Wind Load on a Wire for Purpose of
Determining the Contribution to Load on Supporting Structure
Consider for example the wire A-B-C-D-E-F-G shown in the plan view at the top of Fig. 7.2-2. A
and G represent deadend structures. B, C, E, and F represent suspension structures or
structures with flexible post insulators. When subjected to real winds (not design assumptions)
each span of the wire A-B-C-D-E-F-G may be subjected to its own wind velocity, wind direction,
WA*, and gust response factor, GF*. This is illustrated schematically in part (a) of Fig. 7.2-2.
Obviously we will never be able to predict what combinations of velocity, direction and gust
response factors is appropriate for simultaneous application to each span of a multi-span
system. Therefore, some assumptions are needed for practical design. Our interest here is in
calculating structure design loads at point D. This section describes the wind assumptions
behind the calculations.
The transverse load at point D depends on the unit wind load UHL on the span to its left and the
unit load UHR on the span to its right and on the horizontal tensions in these two spans, HL and
HR.
UHL is calculated with
WA
D
Eq. 7-3 with the gust
BC
( a ) COMPLETE
response factor GFL and
SYSTEM
GF
C GF L
R
the wind incidence angle
E
F GF FG G
B
WAL for the left span as
GF
AB
A
shown in part (c) of Fig.
WA
RRS
WA
LRS
7.2-2. In the great
K
H
J
I
majority of applications,
( b ) RULING SPANS
GF LRS
GF
RRS
your specification will
LEFT
require you to use a
RIGHT
wind normal to the wire,
WA L
WA
R
D
i.e. WAL = 0 or 180
( c ) LEFT AND RIGHT SPANS
degrees.
UHR
is
GF
GF
R
B
calculated with the gust
L
C
E
F
G
A
response factor GFR and
the wind incidence angle
WIND LOADING ASSUMPTIONS WHEN " NORMAL ALL " IS NOT SELECTED
WAR for the right span.
Like WAL, WAR will be
Fig. 7.2.2 Wind Assumptions in Most General Case
required
by
most
specifications to be equal to 0 or 180 degrees). UHL and UHR also depend on the corresponding
average span attachment heights as described in Section 7.2.1.1.3.
If point D is not at a line angle, the horizontal tensions HL and HR have no effect on the
transverse load. If point D is located at a line angle, these tensions are important and are
calculated as described below.
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Assumptions for Level 1
At Level 1, the horizontal tensions in the left and right spans are assumed to be those of their
ruling spans.
If point D is a deadend, a Left Ruling Span (LRS) represents all the spans to the left of Structure
D (H-I in the middle part of Fig. 7.2-2) and a Right Ruling Span (RRS) represents all the spans
to the right of Structure D (J-K in the middle part of Fig. 7.2-2). Ruling spans are defined in
Section I-1. It is assumed that the wind incidence angle on the LRS, WALRS , is the same as
WAL and the wind incidence angle on the RRS, WARRS , is the same as WAR . The gust
response factor for the LRS, GFLRS, is based on the average height of all attachment points of
the spans to the left of D and the length of the LRS. The gust response factor for the RRS,
GFRRS, is based on the average height of all attachment points of the spans to the right of D and
the length of the RRS.
If point D is not a deadend, there is only one ruling span RS = LRS = RRS. It is assumed that
the wind incidence angle on that ruling span is the average of WAL and WAR. Its gust response
factor is based on the average height of all attachment points of the spans between points A
and G.
Assumptions for Level 2, Level 3 and Level 4
At Level 2, Level 3 or Level 4, the complete system between A and G is modeled to determine
the tensions. It is assumed that the wind direction on each span is either normal to the span (if
you select NA+ or NA- in the Structure Loads Criteria table of Fig. 7.3-10a), or is the same on
all spans, i.e. there is a global wind direction as shown at the top of Fig. 7.2-2. The global wind
direction is determined from your choice of Wind Direction (other than NA+ or NA-) in the
Structure Loads Criteria table. The unit wind load on each span is based on its gust response
factor which depends on the span length and average elevation.
7.2.1.3
Wind Load on Supporting Structure
Wind loads prescribed by PLS-CADD can only be applied to supporting structures if these
structures are modeled by TOWER or PLS-POLE (Method 4 structures). The following formula,
which is further modified for the effect of wind direction as shown by Eqs. 7-13 and 7-14) is used
to determine the design wind force, WF, applied directly to a part of a supporting structure
located at height z:
WF
2
= LFW WLF Q (W Z) GRFS CDS A
(7-4)
where WLF, Q and W Z were defined previously (Eqs. 7-1, 7-2 and 7-3) and:
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161
LFW
GRFS
CDS
A
= Load Factor for Wind
= Gust Response Factor for structure
= Drag coefficient of structure
= Exposed area of part of structure
An alternate form of Eq. 7-4 is:
WF
= LFW WLF Q (W)2 KZ GRFS CDS A
(7-5)
where KZ is the height adjustment factor.
The Load Factor for Wind LFW is entered in the Wire and Structure Wind Load Factor column of
the Structure Loads Criteria table (Note: for users of the EN 50341-3-9: UK-NNA wind model,
the number entered for LFW has a completely different purpose - it is used to enter the K-COM
factor of that model).
The Height Adjustment Factor KZ is automatically accounted for in TOWER or PLS-POLE
The structure Gust Response Factor GRFS can be entered manually in PLS-CADD or it can be
determined automatically in TOWER or PLS-POLE.
Manual input of structure gust response factor: If you are not required to use a code that
specifies how the structure gust response factor is to be calculated, you can enter its value
manually in the Structure Wind Area Factor column of the Structure Loads Criteria table.
Automatic calculation of structure gust response factor: If you want to have PLS-CADD
together with TOWER or PLS-POLE automatically calculate the structure gust response factor
for a supported design code, you select the code in the Structure Wind Load Model column of
the Structure Loads Criteria table.
The Structure Drag Coefficient CDS is either specified or determined automatically in TOWER
and PLS-POLE depending on your choice of design code in the Structure Wind Load Model
column of the Structure Loads Criteria table.
The Exposed Area A of the structure is determined by TOWER or PLS-POLE. The area of the
part in the TOWER or PLS-POLE model can be adjusted from PLS-CADD by a factor that you
enter in the Structure Wind Area Factor column of the Structure Loads Criteria table.
When a supported design code is specified in PLS-CADD, it is important that you understand
the changes that were made to the design pressure reported by PLS-CADD and passed to
TOWER and PLS-POLE when we upgraded these programs to Version 7.
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2
Prior to Version 7, the reported design pressure was LFW WLF Q (WZ) GRFS , where W Z
was a single velocity calculated at 2/3 the height of the structure.
2
Starting with Version 7, the reported design pressure is LFW WLF Q (W) . The last portion
of Equation 7-5, KZ GRFS CDS A , is automated entirely in TOWER and PLS-POLE.
7.2.2 Ice Model
7.2.2.1
Ice on Wires
Ice on wires in PLS-CADD can be specified as: 1) a combination of ice thickness and ice
density, 2) a nominal load per unit length of wire, or 3) any combination of the previous two. In
order to cover all the possible combinations, the vertical ice load per unit length of wire, UI, is
calculated by the formula:
UI
=
WLF (3.1416 ( D + tZ ) tZ DENS + W ICE)
(7-6)
where:
WLF
D
TZ
DENS
W ICE
= Weather Load Factor
= cable Diameter
= ice thickness at height z
= ice density
= ice load per unit length
The effects of W ICE and tZ are cumulative, i.e. if both are non zero, the ice load will include the
sum of the two.
Some design codes require that the thickness tZ be increased with height z above the ground
from the reference value “t“ (usually at 10 m - 33ft above the ground). This is handled
automatically by PLS-CADD for the supported codes. The effective height is the same as that
used for wind (see Sections 7.2.1.1.1 to 7.2.1.1.3). The weather load factor WLF, the reference
thickness “t“, the ice density DENS and the ice load per unit length W ICE are entered in the
Weather Cases table.
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7.2.2.2
Ice on Structures
When ice specified on wires, most design codes do not require that you apply that ice on the
members of the supporting structures. However, if your design code requires that you apply ice
on structure members, this is done automatically by the TOWER and PLS-POLE programs from
the ice data that you specify in the Structure Ice Thickness and the Structure Ice Density
columns of the Structure Loads Criteria table.
7.2.3 Load per Unit Length of Wire
The response of the wire system to
wind, ice or any combination of the two
depends on the resultant weather load
per unit length, UR (in N/m or lbs/ft).
UR is the resultant of the horizontal
wind load, UH in Eq. 7-3, the unit wire
weight, UW, and the vertical ice load,
UI in Eq. 7-6. UR is shown on the right
of Fig. 7.2-3.
t
UH
D
UH
UW
UW
UI
UI
UR
NESC
CONSTANT
UR NESC
Under wind, the span blows out with
the angle β (see Fig. J-2), the tangent
of which is UH / (UW + UI). Therefore,
Fig. 7.2-3 Loads per Unit Length of Wire
when a tension section is displayed for
a given climatic condition, the blowout angle of each span of the tension section is the same
because the wind load in each span (UHTS described in Section 7.2.1.2.1) is the same.
7.2.3.1
NESC District Case
Transmission line designers in the United States who are subjected to the National Electric
Safety Code (NESC) have had to endure an archaic system of loads and strengths which has
not seen much improvement over the past 50 years. Besides using arbitrary load and strength
factors, Rule 250B of the NESC still prescribes a method that does not satisfy the basic
principles of statics.
Under Rule 250B of the NESC 2007 (the so-called District Case): 1) the wind velocity (and
pressure) is a fixed nominal value which does not depend on height and span length, 2) the
wind is always applied normal to a span (i.e. there is no possibility of considering varying wind
incidences - angle WA in Eq. 7-3), and 3) the resultant load per unit length of wire is increased
by an arbitrary constant (the so-called "NESC Constant" or "K" constant) for the purpose of
calculating wire tensions. There is no physical nor rational reason for the "K" constant to exist.
The increased resultant load, URNESC , is shown on the left of Fig. 7.2-3. Therefore, any
structure load based on wire tension (transverse line angle load or vertical load in case of a non-
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level span) should be based on the tension caused by URNESC. However, it has always been the
intention of the NESC that the wind load on a structure only be based on the horizontal load per
unit length of wire, UH, times the average length of wire in the two adjacent spans. The NESC
District requirements do not satisfy statics because UH and URNESC cannot occur at the same
time. There is no physical cable or general analytical 3-dimensional cable model (such as that
used by our Level 2, 3 or 4 modeling or by any commercial finite element computer program)
that can possibly be loaded by the NESC District load case when "K" is nonzero. Therefore,
some elaborate steps had to be used to implement the NESC District Case in PLS-CADD.
Ruling Span Method (Level 1 modeling)
For the purpose of determining tensions, sags and the overall 3-D geometry of all the wires in a
tension section, all wires are assumed to be subjected to URNESC. Then, for the purpose of
determining the support reactions and insulator swings at the ends of a particular span, some of
the resulting force components are scaled down by the ratio UR / URNESC as described in
Section 7.3.12.4. This is the PLS-CADD way of making sure that all loads based on mechanical
tension include the effect of "K", while all loads which do not depend on tension (such as the
direct effect of the wind) are based on UR.
Finite Element modeling (Levels 2, 3 and 4 modeling)
For the purpose of determining tensions, sags and the overall 3-D geometry of all the wires, the
structural analysis of the tension section is based on values of UH, UW and UI which are scaled
up by the ratio URNESC / UR. Then, for the purpose of determining the loads on a particular
structure the same process described above for the Ruling Span Method is used.
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7.3
Detailed Design Criteria
This section describes the many design criteria that can be used and checked with PLS-CADD.
The design criteria are selected in the Criteria menus (Fig. 7.3-1). We will describe these menus
in the order in which they appear.
A set of criteria can be saved in a single file which
has the .cri extension. Criteria file can be
developed in standard libraries to be shared
among various projects (for example design
criteria for 69kv wood poles could reside in the file
Wpoles69kv.cri), or they can be developed only for
a specific project. When you save a project, the
criteria in use at the time of saving are saved in the
file Project.cri.
If standard criteria already exist in a file
Standard.cri, all you need to do to use them in a
new project is to load Standard.cri with Criteria/
Load CRI. This action will copy all the data in
Standard.cri into the new project criteria file
Project.cri.
If, after having developed some
criteria, you want to save them to become part of a
permanent library, you can do so with the Criteria/
Save CRI command where you can specify the
name of the library file.
7.3.1 Notes
Fig. 7.3-1 Design Criteria Menus
The Criteria/ Notes menu allows you to enter notes describing the various standards,
assumptions, authors, dates, etc. related to the set of criteria in a particular .cri file. A company
may work with different sets of criteria at any one time, and it is extremely important to
document the origin and limits of validity of a particular set of criteria. There is an option at the
top of the Criteria Notes dialog box which enables the user the option to print or suppress the
criteria notes on the top of all reports.
Important Note: In any line of the Criteria Notes table you can include the complete path and
file name of a set of criteria that may be used as an alternate to the current set of criteria. For
example, you can have the text string “C:\PLS\Wpoles138kv.cri“ in the Criteria Notes table for
a Wpoles69kv.cri file. If you do this, the alternate criteria file (or files) will be included in a
backup of your model created with the File/ Backup command.
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7.3.2 Weather Cases
Many strength and
serviceability
(clearances) criteria
assume that the line
is subjected to a
given combination of
wind, ice (or snow)
and
temperature.
Such a combination
is defined herein as a
"weather case". In
PLS-CADD, all cable
sag
and
tension
calculations,
and
consequently
all
loads and clearance
calculations,
are
made for designated
Fig. 7.3-2 Weather Cases
weather cases. All
weather cases which will be used in a particular design must be described in the Weather
Cases table (see Fig. 7.3-2) which you reach with Criteria/ Weather. A weather case table
typically includes a group of weather cases for checking the strength of the structures, a group
for checking various geometric clearances (to ground, blowout, between phases, swings, etc.),
and a group for checking ground wires and conductors tensions. It also includes the weather
case assumed to cause creep, the heavy load case which potentially causes permanent stretch
of the various cables, and various weather cases needed for displaying the cables at various
temperatures. For example, the conditions for checking structures (first four lines in Fig. 7.3-2)
may include: 1) an NESC combination (see Section 7.2.3.1), 2) an extreme wind condition, 3)
an extreme ice condition with some reduced wind, and 4) an extreme cold condition. There are
usually a number of conditions for checking vertical, lateral and galloping clearances (lines 5 to
13 in Fig. 7.3-2). For checking the cables, the conditions may include: 1) the NESC
combination, 2) no ice and no wind at an everyday temperature, etc. Therefore, for a given
project, the Project.cri file may contain a substantial number of weather cases. Note: The
weather cases in Fig. 7.3-2, which come from the Demo.cri file, are provided for illustration
purposes only and should not be used in connection with actual projects.
Sample
NESC
Criteria
may
be
downloaded
from
our
web
site
at
http://www.powline.com/files/criteria.html These samples are for illustration only and should not
be used unless checked and modified if necessary by an engineer in responsible charge.
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Data in the Weather Cases table include:
Air density factor:
Factor Q in Eq. 7-1
Wind velocity or Pressure:
Basic (or reference) velocity or pressure. You enter one and the
other is automatically calculated with Eq. 7-1
Wire Ice thickness, t:
Thickness of ice assumed uniformly deposited on wire - used in
Eqs. 7-3 and 7-6
Wire Ice density, DENS:
Density used in Eq. 7-6
Wire Ice load, WICE :
Ice load per unit length of wire - used in Eq. 7-6
Wire Temp:
Conductor or ground wire temperature
Ambient Temp.:
Used for fiber reinforced pole modeling as described in Section
3.1.6.2 of the PLS-POLE manual. Not used in any other
calculations at this time.
Weather Load Factor:
Factor applied to wind and ice loads in Eqs. 7-3 to 7-6. Default = 1
NESC Constant, K:
Constant K used only for the NESC District Case - see
Section 7.2.3.1
Wire Wind Height
Adjust Model:
Select None, if you want your input values of wind velocity and
pressure to be used on all wires and structures regardless of their
height above ground
Select ASCE 1991, ASCE 2002, NESC 2012, EN50341-1, IEC
60826, AS/NZS 7000:2010, etc. if you want the wind velocity to be
automatically increased with height according to one of the
available design codes (see Section 7.2.1.1)
Wire Gust Response
Factor, GRFC:
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Gust response factor for all wires (GRFC in Eq. 7-3). You can
type-in a single value or have the gust response factor for all wires
automatically calculated if you select one of the available design
codes.
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7.3.3 Code Specific Wind and Terrain Parameters
After selecting Criteria/ Code Specific Wind and Terrain Parameters, you will be taken to a
series of submenus where you will have to enter code specific information regarding wind and/
or terrain parameters. Make sure that you fill out all the requested information for the design
code you intend to use.
7.3.4 Conditions for Cable Creep and Permanent Stretch
The mechanical
cable model used
by PLS-CADD for
ground wires and
conductors
is
described in detail
in Section 9.1.
This model allows
the program to
make sag and
tension
calculations for a
cable
in
its
"Initial", final after
"Creep", and final
after
"Load"
conditions.
The
Fig. 7.3-3 Creep and Heavy Load Weather Cases
cable
condition
("Initial", "Creep" or "Load") is a specified item in many PLS-CADD functions. The cable is
assumed to be in its "Initial" condition for the few hours which follow its installation. It is in its
final after "Creep" condition after it has been assumed exposed to a particular creep weather
condition for a long period of time, say 10 years. It is normally assumed that the weather case
that causes creep consists of a no wind/ no ice condition at some average temperature. The
average temperature of 60 deg. F is often used in North America, unless the line spends several
months in very cold weather, in which case a colder value is appropriate, say 30 deg. F or less.
The final after "Load" (also referred to as "final after common point") condition assumes that the
cable has been permanently stretched by a specified weather condition (say the NESC District
Case or any other case causing large tensions). The Weather case for final after creep or final
after load conditions are picked from the list of all available weather cases in the Criteria/
Creep-Stretch menu (see Fig. 7.3-3). The program will automatically pick the weather case
producing the largest load on a section by section basis. Shield wires and different conductors
could end up with different after load weather cases.
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7.3.5 Bimetallic Conductor Model
Because the aluminum portion of an ACSR conductor expands at a higher rate than the steel
core portion at high temperature, there is a temperature beyond which the aluminum goes into
compression. In the Criteria/ Bimetallic Conductor Model menu or the particular cable file,
you have the option of assuming that it is either not possible for the aluminum to go into
compression (i.e. it would "bird cage" or buckle outwards) or that it can go into compression.
The settings in the cable file can be entered to receive the bimetallic conductor model behavior
from the settings in Criteria/Bimetallic Conductor Model or from the selection in the cable file.
If you assume that the aluminum can go into compression, you can enter a maximum
compression stress (actually modified by the ratio of aluminum to total area of the cross
section). The ridiculously large maximum stress value used as a default is equivalent to
assuming that the aluminum is welded to the steel and cannot buckle outwards. See Section
9.3.2 for more details.
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7.3.6 Cable Tensions
Design limits for ground
wires or conductors are
normally specified as
maximum tensions or
maximum
catenary
constants
under
specific
weather
conditions. These limits
are specified in the
Cable Tension Criteria
table (Fig. 7.3-4) which
you open with Criteria/
Cable Tensions. For
each limit, you: 1) pick
a Weather case , 2)
pick a Cable condition (
"Initial", "Creep", or
"Load"), 3) enter a
Fig. 7.3-4 Design Tension Limits for Cables
maximum tension as a
% of Ultimate, and/ or a Maximum Tension, and/ or a Maximum Catenary constant, and 4)
specify whether the limits apply to all cables or only to specific cables (Applicable cables
column). For example, US practice may specify three design limits: 1) 60 % when loaded with
the NESC District weather condition (Initial), 2) 35 % of ultimate or less at an everyday
temperature (Initial), and 3) 25 % or less at an everyday temperature (after Creep). In addition,
you may require that whenever a Drake conductor is used, its maximum tension does not
exceed 15,000 lbs under some Extreme Ice case (line 4 in Fig. 7.3-4). Limiting the use of
conductors by specifying a maximum catenary constant (Horizontal tension over unit weight, or
H/w) is becoming the preferred scientific way to specify maximum tensions with respect to
aeolian vibrations (CIGRE, 2001).
The design limits you input in the Cable Tension Criteria table are checked for an actually
sagged tension section with the Sections/ Check function, as described in Section 11.2.2, or
with Lines/ Reports/ Section Usage or Structure & Section Usage + Survey Point
Clearances.
7.3.7 Automatic Sagging
One of the sagging methods used in PLS-CADD is to let the program sag the cables as tight as
possible without violating a certain number of limits. The limits can be the same as those
described in Section 7.3.6 or they can be more restrictive. The Criteria/ Automatic Sagging
menu lets you define the limits for automatic sagging in the Automatic Sagging Criteria table
which is similar to that shown in Fig. 7.3-4.
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The design limits you input in the Automatic Sagging Criteria table are used to determine the
sagging tension of a tension section when you click on the Automatic Sagging button of the
Section Modify box which is available from the Sections/ Modify command. This is described
in Section 10.3.2. A section can also be sagged according to the constraints in the Automatic
Sagging Criteria Table using the AutoSag command in the Sections/ Table.
Important Note: If using the Automatic Sagging routine with a finite element (FE) cable
condition selected and using L3 or L4 level of FE sag tension in the Criteria/ SAPS Finite
Element Sag Tension menu the result can influence tension in adjacent sections since this will
influence structure deflections.
7.3.8 Maximum Tension
Maximum cable tensions are calculated and reported in several places by PLS-CADD. You
need to tell the program whether a maximum tension is: 1) the maximum tension in the ruling
span, a single fictitious span with equal end elevations equivalent to the several spans making
up the tension section, or 2) the actual maximum tension in the tension section, considering
both ends of each of the several spans in the tension section and changes in elevations. See
Appendix I for the definition of ruling span.
7.3.9 Weight Span Model
Depending on the method used to check the strength of your structures, you may need to
calculate a weight (or vertical) span. As discussed in Appendix I.3, there are different ways,
from very approximate to accurate, of calculating weight spans. The Criteria/ Weight Span
Model menu lets you select which calculation method you wish to use for weight spans.
7.3.10 Conditions for Checking Weight Spans of Method 1 Structures
When structures are checked
by the "basic allowable wind
and weight spans" method
(see Method 1 in Section
8.3.1), the actual weight
spans (defined in Appendix
I.3) of their heaviest attached
Fig. 7.3-5 Conditions for Calculating Weight Spans
cable are compared to
corresponding allowable values for three weather conditions. These conditions normally include
a "wind", a "cold", and an "iced" conditions. There must be a one-to-one correspondence
between the weather conditions which were used to develop the allowable weight spans in the
files of Method 1 structures and the weather conditions used by PLS-CADD to calculate actual
weight spans to check these structures. This mapping is done in the Weight Span Criteria
dialog box (see Fig. 7.3-5) which is reached with Criteria/ Weight Spans (Method 1).
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7.3.11 Conditions for Checking Method 2 Structures
When structures are checked by
the "wind and weight spans
interaction diagrams" method
(see Method 2 in Section 8.3.2),
there is one allowable interaction
diagram for each of a number of
combinations of weather cases
and angle ranges. The diagrams
are defined in the files of Method
2 structures. There must be a
one-to-one
correspondence
between the weather conditions
which were used to develop the
allowable interaction diagrams
and the weather conditions used
Fig. 7.3-6 Conditions for Interaction Diagrams
by PLS-CADD to calculate actual
wind and weight spans to check the structures with Method 2. This mapping is done in the
Interaction Diagram Criteria table (see Fig. 7.3-6) which you reach with Criteria/ Interaction
Diagram (Method 2). If your interaction diagrams are developed automatically by the TOWER
or PLS-POLE programs for the load cases described in the Structure Loads Criteria table
(see Fig. 7.3-10), then the weather cases in Fig. 7.3-6 should coincide with those in Fig. 7.3-10.
7.3.12 Load Trees for Method 3 and Method 4 Structures
When the strength of Method 3 or Method 4 structures (see Sections 8.3.3 and 8.3.4 for the
definitions of Method 3 or Method 4 Structures) is checked, loading trees are established for a
certain number of "load cases" and are used for the analysis of the structures. There are many
assumptions which can be used to determine a loading tree. Therefore, it is important that they
be clearly spelled out. This is the purpose of the following sub-sections.
7.3.12.1
Structure Axes and Orientation Relative to Line
Any structure used by PLS-CADD
has its geometry described relative
to the structure local axes. Each
structure has its local transverse
axis, TS, and its local longitudinal
axis, LS, rotated 90 degrees
clockwise from the transverse axis,
when looking at the structure from
the
top
(see
Fig.
7.3-7).
The
LS
LS
LA +
W
LS
LINE
WB
W
LA -
W
TS
TS
SO
SO
WB
TS
SO
Fig. 7.3-7 Structure and Wind Orientations (View from Top)
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structure loading tree should have load components in the directions of the structure local axes.
When a structure is located along a line, its orientation is defined by its orientation angle, SO.
SO is positive if clockwise as viewed from the top. At a line angle, SO is measured from the
bisector of the line angle on the side of positive offsets, i.e. on the right when you march down
the line in the direction of increasing stations. This is depicted at the center of Fig. 7.3-7 at a
positive line angle (LA+) and at the right of the figure at a negative line angle (LA-). At a location
where there is no line angle, SO is measured from the perpendicular to the line, as shown on
the left of Fig. 7.3-7.
If the structure is a XYZ Based Structure then the transverse axis of the structure is oriented to
the right from due North which is 0 degrees orientation. So the ahead direction of the structure
would be pointed due north.
When a wind blows on a structure and its two adjacent spans, an option described in the next
section is to describe the wind direction, WB, relative to the bisector or a global direction (see
Fig. 7.3-7).
7.3.12.2
Wind Direction
There are ten wind direction options available when developing a loading tree in PLS-CADD.
Some of these options are depicted in Fig. 7.3-8 and are discussed in more detail below. The
back or left span is that which corresponds to the direction the conductor is strung where wire is
entering a structure. The ahead or right span is on the other side of the structure where the wire
is leaving the structure. The Drafting/ Show Stringing Direction command can help identify the
direction of stringing for sections with arrows on the wire such that an arrow pointing toward the
structure is a back span and an arrow pointing away from the structure is an ahead span.
With the option "NA+" (which stands
for Normal All Positive), the wind
blows perpendicular to the spans (left
span, right span and span taps, if
any). It blows on a structure located in
a straight portion of the line in the
direction perpendicular to the line. On
NORMAL ALL +
a structure located at a line angle, it
WB
WB
blows in the direction of the bisector
of the line angle. The general wind
BISECTOR +
BISECTOR WB IS INPUT
WB IS INPUT
direction is always in the direction of
positive offsets, as shown by the
NORMAL LEFT (OR RIGHT) + (OR - ) IS
three sketches in the upper left corner
SAME AS BISECTOR + (OR - ) WHERE
ANGLE WB IS CALCULATED SO THAT WIND
of Fig. 7.3-8. With this option, all the
IS PERPENDICULAR TO LEFT (OR RIGHT) SPAN
NORMAL ALL wind incidence angles in Fig. 7.2-2
(WAL, WAR, WALRS, WARRS, etc.) are
Fig. 7.3-8 Available Wind Direction Options (View from Top)
set to zero. At a line angle, this
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situation cannot describe a real wind, but it is often used as a conservative assumption,
especially when nominal wind pressures are specified.
The "NA-" (which stands for Normal All Negative) option is identical to the "NA+" option, except
that the wind blows in the opposite direction of that of "NA+", as depicted by the three sketches
in the lower left of Fig. 7.3-8.
With the option "BI+" (which stands for BIsector Positive), the wind blows in the general
direction of positive offsets and in the direction defined by the wind angle, WB, which is
measured from the perpendicular to the line or the bisector of the line angle on the side of
positive offsets. The situation is depicted by the three sketches in the center of Fig. 7.3-8. The
value of WB should be between -90 and +90 degrees. With this option, the wind incidence
angles for the left and right spans (WAL and WAR in Fig. 7.2-2) are calculated internally so that
the wind velocity vectors on the spans and on the structure are all parallel to each other.
With the option "BI-", the wind blows in the general direction of negative offsets and in the
direction opposite to that defined by the angle WB. The situation is depicted by the three
sketches in the top right portion of Fig. 7.3-8. As with the "BI+" option, the value of WB should
still be between -90 and +90 degrees.
The option "NL+" (which stands for Normal Left Plus) is similar to "BI+", except that there is no
need to input the value of WB. WB is calculated internally so that the wind is perpendicular to
the left span.
The option "NL-" is similar to "BI-". WB is calculated internally so that the wind is perpendicular
to the left span.
The option "NR+" is similar to "BI+". WB is calculated internally so that the wind is perpendicular
to the right span.
The option "NR-" is similar to "BI-". WB is calculated internally so that the wind is perpendicular
to the right span.
The option "GLB" lets you blow the wind in a global direction (relative to north).
The option “MAX” blows wind in an angle increment defined in the Wind Direction dialog box for
360 degrees around a structure and uses the wind direction that produces the max structure
usage for M4 structures and maximum base moment for M1/M2/M3 structures. The transverse
and longitudinal wind is always checked regardless of wind angle increment.
Important Note: The “MAX” option will find the one component in the M4 model with the
highest percent usage from the wind angles selected. The highest usage member is reported
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based on this wind angle. There may be other wind angles that produce a high usage for other
components at a different wind angle.
Note: The options NL+, NL-, NR+ and NR- should not be used with PLS-CADD/ LITE models
as such models do not include the concept of left (back) and right (ahead) spans.
To make sure that unsymmetrical structures are checked for wind in both the positive and
negative directions, it is recommended that each load situation which includes some wind be
described by two load cases: one with the wind in the positive direction and one with the wind in
the negative direction. Therefore, in general, wind load cases should appear in pairs, for
example one load case with "NA+" and the associated load case with "NA-". The program will
issue a warning if it detects unpaired wind load cases.
7.3.12.2.1
Wind Direction XYZ Structures
XYZ Structures as described in section 10.2.8 have their wind applied in the same way for
conductors based on the direction the wire is strung but the wind direction applied to the
structure is based on the line angle between the structures. As mentioned previously and
shown in Figure 7.3-8 the structure wind is applied to the bisector of the angle between the
structures for the NA selection of wind direction. This bisector angle for XYZ Structures is
defined based on the adjacent structures identified by the wires nominated for the angle in the
Structures/ Staking Table column Sets in XY Structure Line Angle Calculation as
discussed in Section 10.2.8.5. The difference is that the sets nominated in this dialog of the
table are used to identify the adjacent structures. Then these structure locations are used to
create a virtual alignment for the ahead and back spans of a structure so the bisector of the
structure can be identified.
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7.3.12.3
Reactions at Ends of Span (in span coordinate system)
When determining a loading tree,
PLS-CADD computes first the
reactions at the ends of all cables
attached to the structure. These
normally include the cables in the left
and the right spans, but they may
also include cables in taps as shown
in Fig. 7.3-9. In Fig. 7.3-9, the arrows
at the ends of the lines representing
the spans are the reactions at the
ends of these spans, while the
opposite arrows on the small square
at the center of the figure represent
the equal and opposites actions
(loads) on the structure.
TA
LA
TL
TL
TR
TA
LR
LL
LB
TR
TB
TB
Fig. 7.3-9 Loads in Span Coordinate System
The reactions at the right end of one cable in the left span are: 1) a vertical force VL, 2) a
transverse horizontal force TL perpendicular to the span and opposite to the direction of the
wind, and 3) a longitudinal force LL equal to the horizontal component of cable tension (see Fig.
7.3-9).
The reactions at the left end of one cable in the right span are: 1) a vertical force VR, 2) a
transverse horizontal force TR perpendicular to the span and opposite to the direction of the
wind, and 3) a longitudinal force LR equal to the horizontal component of tension in the cable.
Similar reactions can be defined at the end of taps.
The sign conventions regarding vertical and transverse forces in the span coordinate system
are as follows: 1) vertical forces are positive if they pull down on the structure, and 2) transverse
forces are positive if their actions on the structure have positive projections in the positive
bisector direction (see Fig. 7.3-9), or the positive offset direction if there is no line angle.
Longitudinal forces in the span coordinate system are always positive.
The procedure used in PLS-CADD for calculating the reactions at the ends of a cable is a three
step process. First, the horizontal tension, H, and the unit wind load on the cable, UH, are
determined based on the gust response factors and wind direction assumptions described in
Section 7.2.1.2.2. From UH, the resultant load per unit length of cable, UR, is determined as
described in Section 7.2.3. Then, H and UR are used in the equations in Section J.1.1. Finally,
the span end reactions are obtained with Eqs. J-11 to J-13 in Section J.1.2. With unequal end
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elevations, the procedure yields end span forces which can be slightly different from what would
be obtained by the simpler concepts of wind and weight spans.
Factored reactions at the ends of bundle in span
Sometimes, load (or safety) factors are applied to the V, T and L span reactions. The span may
also consist of a bundle of cables instead of a single cable. Therefore, factored bundle span
reactions are determined as follows for the left and right spans, respectively:
VL*
TL*
LL*
= LFV { NCL VL }
= LFW { NCL TL }
= LFT { NCL LL }
(7-7)
(7-8)
(7-9)
VR*
T R*
LR*
= LFV { NCR VR }
= LFW { NCR TR }
= LFT { NCR LR }
(7-10)
(7-11)
(7-12)
LFV
LFW
LFT
NCL
NCR
= Load factor for vertical load
= Load factor for wind
= Load factor for tension
= Number of subconductors in left bundle
= Number of subconductors in right bundle
Where:
Similar equations are used for taps.
For example, recent editions of the NESC have specified LFV = 1.5, LFW = 2.5 and LFT = 1.65
for District Loads applied to steel structures.
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7.3.12.4
Design Loads at Structure Attachment Points
The factored reactions at the ends of all the bundles that meet at a structure or insulator
attachment point are combined with the weights (if any) of the insulator, W INS, and
counterweight, W CW, to form the design loads at the structure attachment points. The design
loads constitute the structure loading tree. These design loads are defined by their components
in the directions of the local structure axes. The structure transverse and longitudinal axes, TS
and LS, are shown in Fig. 7.3-7.
Loads from Left Span
The transverse and longitudinal design loads contributed by the left span are the projections of
the span loads TL* and LL* in Eqs. 7-8 and 7-9 in the directions of the structure axes TS and LS
shown in Fig. 7.3-7. The vertical design loads are the sum of VL* in Eq. 7-7 plus the weights of
the attached insulators and counterweights times the Load Factor for Structure weight, LFS.
Loads from Right Span
The transverse and longitudinal design loads contributed by the right span are the projections of
the span loads TR* and LR* in Eqs. 7-11 and 7-12 in the directions of the structure axes TS and
LS shown in Fig. 7.3-7. The vertical design loads are the sum of VR* in Eq. 7-10 plus the
weights of the attached insulators and counterweights times the Load Factor for Structure
weight, LFS.
Loads from Taps
The loads from taps which are not part of the left and right spans are calculated in the same
manner as those in these left and right spans. The end of tap spans are modeled by structures
which are offset from the main alignment or are on a branch, tap or parallel alignment.
You can use Structures/ Loads/ Report to generate the complete structure loading tree report
as well as the factored span reactions of Eqs. 7-7 to 7-12.
NESC District Load Case
The oddity of the NESC District Load Case was first described in Section 7.2.3.1.
The handling of "K" was never a problem when used in conjunction with the traditional Wind &
Weight Spans method for the calculation of structure loads. Such calculations were usually
made as follows. First, the cable mechanical tension, H, was determined, either manually or
using a sag-tension program. H was then used to cut a template with which the cable catenary
curves were drawn in the two spans adjacent to the structure. These curves were drawn as if
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they are in a vertical plane, even though they can only exist in the blown out plane defined by
the direction of URNESC. The horizontal distance between the low points in the adjacent
catenaries were generally used as the Weight Span. The vertical load was then calculated as
the product of UV times the Weight Span. Because the actual location of the low points on
blown out cables with unequal end elevations can differ from that determined with the vertical
template, that traditional calculation of vertical load could lead to substantial errors. The wind
component of the transverse load was calculated as the product of UH times the Wind Span.
Finally, the tension component of the transverse load was calculated on angle structures by
projecting the cable mechanical tensions in the structure transverse direction. The
decomposition of the transverse load into wind and tension components allowed the NESC to
specify different load factors for each.
The traditional Wind & Weight Span method works well for developing loads for a new family of
structures designed to support pre-determined combinations of wind and weight spans. In such
cases, you should use PLS-CADD/ LITE with the Wind + Weight Spans Design Mode option, as
described in Section 15. With that option, PLS-CADD will give results identical to the traditional
method, regardless of whether a nonzero "K Constant" is used.
The traditional method does not work well for the determination of actual loads on structures
already spotted on an uneven terrain, unless the effect of span blowout on weight span is taken
into account. This is one of the reasons why the models described in Appendix J have been
adopted. However, because PLS-CADD uses URNESC and its direction to determine the end
cable forces, some adjustment is needed. Without the adjustment, it would be as though UH
and UV were scaled up to match URNESC and the transverse and vertical loads would be larger
with "K" than without it, a result which we believe is not the intention of the NESC. The
adjustment we have implemented in PLS-CADD in the case of a nonzero "K" it to scale down
VL, VR, TL and TR in Section 7.3.12.3 by the ratio UR / URNESC.
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7.3.12.5
Design Pressures on Structure Faces
A complete load tree for a structure includes not only the design loads at the structure
attachment points but also the design pressures to be applied to the body of the structure itself
in its transverse and longitudinal directions. The design pressures depend on the relative
orientation of the wind and the structure.
Starting with Version 7, the following formulae are used by PLS-CADD to compute the
reference Structure design PRessures, SPRT and SPRL to be used in the transverse and
longitudinal directions of the structure, respectively:
2
SPRT = LFW WLF Q (W) cos[WB - SO]
2
SPRL = LFW WLF Q (W) sin[WB - SO]
(7-13)
(7-14)
where (see Eq. 7-5):
LFW
WLF
Q
W
WB
SO
= Load Factor for Wind (input in Structure Loads Criteria table)
= Weather load factor (input in Weather Cases table)
= Air density factor (input in Weather Cases table)
= Reference wind velocity (input in Weather Cases table)
= Wind direction angle as defined in Fig. 7.3-7
= Structure Orientation angle as defined in Fig. 7.3-7
The structure pressures SPRT and SPRL are available in the loads tree report which you
generate with Structures/ Loads/ Report.
When used in conjunction with TOWER and PLS-POLE, PLS-CADD transmits these pressures
to these programs through their load cases files (“*.lca“ or “*.lic“ files). These pressure will find
their way in the transverse and longitudinal pressures columns of the load case files. Then
TOWER or PLS-POLE will automatically adjust them by the factors KZ , GRFS and CDS
described in Equation 7-5 as required by a particular design code, and multiply them by the
appropriate exposed area A to get the final structure wind forces.
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7.3.12.6
Load and Strength Factors
In order to provide a flexible implementation of Load & Resistance Factored Design (LRFD), or
the similar system of "overload capacity" factors required by the NESC, when PLS-CADD is
used in combination with our structure programs PLS-POLE and TOWER, it is necessary to
coordinate the values of the Load Factors (developed in PLS-CADD) with those of the Strength
Factors ultimately used in the structure programs.
The typical LRFD equation for one load case can be written as:
Load Factor x Nominal Design Loads < Strength Factor x Nominal Design Strength
(7-15)
In Eq. 7-15, the strength side can have a multitude of combinations. For example, for a wood
frame structure with a steel cross arm, a strength factor of 0.65 may be assigned to the wood
poles and a strength factor of 1.0 may be assigned to the cross arm.
Load Factors available in PLS-CADD are:
LFV
LFW
LFT
LFS
=
=
=
=
Load Factor for Vertical load (see Eqs. 7-7 and 7-10)
Load Factor for Wind (see Eqs. 7-8 and 7-11)
Load Factor for Tension (see Eqs. 7-9 and 7-12)
Load Factor for Structure weight
Nominal Design Loads in PLS-CADD are all the loads shown in the previous sections prior to
the application of the load factors.
Eleven Strength Factors can be passed to the structure programs by PLS-CADD for each
factored load case. These factors are:
Strength factor for steel poles, tubular arms or towers:
Strength factor applied by PLS-POLE to the calculated strength of all tubular steel poles, tubular
steel arms and tubular steel cross arms in the model and by TOWER to the strength of steel
angles and bolted connections. It is not applied to steel cables and guys.
Strength factor for wood poles:
Strength factor applied by PLS-POLE to the calculated strength of all wood poles.
S.F. for concrete poles - Ultimate:
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Strength factor applied by PLS-POLE to the ultimate bending capacity of all concrete pole
segments.
S.F. for concrete poles - First crack:
Strength factor applied by PLS-POLE to the moment causing the first crack in a concrete pole
segment.
S.F. for concrete poles - Zero tension.:
Strength factor applied by PLS-POLE to the moment causing no tension in the concrete of a
concrete pole segment. It is the moment that would cause an existing concrete crack to re-open.
S.F. for guys and cables:
Strength factor applied by both PLS-POLE and TOWER to the tension capacity of all cables
and guys
S.F. for non-tubular arms:
Strength factor applied by PLS-POLE to the strength of all arms and cross arms which are not
made of tubular steel
S.F. for Braces:
Strength factor applied by PLS-POLE to the strength of all braces
S.F. for Insulators:
Strength factor applied by PLS-POLE and TOWER to the strength of all insulators
S.F. for Hardware:
Strength factor applied by PLS-POLE and TOWER to the strength of hardware capacities
assigned to insulators.
S.F. for Foundations:
Strength factor applied by PLS-POLE and TOWER to the strength of all foundations
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A strength factor entered as zero in Eq. 7-15 indicates that the particular factored load case
should not be used for checking the components associated with the particular strength factor.
For example, in order to implement the alternate method for wood of the 2002 version of the
NESC District Case for a wood frame with a steel cross arm (not tubular steel), two factored
combinations would be used:
Load case # 1 (for checking the wood poles only):
LFV = 2.2, LFW = 4, LFT = 2, LFS = 2.2
Strength factor for non-tubular arms = 0
Strength factor for wood poles = 1
Load case # 2 (for checking steel cross arm only):
LFV = 1.5, LFW = 2.5, LFT = 1.65, LFS = 1.5
Strength factor for non-tubular arms = 1
Strength factor for wood poles = 0
Factored loads developed by PLS-CADD can be exported as standard load files (in the ".lca"
and ".lic" standard formats discussed in the Structure Program manuals) using the Structures/
Loads/ Write LCA (or LIC) File command. These files include the strength factor information
for each load case. It also includes the wire geometry information for each load case. This wire
geometry for the lad case can be displayed in PLS-POLE and TOWER models. You may also
write multiple LCA files for use in the PLS structure programs for a range of structures in PLSCADD by going to Lines/Reports/Structure Loads Report and checking the box at the bottom
of the dialog box. You can also check the option to create marker showing wire geometry used
to compute loads in the Structure Loads Report which will show all wire positions used for the
load calculation.
The Load Factors and Strength Factors are only used for the check of Method 4 structures by
PLS-POLE or TOWER. They are not used and are not necessary when you check the
strength of Method 1 (Basic allowable spans) or Method 2 (Interaction diagrams between
allowable spans) structures. The Load Factors information is used, but the Strength Factors
information is not used and is not necessary when you check the strength of Method 3
(Critical components) structures.
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7.3.12.7
Unbalanced Loading
PLS-CADD has the ability to develop loading trees for situations where the loads are not the
same on either side of a structure. This situation is defined herein as "unbalanced loading".
There are some commands that allow you to modify the loads in any one of the "back" spans or
the "ahead" spans. Therefore, it is essential that you understand what are back and ahead
spans. Fig. 7.3-9a will help clarify the definitions.
The sketches in Fig. 7.39a are top views of a
main
structure
S
(represented
by
a
square) and the spans
radiating
from
it.
Structures at the ends of
the radiating spans (end
span structures) are
depicted by small circles.
The left of Fig. 7.3-9a
represents
structures
and spans that are part
of a full PLS-CADD
model. The structures
are located by their
2
2
3
3
TOP VIEWS
S
S
4
1
B
A
1
A
4
B
5
STRUCTURES
MAIN STRUCTURE , S
STRUCTURES IN FULL PLS - CADD
A - S - B IS ALIGNMENT
STRUCTURES IN PLS - CADD / LITE
A - S - B IS FICTITIOUS ALIGNMENT
IN LONGITUDINAL DIR. OF STRUCTURE
SPAN # - S IS A BACK SPAN FOR STRUCT. S IF ITS PROJECTION ON ALIGNMENT
IS TO THE LEFT OF S - OTHERWISE IT IS AN AHEAD SPAN
projections (stations) on
Fig. 7.3-9a Definitions of Back and Ahead Spans
the alignment and their
offset from that alignment. In this example, the alignment A-S-B has a line angle at S. Back
spans for Structure S (1-S, 2-S and 5-S) are those for which the stations of the end span
structures are smaller than the station of S. Ahead spans (S-3 and S-4) are the others.
The right of Fig. 7.3-9a represents structures and spans that are part of a PLS-CADD/ LITE
model (PLS-CADD/ LITE is described in Section 15). In such a model the end span structures
are located by their azimuth (relative to the transverse axis of the main structure S) and span
lengths. Therefore, in this case, there is no defined alignment. However, in order to use the
same definitions of back and ahead spans as used for a structure in a full PLS-CADD model,
we define a fictitious straight line alignment that is perpendicular to the transverse axis of the
structure.
To simulate unbalanced loading, PLS-CADD allows you to modify the amount of wire loading on
(or from) up to twenty (20) individual wires attached to a structure. This is done by letting you
modify, for each load case, the original load on the wire or the load transmitted by the wire to
the structure. For each modified wire load (there are 20 possible such modifications labeled #1
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to #20 at the top of the rightmost columns of the Structure Loads Criteria table), you will need
to enter three pieces of data: 1) which wire (or wires) is to be acted upon in the “Wire (s) - Set Phase - Span“ column , 2) what is being modified in the “Command“ columns, and 3) the
magnitude or extent of the modification in the “Value - % - # Subconductors“ column.
What you can modify in the “Command“ columns is described in Sections 7.3.12.7.1 to
7.3.12.7.10 below.
7.3.12.7.1
Adjust Percent of Horizontal Tension
If you specify “Percent Horizontal Tension“ for a particular span, the vertical, transverse and
longitudinal reactions at the end of the span (shown in Fig. 7.3-9 and calculated as described in
Section J.1.2) will be based on a reduced horizontal tension H loads which is the original
unreduced tension adjusted by the percent value you enter in the adjacent “Value - % - #
Subconductors“. This option is only available with ruling span modeling (Level 1).
For example, you could model a broken conductor situation where you expect the Residual
Static Load to be 70% of the original tension by specifying a 0 % of tension in the back span
and a 70% of tension in the ahead span.
7.3.12.7.2
Specify Number of Broken Subconductors
If you specify “# Broken Subconductors“, you will have to enter the number of broken
subconductors in the adjacent “Value - % - # Subconductors“ column. If the affected span has
only one wire, you can only enter one broken subconductor. If the affected span has several
subconductors, you can enter one or more broken subconductors.
With Level 1 load modeling, this option simply remove the load transmitted by the broken cable
to the structure but does not change the loads from the still intact cables in the span (bundle) or
from the cables on the other side of the structure. With Level 2, 3 or 4 modeling, the broken
cable (s) is physically removed from the model, but the finite element analysis determines new
tensions in the system after the removal.
This option can be used with Level 1 modeling to determine the loads on one side only of a rigid
dead end structure: one load case where you break all the subconductors in the back spans and
another one where you break all the subconductors in the ahead spans.
This option can also be used with Levels 2, 3 or 4 modeling to determine the load from a
broken conductor next to a suspension insulator. The analysis would account for the reduction
in tension due to the longitudinal insulator swing.
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7.3.12.7.3
Add a Concentrated Vertical Load
If you specify “Add Vertical Load“, you will have to enter the value of that load in the adjacent
“Value - % - # Subconductors“ column. This load will be added to the vertical load coming from
the selected span. It is multiplied by the Load Factor for Vertical load (see Section 7.3.12.6)
before being added. The transverse and longitudinal components of the finite element structure
loads can be affected since the load is applied to the tip of the insulator prior to sag tension
which can increase the transverse and longitudinal components of the load. The transverse and
longitudinal components are not affected in ruling span since the additional load is simply added
to the ruling span loads and do not impact the sag and tension of the conductor. This, and the
following two options, can be used for all wire modeling levels (Levels 1 to 4).
7.3.12.7.4
Add a Concentrated Transverse Load
If you specify “Add Transverse Load“, you will have to enter the value of that load in the
adjacent “Value - % - # Subconductors“ column. This load will be added to the transverse load
coming from the selected span (i.e. it is perpendicular to the span). It is multiplied by the Load
Factor for Wind before being added. The vertical and longitudinal components of the finite
element structure loads can be affected since the load is applied to the tip of the insulator prior
to sag tension which can increase the vertical and longitudinal components of the load. The
vertical and longitudinal components are not affected in ruling span since the additional load is
simply added to the ruling span loads and do not impact the sag and tension of the conductor.
7.3.12.7.5
Add a Concentrated Longitudinal Load
If you specify “Add Longitudinal Load“, you will have to enter the value of that load in the
adjacent “Value - % - # Subconductors“ column. This load will be added to the longitudinal load
coming from the selected span, i.e. it is in the direction of the span. It is multiplied by the Load
Factor for Tension before being added. The vertical and transverse components of the finite
element structure loads can be affected since the load is applied to the tip of the insulator prior
to sag tension which can increase the vertical and transverse components of the load. The
vertical and longitudinal components are not affected in ruling span since the additional load is
simply added to the ruling span loads and do not impact the sag and tension of the conductor.
7.3.12.7.6
Adjust Ice Thickness
The “% Ice Thickness“ command in previous versions was renamed to “% Wire Ice” in the latest
versions. For more on this command see section 7.3.12.7.8.
7.3.12.7.7
Adjust Vertical (or Transverse or Longitudinal) Load
If you specify “Percent Vertical (or Transverse or Longitudinal) Load“ for a particular span, the
vertical (or transverse or longitudinal) reactions at the end of the selected span (see Fig. 7.3-9)
will be adjusted by the percentage that you enter in the adjacent “Value - % - # Subconductors“
column before it becomes a load on the supporting structure.
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While "unbalanced" loading as described above is available, there is no easy way in PLS-CADD
to generate loads from "pattern" loading, for example ice load on every other span. For “pattern”
loading, you can selectively load individual spans with ice as discussed in Section N.5.
7.3.12.7.8
Adjust Ice Prior to Sag and Tension Calculation
If you specify "% Wire Ice", the Ice Thickness and/or Wire Ice Load on the specified wire(s) will
be adjusted by the % amount that you enter in the adjacent "Value - % - # Subconductors"
column. This option can only be used with Levels 2, 3 or 4 wire modeling. With this method,
longitudinal insulator swings at all suspension structures and longitudinal deflections at all
attachment points with nonzero longitudinal stiffness are accounted for. This option should not
be used with Level 1 modeling because that modeling is not capable of handling longitudinal
insulator swings. If you use this option with Level 1, you will get very conservative longitudinal
loads. This adjustment is applied to the conductor prior to the calculation of sag and tension for
the conductor.
7.3.12.7.9
Adjust Wind Pressure Prior to Sag and Tension Calculation
If you specify "% Wire Wind Pressure", the wind pressure on the specified wire(s) will be
adjusted by the % amount that you enter in the adjacent "Value - % - # Subconductors" column.
This adjustment is applied to the conductor prior to the calculation of sag and tension for the
conductor.
7.3.12.7.10 Adjust Wire Dead Weight Prior to Sag and Tension Calculation
If you specify "% Wire Dead Weight", the dead weight on the specified wire(s) will be adjusted
by the % amount that you enter in the adjacent "Value - % - # Subconductors" column. This
adjustment is applied to the conductor prior to the calculation of sag and tension for the
conductor.
7.3.12.7.11 Rotate Wire Coord. System Clockwise After Sag-Tension
If you specify "Rotate wire coord. system clockwise after sag-tension", the attachment point of
the ahead span or back span of the selected wires will be rotated clockwise based on the
degrees input in the adjacent column and the original loading will be applied based on this new
attachment point. This adjustment is applied to the conductor after the calculation of sag and
tension for the conductor.
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7.3.12.8
Structure Loads Criteria Table
All data needed to determine a structure load tree are included in the Structures Loads
Criteria table (see Figs. 7.3-10a, 7.3-10b and 7.3-10c) which you open with Criteria/ Structure
Loads (Meth. 3,4). There is one line in the table for each load case. The loads data parameters
are defined below:
Fig. 7.3-10a Load Cases for Meth. 3 & 4 Structures
Description:
Self-explanatory
Weather case:
Weather case from list of available combinations of wind, ice
and temperature (from data in Weather Cases table of Fig. 7.32)
Cable condition:
State of cable when calculating load. Initial RS, after Creep RS
or after heavy Load RS if the calculations should be made with
the ruling span method (Level 1). Initial FE, after Creep FE or
after heavy Load FE if the calculations should be made with a
finite element analysis (Levels 2, 3 or 4). Initial RS is the most
common choice.
Wind direction:
Pick list from ten available directions described in Section
7.3.12.2
Bisector wind
direction, WB:
Wind direction defined in Figs. 7.3-7 and 7.3-8. Only needed if
Wind direction is selected as "BI+" or "BI-". Also used to input
azimuth angle when Global Wind Direction is selected.
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Wire Vertical load
factor, LFV; Wire
Wind load factor,
LFW; Wire
Tension load
factor, LFT;
Structure weight
load factor, LFS:
Load factors used in various equations of Sections 7.3.12.3,
7.3.12.4 and 7.3.12.5. The wire loads listed in the report that
you obtain with Structures/ Loads/ Report include these load
factors.
Fig. 7.3-10b Load Cases for Meth. 3 & 4 Structures
Structure Wind Area
Factor:
This factor is not used by PLS-CADD but is passed to TOWER or
PLS-POLE when needed to adjust the exposed area of the model.
When you import older PLS-CADD models (pre Version 7), this
factor is used to display the manually entered structure gust
response factor. For users of the “EN 50341-3-9: 2003 UK-NNA“
wind model, this factor is used to enter the K-COM factor.
Structure Wind Load
Model:
Name of procedure or design code for the calculation of wind load
on exposed area of a structure. This information is not used by
PLS-CADD but is passed to TOWER or PLS-POLE when needed
by these structure programs to determine the factors KZ , GRFS
and CDS described in Section 7.2.1.3. For more information
regarding supported design codes go to:
http://www.powline.com/products/version7_loads.pdf
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Structure Ice
Thickness and
Structure Ice Density:
Uniform ice thickness deposited on structure members of TOWER
and PLS-POLE models, and corresponding ice density. Very few
design codes require that ice be applied to structure members.
Strength factors:
Eleven strength factors to be used as described in Section
7.3.12.6. These factors are not used by PLS-CADD but are
passed to TOWER and PLS-POLE. The rest of the data (see Fig.
7.3-10c) apply to unbalanced loading as described in Section
7.3.12.7.
Fig. 7.3-10c Load Cases for Meth. 3 & 4 Structures
Structures
Groups on Which
to Apply:
You can select to apply the adjustments described in the following
columns to All structures, or to Deadend structures only or to Tangent
structures only (or to structures modeled with TOWER only or with PLSPOLE only) or to a user defined group. There are several predefined
groups available for selection in this column or you can make your own
group to automatically or manually assign to a structure using the
Structure Groups button at the bottom of the table. For more on
Structure Groups see section 7.3.12.9 below.
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Pole Deflection
Check (PLSPOLE only):
Unless you select No Limit, PLS-POLE will use one of eight methods for
checking the pole tip deflection for the selected load case. The deflection
for the first four methods is the exact distance in 3-d between the pole tip
position in its unloaded configuration and its position in the deflected
shape for the load case. The deflection for the last four methods which
contain the suffix VA, is the exact distance in 3-d between the projected
position of the pole tip on the vertical axis based on the length of pole
above the point of fixity based on the coordinates of the base of the pole
and its position in the deflected shape for the load case.
% Pole Height - Allowable Deflection is calculated as a specified
percentage of the pole height above the fixity point (typically height above
ground). Deflection is measured between the unloaded configuration and
its position in the deflected shape for the load case.
% Pole Length - Allowable Deflection is calculated as a specified
percentage of the total pole length (including any embedded portion, but
excluding any cuts). Deflection is measured between the unloaded
configuration and its position in the deflected shape for the load case.
% Pole Tip Diameter - Allowable Deflection is calculated as a specified
percentage of the pole tip diameter. Deflection is measured between the
unloaded configuration and its position in the deflected shape for the load
case.
% Pole Height VA - Allowable Deflection is calculated as a specified
percentage of the pole height above the fixity point (typically height above
ground). Deflection is measured between the pole tip position in the
deflected shape for the load case and the projected position of the pole
tip on the vertical axis as described above.
Input Limit - Allowable Deflection is input directly by the user (for example
3 ft or 1m). Deflection is measured between the unloaded configuration
and its position in the deflected shape for the load case.
% Pole Length VA - Allowable Deflection is calculated as a specified
percentage of the total pole length (including any embedded portion, but
excluding any cuts). Deflection is measured between the pole tip position
in the deflected shape for the load case and the projected position of the
pole tip on the vertical axis as described above.
% Pole Tip Diameter VA - Allowable Deflection is calculated as a
specified percentage of the pole tip diameter. Deflection is measured
between the pole tip position in the deflected shape for the load case and
the projected position of the pole tip on the vertical axis as described
above.
Input Limit VA - Allowable Deflection is input directly by the user (for
example 3 ft or 1m). Deflection is measured between the pole tip position
in the deflected shape for the load case and the projected position of the
pole tip on the vertical axis as described above.
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Pole Deflection
Limit:
This is where you specify the Allowable Deflection described above as a
percentage or a fixed length.
A Deflection Usage (DU) is reported as the ratio ( 100 x Tip Deflection) / ( Allowable Deflection).
PLS-POLE treats the Deflection Usage separately from the Strength Usage of its components.
It considers the Deflection Usage as an additional constraint when it determines Allowable
Spans or Allowable Spans Interaction Diagrams as one of the last four Analysis Options
described in Section 4.2.1. PLS-POLE also considers the Deflection Usage constraint when it
uses one of the automatic design features described in Section 6.
Adjust cable
loads:
You select N (for No) if you do not want to apply any load adjustment to
the wire loads. This is the default which will grey out all the following
columns which need not be considered. You select Y (for Yes) if you
want to make any adjustment to the loads from the intact wires. In this
case, you will be able to access up to ten sets of three columns in which
you specify the adjustments described in Section 7.3.12.7. In one or
more set of three columns you enter the parameters to adjust the cable
loads in the columns to the right.
Wire (s), Set,
Phase, Span:
Select “Back Spans“ to apply the adjustment to all the wires in the back
spans (see definition of back spans in Fig. 7.3-9a of Section 7.3.12.7).
Select “Ahead Spans“ to apply the adjustment to all the wires in the
ahead spans. Select "i : j : Back" or "i : j : Ahead" to apply the adjustment
only to the j-th wire of the i-th set in the back or ahead span. You can
apply the adjustment to any of 3 phases of 60 different sets.
Command:
Select “% Horizontal Tension, # Broken Subconductors, Add Vertical
Load, Add Transverse Load, Add Longitudinal Load, % Wire Ice, %
Vertical Load, % Transverse Load or % Longitudinal Load“ to implement
one of the adjustment methods described in Sections 7.3.12.7.1 to
7.3.12.7.7.
Value, %, or #
subconductors:
This is the value of the additional load you specify (see Sections
7.3.12.7.3 to 7.3.12.7.5). Or it is the percent adjustment you want to
apply to a particular quantity (see Sections 7.3.12.7.1, 7.3.12.7.6 and
7.3.12.7.7): % Tension only available with Level 1 and % Wire Ice only
available with Level 2, 3 or 4. Or it is the number of broken
subconductors (see Section 7.3.12.7.2).
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7.3.12.9
Structure Groups
Structure Groups allows for the application of load cases defined in the Criteria/ Structure
Loads table to a specific set of structures based on specific rules instituted by the user. The
Structure Groups feature augments the capabilities of the Struct. Types on which to Apply
feature that was available in older versions of PLS-CADD by enabling the user to define their
own groups and create rules to apply these groups automatically to a structure or manually
assign the group to a structure. Figure 7.3-12 below shows the Structure Groups Criteria Table.
The first column is the Group Name which is a user defined name to describe the group. All
group names can be changed with exception to the All Group which is the default group defined
in the first row of the table and is reserved as the mandatory group in which all structures
belong. The second column is the Group Description which allows for a more descriptive name
for the Group. The third column gives an overview of the rules applied for the group and gives
access to the Structure Groups Rule dialog box shown in Figure 7.3-13. The Load Cases For
Group Column has the count for how many of the load cases in your Structure Loads table
contain this group. The last column is the Structure in Group Column which contains a count of
the number of structures in each group and a list of the particular structure numbers in each
group. The structure groups that appear in light gray text are automatically assigned to the
structure while the black text names are groups that are manually assigned to a structure.
Figure 7.3-12 Structure Groups Criteria
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To define a rule for a Structure Group you can click in the Rule For Group Membership column
and the Structure Groups Rule dialog box of Figure 7.3-13 will appear with several options to
filter which structures have the Group assigned. At the top of the dialog box you can choose
whether the group membership is automatically assigned by the program based on the criteria
defined in the lower portion of the dialog box or whether the group is manually assigned to a
structure in the Structures/Modify or Structures/ Staking Table. The criteria in the lower
portion of the dialog box is self-explanatory with the user able to select the range of attributes of
a structure to have the Group applied, including items such as structure types, attachment
types, line angles, station range, height range, structure components and elevation range.
There is also the ability to make membership in a group dependent on the membership of
another group.
Figure 7.3-13 Structure Groups Rule
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Once you have created your structure groups and applied them to the particular load cases you
want in the Criteria/ Structure Loads table you will need to assign any manual Groups to your
structures. You can manually assign Groups by either going to the Structures/ Modify dialog
box and hitting the Groups button or going to the Structures/ Staking Table and going to the
Manual Structure Group Membership Column. Either method will bring up the Structure Groups
dialog box in Figure 7.3-14. The top of this box gives a list of all automatically assigned
Structure Groups. The Groups in which the structure is automatically included are highlighted
gray. The bottom of the box includes a list of all Structure Groups that can be manually
assigned. You can assign any of the manual Groups for the structure to be included but cannot
select any of the automatic Groups as this is assigned by PLS-CADD and is for informational
purposes only. If a Structure Group is highlighted in red text then this indicates that the Group
is undefined. This means that the Group previously existed in the Structure Groups table and
was assigned to the structure but has since been removed from the Structure Groups list.
Fig. 7.3-14 Structure Groups
You can also manually assign groups to a structure in PLS-CADD/Lite by hitting the Groups
button shown at the top of the Model Setup dialog box of Figure 15.1-2.
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7.3.13 Conditions for Checking Survey Points Clearances
Clearances from the centerline, side profiles or from survey points can be checked graphically
and this is the most straightforward method. The phases are displayed for the desired weather
cases and cable conditions (see Section 5.4.6.3) and clearance lines are displayed for the
desired voltage (see Section 6.10.2). Any violation can be observed visually.
However, there is a more thorough method for checking survey point clearances as described in
Section 11.2.3.1. The checks are made when you use either the Terrain/ Clearance function or
ask for a complete report with Lines/ Reports/ Survey Point Clearances. The program
determines the positions of the wires in relation to the survey points for the combinations of
Weather Cases and Cable Conditions specified in the Criteria/ Survey Point Clearance and
Danger Tree Locator dialog box shown in Fig. 7.3-11, and then reports any clearance
violations. Clearance violations are based on wire voltages and clearance requirements
established in the Feature Codes table (see Section 6.1.1).
Figure 7.3-11 Conditions for Checking Survey Point Clearances
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For weather cases that include wind, PLS-CADD will always check the clearances for the
designated wind velocity blowing first from the left and then from the right. However, it can also
check the clearances for all the positions of a wire at it swings between the blown-out positions
due to the left and right winds. This option can be used in the rare cases where a lesser wind
than the one specified in your clearance criteria is critical.
You can also input a temperature directly in the weather case column instead of selecting one of
the predefined weather cases from the Criteria/ Weather Cases table.
Meeting survey point clearances is one of the constraints used in the automatic optimum
spotting process described in Section 14.
The combinations of weather cases and cable conditions entered in the Survey Point
Clearance Criteria dialog of Fig. 7.3.11 are also used by the Clearances to TIN and
Isoclearance Lines functions described in Section 11.2.3.4 and by the Danger Tree Locator
function described in Section 11.2.9.
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7.3.14 Conditions for Checking Clearances between Cables
The two combinations of weather
and cable conditions specified in
the Criteria/ Phase Clearances
menu are used as default values
for the calculations of minimum
distances between the cables of
any two sets within a selected
span or within two crossing spans.
For example, Fig. 7.3-12 shows
two cable sets, each with three
phases, within crossing spans.
The selection of the two sets,
weather case and cable condition
is
done
with
Sections/
1
3
SET A
2
WEATHER CASE X
3
CABLE CONDITION J
3
1
1
2
2
MARKERS
1
SET B
2
WEATHER CASE Y
3
CABLE CONDITION K
Clearances/Between
Fig. 7.3-12 Minimum Distances Between Cables
Sections. Minimum distances
are reported and their locations indicated by markers as shown in Fig. 7.3-12. They are also
compared to minimum allowable values entered in the Sections/ Clearances menu.
It is permissible to select Sets A and B in Fig. 7.3-12 as the same set. This can be used to
calculate clearances between cables of the same set for two separate weather conditions, for
example one phase loaded with ice and that immediately below unloaded.
7.3.15 Conditions for Drawing Galloping Ellipses
PLS-CADD can draw single loop and double loop
galloping ellipses that simulate the empirical
envelopes of a galloping conductor according to the
REA Bulletin 1724E-200 (REA, 1992), Cigre Report
322 (Cigre Task Force B2.11.06, June 2007), or
AESO Section 502.2 Bulk Transmission Line
Technical Requirements. It can also determine the
closest distances between these ellipses, whether
they are crossing each other and if so what
percentage of their area overlaps. The parameters
which determine the location and geometry of an
ellipse (see Fig. 7.3-13) are: the "SAG" length, the
span swing angle "SSW", the "B" distance, the
ellipse "MAJOR" and "MINOR" axes, the ellipse
swing inclination "ESW" from vertical and the
(sub)conductor diameter "DIA".
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ESW
SSW
Fig. 7.3-13 Galloping Ellipse
199
For single loop ellipses, PLS-CADD uses the following REA Bulletin equations to determine the
numerical values of the ellipse parameters (lengths are in meters):
ESW
MAJOR
MINOR
B
=
=
=
=
SSW / 2
1.25 X SAG + 0.3048
0.4 X MAJOR
0.25 X SAG
(7-22)
(7-23)
(7-24)
(7-25)
For double loop ellipses, the following equations are used:
MAJOR
=
2
SQRT[ {3 A / 8} {L + 8 SAG / (3 L) - 2 A} ] + 0.3048
(7-26)
MINOR
B
=
=
1.104 X SQRT[ MAJOR - 0.3048 ]
0.2 X MAJOR
(7-27)
(7-28)
where
2
2
L = Span length and A = SQRT [ (L / 2) + SAG ]
With the Cigre method for a single (unbundled) wire the following equations are used:
MAJOR
MINOR
B
ESW
=
=
=
=
DIA X 80 X ln(8 SAG / (50 DIA))
0.4 X MAJOR
0.3 X MAJOR
0
(7-29)
(7-30)
(7-31)
(7-32)
With the Cigre method for bundled wires the following equations are used:
MAJOR
MINOR
B
ESW
=
=
=
=
DIA X 170 X ln(8 SAG / (500 DIA))
0.4 X MAJOR
0.3 X MAJOR
0
(7-33)
(7-34)
(7-35)
(7-36)
For all methods you may optionally input a Galloping Safety Factor (GSF) in Criteria/ Galloping
which multiplies MAJOR in Eq. 7-22 through 7-36. Finally, Criteria/ Galloping also allows you
to set ESW to zero (override Eq. 7-22)
Drawing galloping ellipses and determining the distances between them is done with the
Sections/Clearances/Galloping Ellipses command. The calculations are done for the
combination of weather cases and cable conditions specified in the Criteria/ Galloping menu
shown in Figure 7.3-13a below. According to the REA Bulletin, one combination of 1.27 cm ice
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(0.5 in.), 95.8 Pa (2 psf) wind and 0 deg. C (32 deg. F) temperature has to be specified for the
calculation of the position of the insulator and the span swing angle SSW. Another combination
of 1.27 cm ice (0.5 in.), no wind and 0 deg. C (32 deg. F) is specified for the span "SAG".
Figure 7.3-13a Galloping Ellipse Criteria
In the Galloping Ellipse Criteria dialog you can select the weather cases and wind direction for
checking per the code selected in the calculation methods section. The calculation methods
section allows you to select either the REA method Single or Double loop, Cigre Report 322
method, or the AESO method. If you select both the single and double loop method you will be
able to enter a span length tolerance to switch from Single to Double Loop for the clearance
checks. In the bottom Options section of the dialog box you can enter the Ellipse amplitude
safety factor and the required separation between ellipses as well as the allowable overlap
percentage. The required separation and allowable overlap are mutually exclusive as you
cannot have a separation while at the same time have an overlap. You can also force a vertical
ellipse with a tilt angle of zero if the option is turned on.
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7.3.16 Conditions for Checking Suspension Insulator Swings and Load Inclinations on
2-part Insulators
Lateral swings in suspension insulators (SA in Fig.
7.3-14) or load inclinations (LA in Fig. 7.3-15) at
the common point of 2-parts insulators can be
calculated for up to four separate combinations of
weather and cable conditions. This is done as part
of the Structures/ Check function. The function
also compares the results with allowable values
which are described in the corresponding structure
file. Insulator swing limits or load angle limits are
parts of the constraints used in the automatic
optimum spotting process described in Section 14.
TRANSVERSE AXIS
+
L INS
SA
T
V
INS
INS
T
V
V
CW
Fig. 7.3-14 Insulator Swing Clearances
For each circuit supported by a suspension
insulator, the structure file includes allowable swings for four conditions. For 2-parts insulators,
the file includes allowable load angles. There is a minimum and a maximum allowable swing or
load angle for each condition. The swing angle, SA (or the load angle LA), is measured from
vertical and is positive if the insulator (load) moves in the transverse direction of the structure as
shown in Figs. 7.3-14 and 7.3-15. The allowable values are algebraic and should follow the sign
convention (see Figs. 7.3-14, 7.3-15 and 7.3-16). Note that maximum swing is defined as that
which translates the bottom point of the insulator the farthest in the transverse direction of the
structure.
You need to specify the conditions for which the allowable swings or load angles apply. One
possible set up is:
Condition 1: Everyday condition with no wind and average temperature. This is a condition
under which the line will spend most of its life, and therefore it is the condition most likely to
occur when a serious voltage surge occurs. To avoid flashover under that condition, one may
specify the most restrictive values of allowable swing.
Condition 2: Cold condition with average wind. Because of the cold temperature, this is a
condition under which the vertical load may be too small to prevent a significant insulator swing,
even under average wind. Because the probability of occurrence of a serious voltage surge
under the cold condition is not as high as at any random time, one may specify less restrictive
values of allowable swings than under Condition 1.
Condition 3: High wind condition. High winds are rare events. The combined probability of their
occurrence together with a voltage surge is even smaller, thus it may be appropriate to relax the
swing requirements even more.
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Condition 4: Every day or colder condition with average wind under Final tension such as that
proposed in the REA Manual 1724e-200 for medium and large angle structures. This value may
be slightly less restrictive than Condition 1.
Fig. 7.3-14a Insulator Swing & Uplift Criteria
The Criteria/ Insulator Swing & Uplift menu shown in Figure 7.3-14a is used to describe the
combinations of weather and cable conditions that correspond to the four conditions which were
used to develop the allowable values in the structure model. These four swing check weather
cases and cable conditions are noted in the top of the dialog box.
B
BL
A
AL
C
LA
LA
LA
C
MAX
MIN
B
UP
B
A
C
C
C RIGHT
LEFT
DOWN
A
Fig. 7.3-15 2-Part Insulators
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The procedure used by the Structures/ Check function to compare an actual swing (or
inclination angle) to the corresponding allowable value systematically blows the wind
perpendicularly to each of the two spans adjacent to the structure and in both directions, i.e. the
swing calculation is done twice for each specified weather condition. From these calculations,
the largest and smallest values are kept for comparisons with the maximum and minimum
allowable values.
The actual swing angle SA for a suspension insulator (see Fig. 7.3-14) is determined by the
following equation:
-1
SA = TANGENT [ ( T + TINS / 2 ) / (V + VCW + VINS / 2 ) ]
(7-37)
where T = transverse load from conductor, V = vertical load from conductor, VCW = weight of
optional counterweight, VINS = weight of insulator and TINS = wind load on insulator calculated as
the product of the pressure at the height of the insulator (pressure from Eq. 7-2) times the
insulator wind area (see Section F.1.1.3). For swing calculations, all load factors in Eqs. 7-7 to
7-9 are equal to one.
For 2-parts insulators, the load angle (se Fig. 7.3-14) is determined by the following equation:
-1
LA = TANGENT [ ( T + TINS ) / (V + VCW + VINS ) ]
(7-38)
where VINS = total weight of both sides and TINS = total wind load on both sides of 2-parts
insulator (see Eq. 7-37 for more detail).
Note the number of allowable swing conditions associated with a structure file must match the
number defined in the Insulator Swing Criteria or an error message will appear when checking
the strength of the structure.
7.3.16.1
Structures with Suspension Insulators at Line Angles
There are two methods for handling unsymmetrical structures with suspension insulators at line
angles. With the first method, you need to have two separate structure models (i.e. you need
two separate structure files): a right turn structure for use at positive line angles and a left turn
structure for use at negative line angles. An example of such two structures is shown in the left
part of Fig. 7.3-16. With the second method, you only need to model the right turn (or left turn)
structure (i.e. you only need one structure file). You can use that single model (the right turn
structure) without rotation at positive line angles and rotate it 180 degrees about its vertical axis
at negative line angles. Structure orientation about its vertical axis is defined in Fig. 7.3-7.
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1
2
3
+
SA MAX
1
T
+
SA
MIN
2
FRAME AT POSITIVE LINE ANGLE
+
1
2
3
SA MAX
SA
MIN
T
SA
T
FRAME AT NEGATIVE LINE ANGLE
MIN
SYMMETRICAL STRUCTURE
-
SA
MAX
Fig. 7.3-16 Unsymmetrical Frames
We highly recommend the second method even though it may require that you manually
transpose some phases. The differences between the two methods are further discussed below.
Using two different unsymmetrical structures
If a structure is located along a line without any rotation (SO = 0 in Fig. 7.3-7) its transverse axis
is always oriented in the direction of positive line offsets (positive offsets are to the right as you
march along the line in the direction of increasing stations). Therefore, without rotation, the
structure at the top left of Fig. 7.3-16 (right turn structure) would be used at an alignment point
with a positive line angle, while that at the bottom left of Fig. 7.3-16 (left turn structure) would be
used at a negative line angle.
If the allowable swings (in degrees) for the right turn structure were:
Condition 1:
Condition 2:
Condition 3:
SAmin = 20
SAmin = 15
SAmin = 10
SAmax = 40
SAmax = 50
SAmax = 60
Those for the left turn structure would be:
Condition 1:
Condition 2:
Condition 3:
SAmin = -40
SAmin = -50
SAmin = -60
SAmax = -20
SAmax = -15
SAmax = -10
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Using only one unsymmetrical structure
When you look closely at the two structures at the left of Fig. 7.3-16 you will note that they are
almost identical. If you rotate the right turn frame 180 degrees about its centerline it looks like
the left turn frame, except that the phases (numbers at the top of the frames) are reversed.
Therefore, if you rotate the right turn frame, you will need to transpose the attachment points of
phases 1 and 3, otherwise the outside phases will cross-over in the adjacent spans. Phase
transposition is discussed in Section 10.3.1.
If you only have one unsymmetrical structure model (right or left turn) and use spotting
optimization as described in Section 14, the following algorithm is used: 1) the structure is
declared a right turn structure if the absolute value of SAMAX (see Fig. 7.3-16) is larger than the
absolute value of SAMIN. It is declared a left turn structure otherwise, 2) Right turn structures are
used at positive line angles. At negative line angles, they are rotated 180 degrees with -SAMAX
becoming SAMIN and -SAMIN becoming SAMAX, 3) Left turn structures are used at negative line
angles. At positive line angles they are rotated and the allowable swing angles are changed as
in 2) above. Once the optimization is completed, you may need to manually transpose phases
to avoid cross-overs.
7.3.16.2
Conditions For Checking Insulator Uplift
The bottom of the Insulator Swing & Uplift Criteria dialog box of Figure 7.3-14a contains the
table of weather cases and cable conditions that are used to check whether the wire attached to
the insulators on a structure are in uplift. Uplift on structures is discussed in Section I.3 of the
manual.
Each of the structure models used in PLS-CADD allow for the user to designate whether the
insulator is allowed to go into uplift (negative vertical load). For PLS-POLE and TOWER see
the relevant sections in their manuals pertaining to insulators. For Method 1 structures in PLSCADD see section F.1.1. The allowable uplift of each cable attachment is checked against the
weather cases at the bottom of the dialog box and if uplift is found it will be shown in the
Standard Report within the Structure Check.
7.3.17 Wind & Weight Spans Report
With Lines/ Reports/ Wind & Weight Spans you can generate a report containing the weight
spans of specified structures for as many combinations of weather cases and cable conditions
as you enter in the Criteria/ Wind & Weight Span Report table. This report contains the total
wind and weight span for the structure and also has a Wind & Weight Span By Side report
which gives a breakdown of the wind and weight span for the left and right spans at the
structure.
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7.3.18 Blowout and Departure Angles Report
The function Lines/ Reports/ Blowout and Departure Angle Report described in Section
11.2.3.3.1 is used to check departure angles and maximum wire blowouts (measured as offsets)
for a range of structures for the combinations of weather and cable conditions specified in the
Criteria/ Blowout and Departure Angles table. For these combinations, PLS-CADD
systematically applies the wind perpendicularly to the span involved and in both directions, i.e.
the span is swung out in two opposite directions. The offset in the blowout report is measured
relative to the alignment centerline and reports the maximum blowout as well as the leftmost
and rightmost blowout values.
7.3.19 Default Wire Temperature and Condition, Section Sort Order
Data in the Default Wire Temperature and Condition, Section Sort Order dialog box are
explained in that dialog box. You reach it with Criteria/ Default Wire Temperature and
Condition, Section Sort Order.
7.3.20 Finite Element Modeling Data
You will only need to enter data in the SAPS Finite Element Sag-Tension dialog box (see Fig.
N-5), which you reach with Criteria/ SAPS Finite Element Sag-Tension, if you use Level 2, 3
or 4 modeling as described in Section N.3.
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8.
STRUCTURES
8.1
General
One of the very powerful and unique features of PLS-CADD is its ability to treat structures as
"objects" which can be located, deleted or moved on the terrain at the click of the mouse. The
"structure object" contains not only the information necessary to locate in 3-Dimensions all the
cable attachment points, but also some pointers to the algorithms or programs which will check
the structure strength at its particular location. PLS-CADD currently supports four different
methods of checking structure strength. The "structure object" is described in a structure file.
The structure file therefore concentrates in a single location all the geometric and mechanical
design information that pertains to a given structure type and height. The structure file also
contains data on its insulators and its various parts and subassemblies.
8.2
Structure Top Geometry
In order that the positions of any point on any
cable in any span be known in 3-Dimensions
as a structure is added or moved, it is
necessary that the lengths of the devices
connecting the cables to the structures at the
end of each span (clamps and insulators) and
the locations of the attachment points of
these devices to the structures be well
defined.
For Method 4 structure models developed
with the TOWER or PLS-POLE programs,
the structure attachment points and the
insulators are identified as part of building up
the models. Therefore, their positions relative
to the base of the model are determined
automatically.
Fig. 8.2-1 Structure Top Geometry
For Method 1, Method 2 or Method 3 structures, you need to describe the positions of the
structure attachment points and the geometric properties of the attachment devices (clamps and
insulators) relative to the base of the structure. Collectively, these attachment points and the
attachment devices form the structure top geometry. For example, the top geometry of the tower
in Fig. 8.2-1 includes the structure attachment points (solid squares, triangles and circles) and
the associated devices (clamps for the ground wires, suspension insulators for the circuit on the
left and V-string insulators for the right circuit).
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8.2.1 Cable Sets
A cable "set" (also referred to as a tension section) is defined in PLS-CADD as a group or
ensemble of one to three cables (also called phases) with identical mechanical properties and
tensions. For example, an electrical circuit between dead ends is often modeled as one set.
Corresponding to cable sets are sets of structure attachment points and insulators (or
attachment devices). For the tower of Fig. 8.2-1, the two ground wire attachment points and
attachment devices were made part of Set #1, the three conductors in the left circuit and their
suspension insulators were made part of Set #2 and the three conductors in the right circuit and
their V-String insulators were made part of Set #3. If two different cables of the same circuit are
not sagged at the same tension then they should be made members of different sets. The only
reason for grouping wires together in a set is that come stringing and sagging time you can
string the wires through all the attachment points within the set and sag these wires
simultaneously. If on the other hand you put each wire in independently (3 sets of one wire) then
you will need to repeat the stringing and sagging operation three times, once for each set.
When a set has more than one cable (as illustrated with the WPLFULLM example or in the
tower model of Fig. 8.2-1), each cable is identified by a "phase" number and its structure
attachment is identified by an "attachment" number. There can only be one, two or three phases
per set, therefore the "phase" or "attachment" numbers can only be 1, 2 or 3. When you string a
circuit, you have the ability to take any "phase" and attach it to any structure "attachment". This
allows you to transpose phases at intervals along your line (see Section 10.3.1 for more details).
For Method 1, Method 2 and Method 3 structures, the positions of the structure attachment
points are described in a local coordinate system (x,y,z) located on the vertical axis of the
structure, such that the local x axis is in the general direction of the structure transverse axis,
the local y axis is vertical and oriented downward, and the local z axis is in the general direction
of the structure longitudinal axis (see Fig. 8.2-1). The origin of the (x,y,z) system is at a point
denoted TOP. The TOP point should be located on the structure vertical axis, at a distance HT
(defined as the structure height) above the point BS defined as the structure base point. It is
convenient, but not necessary, to locate TOP at the same elevation as the highest point on the
structure. Locating a structure on the terrain involves pinning point BS on top of a terrain point
P, or at a specified station along the profile. The structure can also be rotated about its vertical
axis by its orientation angle SO, as shown in Fig. 7.3-7.
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8.2.2 Clamps and Insulators
At each of the structure attachment points of a set, one connector or insulator type must be
defined. Available attachment devices are: 1) clamps, 2) strain insulators, 3) suspension
insulators, 4) V-strings or 2-parts insulators, and 5) post insulators. When devices have
specified wind areas, the wind load on them is calculated as the design pressure times that wind
area.
Clamps have no geometric dimensions, i.e a cable attached to a structure with a clamp passes
exactly through the structure attachment point.
Strain and suspension insulators have length, weight and wind areas. In addition, suspension
insulators have minimum and maximum allowable swings as described in Section 7.3.16.
V-strings and 2-parts insulators include two sides, each having length, weight and wind area,
and the ability to take compression or not. In addition, such insulators have minimum and
maximum allowable load angles as described in Section 7.3.16.
Post insulators are handled differently when attached to Method 1, Method 2 or Method 3
structures as opposed to Method 4 structures. With Method 1, Method 2 and Method 3
structures, post insulators have weight but no geometric dimensions. Instead, you need to
define the location of each insulator tip where the conductor is attached. With Method 4
structure, post insulators have geometric dimensions, as they are cantilevered from structure
attachment points.
One of the reasons we have elected to include insulators as part of a structure top geometry in
PLS-CADD is that their allowable swings or load angles (see Section 7.3.16) are specific to the
actual geometry of the structure to which the insulators are attached.
8.2.3 Tension Sections
A "tension section" in PLS-CADD is defined as a cable set, in one or more spans, between
dead ends. A section always starts at a dead end (a point which cannot move), it may be
supported at intermediate points by suspension, 2-parts or post insulators that may move in the
longitudinal direction, and it always terminates at its other dead end. Each tension section has
its own ruling span (see Appendix I), which depends on the geometry of all the spans between
dead-ends.
With the Ruling Span method (Level 1), the horizontal component of tension is assumed
constant over each span of the tension section. With the more accurate Finite Element
modeling (Levels 2, 3 and 4), horizontal tensions in each span may be different and are
calculated by analysis. But with either method, each tension section behaves independently of
any other tension section.
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Therefore, PLS-CADD needs to be able to identify the beginning and end of each tension
section from information in the structure files. This is provided by a simple check ("Section End"
in the Insulator Data dialog boxes of Section F.1.1) regarding whether a particular attachment
point is dead-ended (section end) or not. Attachment points of Suspension, V-strings and 2parts insulators are obviously not section ends. Attachment points of strain insulators are
section ends unless the structure is very flexible. Attachment points of clamps and post
insulators can be sections ends or not. This requires engineering judgment. For example,
tensions on each side of a flexible post insulator (or on each side of a clamp at the top of a
wood pole) may be assumed equal (Level 1) or related (Levels 2, 3 or 4) and are therefore not
section ends. However, if the post insulator (or the clamp) and the supporting structure are rigid,
the tensions on either side are somewhat independent and you could assume a section end
when using Level 1 modeling. The ability of Level 2, 3 or 4 modeling to account for the stiffness
of the attachment point allows for a better modeling than Level 1 which can only handles
situations where an attachment point is either totally free to move or totally fixed,
In summary, any structure model used in PLS-CADD should include a minimum of top
geometry information, that is, for each cable set: 1) the clamps and insulator properties, 2) the
locations on the structure, relative to its base, where the clamps and insulators are attached,
and 3) whether the attachment points of the cables to the clamps and insulators are ends of
tension sections. With that information, the structure can be treated as a 3-dimensional object
which, once located on the terrain, will completely define the 3-D locations and nature of the
support points of each cable in each span.
8.3
Structure Strength
There are four different methods for describing the strength of a structure in PLS-CADD. The
particular method which should be used is specified in the structure file. Therefore, when a
structure is selected from the library of available structures, the method by which the structure
will be analyzed for strength adequacy is already prescribed.
8.3.1 Method 1 - Basic Allowable Spans Method
Method 1 is the simplest method. It is used in traditional manual spotting and by most automatic
spotting programs. It relies on the most elementary concept of actual and allowable wind and
weight spans. The actual wind (or Horizontal) span at a structure, HS, is the average of the
chord lengths of the spans to the left and right of the structure. The actual weight (or Vertical)
span, VS, is approximately equal to the horizontal distance between the low point in the left
span to the low point in the right span as discussed in Section I.3. Low points can be within the
spans or outside. Since the locations of the low points move under different weather and cable
conditions, the vertical span must be defined with reference to a combination of weather and
cable conditions. For each of several weather and cable conditions, say 1) bare conductor
under extreme wind, 2) bare conductor cold and 3) conductor coated with ice, there are
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maximum or minimum allowable values of wind and weight spans that have to be met in order
to avoid violating a structure strength or serviceability criterion.
The actual implementation of
VS
VS
VS
VS MAX2
Method 1 in PLS-CADD is
summarized in Fig. 8.3-1. For a
VS MAX1
(2)
VS
MAX3
range of line angles, allowable
(1)
(
3
)
values HSMAX, VSMAX1, VSMAX2,
ICE
VS MIN
VSMAX3 and VSMIN are prescribed
in the structure file, respectively
HS
HS
HS
HS MAX
HS MAX
HS MAX
for: 1) the maximum wind span,
2) the maximum weight span for
Condition 1, 3) the maximum
VALID FOR GIVEN RANGE OF LINE ANGLES
weight span for Condition 2, 4)
the maximum weight span for Fig. 8.3-1 Allow. Regions for Wind & Weight Spans (Meth 1)
Condition 3, and 5) the minimum weight span, regardless of condition.
Typical choices for Conditions 1, 2 and 3 have been:
Extreme wind with no ice, extreme cold with no wind and no ice, and extreme ice (most
common)
or
Extreme wind with no ice, extreme cold with no wind and no ice, and NESC Heavy
condition
or
NESC Medium condition, extreme wind with no ice, heavy ice with small wind
etc.
Actually, you can use the same condition several times (two or three times), for example:
NESC Heavy condition, NESC Heavy condition, extreme cold with no wind and no ice
The strength of the structure is adequate if the combinations of actual wind and weight spans for
the three conditions fall inside the corresponding shaded regions of Fig. 8.3-1. The actual wind
and weight spans calculated by PLS-CADD for the comparisons with allowable values are
based on the cables in the heaviest cable set, or on the cables of a designated set in the case
of spotting optimization.
In general, maximum allowable weight spans for conditions with some ice are shorter than
allowable values for bare conductors (extreme wind on bare conductors or cold). In addition,
actual weight spans for conditions with ice are generally shorter than those under bare
conductor cases. This is one of the reasons we allow you to make use of three separate
allowable weight span values instead of a single one valid for all possible load cases.
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There are several shortcomings to Method 1, the most serious being the fact that allowable
wind and weight spans for a structure are not intrinsic properties of the structure alone: they
depend on the design criteria, cable conditions, and the number, type and mechanical tension
(for angle structures) of all attached cables. If a designer upgrades a conductor to a different
size or changes a climatic design criterion, the allowable span values are no longer valid.
Therefore, in upgrading or assessment projects, the allowable spans method is not desirable.
The other problem with the basic allowable wind and weight spans method is that it ignores
possible interactions between the allowable spans. For example, a single pole supporting a
short weight span has a larger allowable wind span than when it supports the maximum design
weight span. The difference, mostly caused by the P-Delta effect, can exceed ten percent,
causing some inherent capacity to be overlooked. In order to take advantage of allowable spans
interaction, Method 2 can be used.
8.3.2 Method 2 - Allowable Spans Interaction Diagram Method
With Method 2, an interaction diagram
between allowable wind and weight
spans
is
defined
for
certain
combinations of weather and cable
conditions. For example, Fig. 8.3-2
shows an allowable interaction diagram
(Line 1-2-3- ..) for a given combination
of weather and cable conditions. The
actual wind and weight spans
corresponding to the condition are
calculated. If their combination falls
inside the interaction diagram, then the
strength of the structure is adequate
for the condition.
1
2
INTERACTION DIAGRAM BETWEEN
MAXIMUM ALLOWABLE WIND
AND WEIGHT SPANS FOR
3
A
GIVEN LOAD CASE AND
4
GIVEN MAXIMUM LINE ANGLE
B
VS
ACTUAL
5
HORIZONTAL OR WIND SPAN , HS
0
6
HS
7
9
8
Fig. 8.3-2 Wind & Weight Spans Interaction
The use of Method 2 structures can produce more economical lines than with Method 1
structures, especially when used in conjunction with automatic spotting. Establishing interaction
diagrams may be difficult, unless you have access to structure programs such as TOWER and
PLS-POLE which can determine them automatically for you. Currently, for automatic optimum
spotting with PLS-CADD, only Method 1 or Method 2 structures can be used. This was done
because only these methods provide a sufficiently fast structure strength check. Optimization
algorithms require strength checks for possibly billions of combinations of structure locations.
However, for assessment and upgrading projects, Method 3 (not recommended) and Method 4
(recommended) are much more desirable.
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8.3.3 Method 3 - Critical Components Method
Method 3 structures were fully supported in earlier versions of PLS-CADD and we still support
them for backward compatibility. However, for new projects, we recommend that Method 3
structures not be used. For detailed information regarding Method 3, you should consult an
older version of the PLS-CADD manual.
Method 3 structures were used as substitutes for Method 4 structures when a full structural
analysis was prohibitive in term of time and memory requirements. The simplified Method 3
model utilized a matrix of influence coefficients relating forces and moments in the "critical
components" to unit loads at the structure attachment points and it required your input of the
design strengths of these components. The method was only valid for linear structures.
However, with the availability of efficient programs such as TOWER or PLS-POLE which can
now perform an accurate structure analysis and design check in a fraction of a second (or a few
seconds for a very large nonlinear tower with thousands of members) the need for Method 3
structures no longer exists. With Method 3 structures you could not: 1) use V-strings or 2-parts
insulators competently, 2) model nonlinear structures such as flexible poles for which the PDelta effect is significant or any guyed structure, 3) easily modify member properties or gain
intuition as to the original structure model, 4) obtain structure deflections, and 5) display the
structure with components color-coded by percent strength utilization. Therefore, for these
reasons and others, Method 3 structures are obsolete.
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8.3.4 Method 4 - Detailed Structural Analysis Method
Fig. 8.3-3 Check of Method 4 Structures
Method 4 is used if you want PLS-CADD to check the strength of your structure using our
TOWER or PLS-POLE programs. When a structure is selected for checking, PLS-CADD
determines its design loads and passes them to the appropriate program. The program then
analyzes the structure, checks its design and returns detailed reports and graphical summaries
(such as color coded deflected shapes) to PLS-CADD. The entire process is automated and
should not take more than a second or two. Method 4 is by far the best method for checking an
existing line. It is the most general and accurate of all methods. For example, the wood frames
in Fig. 8.3-3 were modeled as Method 4 structures with the PLS-POLE program. The analysis
results shown as percent utilization (in the right window) were obtained automatically for all load
cases within a second of clicking on the frame in the line (in the left window). The lower smaller
window shows the deflected shape exaggerated by a factor of 5.
As mentioned above, when a Method 4 structure is used, its loading tree is first determined by
PLS-CADD which passes it to the TOWER or PLS-POLE program for the analysis and check of
the structure. The loading tree is determined for a certain number of weather and cable
conditions, together with appropriate load factors as discussed in Section 7.3.12.
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Conventionally, loading trees include force components which are determined either at: 1) the
attachment points of the cables to the insulators
(for example at the lower ends of suspension or
V-string insulators shown in Fig. 8.2-1, or 2) at
the attachment points of the insulators to the
structure (as illustrated in Fig. 8.3-4 for the tower
T
of Fig. 8.2-1). For suspension insulators, the
L V
trees are identical, except for the weight of the
insulators and the wind forces on them. For post
insulators, moments are generated at the
structure attachment points, so the two trees are
quite different. For V-strings and 2-parts
insulators, the design loads V, T and L at the
AX(K)
conductor end of the insulators have to be
BS
resolved into loads at the structure attachment
T
points. This is a complex task, involving
L
nonlinear calculations, which are handled
automatically by our TOWER and PLS-POLE
Fig. 8.3-4 Structure Attachment Loads
programs. Loading trees also include the
transverse and longitudinal pressures acting on the structure itself.
Because of the two possible ways in which loading trees can be defined, it is important that you
understand what is being done in PLS-CADD.
When PLS-CADD exports a loading tree to TOWER or PLS-POLE to check a Method 4
structure or create a loading tree file with Structures/ Loads/ Write LCA file, the tree includes
the factored loads at the connections of the cables with the insulators to which the factored
weight of the connecting insulators and the insulator wind loads are added. This means that for
a V-string or a 2-parts insulator, the tree includes the factored loads at the junction between the
conductor and the two sides of the insulator to which we add the total weight of both sides of the
insulator and the wind loads on both sides. Therefore, for V-strings and 2-parts insulators, there
is no resolution by PLS-CADD of the loads between the two structure attachment points, i.e. the
loads which you see displayed for the right circuit of the tower in Fig. 8.3-4 are calculated by
TOWER or PLS-POLE automatically from the loads at the bottom of the V-strings generated by
PLS-CADD. The .lca file also includes the wire geometry information for each load case and
can be displayed in PLS-POLE or TOWER.
When you use the command Structures/ Loads/ Report in PLS-CADD, the report which is
generated includes factored loads in the span coordinate system and loads in the structure
coordinate system. Loads in the structure coordinate system include the factored weights and
wind loads of the insulators.
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One of the very unique and powerful capabilities of our TOWER and PLS-POLE programs is
that they can automatically determine the allowable wind and weight spans of a structure, given
some loading criteria and attached conductors. With this capability, they are capable of
generating Method 1 or Method 2 structure files automatically. The only reason for doing this,
since you have already developed the superior Method 4 model, is if you are going to perform
some spotting optimization which requires the allowable spans model, or if you want to create
libraries of standard structures rated by their allowable spans.
A detailed technical note describing the optimization process and the creation of Method 1
structures may be found at http://www.powline.com/products/optimization.html.
8.4
Structure Display
The appearance of a structure in the Available structures report or in a 3-D view depends on
how the structure model was generated. Fig. 8.4-1 shows part of the Available structures report
for the Demo line that you can generate by clicking on Structures/ Available Structures list/
Report.
Fig. 8.4-1 Available Structures Report
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8.4.1 Method 1, 2 and 3 Structure Files Generated Directly
If you create or edit a Method 1, 2 or 3 structure file directly with the Structures/ Create New
Structure or the Structures/ Edit Structures menus as described in Appendix F, there is no
information regarding the detailed geometry of the structure apart from its minimal top geometry
described by the cable attachment points. Therefore, you will not see a graphical outline of
these structures in the Available structures report and you will see these structures displayed as
minimal stick structures in 3-D views. A stick structure includes a vertical line along its vertical
axis and horizontal lines going from the vertical axis to any cable attachment point which
actually supports a cable. If no cable is strung yet, you will not see the horizontal line.
For example, the right side of Fig. 8.4-2 shows the outline of a minimal Method 1 double circuit
structure in a 3-D view.
Fig. 8.4-2 Detailed and Minimal Displays
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8.4.2 Method 1, 2 and 3 Structure Files Created by PLS-POLE or TOWER
If you first create a structure model with PLS-POLE or TOWER and use it to generate a Method
1, 2, or 3 structure file, then a detailed line representation of the geometry of the structure is
known and is appended to the file for display. This line representation is also displayed in the
report of Fig. 8.4-1 or in the Structure File Open and File Selection dialogs.
8.4.3 Method 4 Structures
Method 4 structures are always displayed in detail, including their guys if any. See for example
the steel pole at the left of Fig. 8.4-2 and the tower at the center of that figure. You can display
Method 4 structures realistically with their material color if you select Render Structures... in the
Line Display Options dialog box of Fig. 5.4-4b. Otherwise, they are displayed as "lines", or as
"wire frame" or "rendered" (the terminology is described in the TOWER and PLS-POLE
manuals).
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8.5
Parts and Assemblies
PLS-CADD includes powerful functions to manage material databases and generate a variety of
part or assembly (compatible unit) lists. These material handling capabilities are an important
factor in improving a user's productivity. Parts and assemblies are often defined in master parts
and assemblies databases that are maintained by a company independently of PLS-CADD. If
these databases include ODBC drivers, such as most commercial databases (Microsoft
Access, SQL Server, Oracle, IBM DB2, etc.), they can be linked directly to PLS-CADD as
described in Appendix M.
In order to use the parts and assemblies capabilities of PLS-CADD, you first need to populate
the internal parts/assemblies libraries as described in this section. Then you need to describe in
the structure files which parts and assemblies make up the structure file material list. This
process is described in Appendix F. Some parts and assemblies are not always associated with
a specific structure file, but are to be used only at a particular structure site (for example special
foundation material, fences, guys, dampers, extra labor units, etc.). Such "structure specific"
material is specified in the Structure Modify dialog box described in Section 10.2.2. Finally, If
some parts and assemblies are not associated with a specific structure file or structure site but
rather specific to the project or line itself then such "line specific" material is specified in the
Structures/Material/Line Specific Material List or can also be accessed in the Line Specific
Material List button in the Lines/Edit dialog box. Cables and Marker Balls are also accounted
for in the project. These can viewed in the Line Specific Material List. If parts and assemblies
are described at structure locations, in structure files, and/or the line specific material list then
the complete project material list is automatically generated in the form of a report or a staking
material table (see Section 12.2.3). This material table can be linked to commercial data bases
and work order systems (see Appendix M). For detailed information on the reports available
see Section 8.5.6.
PLS-CADD material functionality starts with a parts list on which the user can draw parts to
create a bill of material for a structure file or assemblies for use in the program. Parts and
assemblies are included together in the Parts/Assembly Library file named in the
File/Preferences menu. Part and Assembly list files have the ".prt" file extension. Fractional
quantities of assemblies is not supported.
PLS-CADD not only allows the user to track material and labor cost for installing new items in a
line but also allows the user to assign labor values for retiring and transferring items that are in
an existing line. Hence the properties for each unit allow the user to input a cost for material,
install labor, retirement labor, and transfer labor. The particular cost associated with the unit
and reported in PLS-CADD is based on the status of the unit selected in PLS-CADD.
The four different status settings available for selection in PLS-CADD when populating a bill of
material are New, Retired, Existing, and Transferred. "New" items are items to be installed in a
line. A bill of material report for items with a status of New will report the count of the items
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being installed as well as the material cost of the part or assembly and the install labor for the
part or assembly. "Existing" items are items that exist in a current line that can be acted upon
with either a retire or transfer function. A bill of material report for items with a status of Existing
will report the count and costs of the existing items in a line for the material and install labor. A
line in the As-Built state would have all items marked as "Existing". A "Retired" item is an item
to be removed from a line. Only items marked as existing can be retired. A bill of material
report for items with a status of Retired will report the count of the items being removed from the
line as well as the labor to remove the part or assembly. "Transferred" items are items that are
existing in the line but are being moved or reused on a structure. A bill of material report for the
items with a status of Transferred will report the count of the items being transferred in the line
as well as the labor to transfer the part or assembly.
Several examples using the New, Existing, Retired, and Transferred capabilities of PLS-CADD
are discussed in section 8.5.5. Another example showing project lifecycle is discussed in
Appendix M.5.
8.5.1 Parts Table
You can view and edit the parts table with Structures/ Material/Parts and Assemblies File/
Edit Parts List (see Fig. 8.5-1). A parts table automatically includes as a minimum eleven builtin columns. In addition, with the Structures/ Material/Parts and Assemblies File/ Setup
command, you can up to 20 of your own columns. These columns can have additional
functionality which is described in Section 8.5.3 below. Fig. 8.5-1 shows the parts editor dialog.
The patch name of the file being viewed is shown at the top. Just below this is the Notes
section of the file which allows the user to input any notes about the part file being used such as
the date of the last update or the basis of the prices used in the table. The table contains the
eleven default columns used in PLS-CADD as follows:
Stock Number:
Name used to identify the part or assembly. (Can include letters,
symbols and numbers)
Item Description:
Description of the part or assembly.
Material Unit Cost:
The cost of the part or assembly.
Unit of Measure:
The measurement unit used for the part. For example cable may
be measured in feet where crossarms may be per item. The user
can also select units such as hours, days, and weeks to specify
the use of man labor or equipment. You can also define custom
units as described in section 8.5.3.
Install Labor Unit Cost:
The labor cost to install the part or assembly.
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Retire Labor Unit Cost:
The labor cost to retire the part or assembly.
Transfer Labor Unit Cost:
The labor cost to transfer the part or assembly.
Rule to Apply:
Rule that can be applied to allow dependency of part numbers on
items such as cable part numbers. This can be used for
conductor specific parts that may change depending on the cable
it is connected to, such as suspension clamps. To use this
functionality the user will need to select the rule "Cable Stock
Number =" from the list of commands. Once selected this will
allow the user to specify items in the next two columns. For
a part to be dependent the user must use a generic part in its
place in the model until such time that it is resolved. For example
the user may specify a generic part number for a suspension
clamp and then the program can resolve this into its cable
specific part based on the cable stock number.
Dependent Cable Stock
Number:
Variable Part Stock
Number:
Show in Structure Label:
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If the "Cable Stock Number=" is selected in the Rule to Apply
column then the user can enter the cable stock number that is
related to this particular part. For example if the part is a
suspension clamp for Dove conductor with a stock number of
DOVESCLAMP and it is used with a Dove conductor with a stock
number of DOVE the user would enter the stock number for the
Dove cable DOVE in this column so the program can resolve that
this clamp is only used when a Dove cable is in the model.
If the "Cable Stock Number=" is selected this column is used to
define the variable or generic part in the model that will be
switched for the conductor specific part. For example if the
generic part is SUSPCLAMP for a generic suspension clamp and
the conductor specific suspension clamp for Dove conductor is
DOVESCLAMP then the user would select SUSPCLAMP as the
Variable Part Stock Number for the DOVESCLAMP part.
This column allows the user to choose whether to display the part
in the structure label of the profile or sheets view which is
accessed in the Drafting/ Structure and Section Labeling/
menus. If no is chosen then this part will not appear in these
labels. This is useful when the user only wishes to see major
parts or assemblies in the structure label. Even if no is selected
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the parts or assemblies will still be accounted for in the bill of
material reports.
Figure 8.5-1 Parts Table
At the bottom of the Parts Editor table you can access the Assemblies Editor table by clicking
the Edit Assemblies button. You can also use the Hilite Material in Line button to highlight the
parts currently used in the project with a pale yellow color.
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8.5.2 Assemblies List
An assembly is an item that is made up of several other parts and/or assemblies. Each
assembly has a unique stock number, a description, and a list of the parts and/or assemblies
needed to construct it. The assembly table is edited with the Structures/ Material/ Parts and
Assemblies Files/ Edit Assemblies menu. You select a particular assembly in the Assembly
table by clicking on it (for example Assembly TM-1B-69 in Fig. 8.5-2). Then you click on the Edit
Assembly.. button in the Edit Parts in Assembly column in the Assemblies Editor table to bring
up the Edit Assembly dialog box which is shown in Fig. 8.5-2 below. The Edit Assembly dialog
box allows the user to select how many of which pre-existing parts and/or assemblies is used to
make up an assembly. For example in Fig. 8.5-2 the assembly TM-1B-69 is made up of 1 - YBall, 4 - 10 inch bell insulators, and 1 - Suspension Clamp.
The Assemblies Editor table is made up of the following columns:
Stock
Number:
Name used to identify the part or assembly. (Can include letters, symbols and
numbers)
Item
Description:
Description of the part or assembly.
Material Unit
Cost:
The aggregate cost of the parts and assemblies making up the assembly.
Unit of
Measure:
The measurement unit used for the assembly.
Number of
Parts:
Total number of individual parts contained in the assembly.
Edit Parts in
Assembly:
Allows access to the Edit Assembly dialog box for populating the items in an
assembly.
Install Labor
Unit Cost:
The aggregate cost of the install labor unit cost of all parts and assemblies
making up the assembly.
Retire Labor
Units Cost:
The aggregate cost of the retire labor unit cost of all parts and assemblies
making up the assembly.
Transfer
Labor Unit
Cost:
The aggregate cost of the transfer labor unit cost of all parts and assemblies
making up the assembly.
Show in
Structure
Label:
This column allows the user to choose whether to display the assembly in the
structure label of the profile or sheets view which is accessed in the Drafting/
Structure and Section Labels/ menus. If no is chosen then this assembly will not
appear in these labels. This is useful when the user only wishes to see major
parts or assemblies in the structure label. Even if no is selected the parts or
assemblies will still be accounted for in the bill of material reports.
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The Edit Assembly dialog contains the assembly stock number and assembly description
defined in the Assemblies Editor. The dialog box contains three tables. The first is the
assembly items table containing the parts and assemblies that make up the assembly. The
user can input the stock number and the number of parts in the assembly in this table. The
second and third tables are the parts and assemblies tables that list all preexisting parts and
assemblies. The user can quickly add an item from the bottom two tables to the assembly items
table by right clicking on the stock number cell for the item. This brings up the option in the
menu to Add to Assembly which copies the item to the assembly items table where the user can
input the quantity of the item used in the current assembly.
Figure 8.5-2 Assemblies Table
At the bottom of the Assemblies table there is an Expanded View button. This view gives the
assembly table in a flattened form that may exist in other databases. If an existing database
has a flattened table for assemblies, that matches the Assemblies Editor then you can quickly
copy and paste the cells from one database to another.
Another button at the bottom of the table is the Hilite Material in Line option which will hilite the
table entries that are currently used within the project with a pale yellow.
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8.5.3 Material Setup
The setup of user defined columns available in the Parts and Assemblies tables as well as the
type of data that can be input in these columns and options for these columns are entered in the
Structures/Material/Parts and Assemblies/Setup table. Each row of the table represents a
column that can appear in the parts or assemblies table. The top of the table shown in figure
8.5-3 shows the default columns in grey. These columns cannot be changed by the user and
their default values are shown. Below this are the white rows 14 through 33 which allow for 20
user defined columns for use in both the assemblies and parts tables.
The first column is the title of the column as it will appear in the parts and assemblies tables.
The user can enter up to 4 lines in the cell for the title. The second column is "Include Column
in:". This is used to choose whether the column should appear in the parts table, assemblies
table, or both. The third column is "Data Type For Column". This allows the user to select
whether the data to be entered in the table is text, numeric, list, cost adder, column multiplier, or
file path. After choosing a data type you can populate the fourth column which is the Options for
Column. See Below for a list of data types and the relevant options.
At the bottom of the table is the option to select how to keep the parts and assemblies sorted.
By default it is set to arbitrary but you can select any of the 33 columns to sort the parts and
assemblies.
Also at the bottom of the Material Table Setup is the Define Custom Units button that allows you
to enter your own counting unit for your parts or assemblies. Any user defined counting unit
added to the table will be selectable as the Unit of Measure in the Parts and Assemblies tables.
Text:
If Text is selected in the Data Type for Column then you can enter text
values in the column in the parts and assemblies tables and the maximum
length of the text entry is input in the Options for Column. The program will
default this maximum length to 40.
Numeric:
If Numeric is selected in the Data Type for Column then you can only input a
number in the column in the parts and assemblies tables and the minimum and
maximum value ranges for the number are input in the Options for Column
separated by a space. The program will default this to an extremely high
negative and positive number.
List:
If List is selected in the Data Type for Column then you can only select from
a predefined list of items in the parts and assemblies tables. The list of items
to choose from is input in the Options for Column, where each item should
be entered as a separate line.
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Cost Adder:
If Cost Adder is selected in the Data Type for Column then this
column will be added one of the cost columns. The user can choose which cost
column to add it to by selecting either Material, Retire Labor, Add Labor, or
Transfer Labor in the Options for Column.
Column Multiplier: If Column Multiplier is selected in the Data Type for Column then the input of
this column will be multiplied by a selected other column in the table. You can
choose which columns will be multiplied by this factor by selecting either quantity
used, material unit cost, add labor unit cost, retire labor unit cost, or transfer labor
unit cost in the Options for Column.
File Path:
If File Path is selected in the Data Type for Column then you can select a file
path for a file related to the part or assembly in the parts and/or assemblies table.
For example if you have a manufacturer cutsheet or drawing then the
user could add this as a reference in this column. The user can view this by right
clicking in the row and choosing the option to view the file in the parts or
assemblies table or any of the bill of material reports that include the path.
Cost Override: If Cost Override is selected in the Data Type for Column then this column will
override the cost entered in the parts table or the cost calculated for the
constituent parts of an assembly and the program will use this cost for any
reports generated.
Figure 8.5-3 Material Setup
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8.5.4 Material Population
There are three different ways to attach material to a PLS-CADD project. The first is material
added to the structure file as described in Appendix F for method 1 or method 2 structures or
material that was added to a method 4 file in PLS-POLE or TOWER. This would be considered
the Structure File Material. The other two methods involve using the Structure Specific Material
and the Line Specific Material discussed below.
8.5.4.1
Structure Specific Material
Structure Specific Material is accessed through the material button in the Structures/Modify
menu shown in Figure 10.2-3. This button brings up the Structure Specific Material List
which has a notes section at the top of the dialog box and then the structure specific items table
where parts and assemblies can be manually added to the structure position in PLS-CADD.
Anything added to this section does not influence the structure file itself. Below the structure
specific items table is the parts and assemblies tables. This section works similarly to the Edit
Assembly table discussed in section 8.5.2. At the bottom of the dialog box there is a radio
button that allows the user to switch between viewing the items in the parts and assemblies file
that can be added to the structure specific material list and the items that are in the structure file
material list. Figure 8.5-4 shows the structure specific material list with the items in structure file
displayed.
The items in the structure file highlighted in blue were automatically added by PLS-POLE or
TOWER by use of a library component with a stock number. The black text is an item that was
added manually to the structure file by the user.
Any item that is added to a structure automatically defaults to an item status of New for the
structure specific items as well as the items in the structure file. The radio button in between the
two tables allows you to change the status of the structure file material to existing if needed (like
as-builting a project). The structure specific items status can be changed in the last column by
selecting something other than New in the last column. Further discussion on the use of status
with items is below in section 8.5.5 and Appendix M.5.
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Figure 8.5-4 Structure Specific Material List
8.5.4.2
Line Specific Material
Line Specific Material is similar to Structure Specific Material except it applies to the project as a
whole. This is for items like engineering labor, road work, right of way acquisition labor, etc.,
which are based on the total project and not on a specific structure. The Line Specific Material
List can be accessed through Structures/Material/Line Specific Material List or the Line
Specific Material List Button in the Lines/Edit dialog box. The Line Specific Material List is
specific to each line in Lines/Edit so it is possible to have a different Line Specific Material List
for each line in the Lines/Edit dialog. The main difference between the Structure Specific
Material List and the Line Specific Material List is that the radio button toggle at the bottom of
the dialog box allows the user to view either the items in the parts and assemblies file or the
automatically added items from the cables and concentrated loads used in the line. Figure 8.55 below shows the Line Specific Material List with the option to display the cables and
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concentrated loads checked. Only cables and concentrated loads files which stock numbers
have been specified will appear in this table and the Bill of Material.
Figure 8.5-5 Line Specific Material List
8.5.4.3
Conductor Specific Parts
As mentioned in section 8.5.1, you can have cable dependent parts assigned by using a generic
part number to identify the part and linking it to cable specific parts using the Cable Stock
Number = rule in the Parts Editor table. These parts can be used in the Structure File Material
List, Structure Specific Material List, and the Line Specific Material List. Any time a generic part
is used in any of these places the program will search for a specific set and phase or cable
stock number to relate the part to, so it can use the stock number of the cable attached to the
set and phase to resolve the generic part into its conductor specific part. The Structure File
Material List for a method 4 structure file does this automatically if a generic stock number is
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used in any of the Geometry/Insulator menus of PLS-POLE/TOWER where a set and phase is
defined in the Geometry/PLS-CADD/Insulator Link Table in PLS-POLE/TOWER.
If using a generic part in a method 1 structure file, method 2 structure file, structure specific
material list, or line specific material list then the program will ask you to manually resolve the
generic parts by entering the appropriate set and phase or cable stock number related to the
part. Figure 8.5-6 below shows a Variable Parts resolve table that has ten generic DAMPER
parts that were added in the Structure Specific Material List that need the set and phase
resolved. At the bottom of the table is the existing resolve list items that were resolved from the
Structure File Material List. In order for the generic DAMPER part to be resolved you would
need to enter the set and phase related to each damper. This resolve list dialog box will appear
when you OK out of a part or assembly editor dialog containing generic parts.
Figure 8.5-6 Variable Parts Resolve List
8.5.5 Item Status (New, Existing, Transferred, Retired)
PLS-CADD allows you to assign a status to units to allow for work management in existing
projects as well as providing estimates for new construction projects. Used in conjunction with
the Multiple Lines capabilities, described in section 5.4.6.4 of the manual PLS-CADD, the
program can track the lifecycle of a project. When designing a line in PLS-CADD all items that
are included in the structure file as well as the items in the structure and line specific material
lists default to a status of New. A status of New would reflect that the line has not been built
and requires both material and labor in order to construct it. After a project has been
constructed you can choose to As-Built the line by placing all of the units in a status of Existing
which means the line has been built. The items with an existing status are items that exist on
the line in its current state. A report of Existing items would be a report of the physical assets
on the line after it has been constructed. There are several tools to As-Built a project in PLSPLS-CADD – Version 16.0 © Power Line Systems, 2019
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CADD in the Structures/Material/ menu. These tools are explained below and used in the
project lifecycle example in Appendix M.5.
Every project starts out as a new project when it is built. Then you can As-Built the project to
change all items' status to existing. Once a line has been As-Built, you can perform other
actions on the line such as thermal upgrades or relocations that require the addition, removal,
and transfer of assets. These other actions could be considered new lines in the Lines/Edit
menu so you can track the lifecycle of the line from the initial design to the current state of the
line. In the end, when the project is complete all item status should be existing. You can use
the tools below to change the status of new, retired, and transferred items to existing or remove
an item from the list.
8.5.5.1
Global Change Item Status
The Structures/Material/Global Change Item Status command brings up the dialog in Figure
8.5-7. This function will change all items selected in the dialog to the selected status in the
current line. For example if the user has a line with all new status and wishes to convert it to
existing they can select to globally convert using this command. The top portion of the dialog
allows the user to select the structure range on which the command will operate. The next
section chooses what status the items will be globally converted to. The third section of the
dialog allows the user to select whether to use the operation on the structure file material list,
structure specific material list, line specific material list, or the cables and concentrated loads
that were automatically added by the program. You can also select whether to include or
change the status of items whose current status is retired or transferred.
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Figure 8.5-7 Global Change Item Status
8.5.5.2
Specific Change Item Status
The Structures/Material/Specific Change Item Status command brings up the dialog in
Figure 8.5-8. This command allows you to select a specific item with a specific status from the
Structure Specific Material List and/or the Lines Specific Material List and change their status.
The bottom of the dialog box has four different status boxes with each item that is in the project
appearing in the box. If you want to change the status of one of these items, you can select it
from the list and choose the status conversion you want. The selected item to be changed will
highlight in blue when selected. To select more than one item hold down the Ctrl key while
selecting with the mouse.
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Figure 8.5-8 Specific Change Item Status
8.5.5.3
Global Dismiss Items with Status
Sometimes it is necessary to delete items from a report when making an As-Built project. For
example if the user added ROW Agent labor to the line specific material list to account for the
labor necessary to acquire easements for the line they will probably want to remove this unit
after the line is built so the report will only contain physically existing items in the line such as
poles, conductor, and hardware. The Structures/Material/Global Dismiss Items with Status
command allows you to do this. This command only works on the user input items from the
structure specific material list and line specific material list. You just need to define in the dialog
box which status you want to dismiss as well as whether to dismiss from the structure specific
material list and/or the line specific material list.
8.5.5.4
Global As-Built
The Structures/Material/Global As-Built command allows you to change or dismiss items with
a certain status in the dialog box shown in Figure 8.5-9. This command can be thought of as a
combination of the commands in the previous three sections. This command has the added
bonus of having all of the options in one place as well as the ability to perform a dismiss
command for retired and new items that pair.
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For example if a user is replacing a crossarm in a structure where the crossarm is accounted for
in the Structure File Material List then the user would go to the Structure Specific Material List
and add one item for the crossarm with a retired status and one item for the crossarm with a
new status so the retirement of the old item and install of the new item are accounted for
correctly. However when making the project As-Built the crossarm is accounted for in the
Structure File Material List as an existing item so the user would want to dismiss both the retired
and new items status from the Structure Specific Material List. If the user makes use of the
dismiss retired and new items that pair in the dialog box then the program will remove these
items automatically.
Figure 8.5-9 Global As-Built
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8.5.6 Material Reporting
There are three different material reports available in PLS-CADD. Each report results in a
report window. The user can access several functions by right clicking within the body of the
report window. At the top of the menu there will be the ability to Edit the part or assembly that
you right clicked near as well as the ability to replace parts in an assembly. These are the same
commands available in the menu by going to Structures/Material/Parts and Assemblies File/
Edit Parts or Edit Assemblies or Replace Item in All Assemblies. There is also the option
to have a table view of the report or the ability to export an xml of the report by right clicking
within the body of the report.
8.5.6.1
Bill of Material Report
By using Lines/Reports/Bill of Material you can obtain a summary report of all material used in
a project including the material in the Structure File Material List, Structure Specific Material List,
Jumper Material and the Line Specific Material List. As shown in Figure 8.5-10 below, you can
select the structure range the report will be based upon as well as the item status to include in
the reports. There are also options to include the parts, assemblies, cables, concentrated loads
(marker balls), jumper cables or line specific material list items. If you select the option to
include the cables or concentrated loads then the Sets and Phases selection box allows you to
select which sets and phases the report would be based upon. You can also check the option
to include only insulator material related to insulators that have cables attached to them in the
PLS-CADD model. This way if you have any insulators in the model that are not used then they
will not be reported in the Bill of Material Report. You can choose whether or not to include the
Line Specific Material List in the bill of material report by checking it on or off in the dialog box.
You can also choose whether to have one complete table including all items or to have separate
tables in the report for parts, assemblies, and the line specific material list. If you select the
decompose assemblies option the report will break down the assemblies to its constituent parts.
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Figure 8.5-10 Bill of Material Dialog Box
8.5.6.2
Bill of Material by Structure Location Report
The Lines/Reports/Bill of Material by Structure Location report is similar to the Bill of
Material Report shown in Figure 8.5-10. The main difference is that this report breaks the
material down into the material at each structure location. You can choose whether to have a
combined report of the material for each structure or have a separate report for each structure.
There is also a Select Structures tab that allows you to multi-select a discontiguous range of
structures. The Line Specific Material is not included in this report.
8.5.6.3
Bill of Material Delta Report
The Lines/Edit dialog in PLS-CADD allows multiple lines with different designs as described in
section 5.4.6.4. Each of these different lines has its own Bill of Material based on its structure
file material, structure specific material, and lines specific material. The Lines/Reports/Bill of
Material Delta allows you to compare the bill of material between two different designs in the
Lines/Edit menu. The controls of the dialog box are similar to Figure 8.5-10 except you pick a
reference project and design project for comparison. The result is a delta report that lists the
difference between the reference project and the design project.
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8.6
Creating, Editing or Customizing Structure File
Creating and editing structure files is described in Appendix F. Customizing them is described in
Appendix P.
8.7
Summary of the Advantages of Using Method 4 Structures
For more than a decade many PLS-CADD users have taken advantage of Power Line Systems'
advanced structural analysis solutions. Fully modeling structures in our TOWER and PLS-POLE
programs (i.e. using real models of Method 4 structures) provides many benefits over traditional
wind & weight span approaches (i.e. using Method 1 or Method 2 structures). These benefits
accrue because the intrinsic (physical) properties of a Method 4 structure are modeled
separately from the wires which are attached to the structure and the safety code which is used
to determine its allowable strength. With a Method 4 structure, a load is applied to the structure
and a safety code is then used to check that structure. With Method 1 or Method 2 structures
strength is defined by allowable wind and weight spans which have embedded within them the
number, type, tension and line angle of the supported conductors as well as the applicable
safety code. Modeling the intrinsic properties of a structure separately as opposed to combining
these properties with the wires attached to the structure and the code used to check it has
overwhelming advantages in the following common design situations:
Reconductoring: When you are using Method 4 structures you simply change the wire or
tension and use the Structure/ Check command. With Method 1 or 2 structures you need to
compute allowable wind & weight spans (not a simple task) and create new structure files for
every combination of conductor, tension and code scenario you want to consider before you can
check structures.
Structure upgrades: When you check a Method 4 structure, the program actually checks each
piece of the structure. It will tell you which, if any, parts of the structure are failing. A wind &
weight span check of a Method 1 or 2 structure will tell you if it is failing but doesn't give you
any idea why or what could be done to fix the problem. For example: we once performed an
uprating study that involved reconductoring the latticed towers of the line shown in Fig. 5.4-9.
These structures did not have sufficient strength for the heavier conductor. PLS-CADD
(automatically calling TOWER internally) quickly generated color coded graphics showing the
overstressed members. Many of the structures could be made to withstand the load by simply
replacing four hanger members. The identification of the members needing reinforcement is not
possible with a wind & weight span analysis and in this case resulted in substantial savings over
replacing the entire structure.
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Changing ruling span: Sometimes, through unusual terrain or clearance requirements you end
up with a design that doesn't match the design ruling span very well. Once again, this isn't a
problem for Method 4 structures as you just use the Structure/ Check command. For Method 1
or 2 structures you need to re-derive your allowable spans if you really want to get the most out
of your structures.
Underbuild/ Joint Use: With Method 4 structures, you simply add attachment points to the
structures if they aren't already there string whatever additional wires are needed at the
appropriate tensions and use the Structure/ Check command. For Method 1 or 2 structures
you need a re-compute different sets of allowable wind & weight spans for each different
underbuild scenario.
Unbalanced ice, broken conductors, slack removal/shift for extra clearance: All these
situations leave you with a longitudinal imbalance. With Method 4 structures it is very easy to
figure out if the structures can withstand this imbalance, even accounting for the interaction
between the wires and the effect of structure flexibility. Method 1 or 2 structures are useless in
these cases.
Changes in safety codes: Simple code changes can invalidate all your Method 1 or 2
structure models while they do not affect Method 4 structures. For example:
The 2002 revision of the NESC redefined wind pressures as a function of span length and
attachment elevation. Those who used Method 4 structures simply switched to NESC 2002
wind adjustments in PLS-CADD's Criteria/ Weather table and performed a structure check.
Those who used Method 1 or 2 structures had to re-derive all their allowable wind & weight
spans and redo their standards. In fact, the very concept of being able to compute an allowable
wind span for a structure seems at odds with the new NESC where you can't even compute the
wind unless you know the heights of the ahead and back structures.
Three months after the new NESC took effect, ANSI O5.1-2002 was released which mandated
a reduction in the allowable fiber stress for wood poles. Once again, existing standards with
Method 1 or 2 structures were rendered useless, but users of Method 4 poles simply switched
to the ANSI O5.1-2002 strength check and immediately had updated results.
These two code changes which both occurred in 2002 show why it is so important to model the
intrinsic properties of the structure separately from the code used to check it.
Structure modification: PLS-CADD lets you customize Method 4 structures by dragging guy
anchors around. It also lets you move attachments and/or arms up and down on Method 4
poles. When you are finished with these drag/drop operations you can check the structure with
a simple Structure/ Check. When using Method 1 or 2 structures you have to once again rederive the allowable span values based on the changes to the geometry.
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Improved graphics: When using Method 4 structures PLS-CADD can insert rendered images
of the structures into its views. These graphics are a great help in catching structure modeling
errors. With Method 1 or 2 structures no graphical double check is available.
Clearances to structures/ guys: Method 4 structures graphics are much more than just pretty
pictures. These graphics contain all the information PLS-CADD needs to perform clearance
checks from wires to the structure and its guys. Method 1 or 2 structures do not contain this
information (in fact they don't even specify whether the structure is a lattice tower or a wood
pole or even if it has guys).
Maintenance: PLS-CADD allows you to track changes to Method 4 structures and account for
deterioration of the structures. For example if your maintenance crew tells you that a wood pole
has some shell rot you can model that and immediately check the structure to see if it needs to
be replaced. With a Method 1 or 2 structure you have no means to determine the adequacy of
the structure.
Phase transposition: When switching from a horizontal to a vertical configuration, each wire in
a circuit has its own wind & weight span as well as its own induced line angle. You need to keep
this in mind and manually account for it when using Method 1 or 2 structures, but it is handled
automatically if you use Method 4 structures.
Generation of allowable wind & weight spans: Allowable wind & weight span values or an
interaction of these (which we call interaction diagrams) are currently still necessary for the
optimum spotting of a line by PLS-CADD. Therefore, optimum spotting still requires the use of
Method 1 or 2 structures. However, TOWER and PLS-POLE can use Method 4 models to
generate corresponding Method 1 or 2 models with the click of a mouse thus giving you the
freedom to rapidly experiment with many different structure and conductor configurations.
The preceding situations illustrate the many advantages of using real structure models rather
than allowable wind & weight span models. Wind & weight span models used to be popular in
the days of design on paper with pencils and physical templates because they enabled
"structural analysis" by simply measuring a few distances on a drawing. They are still useful in
low voltage distribution line design where standardization is essential. However, wind & weight
span models do not lend themselves well to modern demands on engineering.
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9.
GROUND WIRES AND CONDUCTORS
9.1
Mechanical Model
The mechanical model adopted in PLS-CADD for cables (ground wires and conductors) can be
used to calculate sags and tensions according to most world practices. In many European
countries, it has been traditional to assume that cables are elastic, with creep accounted for by
an equivalent temperature increase. In North America, non-linear models are the norm, as
pioneered by the Aluminum Company of America (Batterman, 1967) and the Bonneville Power
Administration (Reding, 1976). Another option is to have creep accounted for by a temperature
shift and define a tension at which the shift is applied. The model used in PLS-CADD can be
applied to all three situations. It is based on original algorithms (McDonald, 1990; SAGTENSION, 1990) which use polynomial stress-strain relationships similar to those used by the
aluminum industry in the USA and Canada (Batterman, 1967; Aluminum Association, 1971;
EPRI, 1988, Thrash, 1994).
The condition of a cable within a few hours of its being installed in a transmission line is called
its "Initial" condition. Because it is always under tension, the cable often creeps with time. If one
assumes that the cable remains under constant tension at the creep temperature TEMPC over a
ten-year period, the condition of the cable after the 10-year period is called final after Creep. If
the cable is permanently stretched under some severe weather load, its condition after being
subjected to the severe load is called final after Load. PLS-CADD performs separate sag and
tension calculations for ground wires and conductors in their Initial, final after Creep, and final
after Load conditions. Therefore, two weather cases have to be assumed in the design criteria
before any sag-tension calculation is performed (see Section 7.3.4). These are: 1) the weather
case under which creep is assumed to occur, i.e. generally a combination of no ice, no wind and
average temperature, and 2) a severe weather case which is assumed to create the permanent
stretch of the final after "Load" behavior. The selected severe weather case is often referred to
as the "common point load". The concepts of final behavior after creep or load are described in
more details below.
9.1.1 Initial Behavior - Elastic vs. Nonlinear
Consider a homogeneous cable (ground wire or conductor made up of only one material) in its
initial condition. Its unstressed length at an arbitrary reference temperature TEMPREF will be
referred to herein as LREF. If the cable is perfectly elastic, its stress-elongation (elongation
measured as fraction of unstressed length, i.e. strain) diagram at temperature TEMPREF is a
straight line with constant slope E as shown as line O-A in Fig. 9.1-1. E is the modulus of
elasticity of the cable.
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However, most cables behave in
a nonlinear fashion. As a result,
their
stress-elongation
relationship may look like curve
O-I in Fig. 9.1-1. Actually, a curve
like O-I is obtained by fitting a
function
through
pairs
of
experimental points (stress strain). Each experimental point
is obtained by holding the cable
tension or strain constant for a
few minutes as described by the
controlling standard. When the
stress is first increased to σ1 the
elongation is ε1 (state of cable
represented by point 1). If the
Fig. 9.1-1 Initial Stress-strain Behavior
stress is then further increased to
σ2, the elongation increases to ε2 (point 2 on curve O-I). However, if, after first being loaded to
point 1, the cable tension is released, the unloading stress-elongation curve follows path 1-P1,
which is a straight line with slope EF. For a nonlinear cable, EF is called the final modulus of
elasticity. The value of EF may be close to the value of the slope of curve OI at the origin. At
zero stress the cable which was unloaded from point 1 has a permanent elongation P1. If the
cable is loaded again, its stress-strain relationship will follow the path P1-1 until the stress
reaches level σ1, and then it will follow again the original initial curve O-I until the next unloading
occurs. If loading takes the cable to point 2, its unloading will take place along path 2-P2 and
there will be a permanent stretch P2. Unloading from any point on curve O-I will always take
place along a line with constant slope EF as shown in Fig. 9.1-1.
Cable tensions and sags in the Initial condition assume that the stress-elongation relationship
for the cable is that of the initial curve O-I. In PLS-CADD the curve O-I is described by a fourth
degree polynomial, with the elongation expressed in percent of the cable reference unstressed
length LREF:
σ
=
2
3
4
k0 + k1 ε + k2 ε + k3 ε + k4 ε
(9-1)
where the five coefficients k0 through k4 can be determined by curve fitting of experimental data.
For a linear elastic cable, Eq. 9-1 can still be used with all coefficients equal to zero except k 1
which is equal to the modulus of elasticity, i.e. k1 = E (see example in Section G.3).
For a composite cable made of two different materials (ACSR-, ACAR-, SSAC-conductors, etc.),
each material individually has a stress-elongation curve such as curve O-I in Fig. 9.1-1.
Therefore, the combined tension-elongation curve for the composite cable is obtained by
multiplying the stress-elongation curve for material 1 (referred to as "outer" material herein) by
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the cross section area of that outer material, ARO, and adding to it the stress-elongation curve
for material 2 (referred to as "core" material) multiplied by the core cross section area ARC. For
an ACSR conductor, the outer material is aluminum and the core material is galvanized or
aluminized steel. The combined tension-elongation curve can be normalized to a stresselongation curve by dividing it by the total cable area AT = ARO + ARC. Therefore, the combined
stress-elongation curve for a composite cable can be obtained by simply adding together two
virtual stresses as:
σ = σO (ARO/AT) + σC (ARC/AT)
(9-2) composite stress-strain
where the virtual stresses are given by the polynomials:
2
3
4
2
3
4
σO (ARO/AT) = a0 + a1 ε + a2 ε + a3 ε + a4 ε
σC (ARC/AT) = b0 + b1 ε + b2 ε + b3 ε + b4 ε
(9-3) outer stress-strain
(9-4) core stress-strain
in which the a's correspond to "outer" material and the b's to "core" material. Note that Eq. 9-2 is
also applicable to homogeneous cables, but in such a case ARO = AT, ARC = 0 and all the b's
are zero. It is important to realize that the polynomial coefficients in Eqs. 9-3 and 9-4 do not
model true stresses, but virtual stresses in each material which are true stresses adjusted by
the ratio of the area of that material to the total cross section area.
Unloading after straining the two
materials to a common strain ε
(see Fig. 9.1-2) would take place
along path A-B-P, which is the
superposition of the unloading
paths for each material. Point B is
generally referred to as the "Knee
point". For the same reason that
stresses in Eqs. 9-3 and 9-4 had
to be adjusted by the ratios
(ARO/AT) and (ARC/AT), in order
that superposition apply, the
slopes of the unloading curves in
Fig. 9.1-2 should be:
Fig. 9.1-2 Behavior of Composite Cable
EFO
=
(ARO/AT) x Final modulus of elasticity for "outer" material
(9-5)
EFC
=
(ARC/AT) x Final modulus of elasticity for "core" material
(9-6)
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9.1.2 Final Behavior after Creep
Creep is increasing elongation under constant stress with time. Extensive information on creep
can be found in a CIGRE report (CIGRE, 1977). Most creep in a transmission line occurs during
the first few days after stringing but it continues throughout the life of a line, although at
decreasing rates. The estimate of creep elongation is probably one of the biggest uncertainties
in sag-tension calculations. Steel does not creep much, but aluminum does significantly.
Consider Fig. 9.1-3, in
which curve O-I is the same
as the initial curve in Fig. 91. If the cable is kept under
constant tensile stress σC
for a period of time, say 10years, it elongates further
from its initial elongation
value and reaches the final
elongation value εC. The
stress σC at point 2 is the
average cable stress under
the “final after creep”
weather case specified in
the Creep-Stretch dialog
box of Fig. 7.3-3 (see
Section 7.3-4). The state
Fig. 9.1-3 Behavior after Creep
of the cable that was
represented by point 1 before creep is represented after creep by point 2. The elongation 1-2 in
Fig. 9-3 represents the additional elongation due to creep over the 10-year period. If the stress
had been kept at a constant value smaller than σC, the creep elongation would be smaller than
the elongation 1-2. On the other hand, if the stress had been kept at a value larger than σC, the
creep elongation would be larger than elongation 1-2. These results are represented by curve
O-C in Fig. 9.1-3. Curve O-C represents the relationship between an applied stress assumed
kept constant (at a given temperature and over a period of 10-years) and the resulting total
elongation (short term + creep) of the cable. O-C is called the long term creep curve. It is not
defined for large stresses because cables are usually strung in such a way that high stresses do
not remain for long periods of time.
Now, if the cable is unloaded and then reloaded after having crept to the state represented by
point 2 in Fig. 9.1-3, its stress-elongation relationship follows the path PC-2-3-I. If cable reaches
the stress σ3, it will have a permanent stretch represented by PC if completely unloaded. The
portion O-PC of the path indicates that a cable cannot be pushed into compression. If the cable
is loaded from its unstressed condition, it stays on the straight line PC-3 unless the stress
exceeds the level σ3. If the stress exceeds σ3, the initial curve 3-I controls again the stress-
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elongation relationship. The slope of the line PC-3 is the final modulus of elasticity EF, the same
value which applies to any of the unloading curves in Fig. 9.1-1.
Therefore, in order to completely describe the cable behavior after creep, one needs to know
the location of the permanent elongation after creep (point PC in Fig. 9.1-3). Once point PC is
located, the entire path PC-3-I can be established. That path describes the cable final behavior
after Creep. If the curve O-C is available, the location of point PC can be found for any assumed
level of permanent stress σC. In PLS-CADD, σC is automatically calculated as the cable stress
for the "Weather case for final after creep" specified in the Creep-Stretch dialog box of Fig. 7.33 (see Section 7.3.4).
The creep curve O-C can be determined experimentally by starting with point 1 on the initial
curve and adding an estimated creep elongation 1-2. Curve O-C, like the initial curve O-I, can
be represented by a fourth degree polynomial. In the case of two materials, the combined curve
O-C can be described by its two components as follows:
σ = σO (ARO/AT) + σC (ARC/AT)
(9-7) composite creep
where:
2
3
4
2
3
4
σO (ARO/AT)
= c0 + c1 ε + c2 ε + c3 ε + c4 ε
σC (ARC/AT)
= d0 + d1 ε + d2 ε + d3 ε + d4 ε
(9-8) outer creep curve
(9-9) core creep curve
where the various variables are similar to those defined in Eqs. 9-2, 9-3 and 9-4. It should be
noted that for an "outer" material that does not creep, the five coefficients c's in Eq. 9-8 are
identical to the a's in Eq. 9-3. For a non-creeping core, the d's in Eq. 9-9 are identical to the b's
in Eq. 9-4.
For cables that are assumed to behave homogeneously (like one material) and elastically, a
single value of creep elongation PC may be assumed for all stress levels, Eqs. 9-2 to 9-9
collapse to two simple equations:
σ=Eε
(9-10) linear initial stress-strain
σ = - E PC + E ε
(9-11) constant offset creep curve
that is, all the a's, b's, c's and d's in Eqs. 9-3, 9-4, 9-8 and 9-9 are zero except a1 = E, c0 = -E PC
= -E α t and c1 = E. Even if two materials are used, some designers assume that the cable is
made up of a single equivalent elastic material for which Eqs. 9-10 and 9-11 can be used. To
model the cable using this method, select “Linear elastic with permanent stretch due to creep
specified as a user input temperature increase” in the cable data file. Figure 9.1-3a shows the
stress-strain relationship for this type of linear cable model.
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In addition to treating the entire
composite cable as a single elastic
homogeneous cable with modulus of
elasticity E, some designers (common
European practice) further simplify the
problem by assuming that the creep
elongation PC is equal to the elongation
produced by a specified temperature rise
called
the
“creep
compensation
temperature”.
Figure 9.1-3a Linear Cable Model with Creep Specified
as a User Input Temperature Increase
For a homogeneous elastic cable model the creep may also be assumed to vary proportionally
with stress. Figure 9.1-3b shows the stress-strain relationship for this type of linear cable
model. In this instance Eq. 9-10 still applies but the creep equation becomes:
σ=
ε
1 αt
+
E σ1
(9-11a)
linear creep curve
Where t – temperature shift used to model
long term creep
σ1 – tension at which the temperature shift t
applies
α – coefficient of thermal expansion for the
composite cable
To model the cable using this method, select
“Linear elastic with permanent stretch due to
creep proportional to tension” in the cable
data file.
Figure 9.1-3b Linear Elastic Cable Model with Creep
Proportional to Tension
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9.1.3 Final Behavior after Stretching from Severe Load
Point CP on the initial curve O-I
in Fig. 9.1-4 describes the high
stress of the cable under a
severe weather condition. CP
has been referred to as the
"common point" since it is
common to the initial curve O-I
and the final line PCP-CP. In
PLS-CADD,
σCP
is
automatically calculated as the
cable stress for the "final after
load" weather case specified in
the Creep-Stretch dialog box
of Fig. 7.3-3 (see Section
7.3.4). If the cable has been
Fig. 9.1-4 Behavior after Heavy Load
unloaded after being initially
loaded to the common point CP, any further loading will be on the path PCP-CP-I in Fig. 9.1-4.
Such a path represents the cable final behavior after Load. PCP is the permanent stretch of the
cable after it has been loaded to the common point load. In its final condition after common
point, the cable final sag for any load case is larger or equal to the corresponding initial sag in
the initial condition because of the permanent stretch PCP. If PCP larger than creep elongation PC
in Fig. 9.1-3, final sags after Load will exceed final sags after Creep. If PCP is less than PC, final
sags after Creep will exceed final sags after Load. In this situation "creep controls" the cable
tensions.
A designer may want to assess high temperature sags after some severe weather condition
(designated as the common point condition) has affected the line. For example, the designer
may specify two ice cases: the first consists of a small ice accretion, say .5 inch, and the second
considers a larger amount, say 2 inches. It may be required that high temperature sags after the
smaller icing event be within some code limitations, but it may be acceptable that sags occurring
after the larger icing event temporarily violate the limitations. The larger icing event is a much
rarer event and the line owner may be willing to re-tension the line after such an event. In the
hypothetical situation described above, the lesser icing load case would be defined as the
common point weather case. The larger load case would be included in the loading agenda only
to ensure the structural integrity of the cable and its supports, but not as a limiting sag condition.
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9.1.4 Thermal Properties
As the cable temperature is changed from its reference value TEMPREF to a new temperature
TEMP, the unit elongations of each one of the cable component materials change by the
amount
( ΔL/LREF)MAT = ETMAT (TEMP - TEMPREF)
(9-12)
Where ETMAT = thermal expansion coefficient of material MAT. Temperature changes can easily
be accounted for by sliding separately each material stress-elongation path by the amount
ETMAT (TEMP - TEMPREF) as shown in Fig. 9.1-5.
Fig. 9.1-5 Effect of Temperature Change
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9.2
Creating or Editing Cable Files
In PLS-CADD, ground wires and conductors are referenced by their names. The properties of a
particular cable need only be entered once in the library of ground wires and conductors. This is
done in the Cable Data dialog box (see Figs. 9.2-1 and 9.2-2 and 9.2-3) which you reach with
Sections/Cable Files/Create New Cable File... or Sections/Cable Files/Edit Existing Cable
File.... For example, the data for a Drake conductor is permanently stored in the file named
Drake.
A cable file includes some essential data in the Physical Tab of the Cable Data dialog box
shown in Figure 9.2-1 and optional data in the Electrical Tab of the Cable Data dialog box in
Figure 9.2-2 which is used in the thermal rating and line constants calculations and the Notes
Tab which is shown in Figure 9.2-3. Cable data for a large number of conductors and ground
wires can be downloaded from our web site directly or using the web download commands
discussed in section 5.8.
At the top section of the Physical Tab you have the Information section of the dialog where you
have the following information:
Name:
Description:
Manufacturer:
Stock Number:
Cable Type:
Size Label:
Bimetallic Conductor:
Display Color:
Outer Strands Number:
Outer Strands Diameter:
Core Strands Number:
Core Strands Diameter:
Cable File Name
Alphanumeric description of cable
Alphanumeric description of cable manufacturer
Stock number of cable for future use in material reports
Type of Cable (example ACSR, AAC, TW, etc.)
Alphanumeric description of cable size (795, 7NO8 etc.)
Identify whether cable is made of two different materials
and hides unnecessary data if unchecked.
Default color for conductor. Display of conductor may be
overridden to this color in the Sections/ Display Options
dialog.
Number of Outer Strands in Bimetallic Conductor or Total
Number of Strands in Monometallic conductor
Diameter of Individual Outer Strand in Bimetallic Conductor
or Diameter of Strands in Monometallic conductor
Number of Core Strands in Bimetallic Conductor
Diameter of Individual Core Strands in Bimetallic
Conductor
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In the Cable Model section of the dialog box, you can select to use the complete mono- or bimetallic nonlinear model with creep, the simplified linear model with creep specified as a user
input temperature increase, or the improved linear model with creep proportional to the creep
weather case tension by clicking the appropriate radio button. The simplified model is described
in Section G.2 and the improved linear model is described in section G.3 as well as in the
technote
at
http://www.powline.com/technotes/Improved_Linear_Cable_Model.pdf.
The
nonlinear conductor model is the preferred cable model to use.
Fig. 9.2-1 Drake Conductor Physical Information
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Cable data includes:
Cross section area, AT:
Outside diameter, D:
Unit weight, UW:
Ultimate tension, ULT:
Numb. of independent wires:
Conductor is Gap Type:
Total cross section area, including core and outer strands
Outside diameter used for wind load calculations
Weight per unit length of bare cable
Ultimate (rated) cable mechanical tension
Number of separate cables in a group of wires supported
by a messenger (see Section 9.2.1)
(see Section 9.2.2)
Temperature at which data were obtained:
Temperature at which the experimental data from which the polynomial coefficients
listed below were obtained (not needed for simplified model)
Then for the Outer Strands (or all the strands if the cable is made of only one material and
Bimetallic Conductor is unchecked):
Final modulus of elasticity, EFO:
Final modulus of elasticity of outer material as defined in
Eq. 9-5
Thermal expansion coefficient, ETO: Thermal expansion coefficient of outer material as defined
in Eq. 9-12
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Nothing else is needed if you use the simplified method. Otherwise:
Stress-strain polynomial coefficients, a's:
Creep polynomial coefficients, c's:
Five coefficients in Eq. 9-3 - Outer stresselongation
Five coefficients in Eq. 9-8 - Outer creep
Then for the Core Strands (data only needed for bimetallic cables):
Final modulus of elasticity, EFC:
Final modulus of elasticity of core material as
defined in Eq. 9-6
Thermal expansion coefficient, ETC:
Thermal expansion coefficient of core material as
defined in Eq. 9-12
Stress-strain polynomial coefficients, b's:
Creep polynomial coefficients, d's:
Five coefficients in Eq. 9-4 - Core stress-elongation
Five coefficients in Eq. 9-9 - Core creep
Bimetallic Conductor Model:
Select the behavior for temperatures above the
transition point as discussed in Section 7.3.5. The
selection in this area of the dialog box will control
the behavior of the cable and decide whether to
use the settings in Criteria/Bimetallic Conductor
Model or the settings in the cable file.
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In the Electrical Tab shown in Figure 9.2-2 you can enter the optional Thermal Rating and Line
Constants Properties. See the IEEE Standard 738, CIGRE Brochure 207, or CIGRE Brochure
601 for the definition of the input properties as they relate to thermal rating functions described
in Section 11.2.6. See the EPRI Red Book methods (3rd Edition, 2005 – 2.4 Basic Transmission
Line Impedance and Admittance Parameters) for the definition of the properties as they relate to
line constants.
Fig. 9.2-2 Drake Conductor Electrical Properties
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AC Resistances at two temperatures:
DC Resistance:
PLS-CADD assumes that a conductor resistance,
in the range where calculations are made, is a
linear function of its temperature. Therefore, you
need two data points to define that function.
DC Conductor Resistance
GMR:
Geometric Mean Radius
All Thermal Rating Properties:
See IEEE Standard 738, CIGRE Brochure 207 or
CIGRE Brochure 601
The Notes Tab of Figure 9.2-3 allows you to enter free form descriptions and information about
the cable. You can also copy bitmap images and paste into the dialog which will be saved with
the wire file. Please note that the more data and images that are added will increase the cable
file size.
Fig. 9.2-3 Drake Conductor Notes
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If you click on the Generate Coefficients from points on stress-strain curve button at the
bottom of the Cable Data dialog box, you will be taken to the Cable Data Points table where
you can enter test data from which polynomial coefficients can be determined. This option only
works for cables made of a
single metal or assumed to be
homogeneous. This is discussed
in Appendix G.
Once you have entered or
modified cable data, it is always
a good idea to generate a graph
of these data to make sure that
there are no gross errors. This is
done with the Graph Cable
Properties button. The Graph
Cable Properties button will
generate a graph of the tension
vs. elongation as seen in Figure
9.2-4 above as well as a tension
9.2-4 Tension-elongation for Drake
vs. creep elongation.
For
example, the data for the Drake
Fig. 9.2-4 Tension-Elongation for Drake
conductor shown on Fig. 9.1-2
can be displayed as shown in Fig. 9.2-4. For the Drake conductor, the outer aluminum strands
make up about 86 % of the total cross section area and the galvanized steel core make up the
remaining 14%. The value used for the aluminum final modulus, EFO = 69,669, was obtained
experimentally and reflects several downward adjustments from the standard modulus of
elasticity for a straight aluminum rod (10,000,000 psi). The first adjustment is a division by 100
since strains in PLS-CADD are reported in percent. The second adjustment is for the area ratio
as shown in Eq. 9-5 (area ratio = 0.86). Finally, an additional downward adjustment is caused
by the fact that the cable is made up of layers of wound helical strands as opposed to a single
solid straight rod.
The Graph Cable Properties button will generate a graph of the tension vs. elongation as seen
in Figure 9.2-3 above as well as a tension vs. creep elongation. While the graphs of Fig. 9.2-4
represent the behavior of a Drake conductor at its test temperature (Temperature at which data
were obtained in Fig. 9.2-1), you can see how the curves shift for different temperatures by
clicking on the Graph Tension vs. Elongation button in the Section Modify dialog box of Fig.
10.3-3. This will generate graphs for the temperature of the Weather Case selected in the
Display portion of the Section Modify box.
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The graphs in Fig. 9.2-4a were obtained for the Drake at 240 degrees F. You will note three
knee points at high temperature: one for the initial curve at an elongation of about 0.25%, one
for the behavior after creep at an elongation of about 0.35% and finally one for the behavior
after load at higher elongation.
Fig. 9.2-4a Tension-elongation for Drake at High Temperature
The Sections/Cable Files/Generate Cable Data Report... will create a report with all of the
cable data for any of the .wir files that are strung in any visible line in the .xyz file. This
information will also be included in the project XML export. This same report can also be
generated for any cable when you are in the Cable Data dialog box accessed when going to
Sections/Cable Files/Edit Existing Cable File... by hitting the Cable Data Report button.
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9.2.1 Cables in Bundles
Fig. 9.2-5 shows various ways in which
conductors or communication cables can
be arranged in bundles. Two identical
conductors can be twisted in pairs to avoid
galloping (a). One or more carriers can be
lashed onto a messenger (b). Two or more
conductors can be used in a bundle. For
bundles of two conductors, a horizontal
configuration (c) or a vertical configuration
(d) can be used. Insulated conductors can
be supported by a messenger and
maintained a certain distance apart (e).
HORIZONTAL
BUNDLE
TWISTED PAIR
(a)
MESSENGER
(c)
MESSENGER
CONDUCTORS
LASHED
CABLE
(b)
(e)
VERTICAL
BUNDLE
(d)
Fig. 9.2-5 Cables in Bundles
In the various applications described in
Fig. 9.2-5, the stressed cables (which determine sags and pass loads to the supporting
structures) are shown as grayed circles. Supported cables that only contribute weight, wind and
ice loads to the system, but are not subjected to tension, are shown as open circles.
In order that PLS-CADD correctly model unit conductor loads (weight, wind and ice) and
correctly predict sags and structure loads in bundle situations, it is important that you
understand what input properties should be used in the Cable Data dialog box of Fig. 9.2-1 and
what Number of Conductors Per Phase should be used in the Section Modify dialog box of Fig.
10.3-3.
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9.2.1.1
Twisted Pairs (Fig. 9.2-5a)
Cross section area, AT:
Twice cross section area of single subconductor
Outside diameter, D:
Because the diameter exposed to the wind changes
continuously along the conductor, an average equivalent
circular diameter equal to 1.64 times the subconductor
diameter can be used (Roche, J.B. et al., "T2 Wind Motion
Resistant Conductor", IEEE Transactions on Power
Apparatus and Systems, Vol. PAS-104, No. 10, Oct.
1985). According to the reference, the equivalent diameter
will also provide a good estimate of ice load based on ice
thickness.
Unit weight, UW:
Twice unit weight of single subconductor
Ultimate tension, ULT:
Twice ultimate tension of single subconductor
Number of independent cables, N:
One
Stress-strain and other properties:
Same as those for single subconductor
Number of conductors per phase:
One
9.2.1.2
Lashed Cable onto a Messenger (Fig. 9.2-5b)
Cross section area, AT:
Cross section area of messenger
Outside diameter, D:
Because the diameter exposed to the wind changes
continuously along the conductor, an average equivalent
circular diameter should be used. That equivalent diameter
will be used to determine the ice load based on ice
thickness.
Unit weight, UW:
Total unit weight of messenger plus supported cable
Ultimate tension, ULT:
Ultimate tension of messenger
Number of independent cables, N:
One
Stress-strain and other properties:
Properties of messenger
Number of conductors per phase:
One
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9.2.1.3
Conductor Bundles (Fig. 9.2-5c and d)
Cross section area, AT:
Cross section area of single subconductor
Outside diameter, D:
Diameter of single subconductor
Unit weight, UW:
Unit weight of single subconductor
Ultimate tension, ULT:
Ultimate tension of single subconductor
Number of independent cables, N:
One
Stress-strain and other properties:
Properties of single subconductor
Number of conductors per phase:
Actual number of subconductors (2 for examples in Fig.
9.2-5c and d)
Special consideration for depth of
bundle:
You should take into account the vertical dimension of the
bundle (DEPTH in Fig. 9.2-5d) when checking vertical
clearance. This can be done by lowering the bundle
attachment point by the length DEPTH (for example by
using longer suspension insulators) or increasing the
required vertical clearance by that amount.
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9.2.1.4
Spaced Conductors Supported by Messenger (Fig. 9.2-5e)
Cross section area, AT:
Cross section area of messenger
Outside diameter, D:
Equivalent diameter equal to the sum of the diameters of
all the cables in the bundle (diameter of messenger plus 3
times diameter of conductors for situation in Fig. 9.2-5e).
Unit weight, UW:
Total unit weight of messenger plus supported conductors
Ultimate tension, ULT:
Ultimate tension of messenger
Number of independent cables, N:
Number of spaced cables in bundle (4 for situation in Fig.
9.2-5e). This number is used internally for the calculation
of ice and wind-on-ice loads which take into account the
fact that each cable in the bundle is subjected to a coating
of uniform ice thickness
Stress-strain and other properties:
Properties of messenger
Number of conductors per phase:
One
Special consideration for depth of
bundle:
You should take into account the vertical dimension of the
bundle (DEPTH in Fig. 9.2-5e) when checking vertical
clearances. This can be done by lowering the bundle
attachment point by the length DEPTH (for example by
using longer suspension insulators) or increasing the
required vertical clearance by that amount.
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9.2.2 GAP-type Conductor
In ordinary bi-metallic conductors, the outer material is under tension at the time of installation
(sagging condition). However, in GAP-type conductors, the outer material can slide around the
core in such a way that it is possible, at time of installation when the conductor is clipped-in, to
force a zero tension in the outer material. This basically forces the outer material to behave as a
non-structural material (dead weight only) for temperatures higher than the installation
temperature and it removes all uncertainties regarding creep and sags at high temperature. If
you select Conductor is a GAP-type conductor in the Cable Data dialog box, PLS-CADD will
assume that the installation was made such that the stress in the outer material is zero at
installation and all sags and tension calculations will be made as if the initial stress-strain curve
of the outer material was translated to the right by the distance O - A, as shown in Fig. 9.2-6.
STRESS
σ
COMBINED
OUTER
CORE
INITIAL
σ
ELONGATION
0
A


Fig. 9.2-6 Behavior of GAP Conductor
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9.2.3 Create Bundled Cable
The Sections/ Cable and Concentrated Loads Files/ Create Bundled Cable File dialog
allows you to quickly and easily input the data that is described in Section 9.2.1 to created
Twisted Pair (Figure 9.2-5a), Lashed Bundle (Figure 9.2-5b), and Spaced Bundles (Figure 9.25e) by simply selecting the messenger and inputting the modifiers as detailed in Section 9.2.1 in
the dialog of Figure 9.2-7 below to create the final bundled cable for use in PLS-CADD.
Figure 9.2-7 Create Bundle Cable
You would first select the type of bundle to build in the upper left of the dialog and then the
messenger cable file to use for the bundle. Depending on the type of bundle selected the items
to input on the right side of the dialog will change. Once you complete the data in the dialog for
the new bundled cable and hit OK you will be prompted to save your new cable file with the
name of your choice.
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9.3
High or Extremely High Temperature Considerations
At high, but not extremely high, temperatures (generally considered to be less than 90 degrees
C), ACSR conductors normally shed some of the tension load in their outer aluminum strands
onto their steel core due the higher thermal expansion coefficients of the aluminum vs. steel.
This behavior is automatically handled by PLS-CADD. The normal redistribution of tension
between outer and core strands due to the creep of the outer strands at the assumed Weather
case for final after creep (see Section 7.3.4) is also handled automatically by PLS-CADD.
Therefore, sags at high temperature for any conductor should be well predicted unless
additional accelerated creep at extremely high temperature takes place (in addition to the creep
from everyday tension over 10 years). Additional accelerated creep should only be of concern if
you run your conductors for limited periods of time at extremely high temperatures (generally
considered to be above 90 degrees C). At these extremely high temperatures, you should also
be concerned about the potential for loss of strength. The effects of using conductors at
extremely high temperatures are discussed in the IEEE Guide for Determining the Effects of
High Temperature Operation on Conductors, Connectors, and Accessories (IEEE 1283, 2002).
9.3.1 Additional Creep from Using Conductors at Extremely High Temperatures
As discussed above, the after Creep sags normally calculated by PLS-CADD are based on the
assumption that conductors are subjected to an everyday weather case over a long period of
time, typically taken as ten years. However, additional creep (accelerated creep) may result
from using the conductors at extremely high temperatures (in excess of 90 degrees C) for
limited periods of time. The effect of this additional elevated temperature creep can be
accounted for by artificially increasing the conductor temperature above its actual temperature,
say by ΔT, when making sag calculations (Harvey, 1979). ΔT is a function of the accumulated
times the conductors spend at each increment of elevated temperatures, for example at 100,
125, 150, .. degrees C. The IEEE Guide (IEEE 1283, 2002) has an example showing how to
make the calculation.
9.3.2 Aluminum in Compression
As the temperature of an ACSR conductor increases, a proportionately greater portion of the
conductor tension load gets carried by the steel core because the aluminum thermal expansion
coefficient is larger than that of steel. In fact, beyond a certain high transition temperature the
aluminum may lose all its tension or may even go into compression. Whether one should
assume that 1) the aluminum cannot physically go into compression because it would "bird
cage", 2) the aluminum does go into some compression, or 3) manufacturing built-in stresses in
the aluminum still keep it under tension at high temperature, has been debated over the past 20
years (Barrett, 1983; Rawlins, 1999). Using one or the other assumption may result in significant
sag differences at high temperature. If you assume that the aluminum does not go into
compression, you are assuming that the final stress-strain relationship is bilinear with a knee
point (somewhat similar to the line P-B-A in Fig. 9.1-2). If you assume that the aluminum can go
into compression or is prestressed, you are assuming that the final stress-strain relationship is
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linear (as if line B-A in Fig. 9.1-2 was extended all the way to its intersection with the elongation
axis).
PLS-CADD (Section 7.3.5) lets you make your own assumption regarding the behavior of
aluminum at high temperature. You can assume that the aluminum is incapable of carrying
compression or that it can carry some compression, limited by an upper limit of the virtual stress
in Eq. 9-5. You describe your assumptions in the Bimetallic Conductor Model dialog box that
you reach with Criteria/ Bimetallic Conductor Model. For bi-metallic conductors, the sagtension reports shows what fraction of the total tension is carried by the outer strands and what
fraction is carried by the core.
9.3.3 Steady State and Transient Thermal Ratings
Conductor properties and other data needed to perform steady state and transient thermal
ratings of a line are discussed in Section 11.2.6.
9.4.
PLS-CADD Circuits and phase labels
PLS-CADD has the ability to define and label wires for circuits and phases. These labels are
now part of the UI, integrated into certain reports, can be part of plan and profile drawing sheets,
and used for phasing diagrams.
9.4.1 Defining Circuit and Phase Labels
The command Sections/Electric/Define Circuits and Phases/Labels… lets the user define
the circuit and phase labels to be used for this project. These defined labels are saved with the
project and shared across all lines within that project. Figure 9.4-1 shows the Circuit and Phase
Labels table.
Fig. 9.4-1 Circuit and Phase Label Table
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Each row of the table shown in Figure 9.4-1 represents a different circuit. There is not a limit on
the number of circuits that can be defined. Each circuit has a text label, a display color, and a
display line style. In addition, each circuit can have up to 3 phases defined where each phase
has a label, color, line style and phase angle. If you want to have fewer than 3 phases available
for a given circuit, leave the label blank or repeat the label. The program will ignore blank labels
and consolidate repeat labels. Circuit labels should all be unique. The phase angle is currently
not used by PLS-CADD but is planned to be incorporated in an updated EMF function in a
future release.
9.4.2 Assigning Circuit and Phase Labels
Once the circuit labels are defined, you can start using them in your model. There are two parts
to these circuits: assigning labels and linking sections. Circuits in PLS-CADD are based on the
wire sections. Each section can only be assigned a single circuit label at a time, but several
sections can share the same circuit label whether or not they are linked or next to each other.
All sections which are linked must have the same circuit label. Each phase within a section can
be assigned a phase label. The same phase label can be used for multiple phases within a
section, but only phase labels defined for the circuit assigned to that section are available for the
phases within that section.
Circuits consist of one or more sections linked together. The chain of linked sections in a circuit
must have a distinct start and a distinct end with a simple path from that start to the end. Each
section can link to one other section and each section can be linked to by one other section. In
other words, there can be no branches and no loops when defining a circuit. Sections can only
be linked if they have the same number of phases and the same voltage.
In addition to linking sections, the individual phases are linked as well. The default link has
phase 1 connecting to phase 1 of the other section and phase 2 connecting to phase 2 of the
other section. You can change those links to any combination as long as each phase connects
to exactly one other phase in the linked section. For example you can have phase 1 connect to
the other section’s phase 3, phase 2 connect to phase 1, and phase 3 connect to phase 2.
If the project contains jumpers, PLS-CADD will automatically links the jumpered sections
together including how each phase in one section links to the phases in the other section. You
cannot use the circuit commands to override or change how jumpers link sections. If you want to
change that link, you need to update the jumpers.
While the label definitions are shared between all lines in your project, the label assignments
and section links belong to the line, so you can define the circuits differently for each line of your
project. These label assignments and section links can be defined through
Sections/Electric/Define Circuits and Phases/Table… or through graphical commands. This
table contains one row for every phase of every section in the line. The cells in white are
editable and the cells in grey have been defined within the model. Below is a description of
some of the information contained within this table.
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Fig. 9.4-2 Circuit and Phase Definitions and Labels table
Will be set to ‘Yes’ if there are any jumpers defining the connection for this section.
If ‘Yes’, you will not be able to change either the Connected Set # or the
Connected Phase #. Other columns can be updated.
Connected Like stringing direction for sections, there is a direction for circuits which will affect
Backwards how sections are reported. By default, links connecting circuit sections go from the
end structure of one section to the start structure of the next section. If you want to
connect from the start structure of a section, you need to “flip” that section. This is
for circuit purposes only, this does not affect stringing direction.
Connected You select which other set on the structure this section is linked to. The structure is
Set #
the current section’s End Structure if Connected Backwards is ‘No’ or it is the Start
Structure if Connected Backwards is ‘Yes’. The only options available are valid
sections for this one to connect to and they must have matching voltage and
number of phases. If this section is jumpered on this structure, there will be only
one valid option which is the set that the section is jumpered to.
Connected The structure phase number on the Connected Set # that this phase of the section
Phase #
connects to. This will default to match the phase number of the current section, but
you can change it if the section has multiple phases. Each phase can connect to
only one other phase, so when changing it for one phase, the table will
automatically update the other phase to resolve any conflict.
Connected This shows which other section this section links to. This is determined by the
Section #
Connected Backwards and Connected Set # columns and is shown to help you
trace the section links that are defined.
Circuit
This is where you select the circuit label for this section and all sections linked to
Label
this one. If you change the label for this section, all other linked sections (unless a
section has its Break Link column set to ‘Yes’) will also change to the newly
selected circuit label. You can select from any of the circuits in the Circuit and
Phase Label table described above.
Phase
This is where you select the phase label for this phase. The options available
Label
depend on which Circuit Label was selected and you must select a Circuit Label
before you can select the Phase Label.
Jumpers
Modeled
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Break Link
Notes
This column is used to disable a link between sections. The default value for this
column is ‘No’, but it could be set to ‘Yes’ for a variety of reasons. PLS-CADD will
automatically set this column to ‘Yes’ if you create a link that would violate one of
the rules for linking sections, usually if that link would create a loop or you are
linking to a section that already has another section linking to it. In either case, the
program will set the Break Link of some other section to ‘Yes’ so that your newly
created link is valid. You may also want to set this column to ‘Yes’ to ignore a
section link that is defined by some modeled jumpers. Usually this would be done
so that you can assign different circuit labels to these sections. You may also want
to do this to partition a circuit for electrical analysis.
This column tells you when any other row has been updated because of some
recent change.
Circuit links between sections can be done thru the table described above, but can also be done
graphically with Sections/Electric/Define Circuits and Phases/Graphical. When you use this
command the user is first prompted to click on the section you want to start with and then click
on each subsequent section you want to add to the chain of sections for this circuit. When you
are done, middle click or hit <Enter> and you will see the table view of a single row from the
Circuit and Phase Definitions and Labels table described above, see figure 9.4-3. From this you
can assign labels or use the Transpose button to get to the full table.
Fig. 9.4-3 Circuit and Phase Definitions and Labels
This command will only allow you to create links between valid sections with matching voltage
and number of phases. If the mouse is snapping to an invalid section, the cursor will change to
the invalid symbol. While in this command the status bar will give you information on the section
the mouse is snapping to so you know which section you are about to link.
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The graphical command Sections/Electric/Edit Circuit Connection will bring up the vertical
table view of the Circuit and Phase Definitions and Labels table showing you only the
information for the section and phase that the mouse is snapped to. The Transpose button in
the upper right corner will let the user see the full table with rows for all sections and phases.
The command Sections/Electric/Remove Circuit Connection allows the user graphically
remove circuit links that you have defined. This command will prompt the user to click on one
section and then the other section of the link you want to remove. This is equivalent to clearing
the entry in the Connected Set # column. It is not the same as using the Break Link column
because even though the link has been removed, both sections will retain their Circuit Label
assignments.
The command Sections/Electric/Set Circuit Label allows the user to graphically select a
section with the mouse and a simplified dialog will come up asking you to pick both circuit and
phase labels for that section. Any changes you make will be propagated to all other linked
sections.
Circuits depend on the sections defined within the model. The sections are identified by their
start structure and set and their end structure and set. If you create new sections or modify any
existing section by changing their start or end structure or set, the circuit logic in the program
will treat those sections as new sections without any circuit assignments until you assign circuit
labels or links to them. If you make such a change to a section in the middle of a circuit section
chain, then the chain will be broken into two but both using the same label they had before and
the modified section will appear as a new unlinked section without any labels assigned.
Once the circuits are defined it is possible to hide all wires assigned to a particular circuit label
in all views. The Sections/Electric/Define Circuits and Phases/Labels… command will bring
up the Circuit and Phase Labels table. Within this table for each circuit you want to hide the user
will set the Circuit Line Style to None. Once that is done, any section assigned to that circuit
label will no longer be drawn in any of the views. The section is hidden regardless of which
display option is chosen in Sections/Display Options… In addition, any labels associated with
those sections will also not be drawn. This includes the section label block for Plan and Profile
Sheets. This is useful if you want to print out sheets or create images of other views focusing on
only certain circuits in the line without having to remove the other sections. To restore the
hidden sections, simply go back into the Circuit and Phase Labels table and set the Circuit
Line Style to some value other than None. Even though the sections are not being
displayed, they are still included in any processing or analysis that would normally
include them.
10.
CREATING OR EDITING LINE MODEL
Starting a new project with PLS-CADD is different from loading, viewing and checking an
existing one as was described in Section 5. In this section we will describe the steps necessary
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to create a new line model named Project. The amount of work required to build a model
depends on whether you can reuse items in existing libraries or need to create them from
scratch.
Items normally stored in library files for use across projects include:
Feature codes:
Assume that a feature code file Features.fea has already been prepared
as described in Section 6.1
Design criteria:
Assume that a design criteria file Criteria.cri has already been prepared
as described in Section 7.3.
Structures:
Assume that some dead-end (StructDead.*), some angle (StructAng.*)
and some tangent (StructTang.*) structure files have already been
prepared as described in Section 8.6.
Cables:
Assume that some conductor and ground wire files (Cables.*) have
already been prepared as described in Section 9.2.
Plan & Profile sheets drafting parameters:
You do not need these drafting parameters (see
Section 13.2.5) at this point.
Building a line model involves three basic steps: 1) loading a terrain model and defining the
alignment, 2) spotting the structures, and 3) stringing and sagging the cables
10.1
Loading Terrain Data and Defining the Alignment
The steps to follow in preparing the terrain and defining the alignment depend on what terrain
data you have available.
10.1.1
When a Project.xyz File is Available
You should:





Load the Project.xyz terrain file (format defined in Appendix D) with File/ Open.
You will get a warning that feature codes are undefined. Ignore the warning.
Use Terrain/ Feature Code Data/ Load FEA to import the existing feature code
file Features.fea into Project.fea or use Terrain/ Feature Code Data/ Edit to
create Project.fea from scratch or edit it.
Select the terrain widths and side profile criteria with Terrain/ Terrain Widths
and Terrain/ Side Profiles.
Define the alignment with Add, Insert, Delete or Move P.I. as described in
Section 6.3.1.
Select the station of the first P.I. point with Terrain/ Edit/ Edit Origin if not zero
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

Edit the terrain, if desired, with Terrain/ Edit/ Edit XYZ or by clicking on the Edit
XYZ button of the Terrain Info dialog box which open after clicking on a terrain
point
Save your work using File/ Save or File/ Save As. File/ Save will not only save
the updated Project.xyz file, but also the alignment information in file Project.num
and the feature code file Project.fea in the same directory from which Project.xyz
was imported. File/ Save As will let you not only change the name of the project
but also file your work in a different directory.
10.1.2 When a Project.pfl File is Available
You should:







Load the Project.pfl terrain file (format defined in Appendix E) with File/ Open.
You will get a warning that feature codes are undefined. Ignore the warning.
Use Terrain/ Feature Code Data/ Load FEA to import the existing feature code
file Features.fea into Project.fea or use Terrain/ Feature Code Data/ Edit to
create Project.fea from scratch or edit it.
Select the terrain widths and side profile criteria with Terrain/ Terrain Widths
and Terrain/ Side Profiles.
Unlike with the XYZ terrain, there is no need to define the alignment since the
information is part of the terrain file.
Edit the terrain, if desired, with Terrain/ Edit/ Edit PFL or by clicking on the Edit
PFL button of the Terrain Info dialog box which open after clicking on a terrain
point
Define the x and y coordinates of the first P.I. point and the initial bearing with
Terrain/ Edit/ Edit Origin if you want to change the default values
Save your work as described in the last step of Section 10.1.1.
10.1.3 When No Project.xyz or Project.pfl Terrain File is Available
If you want to create a terrain file from scratch you should:




Select File/ New and enter the proposed terrain file name Project.xyz or
Project.pfl
Proceed as shown in 10.1.1 or 10.1.2 for the feature code file and terrain widths.
Use Terrain/ Edit/ Edit XYZ or Terrain/ Edit/ Edit PFL to create terrain points
Proceed as shown in 10.1.1 or 10.1.2
You can import, filter and/or merge XYZ points from binary PLS-CADD XYZ files by using
Terrain/ Edit/ Merge Points from External File/Merge Points from XYZ file. To import surveu
data that have XYZ or PFL in ASCII formats (.txt, .csv, xml…) use the command Terrain/ Edit/
Merge Points from External File/Merge Points from User Defined XYZ file. If survey data is
not available the command Terrain/Edit/Merge Points from External File/Merge Points from
Internet... will allow for download and importing of topographic data generated from NASA's
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Shuttle Radar Topography Mission (SRTM). See Section D.3 and D.4 for additional
information on importing XYZ data.
10.2
Interactive Structure Spotting
Once you have defined an alignment for a new project, you should use Windows/ New
Window/ Profile View to open a Profile view where you will do the structure spotting. With
PLS-CADD, there are two ways of spotting structures, interactive or automatic based on
minimum cost (the optimization option). Spotting optimization is an advanced option which is
discussed in Section 14. You should not attempt spotting optimization before you are completely
familiar with interactive spotting. Except for a short introduction to optimization in sub-section
10.2.6, this section only covers interactive spotting.
Interactive spotting is the most commonly used method for locating structures on an alignment
or in any other view. It is used almost exclusively for modeling existing lines. For new lines to be
built in highly developed environments, where there are many constraints from the existing
infrastructure, interactive spotting is still the method of choice but automatic spotting can be
helpful if all constraints are identified. In open country with few constraints, automatic spotting is
generally more cost effective.
Structures can be spotted using station based structures along an alignment or can be
independent of an alignment and spotted at a XYZ point in the model. Interactive structure
placement can be referred to as Station Based or XYZ Based Structures. Sections 10.2.1
through 10.2.7 will discuss many common features between both types of interactive structure
placement. Section 10.2.8 will discuss XYZ based structures in detail.
Whether you select a new structure or
modify an existing one, you will be
taken to the Structure Selection box
shown in Fig. 10.2-1. For Method 4
structures (or other structure files
generated by our PLS-POLE or
TOWER programs) an outline of the
structure geometry appears in the lower
right corner of the box.
However, before adding or modifying
structures, you should make sure that
design criteria are available, by either
using Criteria/ Load CRI to import a
library file Citeria.cri into Project.cri or
going through all the Criteria menus to
create new criteria.
Fig. 10.2-1 Structure File Selection Box
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You should also use Terrain/ Feature Code Data/ Feature Code for Ground Clearance and
Interpolated TIN Points to select the feature code that will dictate the height of the ground
clearance line. Then you should use Terrain/ Clearance Line and Terrain/ Side Profiles to
display the proper clearance lines.
You should first spot structures at the ends of your line and at all line angles. There are various
ways of doing this, three of which are described below.
10.2.1
Spotting Structures at Line Angles
10.2.1.1
Terrain Points at Line Angles Have Unique Feature Codes
When you are resurveying an existing line or
scanning its existing drawings, it is
recommended that you assign one or more
distinctive feature code to all P.I. (line angles).
At P.I. locations, you might also use as terrain
point comment the name of the structure file for
the P.I. structure. If this is the case, you can
use Structures/ Automatic Spotting/ Spot at
Feature Code to automatically locate specified
structures at the appropriate line angles. For
example, with the settings in Fig. 10.2-2, PLSCADD will locate the structure tangent.pol at
every line angle point having the feature code
221. The structure type to be selected can be
defined as a plan or profile comment.
Fig. 10.2-2 Spotting a Feature Codes
This will place the structure as a station
and offset based structure along an alignment. If you want the structure placed as a XYZ based
structure you can uncheck the station based option at the top of the dialog box.
10.2.1.2
Locating One Structure Type at all Line Angles
One way to make sure that there is a structure at each line angle and at your first and last
alignment points is to spot one arbitrary structure at all these locations and later use the
Structures/ Modify command to change it to the appropriate type and height. The arbitrary
structure is spotted at all line angles with the Structures/ Automatic Spotting/ Angle
Structures command.
10.2.1.3
Snapping Structure to Line Angle Location
With this method, you spot the desired structure near the angle using the same procedure as
described below for tangent structures. Then you can use Structures/Move/On Snap... to snap
the structure to the exact P.I. terrain point or you can type the exact station of the P.I. point in
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the Structure Modify dialog box which opens when you select the structure with the
Structures/ Modify command.
Once you have located structures at all line angles, you should spot your tangent structures
10.2.2
Spotting Tangent Structures
Fig. 10.2-3 Structure Modify Dialog Box
To spot a structure on the profile, select Structures/Add/Along Alignment and then click
where you want to place the structure. A black stick tracking the mouse cursor shows the
spotting location with the corresponding station displayed in the status bar. Do not try to select
an exact station with the mouse as there is a much easier and precise way to do it in the
Structure Modify dialog box. Once you have selected a structure in the Structure File
Selection box of Fig. 10.2-1, you are taken to the Structure Modify dialog box (Fig. 10.2-3).
You may also get to the Structure Modify dialog box at any time using Structures/ Modify or
the structure context sensitive menu items using Entity Info.
Once in the Structure Modify dialog box you can:
1) Change your structure type by clicking on the Button showing the name of the current
structure near the top left of the box and path to a different structure.
2) Adjust the structure station by typing it in the Station field. You can also perform basic
arithmetic functions within any of these boxes by placing an equal sign before an equation. So
for example you may wish to subtract 25 feet from station 10792. You can do this within the
dialog box by simply entering =10792 - 25. This will result in 10767. If the structure is a XYZ
Based Structure the Station, which is described in further detail in section 10.2.8, then the
Station input will say XYZ Locked.
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3) Raise or lower the structure by the amount typed in the Height adjustment field. You can use
the equation calculator within this input as well.
4) Adjust its offset (distance from center line) by typing a value in the Offset adjustment field.
You can use the equation calculator within this input as well.
If the structure is a XYZ Based Structure the Station which is described in further detail in
section 10.2.8 then the Offset input will say XYZ Locked.
Note: Unlike older versions of PLS-CADD (prior to Version 4.65), more recent versions
take the offset into account when calculating structure loads and the insulator swings for
each individual cable. This offset includes not only the Offset adjustment, but also the
natural offset that may exist between the centerline of the structure and each individual
attachment point. For calculation purposes, each cable is treated as if it had its own
alignment. However, the same ruling span is used for all cables in one set. The ruling
span of one set is based on span lengths between centers of gravity of set attachment
points at each structure. The motivation for the change was the need for improved
accuracy as well as the ability to determine clearances between crossing spans with the
procedure described in Section 11.2.3.2.
5) Change its orientation angle (Angle SO in Fig. 7.3-7) in the Orientation field. You can use the
equation calculator within this input as well. The menu command Structures/Rotate also has
options to rotate a structure graphically using the freehand selection or rotate the structure to
the bisector between two selected points.
6) Write up to fifty lines of comments in the Structure Comments fields. The fifty comment lines
can optionally be shown next to each structure in all Profile views and on profile portions of
P&P sheets (see Section 13). They are selectively turned on or off in Drafting/ Structure and
Section Labeling/ menus. Comment lines can also be used to store DXF or bitmap files
representing pictures. In order to get a file name into a comment line, right click the comment
line and select Pick File. For example, the third comment in Fig. 10.2-3 is the name of a bitmap
file associated with the structure location.
7) Attach weights below suspension insulators by entering their values in the Set Counter
Weight field. The same weight is attached to all insulators of a set. Counter weights can be used
to take care of minor insulator swing problems.
8) View the outline of the structure (if available as described in Sections 8.4.2 and 8.4.3) or any
of the DXF or bitmap files stored in comment lines by clicking on the View button at the bottom
of the dialog. The structure outline view can be rotated and rendered with the 3-controls
described in the TOWER or PLS-POLE programs. The bitmap files will be shown in your current
viewer, for example the Windows Picture and Fax Viewer.
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9) Edit the structure model by clicking on the Edit button. You will be taken to the appropriate
structure editing module as described in Appendix F.
10) Edit the Structure Specific Material List and view the material from the Structure File
Material List by clicking on the Material button. You will be taken to a dialog similar to that of
Fig. 8.5-4. It will not change the material associated with the structure model. For further
discussion on Structure Specific Material see Section 8.5.4.
11) Accept all the data in the dialog by clicking on the OK button or hitting the Apply button
without exiting the dialog.
12) Google Earth button will allow you to view the structure location in Google Earth as long as
the project coordinate system has been identified within the project under Terrain/Coordinate
System.
More information about Google Earth exports may be found at:
http://www.powline.com/products/ge_tips.html
11) The Groups button can assign a Structure Group manually or check the automatically
assigned Structure Group as discussed in Section 7.3.12.9.
12) The Jumpers button allows you to define jumpers between 2 deadends on the selected
structure with up to 3 intermediate idler or jumper strings. This is discussed in further detail in
Section 10.3.8.
Once you are out of the Structure Modify dialog, you are still in structure Add mode. You can
add another structure or get out of the Add mode by right-clicking the mouse.
You can eliminate a spotted structure with Structures/ Remove or Structures/Remove Range.
Removing a structure connected to spans where unstressed lengths have been locked (Levels
2, 3 and 4 modeling only) will show the true behavior of the system where the total length of
wires in two spans become the length of wire in a single span. This is discussed in Section N.4.
10.2.3 Spotting Short Cuts
Once a structure has been spotted, you can speed up the spotting of identical structures using
the Structures/Copy and Structures/Paste or Structures/Automatic Spotting/ N-Paste
features.
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10.2.3.1
Structure Copy/ Paste
Clicking on a previously spotted structure after selecting Structures/ Copy stores all the
information developed for that structure in the Structure Modify box (Fig. 10.2-3) in a buffer.
Then, selecting Structures/ Paste lets you spot the same identical structure with the same
Structure Modify box parameters anywhere where you click on the profile.
10.2.3.2
Structure Copy/ N-Paste
After copying a structure in the buffer as discussed in Section 10.2.3.1, you can spot multiple
copies of that structure at fixed intervals between a start and a stop station. This is done with
Structures/ Automatic Spotting/ N-Paste.
10.2.4 Effects of Spotting (Adding) New Structures in Existing Line Model
If there are no cables (sections) installed in the part of line where you are adding a structure or if
you answer No to the OK To Connect? question, there are no restrictions on the numbers, types
or locations of the structures that you may spot. If there are already overhead cables present in
the span where you want to add a new structure, you should understand that there are some
limits to what you can do.
If all the attachment sets of the structure you are adding are compatible with the existing
overhead cables, then these cables are attached automatically. If an attachment set is a dead
end, then the corresponding tension section is broken into two sections.
If the attachment sets of the structure you are adding are not compatible with the cables, then
only partial connections will be attempted. Cables connected at Set # i of the structure to the left
of the added structure are connected to Set # i of the added structure.
When you add a structure where wires are modeled with Level 1 (or Levels 2, 3 or 4 without
locking the unstressed lengths), it is as though you were putting the entire tension sections
supported by the new structure on pulleys and resagging them again for the sagging condition
in the Section Modify dialog box. If the unstressed lengths are locked with Level 2, 3 or 4
modeling, the behavior is as described in Section N.4.
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10.2.5
Moving Structures
10.2.5.1
Dragging Structure with the Mouse
Structures/Move/Freehand lets you move a structure on the centerline of an alignment or it
can move a XYZ Based Structure anywhere in the model. You select the structure to be moved
with the mouse and you drag it to its new location. As you move a structure, the wind span of
the structure immediately to its left, that of the structure you are moving, and that of the
structure immediately to its right are indicated in the bottom status bar. If the structure is a
Method 1 structure, then the percent of wind span used, i.e. the ratio of actual wind span to
allowable, is also shown. This is an extremely useful feature for interactive spotting. Click on the
right mouse button to get out of Move mode. You can improve your ability to pinpoint a
particular structure location by zooming-in before you move the structure. As mentioned before,
you can fine tune the structure station at any time in the Structure Modify dialog box. If you
want to move a structure exactly at the location of a terrain point you should use
Structures/Move/On Snap.... This is the best option for locating structures at line angles.
When you move a structure where wires are modeled with Level 1 (or Levels 2, 3 or 4 without
locking the unstressed lengths), it is as though you were putting the entire tension sections
supported by the moved structure on pulleys and resagging them for the sagging condition of
the Section Modify dialog box. If the unstressed lengths are locked with Levels 2, 3 or 4
modeling, the behavior is as described in Section N.7.
10.2.5.2
Point
Snapping Structure to Designated
You can automatically snap one or several structures
to the exact location of one or more XYZ or PFL
terrain points.
Snapping to a given terrain point can be done for a
single structure with the Structures/Move/On Snap...
command, or for a group of structures with
Structures/ Automatic Spotting/ Snap StationHeight to Feature Code.
Fig. 10.2-4 Structure Snap Parameters
Structures/ Move on (Snap) will take you to the Structure Snap dialog box (see Fig. 10.2-4)
where you can designate which point on the structure should be snapped to a particular
surveyed ground point.
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For example, with the
settings in Fig. 10.2-4,
the station, offset and
height of the tower
shown in Fig. 10.2-5
will automatically be
adjusted so that the
lower phase (phase 3)
of its right circuit (set
3) will match exactly
the surveyed point
selected
with
the
mouse (solid circle in
Fig. 10.2-5).
Fig. 10.2-5 Phase 3 of Right Circuit Snapped to Survey Point
The snapping feature illustrated in Fig.
10.2-4 for a single structure can be
applied to an entire group of structures
with Structures/ Automatic Spotting/
Snap Station-Height to Feature Code
which will take you to the Snap to Feature
Code dialog box shown in Fig. 10.2-6. For
example, with the data in Fig. 10.2-6, all
113 towers of the Wplfullm.xyz project
had their foundation heights adjusted
automatically so that the attachment
points of the lowest right phase exactly
matched
the
corresponding
XYZ
surveyed locations which were assigned
the feature code 303.
Fig. 10.2-6 Snap to Feature Code
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10.2.6
Brief Discussion of Automatic Optimum Spotting
From given design criteria and a list of available structures and their costs, automatic optimum
spotting allows you to find the combination of structures and structure locations which will result
in the minimum total cost of all structures used. Optimum spotting (or global optimizing) is a
well-developed technology (Olbrycht, 1982; Ranero, 1990; Senouci, 1991; Peyrot, 1993).
Because optimum spotting is an advanced capability not required by all PLS-CADD users, it is
offered as an option which is fully described in Section 14.
10.2.7 Customizing Structures
PLS-CADD provides you with several customizing functions that allow you to quickly create and
modify site-specific structures to reflect changes which have been made in the field or to adjust
the strength of deteriorated components. This is discussed in detail in Appendix P.
10.2.8 XYZ Based Structures
PLS-CADD traditionally allowed Station Based Structures (SBS) to be placed in a project along
an alignment. This required an alignment be established prior to spotting structures. Station
Based Structures have existed since PLS-CADD was created and the interface for working with
them is unchanged. In 2015 support was added for XYZ Based Structures (XYZBS) allowing for
the placement of structures without an alignment.
10.2.8.1
Adding XYZ Based Structures
XYZ Based Structures can be placed several different ways within the model. The first is to use
the menu command Structures/Add/XY Structure which provides three methods to add XY
Structures. The command Structures/Add/XY Structure/Freehand will allow an XY Structure
to get inserted at a selected mouse coordinate. The command Structures/Add/XY
Structure/Along Line... will add an XY structure between two selected points. The command
Structures/Add/XY Structure/At Survey Point will add an XY structure at a selected survey
point.
The Context/ Entity Info menu is presented by clicking an object or coordinate using the Entity
Info described in Section 5.6. Once you click you will be presented a context sensitive menu
whose contents depend on the element selected. One of the items in the menu will be Add XY
Structure as shown in Figure 10.2-7 below.
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Fig. 10.2-7 Add XY Structure
After selecting the command you will be prompted to select the structure file you wish to place
at this point and the Structure Modify dialog will appear with the Station and Offset inputs
showing XYZ Locked as shown in Figure 10.2-8.
Fig. 10.2-8 Structure Modify XY Based Structure
Wnen placing a XYZ Based Structure with the Add XY Structure Along Line command the
entity info snap can be used to select the two points on a line on which you want to add a
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structure. A line will appear between the 2 points you clicked and you will be able to place the
structure along this line. The distance from the first origin joint will be shown as you move the
mouse along the line. You can also hit the “s” key to change the snap settings as you are
moving the structure which brings up the XY Structure Add or Move Along Line dialog box
shown in Figure 10.2-9.
With these settings you can choose to place the structure at multiples of a specified distance
along the line or you can set the percent along the line at which you want the structure placed.
For example if you wanted to place a
structure at the midpoint between two other
structures you would snap to the structure
centers of the two structures to define the
line and set the percent to 50% to place it in
the middle of the line. If you wanted to
place the structure 250 ft from the first
structure you could select the specified
distance option and enter 250 ft. The
second portion of the box determines how
the structure base elevation is computed.
You can use the elevation of the line
connecting the two points or you can use
the TIN to interpolated the elevation at the
structure.
The bottom options allow you to
automatically orient the structure so it is
perpendicular to the line or to offset the
location a certain distance from the line.
The offset can be especially useful if you
are building a line paralleling an existing
line and you wish to maintain a certain
distance from the existing line.
Fig. 10.2-9 Snap Settings
The final option for placement of XYZ based structures is to directly type the data into the
Structures/ Staking Table. As shown in Figure 10.2-10 the bottom rows of the table have the
Station and Offset Adjust. columns greyed out with XYZ Locked in the cell. The XYZ
coordinates and structure file names can be typed directly into these XYZ Locked rows. You
can also copy/ paste into this table as well if you have a spreadsheet with structure locations
and files.
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Fig. 10.2-10 Structure Staking Table XYZ Locked Rows
XYZ Based Structures can also be placed automatically
with two other commands. The first is the Structures/
Automatic Spotting/ Spot At Feature Codes which
places a structure at all feature codes selected in the
dialog using a manually specified structure file or a
structure file specified in the plan, profile, or description of
the xyz point in the model. To make sure the structures
are XYZ based structures make sure the Spot structure
relative to alignment is unchecked as shown in Figure
10.2-11.
The other option to automatically place the XYZ Based
Structures is to type or copy/paste the desired XYZ
coordinates and structure file names into the File/ Import/
Fig. 10.2-11 Spot by Feature Code
Staking Table. The text at the top of the Import Staking
Table dialog lists some special codes to enter in the Line Angle field when working with XYZ
Based Structures. For example, set the Line Angle to 500 to place the XYZ Based Structure
without a PI. There are other codes if you want to create a PI on the current alignment or a PI
on a new alignment at the XYZ Based Structure (501 and 502). Figure 10.2-12 shows this
table.
Fig. 10.2-12 Import Staking Table
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XYZ Based Structures have an option to provide an Orientation Angle. The Orientation Angle is
the clockwise angle between the structure’s transverse axis and the X axis. A value of 0 has
the transverse axis of the structure pointing East (Northbound line). A value of 90 has the
transverse axis of the structure pointing South (Eastbound line).
10.2.8.2
Moving XYZ Based Structures
You can manually adjust the XYZ values of a structure using the Structures/ Modify or
Structures/ Staking Table to move a structure to a different location. You can also use the
Structures/Move/Freehand and Structures/Move/On Snap... command to move it graphically.
You can also use the menu command Structures/Move/XY Structure Along Line... or Entity
Info command Move XY Structure Along Line to define a line along which you wish to move
the structure. The same snap settings shown in the Figure 10.2-9 for adding a structure are
available.
10.2.8.3
XYZ Based Structures in Profile and Sheets View
If you do not have an alignment you can create a “profile like” view using the Virtual Profile as
discussed in section 5.4.12. You can work in this virtual profile to move and place structures
using the move commands discussed in the previous section.
If you want to display actual profile views or sheets views you will need to create an alignment.
The XYZ Based Structures that are within the Terrain/ Terrain Widths max offset for profile
view will be visible in the Profile View and the profile portion of the Sheets View.
10.2.8.4
XYZ Based Structures Stationing
When running reports for wire clearances or terrain data you may still want to know the station
and offset value of the XYZ Based Structures in the model relative to the closest alignment
segment. This is possible if an alignment exists but the alignment is optional when working with
XYZ Based Structures. If the alignment does not exist PLS-CADD reports a span relative
station and offset based on the line connecting the back and ahead structure bases of the span
in question. These span relative stations are identified in reports by the presence of a
“SPAN_RELATIVE” comment at the end of the line as shown in Figure 10.2-13 below.
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Fig. 10.2-13 Span Relative Stationing
If you want to force the program to report span relative stations for spans connecting XYZ
Based Structures even in the presence of an alignment you can do so via the Station and offset
of spans attached to XY Structures in the Settings section of the File/ Preferences dialog.
10.2.8.5
XYZ Based Structures Line Angles
With station based structures the line angle for a structure is based on the alignment and the
structure station on the alignment. Since an XYZ Based Structure is not on an alignment, the
line angle for it is based on the wires connected to it. Virtual alignments are created between
connected structures. By default the line angle is the largest angle turned between any of
these virtual alignments. Hence a 90 degree tap off a structure that otherwise has no line angle
results in it being considered a 90 degree line angle. This may not be the intent in most cases
so you can exclude certain wire sets from the line angle calculation (tap set can be excluded in
this example). Sets can be excluded through the Structures/ Staking Table column “Sets in
XY Structure Line Angle Calculation”. Figure 10.2-14 shows that the structure will only include
reference to Set 6, 7, and 8 for the line angle calculation and the structures involved with the
calculation will be Substation and 2. All other wires and structures are ignored for the
calculation of the Line Angle.
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Fig. 10.2-14 XYZ Based Structure Line Angle
10.2.8.6
Stringing to XYZ Based Structures and Structure Orientation
As mentioned in section 10.2.8.1 the orientation angle of the XYZ Based Structures defaults the
structure transverse axis to face East. If using the Sections/ Graphical Add command to string
wires in your model there is an option to “Attempt to rotate structures affixed to an XY
coordinate (as opposed to a station on alignment) so transverse axis bisects angle” that will try
to orient your structure correctly based on the ahead and back structures in the section. Figure
10.2-15 below shows the option highlighted yellow in the dialog box.
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Fig. 10.2-15 Graphical Section Add Automatic Structure Orientation
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10.2.8.7
Convert Station Based Structure to XYZ Based Structure
If you have the Entity Info snap settings set to snap to a structure and you select a structure
the context sensitive menu will present a Convert Structure to XY Based option which brings
up the Convert Structures From Station Based dialog box shown in Figure 10.2-16. It can
operate on the single structure you selected or a range of structures. Please note that once you
convert to a XYZ based structure you cannot convert back to a station based structure.
Fig. 10.2-16 Convert to XYZ Based Structure
10.2.8.8
Rotate XYZ Based Structures
If you have the Entity Info snap settings set to snap to a structure and you select a structure
the context sensitive menu will present a Rotate XY Structure to Angle Bisector. This
command will automatically adjust the structure orientation angle such that the structure
transverse axis bisects the line angle defined by the attached wires nominated in the
Structures/ Staking Table.
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10.3
Ground Wires and Conductors Installation
Once structures are spotted on the alignment, they can potentially be used to support as many
cables (or bundles of cables) as they have cable attachment points (see discussion about cable
attachment points in Section 8.2). Since the line model generally includes all cables in all spans,
PLS-CADD offers a series of commands for efficiently stringing and sagging cables. Because
all the cables within one cable set have identical properties and tensions, the set, but not
individual cables, is strung and sagged. Cable sets are part of tension sections. Each tension
section is strung and sagged separately. A tension section must have a beginning (at a
structure dead-end attachment point), an end (at a dead-end attachment point of another
structure down the line), and it may be supported by intermediate structures at non-dead-end
attachment points. A tension section can pass over an intermediate structure, for example a
high voltage circuit can pass over a short mid-span distribution pole. Stringing is the operation
that establishes the structure connections for all the cables in a set from beginning to end of the
tension section. Sagging is the operation of tensioning the section to a prescribed value. Both
stringing and sagging are fully described below.
10.3.1 Stringing of Tension Section
We will demonstrate the stringing and sagging process by example.
First, load the Demo.xyz
project, zoom in on the
portion of the line between
Structures #6 and #10, and
use the Sections/ Remove
command to remove all
cables between these two
structures. You now have
two dead-end structures (#6
and
#10)
and
three
intermediate structures (#7,
#8, and #9) ready for
stringing.
Fig. 10.3-1 Section Stringing
Click on Sections/ Add to
start stringing. Then click on the leftmost structure (Structure #6) of the new section that you
wish to create. The Section Stringing dialog box (see Fig. 10.3-1) will appear. It will initially be
displayed with a small size, but you can increase its size by clicking repeatedly on the
maximizing button at the top right of the dialog box or within the structure view. If the structure
where you start stringing is a Method 4 structure (or other types with models initially prepared
by our PLS-POLE or TOWER programs), a sketch of that structure will appear in the right
portion of the Section Stringing box (see Fig. 10.3-1) with each attachment point displayed
with its set and phase number. You should then pick from the list of still available structure
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Attachment sets from which you want to string. For example, select Attachment Set No. 6 to
start stringing the right circuit (a "kiwi" conductor). Since the silhouette of Structure #6 in the box
of Fig. 10.3-2 is displayed as it appears to an observer marching down the line before he
reaches that structure, you are able to select attachment points without ambiguity, even if a
structure is rotated as is the case with Structure #6.
Then click on the Next button at the bottom of the dialog to bring the kiwi conductors to
Structure #7. Selecting Attachment set No. 6 while you are over Structure #7 has the effect of
connecting the conductor to the right circuit on that structure. Had you selected "None" in the
Attachment set field, the conductors would not be connected to Structure #7. This is the way to
by-pass an intermediate structure along the alignment.
Then click on the Next button three more time and select Attachment set No. 16 to connect to
Structures #8, #9 and #10. As you click on Next while at Structure #10, the program senses that
you have connected the conductor to a dead-end attachment point, indicating the end of the
tension section.
Fig. 10.3-2 Conductor Stringing Between Str. #6 and #10
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A small Create box appears
where you click on Yes to
complete the stringing. You are
taken to the default library of
cables where you select the
type, here "kiwi". Once the cable
type is selected, your newly
strung section appears as
shown in Fig. 10.3-2 and you are
taken directly to the Section
Modify dialog box (Fig. 10.3-3)
where you can sag the section
and select parameters for its
display. By default, when you
string a new section and before
you sag it, it is arbitrarily
displayed in red for a catenary
constant of 1000 ft with the color
nominated in the cable file.
After you OK the dialog box of
Fig. 10.3-3, you will be able to
string and sag other sections.
However, after this exercise,
make sure that you do not save
the Demo project as you
Fig. 10.3-3 Section Modify Dialog Box
need to keep it intact (as you
received it on the distribution CD) because we refer to it in many places in this manual.
The wires in the Demo example are modeled with three phase per set. The three phases be
connected to the structures in the order chosen in the Transposition pick list at the top left of the
Section Stringing dialog of Fig. 10.3-1. Using the default order 123 connects the three phases
1, 2 and 3 to the structure attachment points 1, 2 and 3 of the set. Using 321 connects the first
phase to attachment point #3, the second phase to attachment point #2 and the third phase to
attachment point #1. There are cases, such as the situation of needing to rotate a nonsymmetrical structure at a line angle (see Section 7.3.17.1), where the transposition from 123 to
321 (or something else) is necessary.
If you wish to change any one of your stringing decisions, for example make a transposition
change at one or more structures, you can revisit all the steps discussed in this section by
clicking on the Edit Stringing button at the bottom of the Section Modify box.
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The Section Modify dialog box (Fig. 10.3-3) includes four basic areas: the Type area, the
Sagging area, the Display area and the SAPS Finite Element Sag-Tension Options area.
Items in the Sagging area are discussed in Section 10.3.2. Those in the Display area are
discussed in Section 10.3.3. You will only need to deal with the items in the SAPS Finite
Element Sag-Tension Options if you use Levels 2, 3 or 4 modeling. These items are
discussed in Appendix N.
The Type area includes a Button that lets you change the cable type, a Voltage field where you
enter the cable voltage or select from the list of voltages entered in the Feature Code Table and
Conductors per phase field where you enter the number of subconductors in the phase bundle.
Since required clearances to terrain points are voltage dependent, the voltage is a required
number. The number of subconductors per bundle is needed to calculate the total phase load at
the attachment point.
10.3.1.2
Automatic Stringing
PLS-CADD can automatically
string
conductors
between
compatible structure sets using
the
Sections/
Automatic
Stringing command of Fig.
10.3-3a. This allows you to
select an available range of
structures to string wire, the
cable file to string, number of
conductors per phase, and the
specific range of sets to string
wire. The apply button allows
you to string different scenarios
without leaving the dialog. For
example you could string your
shield wires on the required sets
and hit the apply button and
then switch to stringing the
conductor on different sets
without leaving the dialog each
Fig. 10.3-3a Automatic Stringing Dialog Box
time. The option at the top of
the dialog let’s you pick whether to string conductor to only sets with the same set description or
ignore the set description and string to the first compatible set available. The color of the cable
defaults to the nominated color in the cable file.
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10.3.1.3
Graphical Stringing
The traditional method of stringing conductor in PLS-CADD is described in section 10.3.1 above
which involves selecting the beginning structure that has a deadend and then clicking through
each intermediate structure until you reach the next deadend and then repeating the process for
every set on the structure. The Sections/ Graphical Add command allows you to graphically
select the set and phase you wish to string on each structure or just the beginning and ending
structure and detect the intermediate structures and automatically string to these structures.
You can also choose to string other compatible sets on the structures at the same time similar
to the Automatic Stringing command shown above.
The advantage of this method of stringing is that it does away with the requirement that you can
only string in the order of increasing stationing which required the user to define alignments in
the appropriate order as discussed in section 6.3. Without this constraint you can now string to
any structures in the model without regard to their stationing. *Be advised* that stringing
sections between structures out of station order can have an impact on what is considered an
ahead or back span which can influence both load adjustments and wind directions. Previously
an ahead span was taken as the span emanating from a structure to a structure of a higher
station and a back span was taken as the span emanating from a structure to a structure of a
lower station. This also defined the direction of the wind from a standpoint of blowing from left
or right. For more on load adjustment with ahead and back spans see section 7.3.12.7 and for
more on the wind direction definition see section 7.3.12.2. When using the graphical stringing
option the ahead and back spans are defined by the direction you string the wire. So if you
started on a deadend at structure 1 and went to structure 4 then to structure 3 and then to
structure 7 the span that starts on structure 4 and goes to structure 3 would be an ahead span
for structure 4 and a back span from structure 3 without regard to the structure stationing. The
command Drafting/Show Stringing Direction actually draws an arrow on the conductors in
each span showing the direction of stringing which is useful in demonstrating the stringing
direction and identifying ahead and back spans. An arrow pointing toward a structure means
that span is a back span for that structure and an arrow pointing away from a structure means
that span is an ahead span for that structure.
As an example let’s string the same section in the Demo.xyz project that we strung using the
traditional method in section 10.3.1 previously. First, load the Demo.xyz project, zoom in on the
portion of the line between Structures #6 and #10 and use the Sections/ Remove command to
remove all cables between these two structures. You now have two dead-end structures (#6
and #10) and three intermediate structures (#7, #8, and #9) ready for stringing as shown below
in Figure 10.3-3b where you will see that the Method 4 TOWER and PLS-POLE structures (#6,
#9, #10) are shown below the ground line and the Method 1 structure models (#7, #8) are not
shown. Please note that while we are doing this example in the Profile view the command can
be used in any of the views and you may find it useful to do in the 3D view if doing complicated
multiple alignment or tap configurations.
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Figure 10.3-3b Profile View of Demo.xyz with Sections Removed
Click on Sections/ Add Graphical and the mouse cursor will depict a span of wire with the text
Add on it and depictions of the Method 1 files will appear below the ground line. As you move
the mouse around the screen you will see that a rubber band line will snap to attachments on
the structure above the ground line and also below the ground line and the set number of the
selected attachment will appear below the structure as well as in the status bar with the phase
number. You can choose to work in the area above the ground line or with the structure views
below the ground line. You will want to start by selecting a structure with a deadend. If you
select an attachment that is not a deadend to start with you will get the warning that the Section
needs to start on a dead end attachment.
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For our example we want to start by stringing Set 6 on structure #6 which is the right circuit.
Since it is a double circuit configuration it is easier to work with the structures rendered below
the ground line so you are able to more easily select the correct side of the structure. Figure
10.3-3c below shows the selection of the deadend at structure #6, note the set number 6 shown
below the structure and the set and phase number noted in the status bar.
Figure 10.3-3c Add Graphical Start Section
You can then select the attachment point to begin on by left clicking and then select the
attachment points on the other structures which you can do by just dragging the catenary
marker to each of the attachment points and left clicking to select. Just like the previous
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example you will want to click on the right circuit set for each of the structures which is
attachment set 6. Once you get to the deadend at Structure #10 you can choose to end the
section or if there were other structures past the deadend that you wished to string as well you
could keep selecting structures to automatically string the next section as well. For this example
we are ending at structure #10 set 16 which you can do by first selecting the attachment by left
clicking on it and then ending the section by either hitting the enter key or middle clicking on the
mouse. If you choose to end the section on an attachment that is not a dead end you will be
given the warning message “Can’t string section unless it starts and ends on a dead end
attachment. Right click to abort and start over.” Where you can choose to start over or just
continue selecting until you get to a dead end. Figure 10.3-3d below shows the Profile view
after the selection of the attachments with the catenary markers prior to ending the section by
middle clicking.
Figure 10.3-3d Catenary Markers
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Once you middle click or hit enter to end the section the Section Add dialog box shown in
Figure 10.3-3e appears which gives you some connection information about the structures you
have selected with the number of deadend and non-deadend structures connected in the
selection. It also gives you a count of the number of unconnected structures that you may have
skipped over in the selection of range of structures and gives you the option to make connection
to these intermediate structures in the Unconnected Structures section of the dialog box. The
Connections at Dead Ends section gives you the options for allowing connections for dead ends
if stringing multiple sections. This is useful when you have different ahead and back sets for
your sections on dead ends. The Tangled/ Transposed Wires section gives you a count of
spans with crossed phases and how many are fixed if you have the attempt to untangle option
selected. For this example we will uncheck these options and not worry about them since we
have selected all of the structures to be connected. We will touch on this powerful feature in
another example.
As shown in the figure you will have 4 sets that have been detected on the structures that can
be strung from the table. This is similar to the automatic stringing functionality mentioned
previously as we automatically detect the available sets on the structure and include them in the
table for possible stringing. The set we have selected to string starts on set 6 and you will
notice that the String This Set and Copy Earlier Set Data are grey for this row since this is the
set that was graphically selected and must be strung. The columns in the table provide the
following functionality:
String This Set:
You can choose to select Yes or No in order to string all the sets
detected by the program on the structure range selected.
Copy Earlier Set Data:
You can choose Yes or No to copy the stringing data from the
previous selection in the table. If you select Yes then the stringing
data for that cable is greyed out and will copy the data from the
first row above that cable that has No selected in this column.
Start DE Set:
This is an informational column that is always grey that reports the
set number detected for that particular section’s starting deadend.
Start DE Set Desc.:
This is the set description for the Start DE Set that is assigned in
the structure model and is always grey.
Structures Connected:
This is the total number of structures that would be connected to
this section and is always grey.
DE Connected:
This is the number of deadends connected in the section and is
always grey.
The Cable File Name, Voltage, Wires Per Phase, Sagging Condition, Sag Temp., Sag Horiz.
Ten. Display Weather Case, Display Condition, Disp. Wind From, and Disp. Color are the
sagging and display conditions for the section which can be set for each cable in the table if
Copy Earlier Set Data is set to No. If Copy Earlier Set Data is set to Yes then it will copy the
values for the first row above this one that has No in this field. The color will default to the
nominated color in the cable file unless altered.
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If you input a 0 or leave to the default blank value in the Sag Horiz. Ten. Column the value for
the section will be calculated from the setting in the Criteria/ Automatic Sagging table.
For our example to match the single wire that we strung in the previous section using the
traditional Sections/ Add method discussed in section 10.3.1 above you will have No
selected for all the rows except the greyed out row for String This Set.
There are two toggle buttons for quickly toggling the set selection and copy earlier values option
in the table on the right side of the dialog box above the table which are useful when stringing
multiple sections in the table. The third button above the toggle buttons allows you to quickly
string a single set instead of all sets.
To have the section match the traditional method mentioned previously you can select the “kiwi”
cable file, 345 for the Voltage, 1 for Wires Per Phase, Sagging Condition is Initial RS, Sag Temp
is 60 deg F, Sag Horiz Tension is blank to allow for the Automatic Sagging of the section,
Maximum Operating is selected for the Display Weather Case, Mas Sag RS for the Display
Condition, and the color for the section is selected as blue.
Figure 10.3-3e Graphical Section Add Dialog Box
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After hitting the OK button the section below in Figure 10.3-3f will be shown based on your
selected options in the dialog box.
Figure 10.3-3f Graphical Add Result
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As mentioned previously this command can also be used in other views including the 3D view
which may be useful when stringing some complicated multiple alignment scenarios. As shown
in the Figure 10.3-3g catenary markers will be shown in the 3D view to make it easy to identify
the direction you are stringing the conductor and select structure that may exist on different
alignments.
Figure 10.3-3g 3D View Graphical Add
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The Sections/ Graphical Add command can also be used to automatically string conductor
through deadends and create multiple selections based on
the selection of a beginning and ending structure. Below
shows a simple selection that contains four dead end
structures in the profile view with structures that follow the set
convention of 5 and 15 for conductors with the 5 set being
the ahead set and 15 the back set on deadends and 1, 2,11,
and 12 for the two shield wires with 1 and 2 for the ahead set
on deadends and 11 and 12 being the back set on deadends.
From the figure 10.3-3h you can see that you can select the
beginning structure and the last structure in the section and a
large catenary marker will appear between the structures.
After selecting the range, the Section Add table shown in
Figure 10.3-3i will be shown and you can select the options
related to the sections. At the top of the dialog box will be
the Connection information which shows the dead end
structures connected in the graphical selection which in this
scenario is only two. In the Unconnected Structures section
it shows how many structures are spanned and not
connected between the dead ends as well as the possibility
to select a different set number to get information on that set
in the range of structures selected.
In the Connections at Dead Ends section you can choose
among the three options for attaching to dead ends that are
spanned within the range selected. In this instance the
different attachment set number for back and ahead spans,
back and ahead set numbers differ by 10 is selected since it
follows the normal +10 convention for dead ends on the
same structure where we did so with set number 5 and 15 in
this example. The other options available are to have
different attachment set number for back and ahead spans or
use the same attachment set number for both.
Fig. 10.3-3h Multiple Section
Selection
In the Tangled/ Transposed Wires section it will report how many spans show crossed phases
and you can use the Attempt to untangle option and it will report how many spans have crossed
phases with the auto transpose. While this attempts to solve all the crossed spans, if it misses
any you can use the Sections/ Swap Attachments command to quickly graphically fix the
stringing.
In the bottom you will notice that there are three detected sets from the starting structure and
they are 1, 2, and 5. In order to string all three of these sections you have to select Yes for the
String This Set in each row. The set 1 and 2 are identical so you can use the option to Copy
Earlier Set Data in row 2 for set 2. Then you can fill out the data required for each section and
by selecting the Copy Earlier Set Data as Yes you only need to input the data for the shield
wires once.
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Figure 10.3-3i Graphical Add Multiple Section Table
Once you select OK from the dialog, the sections will string and you will then have your sets
strung according to your selections in the table. You will still want to review the results for
possible crossed phases which can occur when you have multiple sets for your shield wire. If
you do have these crossed sets you can use the Sections/ Swap Attachments command to
quickly alleviate the crossing.
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NOTE: As mentioned previously the definition of an ahead or back span for a structure now
relies on the order in which you string the conductor and no longer is based on stationing of the
structures. This can influence load adjustments, wind direction, etc. To see the direction of the
stringing and help identify ahead and back spans you can use the Drafting/ Show Stringing
Direction to show arrows on the spans dictating the direction the conductors were strung. An
ahead span for a structure is a span where the arrow points away from the structure and a back
span is a span where the arrow points toward the structure. Figure 10.3-3j below shows the
arrows and the directions related to the structures.
Figure 10.3-3j Show Stringing Direction
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10.3.2
Sagging Tension Section
The Sagging area includes the parameters needed to sag the section. Sagging is the
specification of a sufficient number of conditions so that the computer can determine what is the
unstressed length of cable in each span at zero degree Celsius right after construction (cable in
its initial condition). From this starting point PLS-CADD uses the cable stress-strain model
described in Section 9, the loading equations of Sections 7.2.1, 7.2.2 and 7.2.3 and either 1) the
ruling span concept described in Appendix I for Level 1 modeling or 2) the concepts described
in Appendix N for finite element modeling (Levels 2, 3 and 4) to determine the cable geometries
and end forces for any combination of weather case and cable conditions. All of these complex
calculations are performed automatically and almost instantaneously, letting you change and
see the effects of changing design parameters interactively.
If you do not select Override calculated ruling span in the top left portion of the Sagging area,
the calculated ruling span for the tension section which you just strung is displayed (1093 ft in
Fig. 10.3-3). All subsequent sag, tension and load calculations involving the ruling span of the
tension section will be based on this value. If you select Override calculated ruling span, you will
be able to enter your own ruling span value. For example, this feature is used when you model
a single span of a crossing line (see Section 11.2.3.2.1) or a tap line which has a ruling span
different from the length of that span.
There are two general options to sag a model: 1) to force a uniform tension throughout the
tension section at the Reference sagging condition, and 2) to force the sag of each span to
match a measured value at a Field condition, not necessarily the Reference condition. The
Reference condition is the combination of Cable Condition, Temperature and Horizontal
Tension displayed in the Sagging area of the Section Modify dialog box. Option 1) is almost
universally used when modeling new lines, but it can also be assumed in some cases of existing
lines even though the measured Field tensions in each individual span are not exactly the same
throughout the tension section. Option 2) is used in existing lines where, by design or due to
some accidental change in wire length or structure position, the tensions in the spans of the
tension section are not uniform and there is no Reference condition for which they would be the
same.
10.3.2.1
Sagging for Uniform Tension Throughout Tension Section at Reference
Condition
If you are using ruling span modeling (Level 1 modeling), this is always the case. If you are
using finite element modeling (Levels 2, 3 or 4 as described in Appendix N), this is the case for
an existing line whenever you assume that, at the Reference sagging condition, the insulators
were plumb (i.e. the tensions were the same in all the spans), but you want the position of the
Field condition used for graphical sagging to be determined by the finite element method
(because you think that the ruling span method would not give good results for that particular
Field condition).
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Following are the four options for sagging a tension section for uniform tension throughout the
tension section at the Reference condition. The first three options are available in the Sagging
area of the Section Modify box. Sagging charts to be used during construction are another
issue discussed in Section 11.2.4. Construction sags are derived quantities totally dependent on
the sagging decisions you make in the Section Modify dialog box.
10.3.2.1.1
Sagging by Tension
If you select Sag With Tension in the File/ Preferences menu, sagging is done by picking a
cable Condition (Initial, after Creep, or after Load), specifying a Temperature and specifying an
Horizontal Component of Tension. The Catenary constant in the grayed field which you cannot
access is simply the horizontal component of tension divided by the cable weight per unit length.
10.3.2.1.2
Sagging by Catenary Constant
If you select Sag With Catenary Constant in the File/ Preferences menu, sagging is done by
picking a cable Condition, specifying a Temperature and specifying a Catenary Constant. The
Horizontal Component of Tension in the grayed field which you cannot access is simply the
catenary constant multiplied by the cable weight per unit length.
10.3.2.1.3
Automatic Sagging
With this method, you pick a cable Condition, you specify a Temperature and you click on the
Automatic Sagging button. The computer looks up the automatic sagging criteria of Section
7.3.7 and pulls the tension section as tight as possible without violating any of these criteria. A
short report shows you which criterion controls. After you close the report, you will note that the
Catenary Constant and the Horizontal Component of Tension at the specified cable Condition
and Temperature have been calculated automatically to meet the autosag criteria. These
remain in effect as the Reference sagging condition of the tension section, even if you later
move structures, until you hit Automatic Sagging again.
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10.3.2.1.4
Sagging
Graphical
Once a tension section is
CABLE POSITION
strung between two dead
B
POINT TO
TO MATCH
ends, graphical sagging lets
SNAP TO
A
you select any phase of any
C
set (thick lower line in Fig.
D
10.3-4) and optionally: 1)
drag it (by keeping the left
button pressed as you
move the mouse) until it
matches a desired position
(this only works if you
select Ruling Span in Fig.
SELECTED PHASE IN TENSION SECTION CAN BE DRAGGED
10.3-6), or 2) have it snap
UP
AND DOWN TO MATCH DISPLAYED CABLE POSITION OR IT
to the mouse cursor
CAN BE MADE TO SNAP AUTOMATICALLY TO SELECTED POINT
location, or 3) have it snap
to the surveyed point nearest
Fig. 10.3-4 Graphical Sagging of Tension Section
the mouse cursor.
With the first option, you will see the entire tension section go up and down interactively as you
drag it with the mouse. This option is very useful when you want to match the sagging of the
model to that of an existing line as displayed by a scanned drawing in the profile view (see
Sections 6.8.5 and 6.8.6) or when you want to provide the proper clearance to any displayed
obstacle.
With the second or third option, PLS-CADD automatically displays the section so that the
designated phase goes through a selected point (for example D in Fig. 10.3-4). This option may
be used if you want to sag a section to match a surveyed position of the cable.
Fig. 10.3-5 Graphical Sag Dialog Box
For graphical sagging you should first quit the Section Modify box if you are in it, and then click
on Sections/ Graphical Sag. The Graphical Sag dialog box of Fig. 10.3-5 will appear. You
select the proper cable by clicking on the Prev. or Next button. Then you select a Cable
Condition and a Weather Case in the two pick lists at the left of the Graphical Sag box which
will correspond to the displayed position of your cable (IMPORTANT NOTE: it is imperative that
you make these selections before you do the graphical sag with the mouse). If you type a
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number in the Weather Case field, that number temporarily creates a new weather case with no
wind and no ice at that temperature. You can select that new weather case. Then you click on
the Options button to select various wire modeling and sagging options in the Graphical Sag
Options box of Fig. 10.3-6.
Fig. 10.3-6 Graphical Sag Options
If you select Fit to survey point closest to mouse in the Graphical Sag Options box, you will be
able to make the cable go through the surveyed point closest to the mouse cursor. If you select
Fit to mouse coordinates, you will be able to drag the selected cable with the mouse.
In order to sag for a uniform tension throughout the tension section at the reference condition,
you should select either one of the first two options, Option 1) or Option 2), in the Fit Mode area
of the Graphical Sag Options box.
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If you select 1) Ruling Span, all internal calculations needed to determine the tension of the
Reference condition from the graphically sagged Field position will be made by the ruling span
method (Level 1).
If you select 2) Finite Element Insulators Plumb at Sagging Condition, all internal calculations
needed to determine the tension of the Reference condition from the graphically sagged Field
position will be made using the finite element method (Level 2, 3 or 4). See Section N.8.1 for
more information regarding this option.
After exiting the Graphical Sag Options you will be able to graphically sag your tension section
(make sure that you have the correct Cable Condition and Weather Case in the box of Fig. 10.35).
If you select 1) Ruling Span, the Tensions (actually horizontal components of tensions) or the
Catenary constants corresponding to both the Reference condition (Sagging Tension) and the
Field condition you are currently snapping to (Display Tension), are calculated and displayed
real time in the dialog of Fig. 10.3-5. The Tension is displayed if you have selected Sag with
tension in the File /Preferences dialog. Otherwise, the Catenary constant is displayed. If you
click on the Apply button at the right of the Graphical Sag box of Fig. 10.3-5, two things
happen: a) the calculated Sagging Tension is automatically copied in the Sagging area of the
Section Modify box but the Cable Condition and the Weather Case remain those that you had
selected in that area prior to doing the graphical sag, and b) the Cable Condition and the
Weather Case which you have entered in the left portion of the box are automatically copied in
the Display area of the Section Modify box.
If you select 2) Finite Element Insulators Plumb at Sagging Condition, the Tension (or Catenary
constant) corresponding to the Reference condition (Sagging Tension) and the Tension in the
span you just clicked on in the Field condition (Display Tension), are calculated and displayed in
the dialog of Fig. 10.3-5 (this happen a short time after you select a point with the mouse). If you
click on the Apply button at the right of the Graphical Sag, two things happen: a) the
calculated Sagging Tension is automatically copied in the Sagging area of the Section Modify
box but the Cable Condition and the Weather Case remain those that you had selected in that
area prior to doing the graphical sag, b) the Cable Condition and the Weather Case which you
have entered in the left portion of the box are automatically copied in the Display area of the
Section Modify box.
If you cancel the box of Fig. 10.3-5 without clicking on the Apply button, the section is not
sagged to match the sagging on the screen. It remains sagged for whatever set of parameters
were in effect before you selected the Sections/ Graphical Sag menu.
The QC Report button produces a report with mid-span cross-section graphics showing the
current wire position in relation to the desired wire position and wire points. This option only
works with fit methods 4 and 6.
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For additional information regarding the Graphical Sag option, you should read the following
document:
http://www.powline.com/products/fe_sagten/fe_graphsag.html
10.3.2.2
Sagging to Match Non-uniform Tensions in Spans of Tension Section
This option is only used in existing lines where the tensions in the individual spans of the
tension section are not the same, either due to some line modification (addition or subtraction of
wire length in some spans, movement of some structures, etc.) or due to some non-uniform
accidental stretching or creep in some spans (clamp slippage, large ice on one span only, etc.).
Such lines can only be modeled by finite element modeling (Levels 2, 3 and 4), based on the
actual lengths of cable in each span, as described in Appendix N. They can only be sagged with
the graphical sag options 3) to 6) of the Graphical Sag Options box of Fig. 10.3–6. In such
cases, the Reference sagging condition (combination of Cable Condition, Temperature &
Tension/ Catenary in the Sections/ Modify box) is an arbitrary condition from which the
Reference unstressed cable lengths in all spans (Ahead Span Unstressed Length column in the
Wire Lengths and Attachment Stiffness table of Fig. N-6) are determined. However, once the
graphical sag is completed, all calculations will make use of the Actual unstressed lengths.
Actual unstressed lengths are determined as Reference values plus or minus a correction
(Ahead Span Unstressed Length Change in the Wire Lengths and Attachment Stiffness table
of Fig. N-6) so that the wire matches exactly the Field condition defined in Graphical Sag.
Options 3) to 6) of the Graphical Sag Options box of Fig. 10.3–6 are described in details in
Section N.8 and in the following document:
http://www.powline.com/products/fe_sagten/fe_graphsag.html
The use of Options 3) to 6) of the Graphical Sag Options box will result in the following:
a) graying of the Reference sagging parameters in the Sagging area of the Section Modify
dialog box, i.e. removing access to them since Reference unstressed lengths are based on
them.
b) using the Weather Case and Cable Condition selected in the Graphical Sag box in the
Display area of the Section Modify dialog box
c) clipping the insulators in the Section Modify box, i.e. forcing you to be in the finite element
world.
CAUTION: Once you have graphically sagged your model and clipped the insulators, you
should not unclip these insulators or you will lose all the work that you have done to match the
model to the Field conditions.
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10.3.2.3
Additional Comments Regarding the Effect of Clipping Insulators
If Clipping Insulators in the Section Modify box is NOT CHECKED and you select a Cable
Condition that includes the suffix RS (Initial RS, Creep RS, Load RS or Max Sag RS) in a
particular dialog box or table that specifies how to do a sag/ tension calculation, how to display
the wires, or how to determine the structure loads, then all sags, tensions and loads for the
tension section will be calculated with the ruling span method (See Appendix I). With the ruling
span method, the actual length of cable in each span is not used in the calculations, as tensions
are based on that of the ruling span. This is the most efficient method which will probably be
used in the great majority of your applications.
If Clipping Insulators in the Section Modify box is NOT CHECKED and you select a Cable
Condition that includes the suffix FE (Initial FE, Creep FE, Load FE or Max Sag FE) in a
particular dialog box or table that specifies how do to a sag/ tension calculation, how to display
the wires, or how to determine the structure loads, the corresponding calculation will be based
on the finite element method as if you had temporarily clipped the insulators of the tension
section (i.e. temporarily checked Clip Insulators in the Section Modify box) as described in the
paragraphs below. However, the clipping is only temporary: it lasts the duration of the
calculation and it is always true that the horizontal tensions in all the spans in the tension
section are the same for the reference Cable Condition and Temperature (in the Sagging area
of the Sections/ Modify box), and these tensions are equal to the reference Horizontal Tension
or Catenary (also entered in the Sagging area of the Sections/ Modify box). This results in
suspension insulators being plumb at the Reference sagging condition.
If Clipping Insulators in the Section Modify box is CHECKED (either manually or as a result of
using the Graphical Sag described in Section 10.3.2.2), all sags, tensions and loads
calculations for the tension section will be based on the finite element method (See Appendix
N). In such a case, all calculations are based on fixed unstressed lengths for each cable in each
span.
At the time you FIRST check Clip Insulators in the Section Modify box (or when Graphical Sag
does it for you), the program assumes that the horizontal tensions in all the spans in the tension
section are the same as the reference Horizontal Tension for the reference Cable Condition and
Temperature defined in the Sagging area of the Sections/ Modify box. This results in
suspension insulators being plumb for this Reference sagging condition. Then, for this
Reference condition, the program determines the Reference cable unstressed lengths of all
spans (Ahead Span Unstressed Length column in the Wire Lengths and Attachment
Stiffness table of Fig. N-6). From this point on, the cable lengths remain fixed unless changed
by the increment specified in the Ahead Span Unstressed Length Change column of the Wire
Lengths and Attachment Stiffness table of Fig. N-6. Moving a structure or changing its
geometry without un-clipping the wires will not affect the unstressed lengths but that will impact
the span geometries and hence will likely result in: 1) the insulators deviating from plumb when
displayed at the Reference condition and 2) the introduction of longitudinal loads on the
supporting structures. Adding or removing a structure without un-clipping the wires will not affect
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the total unstressed length of cable in the tension section, but it will impact both the span
geometries and the length of wire in the spans adjacent to the added or removed structure: this
will also result in insulators deviating from plumb and longitudinal loads.
Another way to understand the differences in your line model behavior when the insulators are
clipped or not clipped is to think about the various stages of design and construction of your line.
When you design a new line (before it is built), you still want the flexibility to change and move
structures and adjust tensions, so the insulators should never be clipped, i.e. Clip Insulators
should NOT be checked in the Section Modify box. In such cases the wire unstressed length in
each span is not fixed in advance. The total length of wire isn't either. This allows you to move
structures and change wire tensions as if the wires were not attached to the structures, even
though the displayed positions of the wires are those which would exist if the wires were sagged
according to sagging conditions in the Section/ Modify box. If you are satisfied with the Ruling
Span method, the wire unstressed lengths will never be needed. Unstressed lengths will only be
needed internally by the program if you select the Finite Element method for some calculations
(by selecting Initial FE, Creep FE, Load FE or Max Sag FE for some Cable Conditions). In such
cases, and just for the duration of the calculations, the insulators are clipped as if you had done
it manually in the Section Modify box.
When you model an existing line, you may need to account for the fact that you have a fixed
length of wire in some spans. For example, if you intend to modify the line by 1) moving or
raising some structures without detaching the wires in a particular tension section, 2) cuttingand-splicing some wire, or 3) sliding some wire in clamps, then all tension calculations in the
affected tension sections should be done by the Finite Element method, based on the lengths
of wires that existed prior to the modifications. Also, if your survey indicates large differences in
horizontal tensions in the span of a tension section, the Ruling Span assumption is obviously
violated and you need to use the Finite Element method. In these cases, the insulators in the
affected tension sections should be clipped, i.e. Clip Insulators should be CHECKED in the
Section Modify box. The Finite Element method can be very demanding in term of computer
time and memory: therefore do not use it unless you have to, i.e. do not clip insulators unless
you have a situation that requires it and limit the clipping to the sections that need it.
Having the insulators unclipped (not fixed length of wire) is not the same as having the wire in
blocks (supported by pulleys). When in blocks, the horizontal tension may vary in the spans of
the same tension section due to some changes in support elevations (hilly terrain). However, if
you want to see what happens to a previously clipped line when you detach a wire at a
particular structure and temporarily support it by a pulley, you need to use the Structures/
Equalize Tension command with the "Actual tension (wire in blocks)" option selected.
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10.3.3
Displaying Tension Section
The display area of the Section Modify dialog box lets you select two of several ways of
displaying the tension section. This was first discussed in Section 5.4.6 which you should be
familiar with. It also includes a Section Note that you can use to describe the section.
10.3.3.1
Angle
Displaying a Tension Section for a Given Catenary Constant and Swing
If you select Display each section at weather case or tension selected in Section Modify in the
Line Display Options box of Fig. 5.4-4a and if you do not select Show selected weather case
in the Display area of the Section Modify dialog box of Fig. 10.3-3, then the tension section will
be displayed for the Catenary constant, the Swing angle and the Wind direction (Wind from)
specified in the right side of the Display area.
10.3.3.2
Condition
Displaying a Tension Section for a Given Weather Case and Cable
If you select Display each section at weather case or tension selected in Section Modify in the
Line Display Options box of Fig. 5.4-4a and if you select Show selected weather case in the
Display area of the Section Modify dialog box of Fig. 10.3-3, then the tension section will be
displayed for the Weather case and Cable condition selected in the pick boxes in the lower left
corner of the Display area and the wind direction specified in the Wind from field.
If you select one of the Cable conditions which ends with RS, the Ruling Span assumption
(Level 1) will be used to display the section. If you select one of the Cables conditions that ends
with FE, the Finite Element assumption (Levels 2, 3 or 4) will be used.
Note: As mentioned previously, when a section is first created or modified, the cables in the
newly created or modified section may be displayed with the default catenary constant of 1000
ft, i.e. the cables appear to be very low (see for example Fig. 10.3-2). If this happens, you
probably do not have the proper settings in the Section Modify dialog.
10.3.4
Reusing Tension Section Sagging Parameters
You can use the Sections/ Copy command to save all the installation parameters of a tension
section (type, sagging and display data in the Section Modify box) in a temporary buffer. These
will be used as the default values the next time you string and sag a section. This feature is very
useful when you string a series of sections which have the same properties, for examples
conductors of the same circuit over several continuous tension sections.
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10.3.5 Section Table
Most of the information you developed in Sections 10.3.1 and 10.3.2 is available and editable in
the Section Table (see Fig. 10.3-7) that you reach with Sections/ Table.
The leftmost columns in the table, which are grayed, include information that results from some
stringing and sagging operations that cannot be edited in the table. Except for the rightmost
column, the information in any other column is identical to that in the Sections/ Modify dialog
box and can be edited. The Section Notes column which allows the user to input a note about
the section also appears in the Sections/ Modify dialog box. This note will appear in the
Section Sagging Data, Section Geometry Data, Stringing Chart Summary and Section Stringing
Data sections of the Lines/ Reports/ Summary. Any changes made in the table relating to the
sag and tension will have some effect on your model when you OK the table or hit the Apply
button.
The last column, “Command To Apply“, lets you issue the following commands that will also be
implemented when you OK the table:
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Clip:
This will have the same effect as checking “Clip insulators“ at the bottom
of the Section Modify dialog box. Important Note: If you use this
command on a section that is already clipped, it will temporarily unclip the
section before re-clipping it, i.e. you will lose all previous modifications to
your unstressed lengths ( “Ahead Span Unstressed Length Change“ in
the Wire Lengths and Attachment Stiffness table described in
Appendix N4 ). If these length changes are the results of some fit to
measured sags, you do not want to use the command.
Unclip:
This will have the same effect as unchecking “Clip insulators“ at the
bottom of the Section Modify box. The section is resagged with the
same tension in all spans as that of the ruling span.
Modify:
This takes you to the Section/Modify dialog box after OKing out of the
table
Delete:
This will have the same effect as Section/ Remove
Autosag:
This will have the same effect as checking “Automatic sagging“ and
OK’ing the Section Modify dialog box
Auto R.S.:
This will have the same effect as not checking “Override calculated ruling
span“ in the Section Modify dialog box
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Manual R.S.: This will have the same effect as checking “Override calculated ruling
span“ in the Section Modify dialog box. You will be asked for a numerical
value of ruling span.
Adjust Sag:
This increases or decreases the sag temperature while maintaining the
current sagging tension.
Find Graph Sag Fit Points: Finds the target points for the Graph Sag Fit to Points
command. This is the same process used for the Method 4 fit in the
Sections/ Graphical Sag command discussed in section 10.3.2.1.4 and
in Appendix N.
Graph Sag Fit to Points: Performs a batch graphical sag of the conductor using the fit
points found using the Find Graph Sag Fit Points command. The
adjustment can be done with Graphical Sag Method 1, 2, or 4. You can
also select to get a least squares fit to all wire points within a specified
distance of a 3 point catenary. There is also an option to obtain just a
report of the mismatch between the target points and the displayed wire
position.
Create Points Along a Wire: Creates points along the specified wire with a specified
feature code at a set interval. This can be used in conjunction with the
Thermal Rating Report to have an underbuild circuit control the thermal
rating for the wires above it.
Delete Concentrated Loads: Deletes all concentrated loads attached to the section.
Clear Length Adjust: Clears unstressed length adjustment from the Wire Lengths and
Attachment Stiffness table for all spans in the section.
Reverse Stringing: Reverses the stringing direction of the section which can influence
the ahead and back span designations on a structure as well as the wind
direction applied on the span. This command can be useful when doing
Graphical Stringing as discussed in section 10.3.1.3. This command is
also available graphically in the Entity Info context sensitive menu when
a wire is selected as discussed in Section 5.6.
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Merge Length Adjust: Merge unstressed length adjustment into the unstressed length
column of the Wire Lengths and Attachment Stiffness table for all spans
in the section.
Set Surveyed Temp.: Sets surveyed temp for all spans in the section in the Wire
Lengths and Attachment Stiffness table as the temperature from the
Display Weather Case column.
Find Survey Temp.: Sets surveyed temp for spans in the Wire Lengths and Attachment
Stiffness table from surveyed wire temperature extracted from XYZ point
plan comments for all spans that contain points within the specified
distance of the conductor. Will use the average of temperatures from
plan comments for spans that reference multiple XYZ points with
temperature values in the plan comment.
Selecting one of
the
sorting
options at the top
of the table will
facilitate editing
in-kind sections,
for example those
with the same
voltage, or the
same conductor,
etc.
10.3.6 Modifying
Tension Section
after Insulators
are Clipped
If you clip the
Fig. 10.3-7 Section Table
insulators of a
tension section, the behavior of that tension section will be based on a finite element model of
the section (and not the ruling span). That model works with the unstressed lengths of the
cables in the spans, i.e. the physical lengths of cables between clip points (attachments to
insulator or clamp). This is all explained in Appendix N. There are different ways of modifying
the unstressed lengths: 1) manual change as described in Section N.4, 2) graphical sag as
described in Section N.8, or 3) using the Structures/ Equalize Tension command. With the
Structures/ Equalize Tension command, you select a clip point and the program will
automatically move the clip point so that the tensions on either side of it equalize. This is done
by modifying the unstressed lengths in the two spans immediately to the left and to the right of
the clip point such that the sum of these lengths remains constant. The user can choose the
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weather case and condition in which the tension should be equalized as well as whether to
equalize tension on one phase or all phases in a structure or structure range.
10.3.7
Swap Attachments
It may be necessary at times to change the stringing of a conductor where it was inadvertently
strung to the wrong set or phase. The stringing of a tension section is discussed in section
10.3.1 above. The user can use the Section Stringing dialog box accessed through the
Sections/Modify command or they can use the graphical swap attachments command
available in Sections/Swap Attachments. The user will graphically select the set and phase
they wish to swap in any of the views and then hold down the left mouse button to drag the
graphical marker to the new location of the conductor and then release the button. The
particular set and phase of the selected conductor attachments are shown in the status bar.
The Sections/ Swap Attachments feature can also be used to delete a connection from a
structure by selecting the attachment with the left mouse button, holding down the left mouse
button, and dragging to the bottom of the structure to release the attachment. You can also
drag an unconnected wire to an attachment on a structure by left clicking near the middle of the
span to be connected and holding down the left mouse button and dragging to the attachment to
be connected then releasing the button to connect the wire.
10.3.8
Jumpers
Jumpers modeled in PLS-CADD give you the ability to evaluate clearances from the jumper to
structures, ground, other jumpers, and other wires. It also allows you to include its material in
the material tracking and reporting features of the program. Jumpers include the ahead and
back section of wire attachments and up to seven idler or jumper strings of insulators. Their
cable properties are the same as the back section of conductor that it is connecting.
Jumpers can be either flexible or rigid. Flexible jumpers can have their geometry defined by
either the length of jumper or the sag of each jumper segment. The length and sag of the
jumper inputted corresponds to the sagging temperature and sagging condition of the section
for the back span. Flexible jumpers are included in the FE Sag-Tension Model and have a
catenary shaped cable element. Rigid jumpers have their geometry defined by a straight line
with up to 10 intermediate points along this line as offsets to define the shape. Rigid jumpers
are not part of the FE Sag-Tension Analysis and any loads from the rigid jumpers are added
post analysis of the wire system.
Important Note: Using the jumper feature can impact your speed of analysis and requires the
use of FE cable conditions. Also you should consider the accuracy of the modeled members as
real wire in normal jumper lengths are neither perfectly flexible or rigid and the program does
not consider rigidity of the wire and the departure angle of wire at supporting hardware. To place
jumpers in PLS-CADD you will need to first enable the feature by going to Criteria/ SAPS
Finite Element Sag Tension and check the Jumper Options box at the bottom of the dialog.
You will also need to ensure that your idler or jumper insulators have a set and phase assigned
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in the structure models. Next you can go to the Structures/ Jumpers command and select a
structure that contains deadends which brings up the dialog box of Figure 10.2-3 and you can
select the Jumpers button that will bring up the Jumper Configuration table for that structure.
Each row in the table represents a jumper on the structure. You will need to fill out the following
columns for each jumper. There are also graphical commands located Structures/Jumpers
that include Add, Delete, Move, Copy, Paste, Edit and Graphical Sag of jumpers.
Jumper Type:
Flexible is selected for a flexible jumper.
Rigid Vert is selected for rigid jumpers that are primarily in the vertical
plane.
Rigid Horiz is selected for rigid jumpers that are primarily in the horizontal
plane.
Jumper Connection 1 – 7:
This defines up to 7 connections for the jumper on the structure. You
would select the set and phase you wish to connect at each point. The
beginning and ending selection would be the deadend set and phase for
the sections you are connecting.
Jumper Con. 1 – 6 Sag or Length:
This defines the geometry of the flexible jumpers by inputting a positive
number for the sag between the attachments points in the section or a
negative number denotes the length of the cable between the attachment
points. Jumper Con. 1 defines the section of cable between Jumper
Connection 1 and Jumper Connection 2 and so on.
Jumper Con. 1 - 6 Rigid Jumper Shape:
This defines the geometry of the rigid jumpers by opening a sub table that
defines different points along the chord connecting the attachments. The
first column in the sub table denoted with an X is the fraction of the chord
between the attachments. For example a 0.5 would denote a point
halfway between the two attachments. The Y and Z columns are the
distance from the chord. For a vertical jumper the z value would define
jumper in the vertical plane between the attachments. For a horizontal
jumper the y value would define the jumper in the horizontal plane
between the attachments. You can still use the both Y and Z columns for
either option as they allow for an offset from the selected plane.
Jumper Stock Number:
Stock number used for material tracking in PLS-CADD
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To see jumpers displayed under different weather and cable conditions you can change the
display weather case and cable condition of the back span of the deadend sections being
connected by the jumper.
Jumpers are considered in the following commands and reports:
Sections/ Clearances/ To Ground
Sections/ Clearances/ To Structure
Sections/ Clearances/ Between Sections
Lines/ Reports/ Structure Clearances
Lines/ Reports/ Wire Clearances
The Lines/ Reports/ Summary
also includes a Jumper Report
that will include a list of the
jumpers in the project, their
modeled length, and connections
as input
in the Jumper
Configuration table. The Lines/
Reports/ Bill of Material options
will also include the jumper
material if a stock number is
included.
Fig. 10.3-8 Jumpers on Structure
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11.
ENGINEERING CALCULATIONS
The line model used by PLS-CADD provides the user with access to powerful engineering
calculations which would not be possible had the terrain and line model not been completely 3dimensional. Complex engineering calculations are available at the click of the mouse or can be
performed globally for the entire line.
11.1
Structures
The following section describes loading and strength check report for structures in PLS-CADD.
11.1.1 Wind and Weight Spans
Wind and weight spans are defined in Appendix I. Weight spans can be computed by one of two
methods, depending on your selection in the Criteria/ Weight Span Model dialog.
Wind & Weight spans reports can be generated for individual or any sequential group of
structures with Line/ Reports/ Wind & Weight Span Report (Fig. 11.1-1). Weight spans are
reported for all cable sets for the combination of weather cases and cable conditions described
in the Criteria/ Wind & Weight Span Report dialog.
Wind and weight spans are also displayed in the strength check report of Method 1 and
Method 2 structures as discussed in Sections 11.1.3.1 and 11.1.3.2. Wind spans are also
displayed interactively in the lower status bar when you move a structure.
Fig. 11.1-1 Wind & Weight Spans Report
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11.1.2
Loading Trees
Fig. 11.1-2 Portion of Load Tree for Typical PLS-CADD Structure
You will use Structures/ Loads/ Report to determine the design loading trees at a designated
structure for the combinations of weather cases and load factors described in Criteria/
Structure Loads (Method 3, 4) (see Section 7.3.12). There are two slightly different versions of
the loading tree report, depending on whether you are working with a regular PLS-CADD model
or a PLS-CADD/ LITE model.
Fig. 11.1-2 shows an example of a portion of a loading tree for a structure in a regular PLSCADD model. It shows the loads for the NESC Heavy load case on Structure #6 of the Demo
line.
The wire loads in the span coordinate system are those of Eqs. 7-7 to 7-12.
The wire loads in the structure coordinate system are those described in Section 7.3.12.4.
The basic factored structure wind pressures are those defined in Eqs. 7-13 and 7-14.
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Fig. 11.1-3 Portion of Load Tree for PLS-CADD/ LITE Structure
Fig. 11.1-3 shows an example of a portion of the loading tree for the structure in a PLS-CADD/
LITE model. The main difference between the format of that tree and that of Fig. 11.1-2 is that,
with PLS-CADD/ LITE, there is no concept of back and ahead spans as all loads are described
for each individually attached wire. The design pressures shown in Fig. 11.1-3 have been
adjusted upward to account for member drag coefficients and some peculiarities of the tower
models to which they were to be applied.
The design loading trees described in this section are those used to check Method 4 structures
as discussed in Section 11.1.3.4. For Method 3 structures, the loads on each individual phase
attachment point in a set are averaged before they are applied to the structure. This averaging,
which is only needed when there are more than one phase per set, is necessary due to the
restriction that the loads on each phase of a set of a Method 3 structure should be identical.
If you want to export the loading trees as standard load files usable by our PLS-POLE or
TOWER programs, use Structures/ Loads/ Write LCA file or Structures/ Loads/ Write LIC
file.
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11.1.3
Strength Checking
The Structures/ Check function
is used to check a structure
strength and insulator swing
adequacies. Immediately after
clicking on the desired structure
Fig. 11.1-4 Strength Check Box
you get the short diagnostics of
the Structure Check dialog (Fig. 11.1-4). For example, the data in Fig. 11.1-4 indicate that, for
its actual position in the line, the checked structure has its strength used at 93.0 percent of its
capacity and its insulator swings are exceeded. Clicking on the Report button takes you to the
more detailed reports of Sections 11.1.3.1 to 11.1.3.4 and clicking on the Edit button lets you
edit the structure file as described in Appendix F. Clicking on the Previous or Next buttons lets
you check the previous or next structure in the line.
As explained in Section 8.3, the strength of a structure can be checked with any one of four
different methods. The method to be used, together with the necessary structure data, is
specified in the structure file. Checking the strength of a Method 1, 2 or 3 structure is almost
instantaneous. With Method 4, PLS-CADD transfers control to one of our Structure programs
and waits for the results of the analysis. This may take a few seconds. The strength usage
report depends on the method used to model the structure.
11.1.3.1
Strength Check Report for Method 1 Structures
If you check Structure # 8 in the Demo line you will get the results shown in Fig. 11.1-4 and the
report shown in Fig. 11.1-5. The percent of strength used, 93.0 percent, is controlled by the
actual wind span, 1116.1 ft, being 93.0 percent of the allowable wind span of 1200 ft. The actual
weight spans for the three specified load cases (906, 898 and 988 ft, respectively) are smaller
than their allowable values (1500, 1600 and 1400 ft, respectively) by larger margins and
therefore do not control the percent of strength used.
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Fig. 11.1-5 Strength Check Report For Method 1 Structure
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11.1.3.2
Strength Check Report for Method 2 structures
Fig. 11.1-6 shows a typical strength check report for a Method 2 structure.
Fig. 11.1-6 Strength Check Report for Method 2 Structures
11.1.3.3
Strength Check Report for Method 3 Structures
We do not show a strength check report for Method 3 structures because: 1) there has been
very little use of Method 3 structures in the past, 2) we no longer recommend their use and will
probably stop supporting them in the future, and 3) there is now some incompatibility between
the new ability of PLS-CADD to assign strength reduction factors by component type (steel
member, wood pole, concrete pole, foundation, etc.) and the lack of type information attached to
each critical component in a model.
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11.1.3.4
Strength Check Report for Method 4 Structures
If you check a Method 4 structure, PLS-CADD determines the cable tensions, calculates the
design loads, selects the strength factors and passes them to the PLS-POLE or TOWER
program. These programs perform the analysis and design checks, and return the results to
PLS-CADD. Within the Structure Check dialog box you have the option of Standard, Summary,
Analysis, Geometry or Pole Overview, see figure 11.1-7. For example, checking Structure #9 in
the Demo line and selecting both the Analysis report and the Geometry window lets you look
at both as shown in Fig. 11.1-8.
Fig. 11.1-7
The Standard report includes reports for analysis that are just done within PLS-CADD like swing
and load angle reports and uplift reports. The Summary report includes a summarized version of
the output from the structural application. The Analysis report includes all input data and
detailed analysis results from the structural application. The Geometry window includes the
deflected configurations of the structure for any selected load case as well as the percent
strength utilization of its individual components. The Pole Overview report is only available in
PLS-CADD/Distribution and produces a formatted report that provides basic information on the
structure, structural usages of various components and graphical representation of the report.
Fig. 11.1-8 Strength Check Report and Geometry for Method 4 Pole
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11.1.4
Leg Extensions and Guy Lengths in Sloping Terrain
If you have a TIN model and a Method 4 structure, PLS-CADD is able to locate the intersection
point of your tower legs or your structure guys with the ground, assuming that these legs or
guys can be extended indefinitely along their original slopes in the structure model. It uses that
information to report the needed leg extensions and reveals as well as guy lengths. In addition,
the 3-D view will show the extensions and reveals as red and blue markers (see Fig. 11.1-10).
To clear the markers, you will need to use the View/ Markers/ Clear Markers command (F5).
The function is available from Terrain/ TIN/ Leg and Guy Extension Report which will open
the Leg Extensions and Guy Lengths dialog box of Fig. 11.1-9. Data in that box are:
Fig. 11.1-9 Leg Extensions and Guy Lengths
Start & End: Structure numbers at which you want to start and stop the reporting
Include Guys or Legs/Poles: Check this to include them in report
Min. (Max.) reveals: The program will display an error message if reveal is less than minimum or
larger than maximum value. Reveal is defined as the vertical distance between the TIN
and the lower end of a leg or guy member in your model, measured at the X-Y
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coordinates of that member end. Reveals are shown as blue lines in the 3-D view and
are positive if the ground is below the end of the leg or guy.
Min. (Max.) slope intersect length: An error message will be displayed if slope intersect length is
less than minimum or larger than maximum. For a latticed tower member, this is the
original length of the member plus the length to its intersection with the TIN. For a guy, it
is the total guy length needed to intersect the TIN.
For each leg or guy member, the program will generate a line in the report indicating the
X,Y and Z coordinates of the ground below the lower end of the member or guy, and the
coordinates where that member or guy would intersect the ground if it were extended to
infinity. The report also contains the lengths of the reveals, as well as original, additional
and total lengths of members and guys.
Fig. 11.1-10 shows the leg extensions and reveals for Structure #5 of the Demo line after
it has been temporarily raised 15 ft (to be significantly above the ground) for the data in
Fig. 11.1-9.
Max allowable difference…: An error message will be displayed the difference from the slope
intersect length and current member length exceeds this distance.
Fig. 11.1-10 Leg Extensions and Reveals
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11.2
Tension Sections
11.2.1 Sags and Tensions
Fig. 11.2-1a Level 1 Tension Calculations for Selected Section
The Sections/ Sag-tension function lets you select a tension section (or an individual cable
element) and determines its mechanical tension for any combination of weather and cable
conditions. It also gives you the sag in the corresponding ruling span (Level 1) or in any
individual cable element (Levels 2, 3 or 4). You get instant tension calculations in the Sag
Tension dialog box after picking a Weather case and a Cable condition.
If you select Initial RS, Creep RS or Load RS as the cable condition (Level 1 modeling), the
Sag Tension dialog box will display sags and horizontal tensions for the ruling span of the
selected tension section as shown in Fig. 11.2-1a for the lowest right phase at the end of the
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Demo line. If you select Initial FE, Creep FE or Load FE (Level 2, 3 or 4 modeling), the dialog
box will display sags and tensions calculated by finite element for the single selected cable as
shown in Fig. 11.2-1b
Fig. 11.2-1b Level 2, 3, or 4 Tension Calculation for Single Cable
Click on the Previous or Next button in the Sag Tension dialog to cycle through the tension
sections (Level 1) or the individual cable elements (Level 2, 3 or 4) crossing the vertical line
where you clicked the mouse. In Fig. 11.2-1a, the tension section for which the Level 1
calculations are made (the lowest cable over 4 spans) is emphasized. The maximum tension
reported is the largest over the ends of all actual spans in the tension section if you select
"using actual geometry of the tension section" in the Criteria/ Maximum tension dialog box
(Section 7.3.8). In Fig. 11.2-1b, the individual cable element for which the Level 2, 3 or 4
tension calculations are made (lowest cable in third span to the right of highest structure) is
emphasized.
Click on Report to get a full sag-tension report for all the weather cases which you have defined
under Criteria/ Weather. With Level 1 modeling you will get the compact report shown in Fig.
11.2-2. With Level 2, 3 or 4 modeling, you will get a more complex report as discussed in
Section N.6.
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Fig. 11.2-2 Level 1 Sag-tension Report for Selected Section
The first part of the Level 1 sag-tension report gives the tensions and ruling span sags for each
weather case and each cable condition (Initial RS, after Creep RS and after Load RS. The
second part shows how each tension is shared between the outer strands (aluminum in the
case of an ACSR conductor.) and the core strands (steel in an ACSR conductor). In some
cases at very high temperature, you will be able to see that the outer aluminum strands have
zero tension in them (if you do not allow compression in the aluminum) or go into compression if
you allow it (see Section 7.3.5). In general, the higher the temperature, the higher the fraction of
the total tension is carried by the core.
With Level 1, Sections/ Sag-tension only calculates the sag in the ruling span of the selected
tension section. However, sags can be obtained span by span for various conditions of
temperatures and cable conditions by using the Sections/ Stringing charts function described
in Section 11.2.4.
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11.2.2 Design Limits Checking
Fig. 11.2-3 Design Check for Selected Section in Fig. 11.2-1a
The Sections/ Check function lets you select a tension section and check the design
requirements specified under Criteria/ Cable Tensions. Lines with violations are shown in red
with a NG (Not Good) at the end of the line.
11.2.3 Clearances
11.2.3.1
Clearances from Survey Points to Phases
The functions under Sections/ Clearances/ To
Ground displays a vertical line at the location
of the mouse cursor and interactively displays
the minimum or the vertical distance from the
ground to the phase closest to the cursor. The
distance is shown in the lower status bar.
The function Terrain/ Clearance lets you click
on a terrain or obstacle point to determine the
vertical and horizontal or radial distances from
the point to all nearby phases. Excess
clearances, i.e. differences between actual
distances and minimum required from the
Feature Codes table (see Section 6.1), are
first calculated. Then their minimum values are
shown in the Terrain Clearance dialog (Fig.
11.2-4a). Clearances are calculated for each of
the conditions described in Criteria/ Survey
Point Clearances or Danger Tree Locator
(Section 7.3.13). For any condition that
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includes wind, the calculations are done for wind from left and wind from right or a continuous
range of wind values can be used if selected in the Criteria/ Survey Point Clearances or
Danger Tree Locator dialog box. Clearance violations are reported when the wires are too
close to the survey point as described in Section 6.1.1.
Rather than checking an individual survey point, you can ask a complete clearance check for all
or a subset of your survey points by using Lines/ Reports/ Survey Point Clearances. There
are three tabs within the Survey Point Clearance Report dialog that define parameters for the
survey point clearance report. See figures Fig. 11.2-4b, Fig. 11.2-4b1, and Fig. 11.2-4b2. The
parameters of this report are described below.
Fig. 11.2-4b Survey Point Clearance Report – Points and Clearances tab
Points to be Considered
Filter of feature codes to be considered for clearance. You
can select which feature codes to check for clearance and
which to exclude from the clearance check.
Horizontal distance from wire
An input to define the horizontal distance from wire to limit the
beyond which survey points and check of points outside this distance from the wire.
centerline points should be
ignored
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Station interval for clearance
check for interpolated points on
centerline ground
Station and offset interval at
which to check clearance to TIN
Maximum offset from wire for
checking clearance to TIN
Wind, Ice and Required
Clearance Options
Type of Clearance Requirement
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An input to define the station interval for survey point
clearance check to the centerline ground. If set to zero the
survey point clearance report will not analyze interpolated
points on centerline.
An input to define the station and offset interval to use to
interpolate ground beneath the wire using the TIN. If set to
zero the survey point clearance report will not check
clearances to TIN beneath the wires.
An input to define the maximum offset to use to check
clearances between the TIN and wire. If set to zero the
survey point clearance report will only check clearances to
TIN in the plane directly below the wire.
Gives you access to edit the Criteria/ Survey Point
Clearances and Danger Tree Locator dialog box, the
feature code table, and the Terrain/ Feature Code Data/
Feature Code for Ground Clearance and Interpolated TIN
Points dialog box. You can also choose to add an optional
concentrated load or ice to the span under consideration.
Option to choose a radial or rectangular clearance check for
the survey point clearance report. If radial is selected only the
vertical required clearance distance defined within the feature
code table. Checked are checked in a radial distance around
the survey point. If rectangular is selected both the vertical
and horizontal required clearance values defined in the
feature code table are used and clearances are checked in
both a vertical and horizontal distance around the survey
points.
If the radial is selected only the Station interval for clearance
check for interpolated points on centerline ground option
within Wind, Ice and Required Clearance Options is
available. There is also an option to create a wire surface TIN
which will show the movement envelope of the conductor that
is considered in the clearance calculations. Also available is
an option to choose to outline the triangle edges of any TIN
surface violations and the triangle in the wire surface TIN. An
example of a wire surface TIN is shown below in Figure 11.24b3.
If rectangular is selected the option for the station offset and
interval to check to the TIN is available as well as the
maximum offset from the wire to check clearance to the TIN
is available within Wind, Ice and Required Clearance
Options.
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Fig. 11.2-4b1 Survey Point Clearance Report – Points and Clearances tab
Select
structures to
use
This dialog allows the user to define specific structures or a range of structures
to run the report on.
Select the
circuits to use
This dialog allows the user to define specific circuit to analyze. The circuits can
be defined within Sections/Electric/Define Circuits and Phases
Selection
summary
Summary of structures, circuits and phases that thermal rating report will
analyze.
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Fig. 11.2-4b2 Survey Point Clearance Report – Points and Clearances tab
Desired Level of Detail
Options for the output of the report. Selections include reporting on
each survey point considered, the point with the minimum vertical
clearance margin in each span, or the minimum vertical clearance
margin for each feature code in the selected span. You can also
choose whether to show results for only the controlling weather case
or show separate results for each weather case checked.
Report on violations only Option to include survey points identified as a clearance violation
only or all survey points checked
Include plan and profile
graphics in report
Type of marker to draw
at clearance violations
Option to included profile and cross section views in the survey
clearance report output. See the example shown in Fig. 11.2-4c.
Options for markers to draw at clearance violations
Clearance box markers
Options to draw markers around survey points showing the required
clearances used for the survey point clearance report.
Options to display markers showing the wire sag position for the
weather cases used in the survey point clearance report
Options to display markers on wire where survey point clearances
are checked.
Sag line markers
Point on wire markers
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Draw green "+" marker
on points where
clearance checked
Draw markers indicating
wire positions
considered
Option to display markers showing the survey points that clearances
have been checked to.
Options to display markers showing the wire position for the weather
cases defined within Criteria/Survey Point Clearance and Danger
Tree Locator…
Fig. 11.2-4b3 Wire Surface TIN
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Fig. 11.2-4c shows a
single survey point (solid
circle) identified as a
violation. Since it is a
violation,
it
will
be
displayed with red text in
reports and red circles in
graphics views. In the
simple example of the
figure, there were only two
conditions for checking
clearances in the design
criteria: a hot condition
without wind and one
condition with wind. When
wind is present, the entire
span rotates about the line
Fig. 11.2-4c Graphics Portion of Clearances Report
joining
its
attachment
points and the intersection point of that straight line with the vertical plane going through the
survey point (rotation point) is identified. The rotation point is displayed in the Cross Section
portion of Fig. 11.2-4c as the common point of the three dotted lines. In addition, the Cross
Section view shows where the wire pierces the vertical plane at the location of the survey point
for all the clearance weather cases (two points when there is wind). The lower point of the
vertical dotted line in the Cross Section view is the position of the wire for the hot condition. The
two sloping dotted lines show the blown-out longitudinal views of the wire under wind, with their
tips as the locations of the wire in the vertical plane of the survey point. Since the rectangle
drawn around the survey point represents the required clearance zone (see Section 6.1.1), Fig.
11.2-4c shows that a clearance violation exists for the wind blowing to the left, but not for the
wind blowing to the right or for the hot case.
Any graphical marker that is displayed after you ask for a clearance check can be erased with
View/ Markers/ Clear Markers.
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11.2.3.2
Clearances between Cables
There are several functions available in PLS-CADD to determine clearances between any
combination of ground wires and conductors. The functions can also be used to compare the
calculated clearances to allowable values that you have to furnish. The between-wire clearance
functions are described in this section.
11.2.3.2.1
Basic Clearance Check
For a selected span, the
function
Sections/
Clearances/Between
Sections determines the
shortest distances between all
the cables of one set under a
given combination of weather
and cable condition and all the
cables of another set (or the
same set) under the same or
a different combination of
weather and cable condition.
The default combinations of
weather and cable condition
are defined in Criteria/ Phase
Figure 11.2-5 Between-wires Clearance Box
Clearances. For example,
using the data in Fig. 11.2-5 in the Demo line will get you the shortest distances between the
middle kiwi phase loaded with the Extreme Ice weather case and the lower kiwi phase without
the ice in the span between Structures #5 and #6. The function is extremely powerful as it
computes the distances in 3-D for arbitrary weather cases, including wind conditions that blow
the cables laterally. The shortest distances between phases are printed in a report and can also
be seen next to red markers located between the pairs of points which are the closest together.
The distances are also updated in real time as you change selections in the dialog box. Blue
dotted line markers are also shown in the view showing the wire positions considered. You can
also make choices on the clearances to check between different weather cases than the
Criteria/ Phase Clearances on the from and to sections or use the currently displayed wire
positions or the user can select the option to use a ***Straight Line Wire*** instead of a weather
case which will model the cable as a straight line interpolation of the cable between the
attachment points. You can also choose to blow wind in different directions for each of the
cables or check wind from both directions in the wind direction section. If you wish to consider
opposite wind direction with the loop check you can check that option in the dialog box. If the
cables are displayed for the same combinations of weather and cable conditions as those used
for the clearances calculation, the marker ends will terminate on the displayed cables. Use
View/ Markers/ Clear Markers to remove the markers.
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How to check clearance to a crossing line
The function Sections/ Clearances can also be used to check distances between cables of
crossing lines for any combinations of weather cases and cable conditions. This is best
described by referring to the crossing of the KIWI wires between Structures #4 and #5 of the
Demo line and the distribution wire between the points labeled "Distribution Attachment" (see
Fig. 11.2-6). That crossing span was modeled with the following steps:
1) Create a dummy dead-end structure with only one set and one phase at the top of the
structure (Structure "attachment" in Demo line). Give it an artificial height, say 0 ft, and a
fictitious strength, say allowable wind and weight spans = 100,000 ft.
Fig. 11.2-6 Crossing Span Created in Demo Line
2) Locate one dummy
structure on each side of the
line with its top at the
location of the left and right
attachment of the crossing
wire. Use Structures/Add/
Along Alignment, click
close to the desired station,
Fig. 11.2-7 Locating Dummy Crossing Structure
make sure that you are not
connecting the dummy structures to the wires above them and type-in the required station,
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height adjustment and offset adjustment to match the support point (see Fig. 11.2-7). If you
have survey points at the structure locations you can use the Structures/Move/On Snap...
command to snap the top of your dummy structures to the surveyed points.
3) String and sag the crossing wire between the two dummy structures. This will create another
tension section between the two original structures. If there is a surveyed point on the crossing
cable, use Graphical Sag (see Section 10.3.2.4) to snap the cable to that point.
4) Then you can use the function Sections/ Clearances/Between Sections to check the
clearance between the crossing wires. This was done for the example in Fig. 11.2-6 by clicking
in the profile view between the two distribution poles and selecting the wires and conditions for
which the clearance is desired in the Section Clearances box (see inset inside Fig. 11.2-6).
When you are done, you will see the minimum clearance markers.
If instead of a single wire, you wish to check the crossing of a multiple cable span, your dummy
structures should include the necessary number of sets and phases.
You cannot use the above procedure if the crossing line is exactly perpendicular to the
alignment of the original line because the vertical axes of the two dummy structures would be at
exactly the same station. However, you can create dummy structures with offset attachment
points to get around this problem.
11.2.3.2.2
Multiple Spans Clearance Checks
If you need to systematically check multiple clearances between wires you will get many options
by going to the Wire Clearances dialog box (see Fig. 11.2-8) with Lines/ Reports/ Wire
Clearances.
The multiple clearance checks will be made for all combinations of designated source wires and
target wires between the Start Structure and the End Structure. The clearance checks will be
made using either 3D (radial) clearances or 2D horizontal clearances in the horizontal plane
depending on the selection in the Measure clearances pull down menu. The horizontal
clearances can be useful if checking blowout conditions between wires and you only wish to
check the horizontal clearances. This clearance check takes into account the diameter of each
of the conductors.
A designated source wire is any wire which has the Voltage selected in the Source Wire portion
of the Wire Clearances dialog box. The clearance calculations will be performed for the
positions of the source wires under the selected Weather Case, cable Condition and Wind
direction. A ***Straight Line Wire*** option can also be selected in the weather case selection
for the wires which will give a straight line interpolation between attachment points of a wire for
the clearance calculation.
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A designated target wire is any wire which has the Voltage selected in the Target Wire portion
of the Wire Clearances dialog. The clearance calculations will be performed for the positions of
the target wires under the selected Weather Case, cable Condition and Wind direction.
The required clearances for the voltages selected are entered in the Required Separation
portion of the Wire Clearances dialog. If actual calculated clearances are less than the required
values, the information will be flagged in red in the optional report or as a marker in the profile
and 3-D views.
The NESC 2002 Rule 235B (US rule), RTE (French rule), ESAA C(b)1-2003, AS/NZS
7000:2010, CEI EN 50341-3-13:2005, ISEC-NCR-83 Increases in Required Separation due to
Asynchronous Wind are optional sag-dependent increases in required clearances meant to
account for the lack of complete synchronization
between the blown-out positions of various wires under
wind.
Several Output Options are available at the bottom of
the Wire Clearances dialog box.
If you select Draw markers along source wires, all
source wires will be drawn for their selected combination
of weather case, cable condition and wind direction,
independently of whatever display condition you have
selected in the Sections/ Display Options. For
example, the thicker of the two positions of each wire in
Fig. 11.2-9 represent the assumed highest positions of
the wires during their dynamic motion caused by a
sudden drop of the ice imposed in the weather case. The
selected wire positions are treated as markers which,
like all other markers, can be cleared with View/
Markers/ Clear Markers.
If you select Consider Ice Jumping in the Source Wire
portion of the Wire Clearances dialog the assumed
position of any source wire from which the clearance
calculations are made is determined as follows. Each Fig. 11.2-8 Wire Clearances Dialog
wire point in the jumped-up position is determined from
Box
its position when the entire span is iced by symmetry
about the point's static position at the same temperature when there is no ice, i.e. with a sudden
ice drop from the entire span the wire jumps above its un-iced condition by the amount that the
ice sagged it down below its un-iced location. This is a conservative assumption and serves to
establish an envelope of possible conductor positions.
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Fig. 11.2-9 shows clearance markers and cables for the data in Fig. 11.2-8 in a circuit modeled
as one set with three phases. The thick lines (markers) represent the upper positions of the
source wires after ice dropping. The thin lines represent the target wires (same wires still under
ice). The two markers in mid span show the shortest clearances between source and target
wires to which a code requirement may apply.
Fig. 11.2-9 Conductor Jumping Clearance after Ice Drop
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11.2.3.2.3
Clearances between Galloping Ellipses
One of the methods
used to determine
clearances between
galloping cables is to
draw
galloping
ellipses.
Galloping
ellipses
are
approximate
envelopes of the
motion of the cables
under
galloping
conditions.
The
function Sections/
Clearances/
Galloping Ellipses
can be used to
select a span and
draw
single
or
double
loop
Fig. 11.2-10 Galloping Ellipses
galloping
ellipses
according to the procedures of the REA Bulletin 1724E-200, Cigre Report 322, or AESO Section
502.2 Bulk Transmission Line Technical Requirements (see Section 7.3.16). It can also be used
to calculate the shortest distances between any pair of ellipses. If the structure file of the
structure at the beginning of the galloping span includes detailed geometric information, then
the structure and the ellipses are drawn at scale on top of each other as shown in Fig. 11.2-10.
The ellipses are drawn for the combinations of weather cases and cable conditions specified
under Criteria/ Galloping. Fig. 11.2-10 shows galloping ellipses in the span to the right of
Structure #4 in the Demo line. It also show a portion of the galloping report (Ignore the parasitic
information coming from the crossing span).
11.2.3.3
Clearance between Wires and Structures - Departure Angles
You can make clearance checks between the energized portion of the wire system and the
models of supporting structures with Lines/ Reports/ Structure Clearances. This function only
works if your structures are modeled with our PLS-POLE or TOWER programs (Method 4
structures). The clearance checks will only be made for the display condition selected under
Sections/ Display Options and for the range of structures and the parameters described in the
Structure to Wire Clearances dialog box shown in Fig. 11.2-11 (note that the Jumper Sag
option is only available if you select “Enable Clearance to Jumper” in the menu Custom Under
Development/ RTE which is available after you press the F1 key while in the Profile view).
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PLS-CADD will identify all the voltages of all
circuits present in your model. In the Structure to
Wire Clearances dialog box, you will have to
enter the required clearances for these voltages.
Depending on the selected Output Options, you
will be able to see the shortest distances between
the wires (or bundles if you enter a Bundle
Diameter) and structures as shown for latticed
towers in Fig. 11.2-13. Distances smaller than
your Required Distances will be shown in red. For
steel poles and frames, the clearance calculations
will be correctly made to the face of the poles or
other components. Clearance calculations also
consider the face of the tower members and their
shape and orientation. For guyed structures, the
clearances between the wires and the guys can
also be calculated and also be reduced in the
sections that contain a Guy Strain Insulator by
Fig. 11.2-11 Structure to Wires Clearance
the factor entered in the dialog box. Clearance
to fictitious members in a TOWER model are not considered in these calculations.
PLS-POLE and TOWER models
let you define optional energized
zones for strain insulators in those
insulator libraries (This feature is
not available in all versions of
these programs). These zones
are defined by cylinders of
diameter CD and length CL as
shown in Fig. 11.2-12. The
energized cylinders have semispherical ends as shown. The
distances A-C and B-D are the
strain insulator lengths. In addition
to the energized cylinders, you
C ' AND D ' ARE DISPLACED
POSITIONS OF POINTS C AND D
BD
UNDER SPECIFIED WEATHER CASE
CL
D
CD
B
ENERGIZED
E
CYLINDER WITH
C' - D'
A
SPHERICAL ENDS
JS
JS
JD
C
BD
F
JA
F'
VIEW IN PLANE PERPENDICULAR
TO LINE C ' - D '
can define the dimensions of an
Fig. 11.2-12 Strain Insulators and Jumper Properties
energized
jumper
attached
between the ends of the strain insulators. In order to define the jumper, the strain insulator must
have an energized zone defined in the insulator library for the strain insulator being used. The
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jumper has the same diameter JD as the optional Bundle Diameter BD which you enter in the
Structure to Wire Clearances dialog box of Fig. 11.2-11. The jumper mid span sag JS is also
defined in the Structure to Wire Clearances dialog. With the optional strain insulators and
jumper dimensions you will get three clearance checks at dead end connections: 1) the shortest
distances from the wires (bundles) to the structure, 2) the shortest distances from the energized
cylinders to the structure, and 3) the shortest distance from the jumper to the structure. This is
shown on the left pane of Fig. 11.2-13. The jumper is assumed to swing with an angle JA (see
Fig. 11.2-12) which is the average of the swing angles of the spans to which it is connected for
the displayed weather case. Jumpers are not manually input, but are assumed to exist between
any pair of strain insulators that: 1) are part of the same set and phase, 2) are located at the
same elevation and offset from the structure (for example strain insulators attached to corners
of box arm in latticed tower), or 3) are attached to the same point on the structure.
Fig. 11.2-13 Clearances for Data in Fig. 11.2-11
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11.2.3.3.1
Departure Angles
Fig. 11.2-14 defines the departure angles that can be calculated using the command Lines/
Reports/ Blowout and Departure Angle Report. You can compare the calculated departure
angles to design limits that you should not exceed based on the geometry of your hardware.
HAB and HAA are the horizontal departure angles in the back and ahead spans, respectively.
VAB and VAA are the vertical departure angles.
The reported Wire Angle Turned is equal to 180 degrees minus the angle CA in Fig. 11.2-14.
F
B , C , E , F , AND S ARE IN
SAME HORIZONTAL PLANE
S
HAA
E
VAA
HAB
CA
C
VAB
B
D
CA
( 180 DEG. - WIRE ANGLE TURNED )
A
Fig. 11.2-14 Departure Angles
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11.2.3.4
Clearance to TIN and Isoclearance Contours
One of the most powerful functions of PLS-CADD is its ability to find the shortest distance
between any cable (for any combination of weather case and cable condition) and the surface of
a TIN model. For example, marching along the lowest phase of the left circuit in the line of Fig.
11.2-15a, we might be interested in the shortest distance between that phase under some
blowout wind and the ground. These shortest distances have been found by the program and
are indicated at each 5 ft interval along the phase by lines connecting the phase to the ground.
A continuous line is drawn on the ground to indicate where 3-D clearances are minimum. There
is an option to show the actual distances next to each inclined line, but it was not used in Fig.
11.2-15a to reduce clutter. The example shows that in windy situations with side hills, critical
clearances to ground can be oblique rather than vertical.
The clearance to side hills problem is solved by using the clearance function which you reach
with Terrain/ TIN/ Clearance to TIN. You are taken to the Clearance to TIN dialog box of Fig.
11.2-15b
where
you
can
chose
among
combinations
of
options
Fig. 11.2-15a Clearance to TIN Model
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Another way to display the
clearances from a TIN
model to the wires is to use
the
Terrain/
TIN/
Isoclearance Lines/Create
Clearance TIN function.
This function creates a
separate TIN model where
the Z coordinate now
represents the shortest
distance between points on
the original TIN and the
nearest wire. While the
Original TIN represents the
ground surface (based on
X, Y & Z coordinates
survey
points),
the
Clearance TIN uses the X
& Y coordinates of the
Original TIN, but the Z
coordinate now represents
the shortest distance to the
wires.
The distance
reflected in the clearance
Fig. 11.2-15b Clearance to TIN Dialog Box
check can be either a vertical
clearance, radial clearance in plane perpendicular to the chord of the wire attachments, or
minimum radial clearance in any direction. This and other options for the Create Clearance TIN
function are described in its dialog box.
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Once you have created a Clearance
TIN, you can display with the same
options as the Original TIN with Terrain/
TIN/Isoclearance Lines/ Clearance TIN
Display Options. If you elect to show
contour lines, these will actually be
isoclearance lines as shown in Fig.
11.2.16a. Each contour line corresponds
to terrain points that have a given
minimum distance to the closest wire.
Fig. 11.2-16a Isoclearance Contours
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11.2.4
Construction Stringing Charts
The sag, tension, return wave time or catenary constant numbers can be used by construction
crews to match the condition of a tension section in the field to that assumed in the design
calculations. The function Sections/ Stringing Chart/ Single Section or Sections/ Stringing
Chart/ Multiple Sections lets you select a span or section range for which stringing sags,
tensions, catenary constants or return wave times can be calculated for a given range of
temperatures and a given cable condition. See figure 11.2-17 and figure 11.2-17a for the
stringing chart dialog tabs and descriptions of the parameters are listed in the table below.
Fig. 11.2-17 Stringing Chart Dialog – Stringing Data tab
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Fig. 11.2-17a Stringing Chart Dialog – Structures and Circuits tab
Option to use actual span geometry from the PLSCADD model. If this option is
selected then the stringing summary report will output data based on spans within
the PLSCADD model. If this option is not checked then the user will be asked to
manually input span length range and span length increment to report on.
Span Range Menu to select what sets to include within the report. The set selection list is still
available to support projects which are not using circuit labels. If you are using
circuit labels, it is best to leave all sets selected in this list. Any set not selected
will not be included in the report regardless of the circuit label assigned and the
circuit selections.
Input for lowest temperature to report on within the summary report
Temperature Input for highest temperature to report on within the summary report
Range
Input on increment to use to report values between lowest and highest temperate
within the summary report
Condition drop down menu lets the user select the cable condition to use for the
stringing summary report.
Option to include mid-span sag into the stringing summary report. Sag values are
mid-span sags as defined in Fig. J-1.
Option to include horizontal tensions into the stringing summary report.
Results
Option to include catenary constants into the stringing summary report.
Option to include return wave times into the stringing summary report. An input
for the number of return waves is required if this option is selected.
Option to included concentrated loads into the stringing summary.
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Select
structures to
use
Option to String Bare Messenger Wire will enable PLSCADD to calculate the
tensions of a bare messenger wire prior to installation of a messenger wire. If this
option is selected the user will be prompted for the weight of the supported wires
that is to be added after stringing.
Option to display the sag results of the stringing summary report in "ft-in" format.
The default value used for sags in the stringing summary report is decimal feet.
Option to create an exportable summary of stringing chart. This option will create
a Stringing Chart Summary for all sections selected within the stringing chart
dialog that can be exported to table or XML format.
This dialog allows the user to define specific structures or a range of structures to
include in the report. Instead of selecting a range of structures to determine which
sections are included in the report, you now can select any number of structures
(they no longer have to be a contiguous range). Any section which includes a
span which has one of the selected structures as its back structure and also has
a circuit label assigned that is selected will be included in the report.
Select the
circuits to
use
This dialog allows the user to define specific circuits to be included within the
report. The first option in the circuit label list is “Unassigned”. Use this option to
include all sections which have no circuit label assigned to them, or deselect it if
you do not want to include sections which do not have circuit labels assigned.
Select the
phases to
use
This menu allows for the selections of electrical phases to include into the report.
The phases are defined within Sections/Electric/Define Circuits and Phases
Selection
summary
Summary of structures, circuits and phases that will be included within the report.
Fig.
11.2-18
shows
the
stringing chart report for
section 1 from the selected
section in Fig. 11.2-1a given
the parameters in Fig. 11.2-17.
Fig. 11.2-18 Stringing Chart for Single Tension Section
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11.2.5
Construction Offsets
PLS-CADD can perform calculations of insulator offsets and sag corrections needed for the
installation of cables in hilly terrains. These calculations are based on the "Long Form" method
described by Winkelman (Winkelman, 1959). This is an approximate method commonly used in
North America. It is based on the assumptions that parabolic shapes are sufficiently accurate to
describe suspended cables and that the cables behave elastically during construction. For
installation in very rough terrains, more exact computer methods (McDonald and Peyrot, 1990)
should be used.
When supports are not at the same elevation, a conductor hanging in stringing sheaves ("in
sheaves") tends to run downhill from the high spans into the low spans as shown in Fig. 11.219. In such stringing situations the conductor horizontal component of tension is higher in the
higher spans (for example span AB in Fig. 11.2-19) than in the lower spans (span CD).
However, when finally sagged and attached to suspension insulators, the conductor horizontal
component of tension should be approximately the same in all the spans and all insulators
should be vertically plumb for a specified design condition. This is depicted as the final
suspended ("in clips") configuration in Fig. 11.2-19.
When
PLS-CADD
determines
insulator offsets and sag corrections,
A
B
the target horizontal component of
CLAMP IS ATTACHED AT
CLIP POINT
tension H0 in the "in clip" configuration
is the initial tension computed for the
specified temperature T in the Offset
C
VERTICAL
LINE
Clipping box. That horizontal tension
S
CABLE IN SHEAVES
is the same as that reported in the
Stringing Chart report at the
AHEAD SPAN
FINAL SUSPENDED
CONFIGURATION
temperature T. For the temperature T,
D
the program determines the different
OFFSET
"in sheave" and "in clip" sags. It also
locates the points on the conductors
where the insulators should be
attached or clipped-in. "In sheave" Fig. 11.2-19 Stringing and Final Conductor Configuration
(or corrected) sags are those used
during stringing. They are equal to "in clip" stringing chart sags plus a sag correction. For
example, in Fig. 11.2-19, the sag correction in span AB should clearly be a negative quantity,
while that in span CD should be positive.
The point where the lower end of a suspension insulator is attached to the conductor is defined
as a clip point shown as a black dot in Fig. 11.2-19. The clip point location at each support is
defined by the clipping offset which is its distance from the vertical line passing through the
structure attachment point of the insulator, S. That distance is measured along the conductor
and is negative if in the direction of increasing station (in the direction of the ahead span). The
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sign convention is related to the fact that a negative clipping offset removes slack in the ahead
span.
Construction offsets and sag corrections are performed for all tension sections by clicking on the
Sections/ Offset Clipping Report menu item. Fig. 11.2-20 shows a portion of a typical offset
clipping report.
Fig. 11.2-20 Typical Offset Clipping Report
The Offset Clipping dialog box allows the user to generate reports for all sections in a structure
ranger or you can generate a report for the wire pulled through a selected range of structures.
The default structure range is from the selected section’s start and end. The structure range
can be changed to accommodate temporary snubs but selecting a sub set of the structures in a
section. The structure range may contain multiple contiguous sections provided the cable type
and tensions match across the sections.
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11.2.6 Thermal Ratings
All thermal rating calculations performed by PLS-CADD are based on the IEEE Standard 738
for Calculating the Current-Temperature Relationship of Bare Overhead Conductors (IEEE,
2006, 2013), the CIGRE Brochure 207, or CIGRE Brochure 601. You should refer to these
documents for all underlying assumptions. Thermal rating calculations let you determine steadystate or transient relationships between conductor temperature and electrical current based on
ambient weather. These calculations, coupled with PLS-CADD's ability to display and check line
clearances at various temperatures, provide you with all the necessary tools to rate your lines.
Thermal rating calculations are accessed through the Sections/ Thermal Calculations IEEE
738 - CIGRE Brochure 207 .. menus.
Prior to asking for any rating calculation, you should make sure that the conductors that you will
run rating calculations for have thermal properties defined in the Physical and Electrical Tabs of
the Cable Data dialog box (see Fig. 9.2-1 in Section 9.2). You will need a copy of the IEEE
Standard and possibly other references to get the necessary data. Please note that the current
values in the thermal calculators are based on a single wire and not a bundled phase
configuration so proper reduction of the current per phase should be done based on the bundle
configuration.
We are constantly improving PLS-CADD as well as our other programs, and we are involved
with several organizations in the joint development of products which link to PLS-CADD. You
should visit our web site for news regarding these developments.
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11.2.6.1
Temperature
relationship
Steady-state Thermal Rating
vs.
current
For given conductor properties and
ambient weather conditions (Fig. 11.221), you can: 1) determine the
conductor temperature for a given
electric current, 2) determine the
current that causes a given conductor
temperature, or 3) display the
relationship between the two (Fig.
11.2-22). If you know the maximum
temperature that a conductor can
have before violating some vertical
clearance requirements in a span,
these calculations let you determine
the maximum current that the limiting
conductor can carry. Finding the
maximum
temperature
that
a
conductor can have in a particular span
is automated in PLS-CADD as described next.
Fig. 11.2-21 Weather Properties
Fig. 11.2-22 Conductor Temperature vs. Current
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Maximum allowed conductor temperature in span
You can use Lines/ Reports/ Thermal Rating Report to determine the maximum temperature
that all conductors can have in a span. The maximum temperature is that for which the vertical
required clearance under a wire just becomes insufficient. That vertical clearance is that to the
TIN model of the ground, if such a TIN is available, and/or to surveyed points within a certain
horizontal offset of the wires. You will be taken first to the Thermal Rating Report dialog box
shown in Fig. 11.2-23 and Fig. 11.2-23a where you are presented with report parameters in
both the Thermal Rating Options and Structures and Circuits tabs.
Fig. 11.2-23 Thermal Rating Report Dialog Box – Thermal Rating Options Tab
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Options
Set and
Temperature
Range
Feature Codes
for Survey Point
Checks
Option to include vertical clearances to survey points. The vertical clearances
are defined in the feature code table. If this option is not selected the report
will not check clearances to survey points.
Option to check vertical clearances to TIN. If this option is not selected the
report will not check clearances to the ground surface.
Option to draw markers at locations that control rating. This draws a red
marker listing the maximum conductor temperature per span displayed at the
controlling station.
Option to draw markers at locations where clearances are checked.
Option to erase markers before running the report.
Option to save rated temperature in a structure comment for use elsewhere.
The Condition drop down menu allows the user to select the cable condition
to use for the report.
Option to select desired attachment sets to include in the report.
Option to Select desired attachment phases to include in the report.
Input to set the minimum wire temperature for the spans being analyzed.
Input to set the maximum wire temperature for the spans being analyzed.
Select from a list the feature codes that clearances should be used to
determine the maximum temperature rating and reported within the Thermal
Rating report.
Input for the maximum offset for survey points and TIN model. This is the
maximum offset from the wire for survey points and TIN model to be included
within the report
Input for maximum offset from wire for ground points to be included in profile
below wire. This is used then the program is unable to determine the ground
elevation below a wire from the TIN model.
Input for maximum length of line segment for inclusion in the profile below the
wire. A maximum segment length field is used to prevent interpolation
between survey points which are too far apart.
Display of Cross
Section and
Options to display cross section and profile graphics and thermal rating
Profile Images report.
in Report
Option to sort and display results per span displayed in the Thermal Rating
Sort Results by
Summary report by maximum wire temperature or critical station.
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Fig. 11.2-23a Thermal Rating Report Dialog Box – Structure and Circuits Tab
Select
structures to
use
This dialog allows the user to define specific structures or a range of structures
to run the report on.
Select the
circuits to use
This dialog allows the user to define specific circuit to analyze.
Select the
phases to use
This menu allows for the selections of electrical phases to include into the
report. The phases are defined within Sections/Electric/Define Circuits and
Phases
Selection
summary
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Summary of structures, circuits and phases that thermal rating report will
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Fig. 11.2-24 Thermal Rating Marker for Selected Span
The maximum temperature is that for which the vertical required clearance under a wire just
becomes insufficient. That vertical clearance is that to the TIN model of the ground, if such a
TIN is available, and/or to surveyed points within a certain horizontal offset of the wires. If a TIN
is not available, the program generates internally a ground profile under each wire by
connecting points in a manner similar to that used for generating the centerline ground profile
and the side profiles as explained in Sections 6.3.2 and 6.4.4. The left part of Fig. 11.2-24
shows profiles generated under the lower phases of the left and right circuits.
The line connecting points on a TIN under a wire is colored purple. The survey points above
which the clearance is checked are colored blue. The profiles which are generated under the
wires are shown in yellow. The shortest vertical clearance to all these items is that determining
the maximum allowed conductor temperature.
Profiles generated under the wires can be removed with View/ Markers/ Clear Markers.
Maximum conductor temperatures are included in a text report and are displayed with a marker
at the controlling location as shown in the right pane of Fig. 11.2-24. If you were to display the
conductor at the exact controlling temperature, it would touch the top of the marker.
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11.2.6.2
Transient Thermal Rating
Transient conductor temperature
The change of conductor temperature following a step increase in current can be determined as
shown in Fig. 11.2-25 with Sections/ Thermal Calculations (IEEE 738 and CIGRE)/
Conductor Temp. for Current Change. For example, you could use this information to find out
how much time you would have in an emergency situation until your required clearance is
violated.
Fig. 11.2-25 Transient Temperature Following Step Current Increase
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Current step increase causing conductor temperature to reach specified level in
specified time
You can determine the electrical current step increase that will cause the conductor to reach a
specified temperature in a specified amount of time using Sections/ Thermal Calculations
(IEEE 738 – CIGRE)/ Transient Thermal or Fault Rating. An example is shown in Fig. 11.226. This is useful to determine the maximum emergency current capacity of a line.
Fig. 11.2-26 Transient Thermal Rating Report
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11.2.6.3
Batch Thermal Calculator
The Sections/ Thermal Calculations (IEEE 738 and CIGRE)/ Batch Thermal Calculator
allows you to perform multiple Steady State Conductor Temperature and Steady State Thermal
Rating Calculations at once and provides a link to import the required data from a current
design. It can also export the results back into the current design as the Display Weather Case
for the sections. Figure 11.2-26a shows the Batch Thermal Calculator table that you can fill out
manually or you can choose to import data from your project.
Figure 11.2-26a Batch Thermal Calculator
Each row in the table represents a calculation and the user can enter a description for each of
these rows and input the necessary data in the table dependent on the calculation selected by
the radio buttons in the upper left corner of the dialog box. Several of the inputs in the table
such as the day of the year and global wind direction may be the same for all of the calculations
in the table. You can select the Default Values button at the bottom of the table and nominate
values for these items. The sort table by option at the bottom of the table gives you control on
how the table is sorted.
You can import conductor data from an existing design into the table using the Import Project
Wires button at the top of the dialog box. This will bring up the Import from Project dialog box
where you can choose which voltages you wish to import as well as set some default values for
these sections.
If the project has a coordinate system defined in Terrain/ Coordinate System/ Define, you can
check the box at the top of the table and have the program calculate the wind to conductor
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angle automatically from the global wind direction and line azimuth if you use the Import Project
Wires command.
The Generate Report button will create a Batch Thermal Calculator Report that documents your
results. It will record all variables you have selected in the table for each calculation.
If you used the Import Project Wires command and performed the calculations in the table you
can choose the Save Temperature As Display Weather Case for Sections at the top of the table
that automatically takes the calculated cable temperature from the table for each section and
populates the Display Weather Case for each of the sections with this calculated temperature.
This calculated temperature for each span is also placed in the Ahead Span Surveyed Wire
Temp column of the Wire Lengths and Attachment Stiffness table. If you imported wires for
each individual span of a section, you will be prompted for what temperature you wish to export
to the model for each section as the Display Weather Case Temperature. You can choose
between the minimum, maximum, or average temperature of all the spans in the section. This
will automatically change the display of the section to the selected option. If you want to display
each of the spans with their as-surveyed temperature then you can select the option ***
Surveyed Wire Temp *** for the Display Weather Case.
The Cable Steady-State Current input for the table is for the individual wire based on the cable
file. It is not for the bundled phase so the engineer would need to decide how to split the
amperage on a phase for input in the table for the wire.
The use of CIGRE Brochure 207 requires strand and core material information when calculating
some results. The use of CIGRE Brochure 601 requires the radial thermal conductivity property
in the cable file.
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11.2.7 Conductor Loss of Strength at High Temperature
When operated at very high temperatures (say above 90 degrees Celsius for aluminum
conductors), conductors may lose strength. This is discussed in the IEEE Guide for Determining
the Effects of High Temperature Operation on Conductors, Connectors, and Accessories (IEEE
1283, 2002).
11.2.8
Electro-Magnetic Field Calculations
All EMF calculations in PLS-CADD are based on the EPRI Red Book methodology (EPRI,
1982). You can use Sections/ Electric/ EMF Calculator to generate graphs of the electric and
magnetic fields for a user defined cross section of the line. The field contributions from multiple
circuits can be accounted for.
For example, use Sections/
Electric/
EMF
Calculator,
select Structure # 9 of the
Demo line and input the phase
angles and currents shown in
Fig. 11.2-27. You will generate
the electric and magnetic field
graphs shown in Fig. 11.2-28.
Fig. 11.2-27 Input Data for EMF Calculation
The vertical lines in Fig. 11.2-28 (green on the screen) show the location of the wires included in
the model. The shield wires were not included because they have zero voltage and no current
(you could manually calculate and input an induced current to have them contribute to the
magnetic field). The innermost vertical line shows the position of the top and bottom phases
while the outermost vertical line shows the location of the middle phase. In addition to the
graphs, the calculator provides an extensive report that details the input and output data as well
as the maximum field values found. The results of this report can be exported to a shapefile or
.kmz file by right clicking within the body of the report.
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The calculations are based on the methodology described in Chapter 8 of the EPRI Red Book
(EPRI , 1982). You should refer to that book for a complete list of the approximations and
assumptions used, but a short list is given here:
1) The wires are infinitely long and straight.
2) Bundles are modeled with an equivalent conductor diameter, deq = D * (nd / D) ^ 1/n where n
is the number of subconductors, d is the diameter of each subconductor and D is the bundle
diameter.
3) The effects of earth return currents (earth resistivity) are ignored when calculating the
magnetic field.
4) The ground is flat and all points reported on have the same elevation as that of centerline.
5) The earth is a perfect conductor.
6) The permittivity of air is independent of weather case and equal to the permittivity of free
space.
7) Shielding effects from structures at ground potential are ignored.
Fig. 11.2-28 Electric and Magnetic Fields in Last Span of Demo Line
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11.2.9
Clearance to Vegetation and Falling Trees (Vegetation Management)
PLS-CADD can be used to check for potential vegetation clearance problems. The procedures
are normally used in conjunction with LIDAR surveys of the right-of-way, where the global
coordinates of vegetation points and ground points have been identified. These features can be
used in support of your vegetation management program (Hooper, 2003:
http://www.powline.com/vegetation.pdf. For more information on this subject, please read the
following technical note:
http://www.powline.com/vegetation/dangertree.html
Fig. 11.2-29 shows two cross sections views of a line at the same location where the ground
surface is known in the form of a TIN model (see Section 6.4 on TIN) and three vegetation
points (A, B and C) have been located. PLS-CADD can perform Grow-In and Falling Tree
vegetation clearance checks accessible through Lines/ Reports/ Danger Tree Locator. Both
checks are performed for the weather cases described in the Criteria/ Survey Point
Clearances and Danger Tree Locator dialog. Problems are identified both graphically and in
the clearance reports.
The left part of Fig. 11.2-29
illustrates how rectangular
RV
grown-in
vegetation
C
C
W
clearance is checked. All you
W
DISPLAYED
T
DISPLAYED
need to do is assign to the
WIRE
B
B
WIRE
feature codes that represent
U
vegetation points values for
RH
the required vertical and
GROW - IN CHECK
FALLING TREE CHECK
horizontal clearances, RH
A
A
and RV. These are equal to
P-C = Q-T
R-B = S-U
the
required
electrical
Q
P
clearances plus an allowance
P-Q = R-S =
S
ROOT BALL RADIUS
R
for vegetation growth and any
additional safety margin. If
GROUND
GROUND
radial clearance is checked
SURVEYED VEGETATION POINT
then the RV value for the
Fig. 11.2-29 Vegetation and Falling Tree Clearances
feature codes selected will be
used for the grow-in clearance check. Points for which the wire falls within the rectangular box
of width 2 RH centered on the vegetation point will be flagged (see Section 6.1.1).
The right side of Fig. 11.2-29 illustrates how the clearance of a wire to a falling tree is checked.
The assumption made for each vegetation point is that it is potentially the top of a tree. PLSCADD automatically locates the base of the assumed tree on the TIN surface (P for point C and
R for point B). It further assumes that a falling tree rotates as a rigid body about the edge of its
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root ball (Q for Tree P-C and S for Tree R-B). You input the radius of the root ball and the
required clearance between the position of the wire and the circular trajectory of the top of the
falling tree. The clearance circle center (Q for Tree P-C and S for Tree R-B) is located at an
horizontal distance equal to the root ball radius from the base of the tree. Points for which the
wire is closer to its associated circle than the required clearance will be flagged.
The Danger Tree Locator dialog box is available when you go to Lines/Reports/ Danger Tree
Locator. The Danger Tree Locator dialog box has four tabs that define the parameters of the
danger tree report. The Vegetation Check tab within the Danger Tree Locator dialog is shown in
Figure 11.2-30 and defines the parameters used for the Grow-In and Falling Tree vegetation
clearance checks.
Figure 11.2-30 Danger Tree Locator – Vegetation Check
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Option to select grow-in clearance check. If the option is not selected then a growin clearance check will not be performed.
Grow-In: Option to select either a radial or rectangular clearance check
Option to define the color of Grow-In clearance markers to be displayed
Option to select falling tree clearance check. If the option is not selected then a
falling tree clearance check will not be performed.
Input for the root ball radius. This parameter is defined as a percentage of the tree
height. The root ball radius defines the rotation point of the base of the tree as
shown in Fig. 11.2-29.
Clearance allowance input is the value used for falling tree clearance check. The
Falling
falling tree clearance check uses this value and does not use the clearance
Tree:
requirement from the feature code table.
Option to define color of Falling Tree clearance markers to be displayed
Input for the Maximum horizontal distance between the tree base and a ground
point for ground interpolation. This parameter is used to estimate the ground
beneath a vegetation point when the project does not have a TIN available.
The Vegetation Feature Codes button allows the user to select the vegetation
feature codes used for the clearance check
Shortcuts to the Terrain/Feature Code Data/Edit and Criteria/Survey Point
Clearances and Danger Tree Locator tables so user can check or change any of
Vegetation
these inputs.
Feature
Input for the horizontal distance from the wire beyond which points should be
Codes
ignored.
Election to include an optional concentrated load or ice to the spans under
consideration. If this option is selected then you will be prompted to choose a
concentrated load file and location of the concentrated load in the spans.
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The Structures and Circuits tab within the Danger Tree Locator dialog is shown in Figure 11.230a and allows the user to define a structure or circuits used to determine what spans to use for
the Grow-In and Falling Tree vegetation clearance checks.
Figure 11.2-30a Danger Tree Locator – Structures and Circuits tab
Select structures to use
This dialog allows the user to define specific structures or a range of
structures to run the danger tree report on
Select the circuits to use
This dialog allows the user to define specific circuit to run the
danger tree report on
Selection Summary
Displays structures and circuits selected for analysis.
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The Report and Markers tab within the Danger Tree Locator dialog is shown in Figure 11.2-30b.
This dialog box controls the output of the report.
Figure 11.2-30b Danger Tree Locator – Report and Markers tab
Select the type of report for output of the danger
tree locator. Options include No Report, Report
window, text file, XML or CSV.
Detailed point report options
For grow-in violations draw line from
offending points to wire
For falling tee violations draw line from root
ball pivot point to top of tipped tree
Draw markers indicating wire positions
considered
Draw a green "+" marker at survey points
with wire offsets that could produce
violations
Sag line markers
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Option to turn on/off markers
Option to turn on/off markers
Option to turn on/off markers
Option to include markers to be displayed for all
the weather conditions selected in
Criteria/Survey Point Clearances and Danger
Tree Locator table.
PLS-CADD – Version 16.0 © Power Line Systems, 2019
You can also choose to enable the work site feature which groups all of the xyz points that are
identified as clearance issues into one worksite based on the information input in Work tab of
the Danger Tree Locater dialog box shown in Figure 11.2-31 below.
Figure 11.2-31 Danger Tree Locator – Work Site tab
Enable work site feature
Maximum separation between points
within work site
Maximum work site size
Draw marker labeling distance from
centroid min. clear point to wire
Draw markers indicating work site
centroid and points associated with it
Draw markers indicating work site
centroid perimeter
If the option is not selected then the work site feature
will not be enabled.
Input allows the user to define the maximum separation
between points in a work site.
Input allows the user to define the maximum work site
size
Option to turn on/off markers
Option to turn on/off markers
Option to turn on/off markers
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Feature code for work site centroid
point
Z coordinate for centroid point
Veg violation TIN options
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Drop down menu to select the feature code used to
create a xyz point at the centroid location of each
worksite.
Options to assign Z value for the work site centroid. It
may be useful to create an independent worksite
feature code for this option.
Three options that allow you to create and save a veg
violation TIN which takes all of the vegetation clearance
violations and makes a surface that can be loaded or
saved in the model using the Terrain/ TIN/ Veg.
Violation/ Load or Save Veg. Violation TIN File
command. You can also use the Terrain/ TIN/ Display
Options command to render the Veg. Violation TIN
similar to a Ground TIN for viewing in the model.
Creating a Veg. Violation TIN is necessary if you want
the work site centroid report to include the area of the
work site. The last option allows you to create a
KMZ/KML or SHP file of the work site areas. The
KMZ/KML will be the actual rendered TIN while the SHP
file will show the perimeter.
PLS-CADD – Version 16.0 © Power Line Systems, 2019
11.2.10
Line Constants Calculator
The Sections/ Electric/ Line Constants Calculator will calculate the resistance, positive
sequence inductive reactance, capacitive reactance, impedance magnitude, and phase angle
for all sets with a voltage in the selected range of spans. The calculations are based on the
EPRI Red Book method (3rd Edition, 2005 – 2.4 Basic Transmission Line Impedance and
Admittance Parameters). Each set for each span is calculated independently and the effects of
ground and ground wires are ignored. PLS-CADD can also calculate zero, positive and negative
sequence values of the line impedance with the Full Line Constants Calculator, see section
11.2.11.
When first launching the command you are able to select a range of structures and the wires
with voltage greater than zero within the selected structure range will be evaluated. After
selecting the range the Line Constants Data dialog of Figure 11.2-32 will appear and you can
select the weather case and cable condition at which to evaluate the wires.
Fig. 11.2-32 Line Constants Data
The table contains the information about each of the wires in the selected range. You can
choose to include this span of wire in the calculations and if the wire is a bundled wire you can
input the bundle spacing. All other data in the table is greyed out and comes from either the
section information or the cable file.
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At the bottom of the dialog you can choose the span geometry you wish to use to calculate the
Geometric Mean Distance (GMD) of each span. You can take the wire locations as being at the
back structure attachment points, ahead structure attachment points, mid-span wire positions,
or you can average the GMD over the entire span based on the calculation occurring at the
specified increment in the dialog.
You will also want to input your frequency and Per-unit System Base to use for the calculations.
If your model is made up of a set number for each phase then you will want to check the using
separate set # for each phase option which will attempt to combine sets with the same Section
Note when calculating GMD. The Section Note can be set in the Sections/ Table or the
Sections/ Modify dialog.
Once the data has been finalized you can hit the Calculate button and the Calculated Line
Constants Data, Positive Sequence Line Constant Span Results, and Positive Sequence Line
Constant Circuit Results reports will be generated. The report will also include all of the input
data from the Line Constants Data dialog in report format as well.
11.2.11
Full Line Constants Calculator
Within PLS-CADD the function Sections/Electric/Full Line Constants Calculator... can
calculate all three symmetrical components (zero, positive and negative sequence values) of the
line impedance. The software accounts for ground wires, ground return, and mutual coupling
between circuits that share the same span. However, the software does not account for mutual
coupling of neighboring spans at this time. The Line Constants Calculator described in section
11.2.10 calculates the positive sequence and does not factor in ground returns or mutual
coupling.
When calculating line constants in PLS-CADD the software leverages the information used to
build the model such as the structure locations, attachment positions, wire positions and height
throughout all spans for specified weather cases. This means that instead of using just a single
set of wire positions per span, PLS-CADD can evaluate the wire positions relative to each other
and the ground at several points throughout each span. This provides a more accurate
representation of the separations between wires particularly for spans over uneven ground and
spans where the wire separations change significantly within the span. The full line constants
calculator can also be run at different weather cases to evaluate the possible effects of changes
in wire positions and temperatures for any specified weather case.
To utilize this function PLS-CADD will require that circuit and phase labels have been set up
within the model. See section 9.4 of the PLS-CADD manual for information on circuit labels.
Also, required for the calculations is that the cable files within the model will need the Geometric
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Mean Radius (GMR) value and AC resistance values populated within the electrical tab in the
cable file. The full line constant calculator will be run at the section display weather case
specified within the model.
Fig. 11.2-33 Line Constants Configuration
When the command Sections/Electric/Full Line Constants Calculator... is launched the Full
Line Constants Calculator dialog will open. Within this the Line Constants Configuration tab of
this dialog the user will have to define the structure range to perform the full line constant on,
circuits to evaluate and circuit labels associated with the neutral or ground wires. Several
calculation parameters will need to be defined before running the report. The spacing between
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measurements to determine average wire positions will define the interval the calculations will
be performed at. The frequency of the line in hertz will need to be defined. The Earth Resistivity
below the line will need to be completed and can vary depending on the type of ground found
below the line. The Per-unit system base is the voltamperage in MVA in the line to be used
within the calculation. A widely used base is 100MVA, but other base values can be specified by
the user.
Fig. 11.2-33a Full Line Constants Report Options
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Within the Full Line Constants Calculator dialog the report tab will allow the user to define the
output of the Line Constants Results report. The options shown in Figure 11.2-33a allow the
user to select additional information that can be selected and added to the output report.
11.2.11.1
Full Line Constant Matrix Calculations
To calculate the full line constants calculator PLS-CADD will first generate the phase impedance
matrix with grounds for every user selected span. The dimensions for this matrix are determined
by the total number of wires within the span that the user is analyzing including conductors and
ground wires. For example, on a double 3-phase circuit with two ground wires, this matrix will be
8x8. PLS-CADD will develop a matrix with terms that are calculated using Carson’s Equations
(from EPRI Redbook section 2.5.2) which take into account the relative wire positions, the wire’s
height above ground, and the mirror image wire position below ground which represents the
ground return current. The program will calculate each term at several positions along the span
and average them together to provide a more representative value of the entire span.
𝑧11
𝑣1
𝑣2
𝑧21
[ ⋮ ]=[ ⋮
𝑣𝑚
𝑧𝑚1
𝑧12
𝑧22
⋮
𝑧𝑚2
⋯
⋯
…
𝑧1𝑛
𝑖1
𝑧2𝑛
𝑖2
⋮ ]∙[ ⋮ ]
𝑧𝑚𝑛
𝑖𝑚
[𝑉𝑎𝑏𝑐 ] = [𝑍𝑎𝑏𝑐 ] ∙ [𝐼𝑎𝑏𝑐 ]
The next step is to reduce the phase impedance matrix by using Kron Reduction to factor out
each ground wire. This reduced matrix becomes the final phase impedance matrix associated
with each span. If the span contains just one circuit, that matrix is a simple 3x3 of the phase
self-impedances and mutual impedances. If the span contains two or more circuits, the matrix is
a 6x6 or larger and contains the 3x3 phase impedance matrix for each circuit plus additional 3x3
matrices for the mutual impedances between circuits.
𝑧𝑚𝑤 ⋅ 𝑧𝑤𝑛
𝑛𝑒𝑤
𝑜𝑙𝑑
𝑧𝑚𝑛
= 𝑧𝑚𝑛
−
𝑧𝑤𝑤
𝑍𝑎𝑎
𝑍𝑏𝑎
𝑍𝑐𝑎
𝑍𝑒𝑎
𝑍𝑓𝑎
𝑍
[ 𝑔𝑎
𝑍𝑎𝑏
𝑍𝑏𝑏
𝑍𝑐𝑏
𝑍𝑒𝑏
𝑍𝑓𝑏
𝑍𝑔𝑏
𝑍𝑎𝑐
𝑍𝑏𝑐
𝑍𝑐𝑐
𝑍𝑒𝑐
𝑍𝑓𝑐
𝑍𝑔𝑐
𝑍𝑎𝑒
𝑍𝑏𝑒
𝑍𝑐𝑒
𝑍𝑒𝑒
𝑍𝑓𝑒
𝑍𝑔𝑒
𝑍𝑎𝑓
𝑍𝑏𝑓
𝑍𝑐𝑓
𝑍𝑒𝑓
𝑍𝑓𝑓
𝑍𝑔𝑓
𝑍𝑎𝑔
𝑍𝑏𝑔
𝑍𝑐𝑔
[𝑍𝐶𝑘𝑡1 ]
[𝑍𝐶𝑘𝑡1 𝐶𝑘𝑡2 ] Ω
= [
] ⁄𝑚
𝑍𝑒𝑔
[𝑍𝐶𝑘𝑡2 𝐶𝑘𝑡1 ]
[𝑍𝐶𝑘𝑡2 ]
𝑍𝑓𝑔
𝑍𝑔𝑔 ]
Each 3x3 phase impedance matrix is then converted to a sequence impedance matrix using
these equations:
[𝑍012 ] = [𝐴𝑠 ]−1 ∙ [𝑍𝑎𝑏𝑐 ] ∙ [𝐴𝑠 ]
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𝑍00
[𝑍10
𝑍20
𝑍01
𝑍11
𝑍21
1 1
𝑍02
1
𝑍12 ] = [1 𝑎𝑠
3
𝑍22
1 𝑎𝑠2
1
𝑍𝑎𝑎
2
𝑎𝑠 ] ∙ [𝑍𝑏𝑎
𝑍𝑐𝑎
𝑎𝑠
𝑍𝑎𝑏
𝑍𝑏𝑏
𝑍𝑐𝑏
1
𝑍𝑎𝑐
𝑍𝑏𝑐 ] ∙ [1
𝑍𝑐𝑐
1
1
𝑎𝑠2
𝑎𝑠
1
𝑎𝑠 ] Ω⁄𝑚
𝑎𝑠2
𝑎𝑠 = −0.5 + 0.866𝑗
𝑎𝑠2 = −0.5 − 0.866𝑗
𝑎𝑠3 = 1
In the above matrix, the z00 term is the zero sequence impedance, the z11 term is the positive
sequence impedance, and the z22 term is the negative sequence impedance. The other terms
are the mutual coupling between sequences.
To determine the capacitance and susceptance, PLS-CADD must first calculate the potential
coefficient matrix with grounds. The dimensions of this matrix are the same as the phase
impedance matrix with grounds described above with a row and column for every conductor and
ground wire. Each potential coefficient is calculated as shown in these equations:
[𝑉𝑎𝑏𝑐 ] = [𝑃𝑎𝑏𝑐 ] ∙ [𝑄𝑎𝑏𝑐 ]
𝑣1
𝑝11
𝑣2
𝑝21
[ ⋮ ]=[ ⋮
𝑣𝑚
𝑝𝑚1
𝑝12
𝑝22
⋮
𝑝𝑚2
…
…
𝑝1𝑛
𝑞1
𝑝2𝑛
𝑞2
⋮ ]∙[ ⋮ ]
… 𝑝𝑚𝑛
𝑞𝑚
𝐷𝑚𝑚′
𝑊ℎ𝑒𝑛 𝑚 = 𝑛, 𝑃𝑚𝑛 = 1.7975 × 1010 ∙ ln (
) 𝑚𝑒𝑡𝑒𝑟⁄𝑓𝑎𝑟𝑎𝑑
𝑟𝑚
𝐷𝑚𝑛′
𝑊ℎ𝑒𝑛 𝑚 ≠ 𝑛, 𝑃𝑚𝑛 = 1.7975 × 1010 ∙ ln (
) 𝑚𝑒𝑡𝑒𝑟⁄𝑓𝑎𝑟𝑎𝑑
𝐷𝑚𝑛
𝑊ℎ𝑒𝑟𝑒
𝑟𝑚 = 𝑟𝑎𝑑𝑖𝑢𝑠 𝑜𝑓 𝑒𝑎𝑐ℎ 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑜𝑟
𝐷𝑚𝑛 = 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑏𝑒𝑡𝑤𝑒𝑒𝑛 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑜𝑟𝑠 𝑚 𝑎𝑛𝑑 𝑛
𝐷𝑚𝑚′ , 𝐷𝑚𝑛′ = 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑏𝑒𝑡𝑤𝑒𝑒𝑛 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑜𝑟 𝑚 𝑎𝑛𝑑 𝑖𝑚𝑎𝑔𝑒 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑜𝑟 𝑚′ 𝑜𝑟 𝑛′
As with the phase impedance matrix, the ground wire rows and columns in the potential
coefficient matrix are factored out using Kron Reduction. This results in the reduced potential
coefficient matrix with dimensions equal to the total number of conductor wires in the span.
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The potential coefficient matrix is inverted to determine the capacitance matrix. Then that matrix
is multiplied by the radial frequency to calculate the susceptance matrix.
1
[𝑉𝑎𝑏𝑐 ] =
[𝑃 ][𝐼 ]
𝑗𝜔 𝑎𝑏𝑐 𝑎𝑏𝑐
[𝐶] = [𝑃]−1
𝑐11
𝑖1
𝑐
𝑖
21
[ 2 ] = 𝑗𝜔 [ ⋮
⋮
𝑐𝑚1
𝑖𝑚
𝑐12
𝑐22
⋮
𝑐𝑚2
…
…
𝑐1𝑛
𝑣1
𝑐2𝑛
𝑣2
⋮ ]∙[ ⋮ ]
⋯ 𝑐𝑚𝑛
𝑣𝑚
𝜔 = 2𝜋𝑓
PLS-CADD knows the length of each wire in every span and can multiply either the phase or
sequence impedance rates by those lengths to get the actual span impedance for each wire.
With the circuit labels, PLS-CADD can also sum the span impedances to get the impedances
for each circuit. Using the phase labels which identify the phases regardless of which structure
attachment position is being used, any effects from transpositioning or changing phase
configuration will be accounted for. For a complete technical note on these calculations, please
see our website.
11.2.12
Lightning Protection Calculator
The Sections/ Electric/ Lightning Protection Calculator will calculate the lightning coverage
surface based on the ground wires of a line. The basis of the calculation is the Electromagnetic
Method (EGM) which is also known as the Rolling Sphere Method. You will first be prompted to
select a range of structures that you wish to evaluate and then the Rolling Sphere Input Data
dialog will appear as shown in Figure 11.2-33 below.
The calculation requires that you have TIN model of the ground surface. At the top of the dialog
you will select the weather case and cable condition you wish to evaluate the lightning
coverage. The table at the bottom includes each span in the selected range of structures.
Those spans with a voltage of 0 KV are automatically selected as Ground Wires and all spans
are included in the calculation by default. You may wish to override certain spans to not be
included in the calculation such as distribution neutral wires, crossing spans, or parallel circuits.
At the bottom of the Rolling Sphere Input dialog the user will define the lightning strike distance
for the calculation and the interval along the wire that is to be considered by the software. As
lightning flashes to earth a downward leader grows. As it approaches earth the electrical
insulating strength of air near the ground is exceeded and a similar upward leader begins to
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grow at the strike point. The lightning strike distance is the smallest distance between the head
of the downward leader and the starting point of the upward leader, see figure 11.2-35. The
lightning strike distance input into the software corresponds to the radius of the sphere required
to shield electrical equipment or conductors along an overhead line or substation from lightning.
Lightning can potentially strike anything within the lightning strike distance. Objects outside of
the lightning strike distance are protected. The lightning strike distance can be based on several
factors including applicable codes, allowable lightning stroke current, surge impedance, and
cost of protection. The calculation interval will define where the sphere is checked along the
ground wire to define the lightning coverage TIN. For further diagnostics you can enable the
markers showing the sphere locations considered for the lightning protection calculator.
After running the function you will be able to display the lightning coverage TIN and you will also
receive a report showing the areas that may not fall under the protective area of the lightning
coverage TIN. This report will give you the length of the exposed wire and the coordinates of
the start and end of this exposed section. After the initial rendering of the lightning coverage
TIN you can always go back to the Terrain/ TIN/ Display Options to change the rendering.
Figure 11.2-34 below shows a rendered lightning coverage TIN and you can see a short section
of exposed conductor near structure 12.
Fig. 11.2-33 Rolling Sphere Input Data Dialog
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Fig. 11.2-34 Lightning Coverage TIN
Fig. 11.2-35 Lightning Strike Distance diagram
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11.2.13
Elevated Temperature Creep
Possible adverse impacts to an operating overhead transmission line which might occur when
operating the line at high temperatures. PLS-CADD can perform calculations defined within
IEEE 1283-2013 – IEEE Guide for Determining the Effects of High-Temperature Operation on
Conductors, Connectors and Accessories. The menu command Sections/Thermal
Calculations (IEEE, CIGRE and TNSP)/Elevated Temperature Creep... will allow you to
select a section and the software will then open the dialog shown in Figure 11.2-36.
Fig. 11.2-36 Elevation Temperature Creep dialog box
Information regarding the selected cable file will be displayed in the Cable Description and
Cable File fields at the top of the dialog. Selections for the Initial ambient conditions of the wire
are needed within the Temperature, Time, and Condition selections. There is also a toggle to
select to model cable strands as cast rods. The Elevated Temperature History table then
requires inputs for the elevated temperature, time of elevated temperature and cable condition
during the elevated temperature. Outputs of the elevated temperature creep are then shown in
the grayed-out section of the Elevated Temperature History table. The Generate Report button
will produce the IEEE 1283-2013 Elevated Temperature Creep Calculations Report. See IEEE
1283-2013 for details on the calculations performed within this function.
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12.
REPORTS AND SUMMARY TABLES
12.1
Reports
PLS-CADD can generate many reports. All reports are sent in the WINDOWS ".TXT" format to
standard Report windows where they can be viewed, edited, saved and printed. They support
Rich Text Format (".rtf") and OLE object embedding.
In Section 11, you have seen portions of a few reports (Figs. 11.1-1 to 11.1-3, etc.). But there
are many more, including several project summary reports available under Lines/ Reports. The
content of all reports should be self-explanatory. Appendix R discusses some of the reports and
their inputs and results.
12.1.1 Viewing and Editing Reports
Viewing and editing the reports is done with the following functions selected from a small
context menu which appears when you right-click anywhere in the report window. You may
insert a page break by pressing Ctrl-Enter. While in any text report a tooltip will appear
indicating the title of the column the cursor is over in cases where the title is off the top of the
screen.
Save as lets you save the report as a rich text (".rtf") file or as an ASCII text file. That file can
later be edited with a word processor and printed.
Append to lets you append the report to the end of an existing file.
Font lets you change the font type and size in the report window.
Autosize Fonts is used to select the largest font for which none of the lines in the report wrap.
With large reports, this may take some time to execute.
Copy lets you copy the report, or a selected portion of it, to the WINDOWS clipboard from
where it can be pasted into any other report. Copy is only available in the context menu after
you have selected the entire report with Edit/ Select all or after you have selected a portion of it
by dragging over it with the mouse.
Cut and Paste can be used as with any word processor once you have selected the report or a
portion of it.
Print lets you print the report directly on any printer supported by WINDOWS.
Open lets you load any text file into the report window.
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Close closes the report window (all data contained in the report are lost).
XML Export allows you to export the selected report to a xml file.
KML or SHP Export allows you to export the selected report to a KMZ, KML, or Shapefile.
Import in Project as XYZ Points allows you to import point data from the report into the project
as a xyz point in the project and lets you assign a certain feature code to these points. Also
gives you the option to set the point descriptor of the imported point to the report name and row
number. If used from the Construction Staking Report the plan comment will be set to the Stake
Description. If used from the PI Report the plan comment will be set to the Line Angle.
Customize allows you to access the current reports schema to make changes. The changes
do not appear in the current report but will appear when the report is run again.
Table View allows you to view certain report data in a tabular format which is easily copied into
a spreadsheet program. The table view also allows you to sort the data in the table in
ascending or descending order based on the column selected. Just left click in the header of
the column and choose the option to Sort Ascending or Sort Descending. There is also a filter
command in this menu that allows the user to filter out or hide any rows that have a value that is
greater than, less than, equal, or not equal to a value input in the dialog box. The user can also
highlight a block of data in the table and the statistical information such as minimum value,
maximum value, average, and sum appears in the status bar. XML Export allows you to export
certain report data to an .xml file.
Report windows can now be made independent of the main application window. These
independent reports may be dragged outside the program to a separate monitor but otherwise
maintain all the normal functionality of the report windows. This behavior is controlled by a tristate setting in the File/ Preferences where you can select the “Open reports in separate free
floating windows”. You can choose to never do so, always, or when in the presence of multiple
monitors. No matter what selection you choose you always have the ability for independent
control of the windows by right clicking within the body of the report and you can choose to
Detach the report to another monitor or if the report has already been detached you can choose
to Attach it back to the application. For an example of this please see the example video at
https://youtu.be/ahv0WiW623w
Any of the report windows can be dragged to the upper edge of the application window to have
it maximize across the application window or to either side to have the report window size to half
the application window.
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Reports allow you to press the Ctrl + (Control and plus key) or Ctrl – (Control and minus key) to
jump to the next and previous schemas in a report. This is also available in the Edit/ Next
Result or Edit/ Previous Result menu which can be used to create a button on a custom
toolbar as discussed in Section O.4.
12.2
Summary Tables
In addition to summary reports, PLS-CADD provides you with summary tables which can be
exported to spreadsheets or databases. You can click in the upper left corner of the table to
access a menu with many useful commands. Among these is the Export XML command which
will save the table as an XML file. See Appendix M for instructions for exporting to database.
See our web site for a description of how this can be used to integrate with a GIS or a material
work order system.
12.2.1
Structures Staking Table
Fig. 11.2-35 Lightning Coverage TIN
For each structure in the line, a structure staking table (see Fig. 12.2-1) can be generated
including a column for its:
Structure Number:
Structure Number as assigned in Drafting/ Structure and
Section Labeling/ Structure Numbers
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Station:
Structure’s true station or equation station dependent on the
settings in File/ Preferences. If the structure is a XYZ Based
Structure then the Station column will read XYZ Locked.
Height Adjustment:
Adjustment to Structure Height. Positive is up.
Offset Adjustment:
Adjustment to Structure Offset. Positive is right of alignment. If
the structure is a XYZ Based Structure then the Station column
will read XYZ Locked.
Orientation Angle:
Adjustment to Structure Orientation. Clockwise is positive.
Global Coordinates X,Y:
X,Y Coordinate of the Structure
Centerline Z Elevation:
Centerline elevation at structure station based on centerline.
TIN Z Elevation:
Elevation at structure station based on TIN.
Ahead Span:
Longest ahead span on structure based on the base coordinates
of the structures.
Line Angle:
Alignment line angle at the structures true station.
Transverse Axis Azimuth:
Azimuth measured clockwise from north of structure’s transverse
axis.
Structure Name:
Name of structure file at this location.
Structure Description:
Description entered in the structure file
Struct. Height:
Structure height per structure file.
adjustment.
Does not include height
Embedded Length:
Embedded length per structure file.
adjustment.
Does not include height
Structure Specific Material:
Access the Structure Specific Material List for the structure as
discussed in Section 8.5.4.1
Counter Weights:
Insulator Hold Down Weights, if any
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Automatic Structure Group Membership:
List of Structure Groups assigned by the program automatically.
Manual Structure Group Membership:
List of Structure Groups assigned manually by the user. Allows
user to assign Structure Groups and access to the Structure
Groups dialog box.
Structure Comments 1 – 50:
Up to 50 user comments assigned to the structure.
The structure staking table is displayed with the Lines/ Reports/ Staking Table or the
Structures/Staking Table commands. Some columns in the table are grayed, indicating that
they include derived data that cannot be edited inside the report table. If a row is highlighted in
light purple it indicates that this structure is a site specific structure. For more on Site Specific
Structures see Appendix P.
12.2.2
Bill of Material by Structure Location
For each structure location in the line, the Bill of Material by Structure Location Report (Fig.
12.2-2) includes one or more lines of data describing the material to be used at that location.
The material data includes not only the pieces making up the structure (Structure File Material
List), but also any Structure Specific Material to the structure site, such as foundations, signs,
dampers, etc (material described in the Material button of Structure Modify dialog box). There
is one line in the table for each different part or assembly. The Bill of Material by Structure
Location is generated with Lines/ Reports/ Bill of Material by Structure Location command.
In order to get the table of Fig. 12.2-2 you will need to right-click inside the Bill of Material by
Structure Location Report and select Table View/ Combined Bill of Material. If you select
XML Export/ Combined Bill of Material Report, you will be able to create an XML file that
contains the same information.
Fig. 11.2-36 Lightning Strike Distance
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12.2.3
Bill of Material
Once your model is complete, you can generate the entire list of parts and assemblies using
Lines/Reports/Bill of Material. The table shown in Fig. 12.2-3 will be generated.
Fig. 12.2-1 Structure Staking Table
12.2.4
Table Functions
There are many functions available when working within a report or input table in PLS-CADD
that are similar to many common spreadsheet functions. You can quickly highlight a selection in
a table and choose to copy, paste, fill, or pattern fill the cells based on the selection. You can
highlight an area of a table and use the find command to find a particular item of text. When an
area in a table is highlighted the status bar will report many statistical results based on the
selected data. If you click in the column heading you can choose to sort the table in ascending
or descending order based on the selected column. There is also a filter selection to filter the
data based on user inputs. When inputting data in a table the user can choose to hit the control
plus apostrophe key while in a cell of the table and it will copy the value from the above cell into
the selected cell. You can also use the Copy & Fill Column command to quickly populate the
data in an entire column with a single value. This command is very useful in input tables such
as the Structure Staking Table or the Sections Table.
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12.3
XML Exports
As discussed throughout the manual there are several ways to get an xml export of data from
the program. Individual reports can export an XML file of their data by right clicking within the
body of the report and selecting Export XML or you can automatically generate a XML Export of
most of the data in the project. XML files can be used to populate other software programs for
post processing of data or population of GIS databases. An example of customizing reports
using an XML export out of PLS-CADD can be found at
https://youtu.be/QIT7s_s3uG8
The project XML can be exported by going to File/ Export/ XML or you can automatically export
the XML upon saving the project .xyz file by enabling the feature in the Settings section of the
File/ Preferences dialog as discussed briefly in
Section 5.2. The project XML Export includes a great
deal of data and you have the choice to export either
a complete or condensed XML file. The complete
export includes stringing charts, sag-tension, wind &
weight spans and structure loads which can take a bit
longer to export than the condensed version. You are
prompted to make a choice on condensed or
complete when you manually export a XML or you
can pick the Summary or Complete XML in the
Settings section of the File/ Preferences dialog.
The reports included in the project XML can be
controlled using the customization of reports through
the View/ Edit Customizations/ Tables discussed in
Section O.3 where you can check on or off if the
report being customized is included in the XML Export
or you can use the File/ Export / XML Settings
dialog box shown in Figure 12.3-1 to check on or off
what reports are included in the project XML Export.
Certain reports are “parents” of other reports and not
including them will cause their “children” to be
excluded from the XML Export as well. An example
of this relationship is the “Span and Wire Summary For Structure Ranger” is the parent for
several of the loading reports and the “Structure Locations and Usage Report” is the parent from
some of the structure summary reports.
Figure 12.2-2 Bill of Material By
Structure Location
In the File/ Preferences/ Settings section there is an XML Export includes option where you
can choose whether the XML Export should include just the active line model from the Lines/
Edit dialog or include all line models from the Lines/ Edit dialog.
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13.
PLAN & PROFILE DRAWINGS
13.1
Overview
Plan and Profile sheets (P&P) are produced automatically by PLS-CADD according to user
specified parameters. You have complete flexibility in choosing scales and page appearance as
demonstrated in Figs. 13-1.1 to 13.1-4. The drawings can be sent directly to a Windows®
printer, or they can be exported as DXF files readable by most CAD systems (AutoCAD ®,
MicroStation ®, etc.) for further enhancements, or they (together with other project documents)
can automatically be converted to PDF documents on your web site as a truly universal way to
share them with all interested parties.
Figure 12.2-3 Bill of Material
For example, load the wpl_demo.xyz project and tile the Plan, Profile and Sheets windows.
You will get a view similar to that shown in Fig. 13.1-1. The P&P sheets are drawn almost
instantly. The amount of text to be displayed in each selected window (Plan, Profile, or P&P
sheet) is specified under Drafting/ Structure and Section Labeling/ menus and other
Drafting/ menus. Selecting the option Drafting/ Show P&P Sheet Rectangles will display the
rectangles defining each P&P sheet in all views (see Fig. 13.1-1).
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Fig. 12.3-1 XML Export Settings
If you zoom-in on the 14th P&P sheet of Fig. 13.1-1 it will appear like the one in Fig. 13.1-2.
The drafting options for the wpl_demo line can be seen in the Drafting/.. menus. They were
read from the Wplfullm.pps file.
Among some of the wpl_demo line drafting options which were used to draft the page of Fig.
13.1-2 were: 1) showing the plan portion of the drawing at the top of the page, 2) not cutting the
alignment at each line angle, i.e. showing it as it would appear from an aerial view, and 3)
displaying vertical lines at each terrain point in the profile view.
The scales chosen for the P&P sheets in Figs. 13.1-1 and 13.1-2 were based on their final
printing destination which was a small size printer.
Fig. 13.1-3 shows a portion of another P&P sheet example with a different set of scales
intended for a large plotter. Maps attached as DXF drawings were automatically cut by PLSCADD in the plan portion of the sheets.
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The alignment was broken at each line angle in the plan portion of the sheet using the Long
Axis Plot and Standard options at the right of the Drafting/ Scales menu together with a Gap at
line angles of 200 ft.
Fig. 13.1-1 Three Windows Showing Global Paging of wpl_demo Line
You will note at the top of the profile portion of the sheet in Fig. 13.1-3 the optional printing of
part and assembly lists at each structure location. The entire text block which include the
structure number, parts, assemblies, etc. can be moved with the mouse using Drafting/
Structure Text Position/ Move.
Fig. 13.1-4 shows our fourth P&P sheet example. The DXF map and the bitmap photograph
shown in the plan portion of the drawing were automatically cut and displayed on top of the
alignment. The DXF and bitmap were previously attached to the line model Plan view with
Drafting/ Attachments/ Attachment Manager (see Section 6.6).
The text and boxes shown below the plan view of Fig. 13.1-4 were drawn as additional DXF
attachments to the Sheets (not to the Plan view). The Power Line Systems logo was drawn as
a bitmap attachment to all Sheets.
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Fig. 13.1-2 14th P&P Sheet for Line in wpl_demo Line
DXF or bitmap attached to Sheets are located with reference to the page X,Y coordinate
system. The page coordinate system has its origin at the lower left corner of the page, with X
positive to the right and Y positive up. Z is always equal to zero.
13.2
Sheets Layout
You have complete flexibility regarding your preferences for P&P sheets layout, appearance
and content. And remember, as discussed in Section 5.1, that the generation of P&P sheets is
not an additional process at the end of the design stage. P&P sheets are simply another view of
your design, instantly redrawn as you make changes to that design. You will find this a unique
feature of PLS-CADD. Using the settings in the Drafting/ Plan Profile Sheet Configuration/
Pages and Station Range you can also include title pages, notes pages, and appendix pages
at the beginning or end of your drawing pages in the plan and profile view. For more on this see
section 13.2.2.1 below.
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13.2.1 Page Size
P&P sheets can be drafted on any size printer or plotter
supported by Windows ®, from standard printers to large paper
roll plotters. The first thing you need to do is select a page size
using Drafting/ Page Size. Make sure that your selected Page
Height and Width (see Fig. 13.2-1) are equal to or smaller than
the largest allowable printer values.
13.2.2 Page and Sheet Layout
Once you have a page, you select the layout of the sheet.
Think of a sheet as a rectangle with its own borders. The sheet
can be smaller than the page as illustrated in Fig. 13.2-3.
A sheet is made up of 6 basic areas within
which standard items are drawn automatically.
The relative position of each area within the
sheet is defined by its: 1) Xmin = location of left
side of area as a percent of the sheet width
(measured from left), 2) Xmax = location of the
right side of the area as a percent of the sheet
width, 3) Ymin = location of the top side of the
area as a percent of the sheet depth (measured
from top), and 4) Ymax = location of the bottom
side of the area as a percent of the depth of the
sheet. You define the relative positions of all
these areas with Drafting/ Page Layout.
For example, the P&P drawing in Fig. 13.1-2
was generated with the page layout parameters
in Fig. 13.2-2. The plan view is drafted in the
upper 30 percent of the sheet and the profile
between 40 to 94 percent of the depth. The lower 6
percent is reserved for printing the stations.
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Fig. 13.1-3 Part of P&P Sheet
Drafted Using the Long Axis
Option
Fig. 13.1-4 P&P Sheet Automatically
Drafted by PLS-CADD
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The P&P drawing of Fig. 13.1-4 was
generated for a 25.4 x 20.1 cm page size with
the layout parameters of Fig. 13.2-3. The
sheet rectangle only occupies 93 percent of
the page depth. The scales and title areas are
drafted below the sheet rectangle. Also
drafted below the sheet rectangle are lines
and text defined in a DXF attachment as well
as the Power Line Systems company logo
defined in a bitmap attachment.
The location of the various lines and text of an
attached DXF file is defined in the page
coordinate system. The page coordinate
system has its origin at the lower left corner of
the page, with its X-axis to the right and Y-axis
up.
The location of an attached bitmap is
Fig. 13.2-1 Page Size
determined by pinning its upper left corner to
the page, i.e. by giving the page coordinates of the bitmap upper left corner. For example, the 1
x 4 cm logo in Fig. 13-4 was pinned at X = 18.2 cm and Y = 1.14 cm.
It may take you a substantial amount of time to get the proper sets of page parameters and the
properly sized attachments the first time you deal with drawings. However this is a worthwhile
investment as, when you have decided on the proper combinations, these can be saved for
automatic use on any project as discussed in Section 13.2.5.
See Figures 13.2-3a and 13.2-3b below for a graphical description of the areas in the Drafting/
Plan & Profile Sheet Configuration/ Page Layout.
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Fig. 13.2-3a Basic Sheet Layout
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Fig. 13.2-3b Detailed Sheet Layout
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13.2.2.1
Pages and Station Range
The Drafting/ Plan Profile Sheet Configuration/ Pages and Station Range command will
bring up the dialog shown in Fig. 13.2-3c below. At the top of the dialog box the user can define
the start page number for the entire page section in case you wish it to start on a different
number than 1. You can also place additional blank sheets to the sheets view to act as title
pages, notes pages, or appendix pages. These new pages can also be added or deleted with
the context sensitive commands using Entity Info. The Title Pages, Note Pages, Drawing
Pages, and Appendix Pages are subsection of the entire P&P sheets view. The title and notes
Fig. 13.2-2 Layout for Fig. 13.1-2
pages will be added to the beginning of the sheets view prior to the plan and profile drawings
while the
appendix pages will be added after the plan and profile drawings. These designated sheets can
be used to add additional information about the project using text, inset plan details, or
attachments that each can be placed independently on these types of sheets. The bottom of
the dialog box allows you to select three different option to define what station range appears on
the sheet. The first is to generate the drawing sheets for the full alignment. The second allows
you to specify a single station range for the drawing sheets. You can either manually input the
start or stop station you would like to be paged or you can select a structure number at the drop
down menu on the right of these inputs that will automatically populate the station fields with the
station value of the selected structure. The third option is to specify multiple station ranges for
the drawing sheets where you can manually input up to 256 different station ranges for paging.
These ranges can overlap if you have them input them so they overlap in the table. You can
also select these different ranges using structures by clicking on the Select Structures to
Determine Start and Stop Stations button at the top of the table. This will allows you to multiselect a ranges of structures based on the numbers and also give you the ability to input an
ahead and back margin to page beyond the selected structures. Figure 13.2-3d below shows
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an overview of the sheets view with one title page, one notes page, and one appendix page and
how they relate to one another.
Figure 13.2-3d Title, Notes, Drawing, Appendix Pages
13.2.3
Scales and Plan Display Type
You should next define the drawing scales in the Scales dialog (Fig. 13.2-4) which is reached
with Drafting/ Plan & Profile Sheet Configuration/ Scales. The scales parameters are:
Horizontal and Vertical Scales represent actual distances in ft (m) corresponding to one in. (cm)
on paper.
Profile Station and Profile Elevation Label Intervals set the horizontal and vertical intervals at
which stations and elevations numbers are displayed. You also have the option to display the
elevation labels at breaks in the profile.
Fig. 13.2-3 Layout for Fig. 13.1-4
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Data in the Profile View Station and Elevation Grid fields are used to set the horizontal and
vertical intervals at which vertical and horizontal grid lines are displayed in the profile portion of
the sheet.
Data in the Plan View Station Labels and Tick Marks are used to set the intervals at which
stations and tick marks are displayed in the plan portion of the sheet.
Data in Margins and Overlaps provide you with additional control regarding automatic page
breaks. For example, the Allowable Overlap for Common Tower is the maximum number of ft
(or m) of profile overlap allowed from one page to the next in order to get the last structure on a
page to be repeated on the next page. With steep ground, it may be necessary to break the
profile view into several pieces in order to make it fit on one page. In such cases, Profile
Elevation Break Abort Margin controls the minimum distance from the end of the page at which
a profile break is allowed. Profile Bottom Margin is the desired margin (in ft or m) at the bottom
of the profile view. It can be used to reserve space for additional DXF or bitmap attachments.
Sometimes when your wires cross a valley, it is impossible to show the ground profile and the
wires simultaneously and the drafting is interrupted. In such cases you can specify that,
whenever the distance between the lower wire and the ground profile exceeds the number
specified under Cut profile if distance to wires exceeds, the ground profile will go off the edge of
the drawing.
If you check Long Axis Plot, the center line in the plan view is displayed parallel to the horizontal
side of the page by breaking the line at each P.I. point. This allows structures to be displayed at
the same station (same vertical line) in both the plan and profile portions of the drawing. You
can specify a gap width at each line angle. The drawing of Fig. 13.1-3 was produced with the
Long Axis Plot option and a nonzero gap. Without the option (Figs. 13.1-2 and 13.1-4), the
program locates the pages for optimum use of the drawing paper given the scales and layout
parameters. There is also a minimum line angle for line angle gap that allows an input for
suppressing gaps at very small angles that commonly occur in projects where a PI is located at
every structure such as LIDAR surveys.
There are actually several variations of the Long Axis Plot option. The Standard option will draft
the profile zone with standard grid lines as shown in Figs. 13.1-2 and 13.1-4. The EDF (France),
CFE (Mexico) and REN (Portugal) options are customized displays at the bottom of the profile
zone.
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13.2.4 Detailed Text and Lines Appearances
What particular text, including part and assembly lists, is displayed next to each structure in the
profile and plan portions of the sheet is specified with Drafting/Structure and Section
Labeling/ Sheet Profile (or Plan) View. Other parameters affecting the appearance of text and
lines are selected in the Text Orientation, Position and Background table that you reach with
Drafting / Text Position, Orientation and Background, and in the Layers, Colors, Pen Style
and Pen Thicknesses table that you reach with Drafting/ Text Size, Line Width, Style, Color,
and Layers. You can drag the structure text that initially appears at the top of the profile zone or
the structure numbers in the plan view to another location with Drafting/ Structure Text
Position/ Move. The structure label can also be hidden individually by accessing the context
menu in Entity Info for the structure snap and selecting the Structure Label/ Toggle Display.
13.2.5 Saving Drawing Parameters
The drawing parameters selected in Sections 13.2.1 to 13.2.4 for a project named Project are
automatically saved in a file named Project.pps when saving the project. These parameters can
also be saved under a different name and later read-in using Drafting/ Save PPS or Load PPS.
Drawing parameters which have been found suitable are generally saved in a master file from
which they can be imported for each new project.
13.3
Lines and Annotation
PLS-CADD includes some line and text drafting functions which can eliminate your need to
export P&P sheets to a CAD system for final editing. You can draw lines, polygons or text
anywhere on any Plan view, Profile view, individual P&P sheets, all P&P sheets, or individual
Inset views. The P&P sheets are made up of four different subsections. These subsections
are the Title Pages, Note Pages, Drawing Pages, and Appendix Pages. These pages are
setup in the dialog discussed in section 13.2.2.1 above.
Annotation can be placed
independently or globally across all sheet types or the individual subsections Title, Notes,
Drawing, or Appendix pages of the sheets view or Inset views contained on these sheets.
This can be done interactively or by describing the drawing entities in a table.
13.3.1 Interactive Drawing of Arrow, Line, Polygon or Text
Arrows, lines, polygons, and text annotations can be drawn interactively using the Add, Edit,
Delete and Move functions under the Drafting/ Lines and Annotation menu.
13.3.1.1
Adding New Arrow, Line or Text
You can draw arrows, lines, and text anywhere using the Add
command. You will be able to draw the selected item in the
active window with the parameters you select in the small box at
the upper left corner of your screen where you left-click the
mouse. Press the Enter key or the middle mouse button to finish
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Figure 13.2-3c Pages and
Station Range
drawing a particular entity. Therefore, you should fill the data in the box before clicking. When
you are done adding an arrow, line, or text, right-click the mouse to get out of Add mode. Enter
your text annotation in the Text field, its size in the Text Height field and its orientation in the
Text Angle field. The default text size is the default Graphics Font selected in the File/
Preferences menu.
If you select Add/ Line, Add/ Arrow To, Add/ Arrow From, Add/ Polygon, Add Dimension or
Add/ Text you will be shown a text box similar to Figure 13.3-1 that will allow you to enter the
appropriate information depending on the type of annotation you are adding.
A Project Line can be selected for all annotation. This allows you to enter specific text related to
different line designs within the model. The Project Line is picked from the list of designs in
available in the Lines/ Edit dialog box (Section 5.4.6.4). If not making any annotation
dependent on a specific design then you can leave the All (Global Annotation) selected which
will appear in all designs.
If you go to Drafting/Lines and Annotation/Snap Mode, it will bring up the Annotation Snap
Modes dialog box which allows you to select different entities to snap text, lines, dimension, etc.
when placing the annotation. Some of these different entities can be items such as survey
points, wires, dxf and shapefiles, structure joints, etc. The entities highlighted in blue in the
dialog box will be the items the Lines and Annotation commands will snap to. If you are creating
a dimension line then you have the option to choose whether the dimension line is a 2D or 3D
line depending on which radio button is highlighted in the dialog box.
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Annotation Type
First Click Appearance
Ending Click Appearance
Line
Arrow To
Arrow From
Polygon
Section Bubble
Arc
Ellipse / Circle
Dimension Angle
A
Dimension
123
Dimension Snap
29.
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13.3.1.2
Editing Existing Line or Text
After selecting Edit, your mouse cursor will snap to the
closest line or text item on your screen. The location of
the selected item is highlighted with a red ball. Data for
the selected item can be edited in the dialog box of Fig.
13.3-2 which opens when you left-click the mouse.
In the Edit dialog box, you are able to specify the exact
location of your item. If the item is in a Plan view, X and Y
are its global coordinates (Z is not used). If the item is in a
Profile view, X is its station and Z is its elevation (Y is not
used). If the item is in a Sheet view, X is its horizontal
distance from the left of the page measured as a fraction
of the page width and Y is its vertical distance from the
top of the page measured as a fraction of the page height.
4.0
13.3.1.3
Moving,
Polygons or Text
Rotating
or
Deleting
Lines,
After selecting an item with one of the Move, Delete, or Rotate functions in the Drafting/Lines
and Annotation menu, you can drag it (keep the left mouse button pressed) to another screen
location, rotate the object about its center, or delete it by left-clicking. Right-click the mouse to
get out of Move or Delete mode. If moving text in the sheets view you can hold down the Tab
key in order to maintain the offset that was used for the text placement originally.
13.3.2 Editing Drawing of Line or Text in Table
All data describing the drawing of lines or text are actually summarized in the Annotation table
which you open with Drafting/ Lines and Annotation/ Table Edit. These data correspond one
to one with the data listed in the Edit Annotation box of Fig. 13.3-2 and can be edited directly
in the table. For example, the data shown in the table of Fig. 13.3-3 are from the Demo line
example. They result in some of the text shown inside the title block of the P&P sheet of Fig.
13.3-4. Each cell in the Text column can have several lines of text. The end of a line (carriage
return) is indicated by the "\n" code. The lines dividing the title block in Fig. 13.3-4 are described
in a DXF file initially prepared in AutoCad. That DXF file, "plsborder.dxf", was attached to the
project as described in Section 6.6.1. They could also have been drawn as annotation lines.
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The table also allows you to pick a project line for the annotation as well as setting line types if
using a line annotation command. If you wish to use the cloud line type you can select yes in
the Cloud column or when you are placing the line manually. The table inputs are detailed
below.
ABC 123
Column Title
Description
Project Line
The particular project from Lines/ Edit that the annotation will be
placed upon. When the project is shown in the Lines/ Edit dialog the
annotation will appear. If All (Global Annotation) is selected the
annotation will appear across all projects.
Coordinates
Basis for where the annotation will be placed which dictates the
coordinates for the next three columns. The options are Plan, Profile,
Plan&Prof, Single Sheet, All Sheets, Title Sheets, Note Sheets,
Drawing Sheets, and Appendix Sheets.
Plan X
Prof Station
Sheet %width
Designation of the annotation location depending on the coordinates
selected. For plan views the X coordinate, for profile views the station
value, and for a sheet view the % of sheet width from the left side of
the sheet.
Plan Y
Prof Offset
Sheet %height
Designation of the annotation location depending on the coordinates
selected. For plan views the Y coordinate, for profile views the offset
value, and for a sheet view the % of sheet height from the top of the
sheet.
Plan Z
Prof Z
Sheet Z
Designation of the annotation location depending on the coordinates
selected. For plan views the Z coordinate, for profile views the Z
value, and for a sheet view the % will default to 0.
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Column Title
Annotation Type
Description
None to start a new line or for text, Line to draw line to previous record
in table, close to form closed polygon to previous record in table.
Arrow and dimension allow for the creation of the arrow lines and
dimension lines of text.
Text (see status bar Text to be displayed.
for special codes)
Test Justification
Text Justification
Text Rotation Angle
Rotation Angle of Text
Sheets View Text Hgt.
Height of Text in the Sheets View
Sheet View Page
Page Number for Sheets Specific Text. The specific sheet number
from the total number of sheets is shown followed by the subsection
sheet specific number per the subsection. If text is on a subsection
sheet that is deleted then a “–“ will appear for the specific total sheet
number and the subsection sheet/total sheets page will show with the
previously designated subsection sheet number prior to its change.
Color
Color of Line or Text
Line Type
Line Type (Solid, Dash, Dot, Dash-Dot, Dash-Dot-Dot,None)
Sheet Line Thick.
Line thickness to display on the sheet.
Cloud
Yes or No to designate whether the line will be drawn cloud or regular
line.
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Special Codes for in the list below can be used for the automatic insertion of annotation for the
following items:
Special Code
Automatic Insertion Text
%p
Overall P&P Sheet Number
%q
Total Number of Sheets (including all subsections)
%n
Project Name
%m
Project Directory
%d
Date when project last saved
%t
Time when project last saved
%L
Line Name for the Lines/ Edit dialog
%s1
Start Station on the Drawing Pages
%s2
Stop Station on the Drawing Pages
%s3
Start Structure Number on the Drawing Pages
%s4
Stop Structure Number on the Drawing Pages
%C1…%C50
Specific row of annotation in the Criteria/ Notes
%R1…%R??
Specific row of annotation in the Project Notes in the Lines/ Edit dialog
%dim
Distance between dimension line endpoints (optionally followed by
desired digits after decimal, for example “%dim0” or “%dim2”)
%coordsys
Current coordinate system selected in the Terrain/ Coordinate System/
Define dialog box for the project
%partitionpage
Overall page number for the subsection where the text is placed (Title,
Notes, Drawing, or Appendix pages)
%partitionpagetotal
Total number of pages in the subsection where the text is placed (Title,
Notes, Drawing, or Appendix pages)
%allpage
Overall P&P Sheet Number
%allpagetotal
Total Number of Sheets (including all subsections)
%username
Name of current user
%version
Name and version number of the program
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13.3.3 Re-using Lines and Text in Different Projects
Unlike the drawing parameters which can be saved and re-used in different projects as
described in Section 13.2.5, the line and text data in the table of Fig. 13.3-3 are not saved in the
Project.pps file. However, because the table in Fig. 13.3-3 is a standard spreadsheet table, you
can select elements of that table or the entire table itself, copy and paste them in the table of a
new project to duplicate the lines and annotations of an existing project. Or you can use
Drafting/ Lines and Annotations/ Merge in Annotation from Another Project to do
practically the same thing.
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13.4
Direct Printing of P&P Sheets or Exporting DXF or PDF Files
P&P sheets can be printed directly, sent to a CAD system for further work or sent to a web site
with other design documents for immediate sharing with others in your design/ construction
team.
To print drawings directly, select File/ Print. You then have two choices. A printout of the
current picture on the screen can be obtained by selecting Yes in the Screen Dump dialog. Or
you can print any number of scaled plan and profile sheets by selecting No and choosing the
proper parameters in the subsequent dialogs.
Our connection with CAD systems is exclusively through the DXF format. To export your
drawing to a CAD system, select File/ Export/ DXF. After specifying a file name, you will be
asked whether you want to export a 2-dimensional or a 3-dimensional file. A 3-D file export is
only applicable to a 3-D view or a structure view. Therefore you should select 2-dimensional.
You will also be asked whether to include all sheets in a single CAD drawing or to have one
separate CAD drawing for each sheet if you are in the Sheets View. You will also have four
different options for the detail to include in the DXF which are:
Low:
Text positioned by PLS-CADD, Cables drawn with 30 points, insulator sheds not
drawn, cables not rendered, 3 digits of precision
Medium:
Text positioned by PLS-CADD, Cables drawn with 45 points, insulator sheds
drawn with 12 sides, cables not rendered, 3 digits of precision
Standard:
Text positioned by CAD system, Cables drawn with 45 points, insulator sheds
drawn with 12 sides, cables not rendered, 3 digits of precision
High:
Text positioned by CAD system, Cables drawn with 60 points, insulator sheds
drawn with 20 sides, cables not rendered, 3 digits of precision
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Fig. 13.3-2 Edit Box
Prior to exporting, you can assign different layers to different entities in the Layers, Colors, Pen
Style and Pen Thicknesses table described in Section 13.2.4. However, as our drawing
capabilities have improved and as we have enabled you to distribute these drawings on the web
(see below), we find that more and more users no longer take the extra step of exporting to
CAD.
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13.5
Inset Plan Detail or Sheet Index Map in the Sheets View
Inset plan details can be inserted into any of the sheets using Drafting/ Inset Views /Add Inset
Plan Detail. A sheet index map can be inserted into any of the sheets using the Drafting/ Inset
Views/ Add Sheet Index Map. If you are working in the Sheets View drag to define an area
for an inset viewport in the sheet view you are wishing to see the inset plan detail. This will bring
up the Sheet Inset Plan View table shown in Fig. 13.5-1 below which contains options for the
display of the inset view. If you are working in the 3D or Plan View you will be able to first
define the area of the project you wish to display and then the Add Inset Plan View of Figure
13.5-2 will appear and you can select the page to add the inset view and the inset views
position. The advantage of this method is you can rotate the 3D view into a desired viewpoint
before adding the view window. Once the inset view has been added the commands
Drafting/Inset Views/Pan, Rotate, or Zoom Inset View will allow the user to select an inset
view and then pan, rotate or zoom using the mouse and keyboard commands.
Figure 13.3-3 Drawing Data For Title Block Sheet in Fig. 13.3-4
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The Inset Plan Detail can either be rotated using the Longitude and Latitude settings in the
table to enable a 3D view of the area. The Sheet Index Map can only be rotated about its
longitude since it is a plan view only. The Sheet Index Map also gives other controls to allow
for labeling of sheets and borders to provide an overall view of the sheets of the project. This
can be used to show an overview of the project that may typically be used on a title page or
notes page. Also if you have the Entity Info model enabled you will be able select items inside
the Inset Plan Detail and also choose to edit the table properties if you have the snap model
selected for Inset Plan Details in the context sensitive menu.
Fig. 13.4-1 Portion of the Second P&P Sheet for the
DEMO Line
Name:
Sheet Page Number:
Inset View Xmin % Page Width:
Inset View Ymin % Page Height:
Inset View Xmax % Page Width:
Inset View Ymax % Page Height:
Draw Order:
Inset View Annotations:
X,Y,Z:
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Inset View Title
Page number of sheet on which to display
inset view. Also include the subset number
whether is located on the title page, notes,
drawing, or appendix sections of the sheets
X coordinate for left edge of inset view as %%
of sheet width
Y coordinate for top edge of inset view as %%
of sheet height
X coordinate for right edge of inset view as
%% of sheet width
Y coordinate for bottom edge of inset view as
%% of sheet height
Order this view is drawn in relation to other
views
Sub-Table for editing annotations in the
instance of the Inset View
X,Y,Z coordinate of point displayed at the
center of the inset view
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Depth of Field Limit:
Longitude, Latitude:
Scale:
Note:
Show Structure Geometry:
Show Cable Attachment Label:
Show Wires:
Show Guy Anchors:
Show Structure Annotation and Attachment:
Show DXF and Shapefiles:
Show Attached Images:
Show TIN:
Show Survey Point Symbols:
Draw Inset View Border:
Draw Inset View Name:
Transparent Background:
Show PI Labels:
Show Structure Labels:
Show Plan Annotation:
Automatic Longitude Rotation:
Index Map:
Draw North Arrow:
Show Scale:
Clips display so nothing is seen beyond this
distance from the X,Y,Z at the center of inset
view
Controls the rotation of the inset view to show
3D views. For Sheet Index Maps the Latitude
is not input in the table since the plan view is
only allowed for the Sheet Index Maps.
Horizontal Scale of the inset view
Text that will be displayed in the upper left
corner of the inset view box
Shows geometry for PLS-POLE and TOWER
models in the inset view
Option to display the circuit label, phase label,
both labels or none
Shows the conductors in the inset view
Shows the guy anchors for PLS-POLE and
TOWER models in the inset view
Shows any annotation or attachments that are
attached to the PLS-POLE or TOWER models
in the inset view
Shows any DXF or Shapefiles that are
attached in the
Drafting/Attachments/Attachment Manager
in the inset view
Displays any attached images in the
Drafting/Attachments/Attachment Manager
in the inset view
Displays the TIN in the inset view
Shows the feature code survey point symbol in
the view
Shows the border for the Inset View
Shows the Inset View Name for the Inset View
Setting to yes allows entities to be seen if
below the current Inset View and overlapping
Shows the PI Labels for the Inset View
Shows the structure labels for the inset view
Shows the plan view annotation in the inset
view
Forces index map to use the same longitudinal
orientation as the plan view on that page
Displays whether the view is considered a
sheet index map or inset plan detail view
Shows the north arrow for the sheet index map
Shows the scale for the sheet index map
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13.6
Inset Report Views
Inset Report Views provide a way of converting
any schemable report output into a table of
annotations that can be displayed on your
sheets. Inset Report Views behave in the same
manner as other Inset Views and can be
updated automatically with changes to the
output by rerunning the respective report. The
formatting will match the schema report, so if for
example you made customizations to the
number of significant digits, or if the text was
blue to signify a warning, these would show
formatted as such in the Inset Report View. The
text entities will also be scaled so that the
largest text entity is small enough to fit in its
cell.
13.6.1 Adding Inset Report Views
To add an Inset Report View you’ll need to
generate a schemable report. (Almost all
reports in PLS software are schemable) Once
the report is generated you can right click inside
it and select the option in the context menu to
Add as Annotation to Inset View. You can also
select the icon in the report navigator toolbar.
The Add Inset Report View dialog box will then
appear. (see Fig. 13.6-1) This dialog box allows
Fig. 13.5-2 Add Inset Plan View
you to specify which sheet you’d like the
annotation to be placed on, what size the Inset View should be relative to % of page size,
whether or not to lock the settings of the annotations (see 8.3.2.3), what schema data columns
to include in the report, and what footer to place at the bottom of the report. If you have the
preview page option selected it will automatically zoom to the page selected and preview the
size of the report view. The size can be changed by inputting the percentages manually,
clicking on the arrows to the right of the input, or by using the arrow keys. You can also select
any part of a report and create an annotation report Inset View of a subset of the data. To
accomplish this right click in a report and select the Table View option. Then highlight the
desired section of data and you’ll see a context menu appear with the option to insert the data
as an annotation Inset Report View.
Fig. 13.5-1 Sheet Inset Plan View Table
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13.6.2 Moving, Editing, & Deleting Inset Report Views
You can move, edit, or delete an Inset View by navigating to the menu Drafting/Inset Views/ or
you can graphically select an Inset View by left clicking on one using Entity Info. To ensure that
you’re snapping to the correct entity you can press the ‘S’ key or left click and select snap
settings from the context menu and select the snap settings to only be on Inset Views.
13.6.3 Updating Inset Report Views
If an Inset Report View is not locked its contents will be updated any time the associated report
is run and the settings are not currently locked. The Drafting/ Inset Views/ Table Edit Inset
Report Views table includes two columns for the report title and the time and date that the
report was last generated to easily identify what reports need to be updated.
13.6.4 Splitting Inset Report Views
Inset Report Views can often times have large amounts
of information that if presented in a single table can yield
text sizes that are too small to read. In such instances the
ability to split Inset Report Views into multiple smaller
Inset Views is very helpful. To split an Inset Report View
navigate to Drafting/Inset Views/Split Inset Report
View or select it from the context menu when clicking on
an Inset Report View. You’ll then be able to split the Inset
Report into a number of Inset Views horizontally or
vertically, or you can split the Inset View by a specified
amount of rows or Inset Views. (see Fig. 13.6-2)
13.6.5 Locking Inset Report Views
Fig. 13.6-1 Add Inset Report View
Inset Report Views can be locked so that their settings do not change. This means that any
annotation inside Inset Report Views can be customized, but updates or autoscaling will delete
customizations unless locked. This feature can be useful if you want to show the same report
but at different stages in the design process, or if you’ve made changes to color or line weights
of the annotations.
13.6.6 Building Inset Report Views
You can create your own custom Inset Report View by navigating to Drafting/Inset
Views/Build Inset Report View... This feature can be very useful if you have a report that was
created in another program like an Excel spreadsheet. You can copy/paste information from
your spreadsheet into this table and generate an Inset Report View of it. Additionally, you can
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also use this feature to create any existing report that you ran in the current session of PLSCADD by clicking on the drop down menu shown in Fig. 13.6-3 below and clicking the load
button.
Fig.13.6-1 Position Inset Report Annotation
13.6.7 Empty Inset Views
You can create Empty Inset Views by navigating to Drafting/Inset Views/Add Empty Inset
View. This feature can be used if you wanted to create a group of annotations that are tied
together. This way they can be moved or resized together as a single entity. This would be
useful for creating a custom diagram with labels and such.
13.6.8 Display Order of Inset Views
Every Inset View is assigned a display order number based on the order in which it was added
to the project. This number displays the order in which Inset Views are drawn. So if for example
two Inset Views were placed directly on top of each other the Inset View with the lower number
will be drawn first and the other Inset View will be drawn on top. You can manually adjust the
display order numbers for Inset Views by navigating to Drafting/Inset Views/Table Edit Inset
Structure Views... or Drafting/Inset Views/Table Edit Inset Report Views... You can also
click on an Inset View with Entity Info and use either the Bring to Front or Send to Back
command to quickly change the draw order of an Inset View that’s undesirably overlapping
another Inset View.
13.6.9 Pan, Rotate, or Zoom Inset Views
The command Drafting/Inset Views/Pan, Rotate, or Zoom Inset Structure View will allow the
user to utilize the mouse & keyboard to Pan, Rotate or Zoom within the inset view. When this
command is used the user will first be asked to define the inset view these commands will be
used within. To rotate hold the Ctrl key while moving the mouse. To pan hold the Shift key while
moving the mouse. To zoom use the scroll mouse wheel. Press Enter to adjust the scale to fit.
Left click with the mouse to start the selection over or right click to exit this command.
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13.7
Inset Structure Views
Drafting/Inset Views/Add Inset Structure View allows you to select an area on the sheets
view to place an inset view of the structure based on the Method 4 PLS-POLE or TOWER
models. When first selected you will be prompted to define the area for the viewport on the
sheets view and then the Add Structure View dialog of Figure 13.7-1 will appear and you can
select from the list of Method 4 structures in the available structure list and if selected the
preview of the structure will appear on the right of the dialog. You can also choose to select the
structure based on the structure number at the top of the list. Once selected you can then pick
whether you want an isometric, plan, longitudinal, or transverse view of the structure and then
hit continue and you will be brought to the sheet inset view to make selections for the view.
You can also insert an Inset Structure View by using the Entity Info context sensitive command
to select a Method 4 structure and selecting this from the context menu. When this is selected
you will be taken to the Add Inset Structure View dialog where you will be able to select the
sheet you wish to add the structure, interactively selective the position of the viewport, and the
type of view.
Fig. 13.7-1 Add Structure View
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13.8
Inset Phasing Diagram
Drafting/Inset Views/Add/Inset Phasing Diagram... allows you to define an area on the
sheets view to place an inset view of any structure within the PLS-CADD model. The Phasing
Diagram inset view has more attributes and options available than the inset structure view, can
be used with any structure type and is intended to be used in conjunction with the circuits and
phasing labels to display the circuit and phasing configuration at a particular structure location.
When this command is run the user will first have to define what structure to use for the Inset
Phasing Diagram in the Create Phasing Diagram dialog box. Once the structure is selected the
user will have to define the area for the Inset Phasing Diagram within the sheets view. Finally
the user will have to define what attributes are displayed within the Sheet Inset Plan View
dialog. See section 13.5 for descriptions for the attributes within the Sheet Inset Plan View
dialog. This is the same dialog box used for the Sheet Inset Plan View but the Inset Phasing
Diagram has been set up to specifically feature a particular structure defined by the user.
14.
OPTIMUM STRUCTURE SPOTTING & OPTIMUM POLE SELECTOR
14.1
Automatic Optimum Structure Spotting
Optimum (minimum cost) automatic spotting is an extra cost option of PLS-CADD. The current
algorithms require that the strength of the structures be described by allowable wind and weight
spans, i.e. the structures should be modeled as Method 1 or Method 2 structures. However,
you can easily create Method 1 or Method 2 structures from Method 4 structures if you have
our structure programs TOWER or PLS-POLE. Therefore, the limitation is not as serious as it
appears.
After reading the information in this section, you may want to read our technical note available a
http://www.powline.com/products/optimization.html for more guidance.
Optimum spotting is one of the most challenging problem in transmission line design. Spotting
optimization falls in the general category of problems referred to as dynamic programming
(Bellman, 1957). Many papers have been published on the subject (Olbrycht, 1982; Ranero,
1990; Senouci, 1991; Peyrot, 1993). The mathematical formulation of the problem is as follows.
Given a set of design constraints and criteria, find a set of discrete structure locations (X i, i = 1
to n) and the corresponding structures (Ti, i = 1 to n) to minimize the total cost of the line. "n" is
the total number of structures in the line. Since the cost of the ground wires and conductors is
not affected by the spotting, the total cost to minimize is:
C(Ti,qi)
(14-1)
where the special cost parameter qi indicates that the cost of erecting structure i at its particular
location may be affected by soil conditions or other considerations at the site. The discretized
feasible structure locations Xi only exist at fixed locations on the center-line, for example at
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intervals of 10 m and at all high points in those intervals. The interval has a significant effect on
solution time and accuracy (Ranero, 1990; Peyrot, 1993). The structures must be taken from a
library of available structures. That library normally includes structures of different types (poles,
H-frames, etc.), strengths (tangent, light angle, dead end, etc.), materials (wood, concrete, steel,
etc.) and heights.
14.1.1
Terrain Constraints and Design Criteria
The following terrain constraints and design criteria must be satisfied after the structures are
spotted and the cables are strung in a line:
1)
The location of each structure must be permissible, i.e. it must not be in one of the
prohibited zones which can be defined on the ground. Prohibited zones can be defined
as such or can be assigned a special cost parameter qi that results in a very expensive
structure at the site. Prohibited zones can be waterways, highways, special properties,
rocky or marshy zones, etc. It may still be possible to erect a structure at a difficult
location, but the resulting cost should be reflected through the use of the special cost
parameter qi.
There may be terrain locations where structures are required (for example at all line
angles), but their types and heights are not specified. There may also be locations where
specific structures (type and height given) are required. Input of terrain constraints is
discussed in Section 14.1.4.
2)
The strength of the structures must not be exceeded. In an existing line model, PLSCADD supports four methods for checking the strength of a structure (Section 8.3).
Because spotting optimization algorithms normally go through very large numbers of trial
combinations of structure locations and strength checks, it is essential that the strength
verifications be done extremely efficiently. Therefore, only Method 1 (basic allowable
spans), Method 2 (allowable spans interaction) can be practically considered. Currently,
only Method 1 and Method 2 structures can be handled in optimum spotting with PLSCADD. If a line is optimized for a family of Method 1 structures, and then optimized
again for the same family of structures with strengths described with Method 2, a more
economical design will generally be obtained with Method 2. However, because the
strength data for Method 2 are generally more difficult to obtain that those for Method 1,
Method 1 is the most frequently used. Selecting structures to be considered in
optimization and inputting structure costs is discussed in Section 14.1.5.
3)
Minimum vertical clearances to the ground or to obstacles must be maintained for the
lowest conductor for specified weather and cable conditions (see Section 7.3.13).
4)
Maximum and minimum values of insulator swings under specified weather conditions
have to be observed (see Section 7.3.17).
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5)
A minimum vertical load must be maintained at certain structures. This constraint is
enforced in PLS-CADD by specifying a minimum allowable weight span under the
tightest bare cable condition, i.e. a cold condition. A cold condition is always defined
when describing structure strength by Method 1 (see Sections 7.3.10 and 8.3.1). An
interaction diagram for the cold condition must be defined if Method 2 is used (see
Sections 7.3.11 and 8.3.2).
6)
Minimum lateral clearances to obstacles on the ground must be maintained under
specified weather conditions (see Section 7.3.14). Because 1) this criterion seldom
controls the spotting of structures unless there is a narrow right-of-way, and, 2)
calculations of lateral clearances are relatively time consuming, the lateral clearance
constraints are not currently supported by the automatic spotting module of PLS-CADD.
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14.1.2 Basic Spotting Algorithm
The practical limitation which must be overcome in automatic spotting is the potentially large
number of combinations of structure locations, types and heights which have to be tried. With
"m" different possible locations and "n" different structure types to chose from at every location,
n
the number of possible combinations has the order of magnitude of m . Structure type is defined
from here on as a particular height of a given type of structure. Consider a 9.14 km (30,000 ft)
line whose terrain is discretized every 3.05 m (10 ft) and for which 48 combinations of structure
types are available. These line parameters correspond to a real line thoroughly investigated with
PLS-CADD. The number of different combinations of locations and heights is of the order of
(30,000/10)48 . Checking the feasibility of this number of combinations is far beyond the
capability of current computers. For this reason, optimum spotting has to be formulated as a
dynamic programming problem. The basic formulation is that of finding the least cost path
through a graph of nodes. Each node Ni,j represents the lowest cost solution for a valid line
solution between the start of the line and structure "j" at location "i". The cost at a node is
defined by the following recursive cost function:
Ci,j = Pj + min { min [ Ck,l + F(Nk,l,i,j ) ] }
k from 0 to i-1
(14-2)
l from 0 to # of structure types
where
Ci,
Pj
k
l
= cost at node Ni,j
= cost of structure j
F(Nk,l,i,j )
= feasibility function. It has value 0 if the line formed by
adding structure j at location i satisfies all the seven constraints defined
above. Otherwise it has infinite value.
= location index
= structure type index
The goal is to find Nm,j having the lowest line cost between the beginning and end of the line, i.e.
whose cost is min (Cm,j). The basic spotting algorithm is as follows:
Start at beginning of line
Start loop on possible structure location "i"
Start loop on possible structure type "j"
Find the previous structure and location (i.e. node)
which will result in the lowest cost solution meeting all constraints
up to this point. Store for future reference information about the
solution up to this point, including structure types and locations
involved (Ci,j, Ni,j).
End loop on possible structure type "j"
End loop on possible structure location "i"
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Then search through all the solutions that made it to the end of the line and pick the lowest cost
solution.
The above algorithm is used in most automatic spotting programs together with a number of
speed up techniques. It checks only m2 x n2 /2 combinations compared to a possible number of
the order of mn resulting in a problem which can be solved on current computers. The 30,000 ft
line example now involves only 30002 x 482 / 2 = 1 x 1010 combinations. This number can easily
be handled by current computers which are capable of millions of operations per second. By
refining the algorithm further in PLS-CADD, it was possible to solve the same problem by
looking at only 106 million combinations.
When it can be used, optimum automatic spotting can deliver substantial savings. Recent
studies in Europe (Ranero, 1990) and the US have shown that optimum spotting can economize
the costs of one or more structures for each 10 km of line. While the theory and computer
algorithms behind optimum spotting are complex, its practical implementation is PLS-CADD is
straightforward as described below.
14.1.3 Simplified Line Model
While PLS-CADD normally uses a full 3-dimensional model of the line with all cables, it
temporarily reduces that model when it seeks an optimum spotting of the structures. The
reduced model includes the structures, but only the lowest conductor of a designated cable set.
This is done to speed up solution time, given that; 1) the position of the lowest conductor in one
set is that which normally controls the checking of vertical clearances, and 2) the weight span
of that conductor is the one normally used in comparisons with allowable weight spans when
checking the strength of Method 1 or Method 2 structures.
Therefore, the shapes of a single conductor (in a designated set) under the weather cases
specified for the calculation of; 1) vertical clearances (worst of cases listed in Section 7.3.13),
2) three insulator swing conditions (see Section 7.3.17), and 3) three weight spans (see Section
7.3.10) or any number of weight spans (see Section 7.3.11), are the key parameters which are
used to determine if a particular spotting combination is acceptable. Each shape is entirely
defined by its blowout angle and catenary constant C which itself depends on corresponding
weather, cable and sagging conditions, as well as the ruling span of the tension section.
Because 1) the ruling span is not known before a spotting is attempted, and 2) the ruling span
may be changed by the trial optimum spotting, the basic optimum spotting algorithm described
in Section 14.1.2 has to be the inner loop of an iterative procedure which compares assumed
ruling spans to the actual ruling spans resulting from the optimum spotting. This will be
illustrated later. One must distinguish between the first trial spotting and any subsequent respotting. Before the first trial spotting, tension sections must be defined together with some
assumed ruling spans. The results of the first trial spotting will completely define the tension
sections and ruling spans for the second spotting (first re-spot). Tension sections and ruling
spans for the "i-th" re-spotting are used to calculate the input catenary constants for the "(i+1)422
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th" re-spotting. The procedure is stopped when the assumed and derived tension sections and
ruling spans match with a sufficient degree of accuracy, say five percent of the ruling spans.
14.1.4 Editing of Terrain and Required Structures Constraints
We will use the terrain profile Spotdemo.pfl to illustrate PLS-CADD optimization capabilities.
With an aspect ratio of 20 (using Drafting/ Profile View Aspect Ratio) you should get a Profile
view similar to that shown in the lower part of Fig. 14.1-1.
It is a good idea to
display the required
ground clearance line
for the voltage of the
circuit that will be used
for optimization, 345
kv in our example.
This is done with
Terrain/
Clearance
Line. Actual required
vertical
clearances
used
by
the
optimization are those
for
the
Voltage
specified
in
the
Optimum
Spotting
dialog box described
later in Fig. 14.1-7.
Fig. 13.6-2 Split Inset Report View
Once you have an alignment and a profile on which to spot structures, the first thing you need to
do is to define your terrain and structure constraints. This is done with the Structures/
Automatic Spotting/ Spotting Constraints/ Edit (Table Based) command which opens the
Spotting Constraints table of Fig. 14.1-2 where you can add or delete the constraints within
the table. For more on the table and the different types of constraints see Section 6.10.3.
You can also use with the graphical commands Structures/ Automatic Spotting/ Spotting
Constraints/ Add (Graphical) or Delete (Graphical) commands to speed up the editing of
constraints.
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Fig. 14.1-2 Terrain Constraints
When you save a project, all the associated terrain constraints are saved in the file Project.con.
When you load a project, all the applicable constraints are read in. For example, the constraints
for the Spotdemo line were automatically read from the Spotdemo.con file when you loaded
Spotdemo.pfl. If you wish to save constraints to (or load constraints from) a file which does not
have the name of your project, you can use the Structures/ Automatic Spotting/ Spotting
Constraints/ Save CON (or Load CON) command.
You can get a constraint report with Structures/ Automatic Spotting/ Spotting Constraints/
Report.
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14.1.5 Editing of Structures Available for Optimization
Once you have specified the terrain constraints, you should define which structures should be
considered for optimization. This is a two step process.
First, a preliminary list of
candidate structures is
generated by selecting
them from their original
directory and bringing them
into, or removing them
from, the list of available
structures (Fig. 14.1-4).
This is done by with
Structures/
Available
Structures List/ Add-Del
Structure.
Then, the final selection of
structures which will be
considered in the spotting
Fig. 13.6-3 Create Inset Report View
optimization is made in the
table opened with Structures/ Available Structures List/ Edit (Fig. 14.1-5). The grayed
columns in Fig. 14.1-5 show useful information that cannot be changed in the table. All the
structures selected in the right portion of the dialog box of Fig. 14.1-4 get listed in the table of
Fig. 14-5.
Structures data in the table of Fig. 14.1-5 include:
Structure Name (Grayed):
Structure file name from list in Fig. 14.1-4
Structure Description (Grayed):
Description as included in structure file
Cost from Parts List (Grayed):
This shows the total cost of a structure as the sum of the costs of its parts/ sub-assemblies, if
the parts/ sub-assemblies making up the structure have been defined in the structure file and if
costs have been assigned to the parts/ subassemblies master lists (see Sections 8.5 and
8.6.1.3). This cost can be used as a guide for your input of the actual structure cost in the Cost
for Optimization column.
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Cost for Optimization:
This is the actual structure cost which will be used for the spotting optimization. It should include
the total as-built cost, i.e. it should include not only the costs of materials but those of
foundations and erection.
Use for Automatic Spotting:
Set this data to "Yes"
if your final decision is
to allow the structure
to be considered in
the
spotting
optimization.
Set for
Spotting:
Automatic
This is the set number
of the conductor that
will be used to check
vertical
clearances
and insulator swings
(if any), and to
compute actual weight
Fig. 14.1-1 Terrain for Spotdemo Line
spans for comparisons
with allowable values (see Section 14.1.3).
Auto spot. Minimum Line Angle:
By inputting a nonzero number in this column you can speed up the spotting process by
preventing the structure from being tried at any line angle less than that input number. Do not
input a nonzero number unless you are sure that eliminating the potential use of the structure at
smaller line angles will not affect the optimization. You should only use this feature for structures
designed for large line angles which you do not want to be tried at tangent or small angle
locations.
Auto spot. maximum line angle (Grayed):
This is the maximum allowed line angle for the structure. This number comes from the
maximum line angle in the last line of the Structure Allowable Spans table (Fig. 8.5-1).
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Number in Selected Line (Grayed):
Once a line is spotted, this number indicates how many structures of the given type are used.
Structure Strength Model (Grayed):
S for Allowable Span method (Method1)
I for Interaction diagram (Method 2)
C for Critical components method (Method 3)
A for direct link to analysis (Method 4)
Structure File Name and Path (Grayed):
Self explanatory.
Lowest Cable Height (Grayed):
Height above ground of attachment point to
insulator of lowest conductor in set controlling
spotting optimization.
Structure Strength Data (Grayed):
For Method 1 structures, copy of the last line of the
Structure Allowable Spans table (Fig. 8.5-1).
14.1.6 Running the Optimization
Once the terrain, constraints and
available structures have been selected,
the optimization can be started with
Structures/
Automatic
Spotting/
Optimum Spotting/ Select Station
Range. You are asked to click on the
Start Station where spotting will start
and then on the Stop Station where it
will end. This is done by typing-in the
station or snapping to the closest
existing structure, or PI, or Spotting
Constraint. For example, start the
optimization by clicking near the
leftmost PI on the Spotdemo.pfl terrain Fig. 14.1-4 Establishing a List of Candidate Structures
and then click on the rightmost PI where
you want the optimization to end. You also have the choice under Structures/ Automatic
Spotting/ Optimum Spotting to Use Last Station Range you selected or Use Station Range
of Longest Alignment in Project to quickly select the range to optimize.
You will be taken to the Open Cable File dialog (Fig. 14.1-6) where you select the lowest
conductor (that which controls all vertical clearances and weight spans calculations). Select the
Rail conductor for the Spotdemo example. You will then be taken to the Optimum Spotting
dialog box (Fig. 14.1-7).
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Necessary data in the Optimum Spotting dialog box include:
Voltage:
This conductor voltage (345 kV in
Spotdemo example) is used to
check vertical clearances
Conductors/ Phase:
Number of subconductors in bundle if
low phase controlling spotting
optimization is a bundle.
Ruling Span:
Your currently assumed ruling span
(1000 ft in Spotdemo example). This
Fig. 14.1-5 Available Structures Data
value will automatically be changed
to that of the actual spotting by the program if you select the “Respot if ruling span more than
5% off“ option.
Sagging information:
You can sag the conductor by checking “Automatic Sagging“ or by entering the Initial horizontal
component of sagging tension “Sag Tension“ or the Initial sagging catenary constant “Sag
Catenary“ at the corresponding sagging temperature “Sag temp“. The “Sag Tension“ field is
visible if you have selected Sag With Tension in the Preferences dialog available from File/
Preferences. Sagging with tension is discussed in Section 10.3.2.1. The “Sag Catenary“ field is
visible if you have selected Sag With Catenary in the Preferences dialog. Sagging with the
catenary constant is discussed in Section 10.3.2.2. Automatic sagging is discussed in Section
10.3.2.3.
In the example, we chose “Automatic Sagging“. Given the automatic sagging conditions
described in Criteria/ Automatic Sagging, we expect, in the final spotted design, to find the
conductor at, or near, 20% of ultimate after creep at 60 degree F (everyday)
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Vertical Clearance Buffer:
Vertical Buffer added to required vertical clearance
requirement. Defaults to 0.
Minimum and Maximum spans:
These are additional constraints put on the structures
spotting (With the data in Fig. 14.1-7, there will not be any
span shorter than 350 ft and none longer than 1200 ft). For
example, a maximum span may be specified to avoid
galloping clearance problems.
Station spacing:
When optimizing, PLS-CADD tries all possible combinations of available structures at intervals
not exceeding the maximum Station spacing and at any high point within the intervals. For the
Spotdemo example, we have chosen Station spacing = 20 ft. Station spacing in the range of 5
to 20 ft (2 to 8 m) are generally appropriate. However, at the preliminary design stage, you may
use a larger number, say 100 ft, in order to quickly get an approximate solution. As you will find,
solution time increases rapidly with smaller station spacing.
Respot if ruling span more than 5% off:
This option will let the program automatically re-spot portions of the line if the as-spotted ruling
span is more than 5% different from the assumed one. This option may be time consuming, so
you may not wish to use it on your first trial. However, once all the parameters of a design have
been debugged, this is the recommended option. It will guaranty that the final design meets all
your design criteria.
Merge solution with current line:
This item should be checked if you wish to merge the optimum spotting solution with any line
portion which already exists to the left of the Start Station (or leftmost structure) and to the right
of the End Station (or rightmost structure). The existing portions and the newly spotted segment
will be merged into a single line.
If this item is not checked, the newly spotted segment will be considered a new line by itself, i.e.
another line on the same alignment (see Section 5.4.6.4 for a discussion of multiple lines).
Existing structure locations only:
If you have an existing line, you can use this option to force the optimization to only use the
existing structure locations. This option is similar to making all existing structure locations
required locations.
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H-frame base height adjust:
When spotting wood H-frames in terrain with side slopes, the selected frame may have to be
lowered so that the pole on the lowest terrain side has enough embedment length: the other
pole is sawn off or embedded more deeply. Therefore, the program needs to know the offset of
the poles (distance from center of the frame). This option only works if you have a TIN model. It
will automatically height adjust your frames so that the ground line of the poles meet the lowest
side profile at the offset specified.
Show Advanced and Exotic Options:
Some legacy methods and new user specific options are available when this option is checked.
Figure 14.1-7a below shows these available options that are rarely used.
Figure 14.1-7a Advanced and Exotic Options
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Allow conductor data override:
This item is checked if you wish to input your own catenary constants for the conditions of
Sections 7.3.10, 7.3.11, 7.3.13 and 7.3.17. This option is not normally used but may be
convenient to compare a PLS-CADD solution to solutions by other optimizing programs which
require you to input catenary constants instead of defining design criteria by reference to
weather cases.
Suboptimal or spot interval loop:
This optional item lets you select ranges of spotting intervals and suboptimals to explore the
effect of these variables on the solution. This option is only used as a debugging or research
tool.
Forward, Reverse or Both:
If you select the Forward direction, the optimization will proceed in the direction of increasing
stations between the selected Start and End stations. If you select the Reverse direction, the
optimization will be conducted in the direction of decreasing stations, starting at the End station.
For a small station spacing, optimizing in the forward or reverse directions should give you
designs with very similar costs, but possibly different structure spottings.
Parabola or Catenary:
If you select Parabola instead of Catenary as the cable model, you will speed up time to
solution. You may want to use the parabolic option at the preliminary design stage, but switch to
the catenary model for a final design. Both options should give almost identical results if sag-tospan ratios do not exceed five percent.
Abort spotting if no complete solution:
Check to abort immediately if can’t find an error free solution rather than generating a design
with error(s).
Insulator Counter Weights For Solving Swing Problems:
One of the items checked in the optimum spotting of the line is the swing of insulators. This
option allows you to enter a weight increment, maximum weight, stock number of weight for cost
considerations, and number of phases to add counter weights on a structure. The increased
weight can alleviate certain swing problems and permit a structure to pass the swing criteria. It
should be noted that when adding insulator counter weights this value will influence the
structure’s available weight span for the weight span check.
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Once you click on OK at the bottom of the Optimum Spotting dialog box, the optimization
process begins. You will see short vertical lines being drawn on top of the profile from the left of
the screen. These lines together with the information in the Optimization status box at the
upper left of the screen indicate the optimization progress along the line. At each line, each
possible structure is tried (36 different types in the Spotdemo example) with all previous
possible combinations of structures and locations.
For the selected optimization parameters, the entire spotting of Spotdemo takes less than one
minute on a slow 200 MHz Pentium machine. Once the optimization is done, the progress report
of Fig. 14.1-8 is opened. It shows that the final design consists of 3 tensions sections with ruling
spans of 921 ft, 1186 ft and 934 ft, respectively. The final design took several trials because the
initial assumed ruling span (1000 ft) was too different from the actual ruling spans. When
clearance calculations or weight spans are calculated with the wrong ruling span, the design
may not be valid.
After you close the report of Fig.
14.1-8, you will see the actual
spotting of the line with the
lowest conductor of the set which
you selected as that controlling
the spotting optimization. This is
shown by the profiles of Fig.
14.1-9. The best way to get
information regarding the three
tension sections and their ruling
spans is to open a line summary
report with Line/ Reports/
Summary
or
simply
use
Sections/ Modify.
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Fig. 14.1-6 Conductor Selection
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Fig. 14.1-7 Optimum Spotting Required Parameters
You will find that the design in Fig. 14.1-9 includes 35 structures for a total cost of $ 569,560.
Most structures are used at close to 100% and the conductor is very close to the clearance line
at its lowest position (which you can display by choosing “Hot 212“ and “Max Sag RS“ in the
“Display all sections for weather case below“ fields of Sections/ Display Options. You can
verify with Sections/ Sag Tension that all three tension sections are almost exactly at 20% of
ultimate at 60 degrees after creep (one of your design criteria).
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14.1.7 Accepting Automated Spotting
As you will quickly learn when you try optimization on real projects, there is no such thing as
"Black Box" optimization. In practice, some manual adjustments are often required before a
computer-spotted design can be sent out for construction. There are also some cases where
only parts of a line can be optimized, the rest having to be designed interactively with custombuilt structures. The ability of PLS-CADD to integrate automatic and interactive spotting is one
of its uniquely powerful features.
After optimization, you should always make a visual check of vertical clearances. On rare
occasions, you will see the anomaly depicted in Fig. 14.1-10, where it appears that the
automatic spotting allowed the lower phase at the controlling hot temperature to encroach the
ground clearance line (dotted line above straight line CD). This happens because the algorithm
that checks clearances to ground points checks these clearances at every single surveyed point
and also checks the clearance of the lowest point of sag (Point A in Fig. 14.1-10) above the
ground clearance line (dotted line parallel to the profile). For computational efficiency, the
algorithm does not look for the possible intersection between the catenary curve and a sloping
dotted line, except at surveyed points. Therefore, if you run into the situation depicted in Fig.
14.1-10, there is a very simple fix to remedy that situation. All you need to do is add a ground
point (say point D in Fig. 14.1-10) on the profile in the region of encroachment by clicking with
the mouse on the straight line between B and C after using the command Terrain/ Edit/ Add
PFL Points. After you rerun the spotting optimization with the new point, the clearance problem
will disappear.
Even after re-spotting you cannot be
sure that your line is adequate until
you have strung all the circuits and
made the 3-dimensional engineering
checks.
Remember
that
the
simplified optimization model only
includes the lowest phase of one
designated conductor set.
Fig. 14.1-8 Progress Report
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14.2
Automatic Optimum Pole Selector
While Section 14.1 discussed the automatic optimum spotting of a family of structures, this
section covers the automatic optimum selection from a family of poles of given heights and top
geometry at predetermined locations along the profile. Automatic optimum pole selection is only
available if you have the extra cost optimum spotting option of PLS-CADD. The primary
advantage of this option is that it works directly with a Method 4 structure.
The pole selector dialog box is reached with Structures/ Automatic Spotting/ Automatic Pole
Selector command (see Fig. 14.2-1).
With the various options, you will be able to automatically replace the shaft of failing poles with
stronger ones or replace the shaft of over-designed poles with less expensive ones. This can be
done with poles of the same material as those in your model, or some replacement material
(available pole shaft materials are currently steel, wood, laminated wood, and concrete). For
example, if you have a wood pole line that you are re-conductoring, you can use the pole
selector option to automatically
replace all failing wood poles by
the least expensive steel poles
available in your steel pole
components library.
Fig. 14.1-9 Optimum Spotting of Demo Line with Parameters of
Fig. 14.1-7
For a full discussion of this
very powerful option you should look at the following document:
http://www.powline.com/products/automaticpoleselector.html
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14.3
Optimum Body and Leg Extension Selection
Starting in version 15.30, PLS-CADD with optimum spotting can automate the selection of body
and leg extensions (BLE) for lattice towers which have been built using the Family Manager
feature in TOWER.
14.3.1
TOWER Model Requirements for Optimum BLE
In order to use the BLE selection feature PLS-CADD must have optimum spotting enabled with
the license. The lattice towers must be saved in version 15.30 or newer of TOWER and must
have all possible body and leg extensions created in the Family Manager feature of TOWER for
each unique tower type. It is not necessary to have every potential combination of body and leg
extensions created in the Family Manager. You just need to model each potential body
extension and each potential leg extension.
Within the Family Manager settings in TOWER, there is a Naming button which provides options
to customize how TOWER assigns names to any new body and leg extension configurations
created by the BLE Selection feature in PLS-CADD. Also, in Family Manager, you can define
the Maximum Differential Leg Heights. This setting will be used by PLS-CADD if it needs to
generate additional towers with different body and leg combinations which are not built in Family
Manager.
14.3.2
Optimum Body and Leg Extension settings
The Optimum BLE Selection feature can be found at Structures/Automatic
Spotting/Optimum Body and Leg Extension Selection in PLS-CADD. The Optimum BLE
Selection dialog box is shown in Fig. 14.3-1. This feature works by reading the Family Manager
compliant .tow files and finds the optimum combination of body and leg extensions to fit the TIN
ground surface at each location. The optimum combination is defined as the minimum tower
weight configuration that satisfies the input parameters. To use the BLE selection feature, you
must first have a PLS-CADD model with structures spotted and a ground TIN model created.
The structures may be either M1 or M2 (stick structures) or M4 (PLS-POLE or TOWER)
structures.
The user will need to select the parent Family Manager TOWER model that you have in the
PLS-CADD model. Use the Auto-detect parent Family Manager model for each structure
option to run the optimum selection on all existing TOWER models spotted on the line. Use the
Manually specify the parent Family Manager Model option to run the optimum selection on
all stick structures and PLS-POLE models on the line.
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Fig. 14.1-10 Clearance Encroachment
When evaluating each structure site for the optimum BLE combination, you have the option to
force PLS-CADD to only evaluate BLE combinations that have been built in the TOWER Family
Manager or to allow PLS-CADD to create all possible BLE combinations based on the tower
geometry. If you select the second option, you have the option to specify a folder where any
new BLE combination tower models will be saved. If you do not specify a folder, any new BLE
combination towers models will be saved to the same directory as the parent Family Manager
model. Note that PLS-CADD will add any new BLE combinations used in the optimization back
into the Family Manager table of the parent TOWER model.
When running the optimum BLE selection, you can choose to create a report only or have PLSCADD make the necessary changes to your model. When you elect to modify the line, PLSCADD will create a copy of the current line model and all of the structure changes will be made
in the new line and this will become the active line. The original line will be unaffected by the
changes. The original line and the new line can be viewed under Lines/Edit in PLS-CADD.
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You also have the ability to specify specific ranges for foundation reveal and wire attachment
movement. The Allowable foundation reveal is the vertical distance between the ground TIN
and the bottom leg joint. The Allowable attachment movement is the vertical distance the wire
attachment points are allowed to move when evaluating BLE combinations. However, be aware
that if no vertical movement of wire attachment locations is allowed, an optimum solution may
not exist at a structure location.
Additional settings are provided for lattice towers with grillage foundations to ensure that the
center of the grillage is always set a minimum distance below TIN ground surface. The Grillage
Stub Angle Length is the length along the slope of the main leg (true 3D length) from the
bottom of the leg extension to the top of the grillage base. This creates an X, Y, Z reference
point at the top of the grillage base, which is called the grillage center top in PLS-CADD. PLSCADD then calculates the vertical projection of the stub angle length from the X, Y, Z reference
point and this vertical projection becomes the default grillage setting depth.
You can enter a value for the Allowable grillage reveal at center top grillage. This value
defines the maximum reveal, either positive or negative, of the grillage setting depth top relative
to the TIN model. In effect, this value can be used to control the minimum grillage embedment
depth relative to the TIN surface for the optimum BLE selection calculations. The distance from
the top of the default grillage setting depth to the TIN surface will be reported by PLS-CADD as
the grillage reveal. Fig. 14.3-2 illustrates the foundation reveal and grillage reveal for a leg
extension with four different TIN surface location scenarios.
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Fig. 14.2-1 Optimum Pole Selector Box
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15.
PLS-CADD/ LITE
PLS-CADD/ LITE is a limited version of PLS-CADD restricted to calculations of sags, tensions,
loading trees, clearances between wires, stringing tables and conductor current vs. temperature
relationships for the wires radiating from a single structure. Its capabilities are also available in
the full version of PLS-CADD. The structure attachment points can be designated points in
space or attachment points of a structure model developed in the TOWER or PLS-POLE
program. With PLS-CADD/ LITE one is able to rapidly create a model without having to manage
the full terrain information of PLS-CADD. Since a PLS-CADD/ LITE model only includes single
spans radiating from a structure, sag and load calculations for the model are based on the
Ruling Span method (Level 1 wire modeling).
Fig. 15.1-1 Wood Pole Strung in PLS-CADD/ LITE
If a structure model has been developed in the TOWER or PLS-POLE program, that model can
quickly be strung with wires in any direction by entering data in a single table (see Fig. 15.1-2).
Then the corresponding loading tree can be calculated for that structure and the structure
checked at the click of the mouse. The structure shown in Fig. 15.1-1 actually consists of a
wood pole guyed in several directions through stub poles and span guys. The pole, cross arms,
insulators, associated stub poles and all guys are part of a single PLS-POLE model.
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Fig. 15.1-2 One Possible Configuration of the Model
While PLS-POLE and PLS-CADD/ LITE working together form the ideal combination for
conducting joint-use studies of existing wood or other poles, either one of these programs can
be used by itself in stand-alone mode.
A project developed by PLS-CADD/ LITE is saved in a file named Project.loa. The ".loa"
extension is required to distinguish PLS-CADD/ LITE files from regular PLS-CADD files which
have the ".xyz" or ".pfl" extension. Therefore, it is essential when you create a new PLS-CADD/
LITE project to name the project file with the ".loa" extension, as this is the only piece of
information that lets PLS-CADD know that it should run in PLS-CADD/ LITE mode.
In order to use PLS-CADD/ LITE you need first to develop design criteria in the Criteria menus
(this was described in Section 7) and you need to have the appropriate ground wire and
conductor models (these models were described in Section 9). Then you will install and sag the
wires that radiate from your structure as described below. When you start a new project you can
set up your work quickly as described in Section 15.1.5.
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15.1
Installing and Sagging Wires
In PLS-CADD/ LITE, if you do not select “Use an Existing Structure File“ at the top left of the
Model Setup dialog box of Fig. 15.1-2, there is no concept of cable sets and phases. In such a
case, the Origin Label column (3rd column in the table of the Model Setup dialog) will not
appear, but it will be replaced by three columns for the X, Y and Z coordinates of the structure
attachment points.
If you select “Use an Existing Structure File“ at the top left of the Model Setup dialog, the Origin
Label column will display the sets and phases (set:phase) which must be defined in the TOWER
or PLS-POLE model of the structure: the X, Y and Z coordinates of the corresponding structure
attachment points are not displayed, even though they are known to the program.
In either case, all you need to do is describe how individual wires radiate from the structure
attachment points (one wire in each line of the Model Setup table). While we say that the wires
radiate from the structure, it is not necessary that they all terminate on the same vertical axis.
Actually, one of the powerful features of PLS-CADD/ LITE is that the various wire attachment
points on the structure may have arbitrary offsets from whatever vertical reference axis is
associated with the structure. In the right pane of Fig. 15.1-1 you can see wires with different
offsets radiating from cross arms perpendicular to each other. Ignoring offsets, as is commonly
done by other loading programs, can result in serious errors in the calculation of design loads,
especially with short spans.
Each wire has two end points,
the origin being the attachment
point to the structure and the
end being at the other extremity
TA
of the span. Internally, these end
points are located in a global
LA
TC
TD
X,Y,Z coordinate system, where
Y is North, X is East and Z is up.
TA
TC
TD
LD
LC
However, structure loads are
TB
LB
defined by their components in
TB
the structure transverse and
longitudinal
directions.
Therefore, you will need to
define the structure transverse
direction (direction shown in the
plan view of Fig. 15.1-3) relative
Fig. 15.1-3 Top View of Radiating Wires
to the global Y-axis. This is done
by entering the Bearing of Transverse Axis (angle from Y-axis to transverse structure direction
between -180 and + 180 degrees, positive if clockwise) in the top left part of the Model Setup
dialog (see Fig. 15.1-2). The arrows labeled TA, TB, TC and TD in Fig. 15.1-3 show the wind
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reactions at the ends of the wires and the corresponding loads on the structure (in the span
coordinate systems). These wind loads are reported by PLS-CADD/ LITE as positive quantities
if their actions on the structure have positive projections in the direction of the structure
transverse axis: this is the case for all the wind load arrows shown in Fig. 15.1-3.
While the single PLS-CADD/ LITE structure is not located on an alignment like any structure in
a full PLS-CADD model, spans can be categorized as back and ahead spans when the
definition is needed as described in Fig. 7.3-9a of Section 7.3.12.7.
All data needed to install and sag wires are entered in the Model Setup dialog box which you
reach with Line/ Setup. The columns which make up the table of the Model Setup box depend
on your choice of method for installing and sagging the wires. In that table, you will need to
enter the following data for each wire:
15.1.1
Data Needed Regardless of Selection of Installation and Sagging Methods
Description:
Alphanumeric description of wire
Cable File Name:
Clicking on this button takes you to the cable library where
you select a wire type
Wires in Bundle:
In case you attach a bundle of wires to the structure, this is
the number of wires (subconductors) in the bundle
Ruling Span:
Length of ruling span used to make sag-tension
calculations (default is horizontal projection of span). The
calculator function can be used in this cell as described in
Section 3.4 to calculate the ruling span of a known set of
spans.
Display weather case:
You can either select a “Weather Case“ from the list of
available weather cases (defined in Criteria/ Weather) or
you can type in a “Temperature“. The weather case or the
temperature (without wind) will be used for displaying the
wire. If the weather case includes wind, the wires will be
displayed twice, once for the wind blowing perpendicular to
the wire in one direction and once for the wind blowing in
the opposite direction
Display Condition:
Wire condition (Initial, after Creep or after Load) used for
displaying the wire
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Display Color:
Color used for displaying the wire. Defaults to the color
nominated in the cable file but can be changed if needed.
The Model Setup table has the option to sync colors from
cable file or default to standard color selection at the top of
the table.
Insul. Counter Weight:
Weight that is added to the design vertical load produced
by the wire at the structure attachment point. This may be
used to include the insulator weight in your loading tree if
your structure program does not take care of it
automatically (TOWER and PLS-POLE can add insulator
weights to loading trees) or to handle the counterweight
that may be hung at the tip of a suspension insulator to
decrease insulator swing.
Voltage:
Voltage of wire. Defaults to 0. Used by some codes to
identify ground wires (0 kV) and adjust their properties.
For example: CAN/CSA-C22.3 No. 60826-10 adjusts
groundwire ice to match conductor ice weight. IS 802
1995 adjusts groundwire drag coefficients.
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15.1.2
Defining Attachment at Structure
15.1.2.1
With Global Coordinates of Attachment Points
This option is enabled if you do not select “Use Existing Structure File“ in the top left area of the
dialog box.
Data outside of the wires table:
Base Z:
Elevation at base of structure used to draw horizontal line
representing ground
Data needed for each wire:
Origin X, Y and Z:
15.1.2.2
Global coordinates of the attachment point to the structure
By Importing a Structure Model with Already Defined Attachment Points
This option is enabled if you select “Use Existing Structure File“ in the top left area of the dialog.
With this option, you can import a TOWER or PLS-POLE model with predefined attachment
points for sets and phases.
Data outside of the wires table:
Base X, Y and Z:
Global coordinates of the point at the structure base which has 0,
0, 0 local coordinates in the structure program. PLS-CADD/ LITE
will use this information to obtain the global coordinates of all
structure attachment points as defined in the TOWER or PLSPOLE model and display identifying names for these attachment
points in the column labeled Orig. Label. The identifying name is
"i : j", where "i" represent the set number and "j" the phase number
in the PLS-CADD Link table of TOWER or PLS-POLE.
Groups:
Opens the Structure Groups dialog where you can manually
assign groups for the assignment of load cases from the Criteria/
Structure Loads table.
See section 7.3.12.9 for more
information.
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15.1.3
Defining End of Each Span
For each wire, the location of the span end (the origin being the structure attachment point)
needs to be defined. There are three options available. The columns which are displayed in the
wires table depend on your selection in the Span End Attachment Point area of the Model
Setup dialog. If you select more than one option in the Span End Attachment Point area, you
will enable the End Mode column in the wires table where you will be able to select a particular
option for each individual wire. If you select Ground elevation, a column labeled End Ground
Elevation Z will appear in the table below in which you should enter the Z of the ground at the
end of each span. This value is used to determine the height above the ground of the end of
each span for the purpose of determining the wind load for those codes that make the wind
velocity dependent on height above the ground.
15.1.3.1
With Global Coordinates of End Point
If you select XYZ Coordinates (or Coordinates in the End Mode column) you will enable the
End X, End Y and End Z columns in which you will enter the global coordinates of the span end
for each wire.
15.1.3.2
With Azimuth, Span Length and Vertical Projection
If you select Azimuth and Span Length (or Projections in the End Mode column) you will enable
the Span Azimuth, Span Horizontal Projection and Span Vertical Projection columns. The
azimuth is, in the plan view, the clockwise angle, between -180 degrees and +180 degrees,
measured from the structure transverse axis to the span direction (see Fig. 15.1-3). The Span
Vertical Projection is positive if the structure end of the span is lower.
15.1.3.3
With Wind Span and Weight Span
If you select Wind and Weight Span (or Wind Span in the End Mode column) you will enable
the Wind Span and Weight Span columns. The program will display the span as if it had a
length equal to twice the wind span and equal end elevations. This option is not used when you
know the actual span geometry. You will only use it when you need design loads based on
assumed maximum wind and weight spans, for example in the case of the design of a structure
for future use. With this option, the program will calculate the loads at the end of each wire as
follows:
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Transverse load =
Transverse load per unit length of wire times Wind Span
Vertical load
Vertical load per unit length of wire times Weight Span
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15.1.4
Sagging Wires
Due to the diversity of situations where PLS-CADD/ LITE may be used to determine loads on
an existing or planned structure, we provide you with five different methods for sagging a wire.
The appropriate columns which are displayed in the wires table depend on your selection in the
Sagging Options area of the Model Setup dialog. If you select more than one option in the
Sagging Options area, you will enable the Sagging Mode column in the wires table where you
will be able to select a particular option for each individual wire.
15.1.4.1
Specifying the Horizontal Component of Tension for Given Temperature
and Cable Condition
If you select Tension (or Horizontal Tension in the Sagging Mode column) you will enable the
Sagging Condition, Wire Temperature and Horizontal Tension columns in which you will
enter the wire condition (Initial, after Creep or after Load), the wire temperature and the
horizontal component of tension at sagging, respectively.
15.1.4.2
Condition
Specifying the Catenary Constant for Given Temperature and Cable
If you select Catenary Constant (or Catenary in the Sagging Mode column) you will enable the
Sagging Condition, Wire Temperature and Catenary Constant columns in which you will
enter the wire condition (Initial, after Creep or after Load), the wire temperature and the
catenary constant at sagging, respectively.
15.1.4.3
Specifying Mid Span Sag for Given Temperature and Cable Condition
If you select Mid Span Sag (or Mid Span Sag in the Sagging Mode column) you will enable the
Sagging Condition, Wire Temperature and Mid Span Sag columns in which you will enter the
wire condition (Initial, after Creep or after Load), the wire temperature and the mid span sag at
sagging, respectively.
15.1.4.4
Specifying Coordinates of One Point Surveyed Along Wire for Given
Temperature and Cable Condition
If you select Surveyed Point on Cable (or Pt. on Cable in the Sagging Mode column) you will
enable the Sagging Condition, Wire Temperature, Cable X, Cable Y and Cable Z columns in
which you will enter the wire condition (Initial, after Creep or after Load), the wire temperature
and the global coordinates of a point surveyed within the span, respectively. This method is
normally used when the global coordinates of both span ends and the intermediate point are
surveyed at the same time.
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15.1.4.5
Using the Autosag Function
If you select Tension from Automatic Sagging Criteria (or Autosag in the Sagging Mode
column) the wire will be sagged automatically as tight as it can be without violating any of the
automatic sagging criteria defined for your project (see Section 7.3.7).
15.1.5
Starting New Project
Fig. 15.1-4 Getting Started with New PLS-CADD/ LITE Project
If you chose PLS-CADD/ LITE after clicking on File/ New, the dialog box of Fig. 15.1-4 will
appear. With the proper selections in that box, you will be taken directly to the Model Setup
dialog box of Fig. 15.1-2 which will have already been customized for you to enter span data
without any further consideration.
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15.2
Viewing PLS-CADD/ LITE Model
When you load an existing
PLS-CADD/ LITE project
or when you click on OK at
the bottom of the Model
Setup dialog box, you will
get by default two views of
your model as shown in
Fig. 15.2-1. The left pane
will show a profile view
(projected perpendicular to
the structure transverse
axis) and the right pane will
show a 3-D view. You can
manipulate these views or
open
additional
view
windows exactly as you
would with the full PLSCADD program. If you do
Fig. 15.2-1 Tower Imported in PLS-CADD/ LITE
not import a structure
model, you will see the wires and their attachment points, but no structure. For example, Fig.
15.2-2 shows the profile view (bottom right window), 3-D view (upper right window) and the
loads report for a simple two-wire system that represents a drake conductor attached at a
structure located at a 10 degree line angle. It took two lines of data in the Model Setup wires
table to generate the model. The system is subjected to two load cases, the NESC Heavy
Loading condition with wind blowing in both the positive and negative structure transverse
directions.
Many of the view controls for the structure are shown in the View menu including the View/
Display Options/ Show Structure Compass which shows a compass at the base of a
structure when enabled that depicts the structure coordinate system directions. It will also
include a green ground plane at the base of the structure when enabled.
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15.3
Engineering Calculations and Reports
Once your PLS-CADD/ LITE model has been developed you can use the following structure
functions:
Structures/ Loads/ Report:
This function determines the design load information on the structure. As can be seen in Fig.
15.2-2, the loads report includes first for each load case and for each wire:
Fig. 15.2-2 Design Loads for a Simple Two-wire Model
1) The Wire Loads in the span coordinate systems. These loads are the arrows shown in Fig.
15.1-3 and are strictly equal to the reactions at the end of each wire times the appropriate load
factors as discussed in Section 7.3.12.3. The vertical loads do not include the weights from
insulators or counterweights.
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2) The Structure Loads applied by each wire individually to the structure in the structure
vertical, transverse and longitudinal directions. The vertical loads now include the factored
weights of insulators or counterweights.
Then the report shows the sums of the loads from Item 2) above for all the wires that come to
the same structure attachment point. These loads are the final design loads at the structure
attachment points.
Finally the report lists the factored design computed as described in Section 7.3.12.5.
IMPORTANT NOTE:
You should be aware of the two different methods which are used to calculate design
structure loads at a wire attachment point, depending on whether the wire is modeled by
its actual geometry (Sections 15.1.3.1 or 15.1.3.2) or by wind/ weight spans (Section
15.1.3.3).
When a model is modeled by its actual geometry, the loads are always calculated as
described in Section 7.3.12. There may be slight differences between these loads and
those that you might get by simpler traditional methods which do not consider the length
of wire in the span nor the span blowout under wind.
When a model is described by its wind and weight spans, the unfactored loads in the
span coordinate system (those shown in Fig. 15.1-3) are based on the traditional
assumption that: 1) the transverse wind load, T, at the end of a wire is equal to UH (see
Fig. 7.2-3) times its wind span, 2) the vertical load, V, is equal to ( UW + UI ) times its
weight span, and 3) the longitudinal load, L, is the horizontal component of tension in the
ruling span caused by the resultant UR.
Structures/ Loads/ Write LCA file:
This function writes the loading tree and structure design pressures in a standard vector loads
file (*.lca format) which can be used directly by our TOWER and PLS-POLE programs.
Structures/ Loads/ Write LIC file:
This function writes a wire loads file (*.lic format) that can be used by our TOWER and PLSPOLE programs to determine allowable spans.
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Structures/ Check:
If you have attached wires to a Method 4 structure (after having selected Use Existing Structure
File in the Model Setup dialog box), you can use this function to apply the loading tree to the
structure and have the applicable structure program (TOWER or PLS-POLE) automatically
analyze the structure under that loading tree and report the results, both graphically or in text
form. For example, the tower in Fig. 15.2-1 was analyzed and checked automatically by the
TOWER program within two seconds of clicking on it in PLS-CADD/ LITE.
Note: The Structures/ Check function is not applicable to Method 1 and Method 2 structures
in PLS-CADD/ LITE
Structures/ New:
This command lets you create a Method 1 or a Method 2 structure. It cannot be used to create
Method 4 structures. Such structures are created in the TOWER or PLS-POLE programs.
Structures/ Modify:
This commands lets you edit the structure selected in the top left area of the Model Setup dialog
box. For Method 4 structures, you will automatically be taken to the TOWER or PLS-POLE
program.
In addition to the structure functions described above, PLS-CADD/ LITE lets you access most
of the full PLS-CADD section functions (see Section 11.2).
Sections/ Check, Sections/ Sag-Tension, Sections/ Wire Clearances, Sections/ Structure
Clearances, Sections/ Stringing Charts, Sections/ Galloping and Sections/ IEEE Std. 738.
Sections/ Galloping only works if you import an existing structure.
As an example of the potential use of Sections/ Wire Clearances, consider the two crossing
wires shown in Fig. 15.2-3, a high voltage conductor (parallel to the X-axis) on top of a crossing
telephone line. The model (file "litex4.loa" ) was created in a few minutes by entering the global
coordinates of the four wire attachment points and the sagging tensions of the wires. Sagging
could have been done by forcing the wires to pass through intermediate surveyed points: in
such a case, creating the model would have required the entry of the coordinates of a total of
only six surveyed points in two lines of the wires table. The left pane in Fig. 15-7 is a profile view
parallel to the X-axis (with vertical scales exaggerated by a factor of 10). The right pane is a 3-D
view of the two wires.
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Using the Sections/ Wire Clearances function, we can determine the minimum 3-dimensional
clearance between the conductor at 240 degrees and the telephone wire below at 120 degrees
(see Fig. 15.2-3). Solving this very complex problem was immediate in PLS-CADD/ LITE. The
value of the minimum clearance and its location is shown by markers in the various views of Fig.
15.2-3.
Finally, you can obtain a complete report regarding all design criteria, loads, sags and tensions
using Line/ Report.
Fig. 15.2-3 Crossing Wire of Litex4.loa Model
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16.
PLS-CADD/ ULTRALITE
PLS-CADD/ ULTRALITE is a more limited version of PLS-CADD/LITE restricted to calculations
of sags, tensions, and stringing tables for one wire. Its capabilities are also available in the full
version of PLS-CADD and PLS-CADD/LITE. Since a PLS-CADD/ ULTRALITE model only
includes a single span the calculations for the model are based on the Ruling Span method
(Level 1 wire modeling).
A project developed by PLS-CADD/ ULTRALITE is saved in a file named Project.ult. The ".ult"
extension is required to distinguish PLS-CADD/ ULTRALITE files from regular PLS-CADD files
which have the ".xyz" or ".pfl" extension. Therefore, it is essential when you create a new PLSCADD/ ULTRALITE project to name the project file with the ".ult" extension, as this is the only
piece of information that lets PLS-CADD know that it should run in PLS-CADD/ LITE or
ULTRALITE mode.
16.1
PLS-CADD/ ULTRALITE Project
When launching PLS-CADD you will see the Project Wizard dialog discussed in Section 5 and
you can select the option to Create a New Project and select the option for PLS-CADD/
ULTRALITE. You will then be taken to the main dialog box for PLS-CADD/ ULTRALITE shown
in Figure 16.1-1 and 16.1-2 below. Figure 16.1-1 is an overall view of the window while 16.1-2
shows the input data in the upper left corner of the dialog.
Fig. 16.1-1 ULTRALITE Main Screen
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Fig. 16.1-2 ULTRALITE Inputs
The different sections of the dialog are as follows:
Unit System
The first section of the dialog is the Unit System for the model and its reports. You can choose
between Imperial (lengths in feet, forces in lbs), SI (lengths in meters, daN force) and SI
(lengths in meters, N force).
Design Criteria
This section allows you to load or edit the necessary design criteria such as weather cases and
sagging limits for the sag tension calculations. If you select Load you will be able to choose
whether you wish to load the criteria file from a local or networked drive or download directly
from Power Line Systems website as discussed in Section 5.8. Once a criteria file is selected
you will be taken to the Design Criteria dialog box, which is a minimal version of the criteria that
is discussed in Section 7. Figure 16.1-3 shows the Design Criteria dialog box.
At the top there is a Notes section that allows you to enter notes describing the various
standards, assumptions, authors, dates, weather etc. related to the set of criteria. This is similar
to the Notes section discussed in Section 7.3.1.
The Weather Cases section is an abbreviated version of the Weather Cases table discussed in
Section 7.3.2.
The Weather Case for Final After Creep and Weather Case(s) For Final After Load allow you to
enter the weather cases to use for the calculation of the Load and Creep wire conditions in the
sag tension reports and display as discussed in Section 7.3.4.
The Tension Limits for Automatic Sagging and Checking of Wires allows you to enter your
sagging limits for the span. For example if you wish to sag the wire to 40% of the cables
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ultimate strength under the initial cable condition for the NESC Heavy weather case you could
input this as the % of Ultimate for that weather case and cable condition. The use of this table
is discussed in greater detail in Section 7.3.7.
After hitting OK out of the Design Criteria dialog box you may be presented with a dialog for
code specific input requirements if any of the weather cases in your criteria file have information
required for the Wire Wind Height Adjust Model or Wire Gust Response Factor.
Fig. 16.1-3 ULTRALITE Design Criteria
Span Geometry
The Span Geometry section allows you to input the following information:
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Wire Properties:
Span Horizontal
Projection:
Span Vertical
Projection:
Attachment Height
Above Ground:
Ruling Span:
This is the selected wire for the span. When you click in this field you will
be able to select a wire file from a drive location or download it directly
from Power Line Systems’ website.
The horizontal distance of the span
The vertical difference between the attachments of the span. A negative
value means the ahead attachment of the span is lower than the starting
attachment and a positive value means it is higher.
Average height above ground used for codes that adjust wind or ice due
to the height of the span above ground
Ruling Span for the span in question. If the automatic button is selected it
will default to the span length of the horizontal projection. If unchecked
you can enter an override value. You can also select the calculate button
which brings up a table that computes the ruling span from user entered
horizontal and vertical projections of the spans in the section.
Sagging Parameters
The sagging parameters section dictates how the span is sagged. It includes the following:
Wire Temperature:
Wire Temperature the sagging data is based upon.
Wire Condition:
Wire Cable Condition for Sagging (Initial, Load, Creep)
Sagging Method:
There are five sagging method options. The wire can be sagged by
entering the Horizontal-Tension, Catenary Constant, Mid Span Sag,
Slack, or using the AutoSag feature as discussed above and in Section
7.3.7. The Horizontal-Tension, Catenary Constant, and Mid Span Sag
options are self-explanatory. The Slack option allows you to enter the
extra wire in a span between the two attachment points. As you select a
different sagging method the input dialog fields for these items are open
while the others are not used but there values are calculated and
reflected in their respective field.
Tension Limit Status: Indicator that tells if current sagging tension produces results that violate
the Tension Limits for Automatic Sagging & Checking of Wires from the
Design Criteria.
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Reports
The Sag-Tension report and the Stringing Chart report are the only reports that can be
generated within PLS-CADD/ULTRALITE. The Sag-Tension reports gives a full sag-tension
report for all the weather cases which you have defined in your Design Criteria. The String
Chart report allows you to get a stringing sag and tension report for a range of temperatures and
span lengths. The report can include sags, tensions, catenary constants, and return wave
times. You can also choose to string bare messenger wire if working with lashed or bundled
cables.
This section also allows you to input a value of characters per line for the reports if you plan on
printing to a certain page size.
Span Graphic
The Span Graphic section allows for the display of the wire at the inputting sagging conditions
under different weather cases and cable conditions. This is controlled and shown on the right
side of the dialog. At the top of this section you can enter a profile view aspect ratio to scale the
vertical exaggeration of the view. It is useful in many situations when viewing spans with small
or limited sags.
The Wire Display Weather Cases and Conditions allows you to display the sagging weather
case and cable condition and up to two other weather cases and cable conditions. You select
these with the drop down menu and you can choose to show wire for all three cases. However
you are only permitted to Label the Sag on one of the weather cases. As you change the
weather cases and cable conditions the Horizontal Tension, Maximum Tension, Mid Span Sag,
Vertical Sag, Horizontal Blowout, Span Slack, Span Catenary Constant, and Maximum Tension
are updated in the section to the right of the selection.
The bottom includes the two actual span graphics. These are a profile view of the span as well
as a 3D View. These graphics show the sag labels based on your Label Sag selection as well
as span length, vertical difference in attachments, and height above ground. In the 3D View you
can also see the horizontal displacement of span due to a wind loading on the wire. This
blowout is also labeled in this instance.
Project Commands
On the left side of the dialog you can choose to Save the project, Close the project, or create a
project Backup. Please note that a backup is not necessary to send the project as a PLSCADD/ULTRALITE project is completely contained in the .ult file. The Backup option was
included should a file need to be submitted to technical support.
The last command allows you to Convert to PLS-CADD/LITE if you wish to use the expanded
capabilities of PLS-CADD/LITE, as discussed in section 15.
Example Video
To see a demonstration video of PLS-CADD/Ultralite see: https://youtu.be/ygRBYHG-cVs.
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17.
DISTRIBUTION LINE MODELING WITH PLS-CADD & PLS-POLE
PLS-CADD/Distribution is a version of PLS-CADD with limited functionally focused on design
of overhead distribution lines. The limited functionality results in an easy to use program tailored
specifically to the features and commands typically used on distribution projects. PLSCADD/Distribution will allow the user to create a 3D model of a distribution line and perform to
clearance calculations, sag/tension calculations, engineering functions within the model. PLSCADD/Distribution will work in conjunction with PLS-POLE/Distribution to perform any
structural calculations of steel or wood pole model (.pol file). PLS-POLE/Distribution is a
limited version of the PLS-POLE program which has been tailored for use on wood and steel
distribution pole structures. All capabilities of PLS-CADD/Distribution and PLSPOLE/Distribution are available in the full version of the applications.
17.1
PLS-CADD/DISTRIBUTION
PLS-CADD/Distribution is a version of PLS-CADD with many advanced features removed that
makes a simpler interface intended to model overhead lines distribution lines.
Fig. 17.1-1 PLS-CADD/Distribution
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459
PLS-CADD/Distribution can come with or without the SAPS Finite Element Sag-Tension
application enabled within the software. If SAPS is enabled within PLS-CADD/Distribution there
will be a red check mark near SAPS Finite Element Sag-Tension and Advanced Distribution on
the About PLS-CADD dialog, see Figure 17.1-1. The Advanced version of PLSCADD/Distribution will have the ability to utilize Finite Element analysis options. The Finite
Element options will allow for analysis of unbalanced structure loading, structure deflections,
add concentrated loads or marker balls to wires or use of L3 and L4 Finite Element options to
analyze the wire system interaction between structures.
PLS-CADD/Distribution is built on the concept that a Supervisor or Engineer of Record will
utilize PLS-CADD to create standard criteria files (.cri) and PLS-POLE to create standard
structure framesets (.frm).
These standard files will be referenced into the PLSCADD/Distribution model, allowing the distribution designer to build structures from the preestablished framesets, spot structures, string wires and perform final design checks based on
the predefined criteria file. Criteria and framesets cannot be modified or edited in PLSCADD/Distribution and should be created and reviewed by a user with a full version of the
PLS-CADD software.
PLS-CADD/Distribution does not allow for alignment based structures but instead uses only
XYZ structures as discussed on section 10.2.8 of this manual. As a result many of the features
that require an alignment are not available. Structure models can be created in PLSPOLE/Distribution using either wood or steel poles and by attaching the predefined framesets
to the poles. See section XX of the PLS-POLE manual for details on PLS-POLE/ Distribution.
Down guys and span guys can be included as framesets or added to the poles individually.
Adding guys individually allows the user to customize the location of the guys in PLSCADD/Distribution to match site specific conditions.
PLS-CADD/Distribution allows many of the typical PLS-CADD reports to be run, including wire
usage, structure usage and clearances from wires to survey points or ground surface. Sagtension reports, stringing charts and construction staking reports are also available. More
advanced reports, such as thermal rating, vegetation and danger tree clearances, and line
constants calculations are not included in PLS-CADD/Distribution.
The user interface of PLS-CADD/Distribution is nearly identical to that of PLS-CADD. A new
set of distribution toolbar buttons is provided and some of the commands have been renamed to
use terminology more commonly used in the distribution industry. Commands and features of
PLS-CADD which are not included in PLS-CADD/Distribution have either been removed
entirely or are greyed out.
17.1.1
Opening and creating new projects
PLS-CADD/Distribution is a limited version of PLS-CADD and any project built and saved in
PLS-CADD/Distribution can be opened in PLS-CADD and vice versa. Projects can be created
or opened in a similar manner as typical PLS-CADD projects. See section 5 of this manual for
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details on loading or viewing an existing model. Settings and user defined locations used within
File/Preferences and are the same as within the PLS-CADD. See section 5.2 of the PLSCADD manual for more details on File/Preferences.
17.1.2
Creating a criteria file for PLS-CADD/Distribution
PLS-CADD needs to be used to set up criteria files (.cri) for PLS-CADD/Distribution. See
Section 7 of this manual for descriptions of the different options available in the Criteria menu
within PLS-CADD.
There is no access to the Criteria menu options within PLS-CADD/Distribution. If you need to
edit any options within the criteria file you will need a full version of PLS-CADD. To load an
existing standard criteria file or select one of the available ones on our website you can use the
menu commend District Loading/Select District Loading... or
button. The command
District Loading/Report... will produce a criteria report that will allow for review of the criteria
defined within the .cri file.
The Supervisor or Engineer of Record needs to be careful when defining using Ruling Span or
Finite Element analysis options when creating criteria files for use in PLS-CADD/Distribution.
For standard versions of PLS-CADD/Distribution Finite Element analysis options are not
available. When creating criteria files for the standard and advanced versions of PLS-CADD it is
recommended that the criteria notes clearly define if the .cri file uses Ruling Span or Finite
Element design assumptions.
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17.1.2.1
Distribution Toolbar
Within PLS-CADD/Distribution a new distribution toolbar provides buttons used for many of the
commands commonly used within this application. This toolbar can be toggled on/off with the
command View/Toolbars/Distribution Toolbar. Figure 17.1-2 shows the distribution toolbar
and descriptions of each command are shown in the table below.
Fig. 17.1-2 Distribution Toolbar in PLS-CADD/Distribution
PLS-CADD/Distribution Tool Bar Command Summary
Load FEA File
Load feature code data from FEA file
Select District Loading
Load
district
loadingsystem
criteriafor
from
file, orwhich
download
criteriaforfiles
from the web
Set the
coordinate
this.cri
project
is required
all cartographic
functionality
Define Coordinate System
Merge from KML/KMZ
Terrain
Commands
Merge From Internet
Merge from LAS/LAZ
Merge Points from User XYZ
Create TIN
Attachment
Commands
Structure
Commands
Wire
Commands
Open PLS
Applications
WMS Import
Merge points from LAS or LAZ files into the PLS-CADD model
Merge points from user defined xyz file into the project This command is typically used
when importing survey data in ASCII format
Create Digital Terrain Model from XYZ Points
Attachment Manager
Use Web Map Services to import raster imagery into project
Attach, detach and position raster and vector attachments within the project
Structure Add XY
Add structure at XY point
Structure Add XY at survey point
Add an XY structure at the currently selected survey point
Structure Add XY along line
Add an XY structure along a line defined by two points or entities
Structure Delete
Delete a selected structure
Structure Modify
Opens structure Modify dialog box for a selected structure.
Structure Move
Move structure to location specified by mouse
Structure Move On
Move structure to survey point closest to mouse
Structure Move XY along line
Move an XY structure along a line defined by two points or entities
Structure Rotate Freehand
Graphically rotate the selected structure
Structure Rotate Bisect
Rotate the selected structure by picking two other points to bisect
Framing Rotate
Graphically rotate the selected frame set
Rotate Structure Arm
Structure Check
Rotate a selected arm so it is perpendicular to a selected wire
Check strength of selected structure
Sections Add Graphical
Graphically create a new section on clicking on desired attachment points
Section Delete
Delete a section of wire by selection
Section Modify
Modify section stringing properties
Graphically Relocate Wire
Graphically drag wire from one attachment point to another
Automatic Sagging
Section Check
Sag span per criteria defined within automatic sagging criteria
Check section tension agains criteria defined within cable tensions criteria
Start PLS-CADD
Opens an instance of PLS-CADD
Start TOWER
Opens an instance of TOWER
Start PLS-POLE
Opens an instance of PLS-POLE
Start SAPS
Opens an instance of SAPS
Opens an instance of CAISSON
Start CAISSON
17.1.2
Merge or create points into PLS-CADD model from KML/KMZ files
Merge points from the internet within the PLS-CADD model. This function will allow the
import SRTM (Shuttle Radar Topography Mission) or NED (National Elevation Dataset)
ground data directly into PLS-CADD
Terrain Functionality
Survey data and Terrain models can be created, loaded and displayed in PLSCADD/Distribution. The commands associated with terrain data commands are located within
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the Survey Data menu and the left portion of the Distribution tool bar, see Figure 17.1-1. Since
alignments cannot be defined within PLS-CADD/Distribution then terrain functions such as
interpolated points, terrain widths, clearance lines, side profiles and multiple alignments are not
available.
17.1.2.1
Coordinate System Definition
The project coordinate system can be defined with the command located Survey
Data/Coordinate System/Define. See Section 6.2.1 for more information on Coordinate
Systems within PLS-CADD.
17.1.2.2
Loading Survey Data
PLS-CADD/Distribution can load survey data using the same commands as located within
PLS-CADD. Section 6.2 and Appendix D of this manual discusses the details of the features
and commands associated with the XYZ Terrain Model in PLS-CADD. Some of the traditional
commands may appear different as they have been updated for PLS-CADD/Distribution. The
menu command Survey Data/Edit will present options to edit survey points, delete/deactivate
or export points, merge points from external file export or change the feature code of survey
points.
17.1.2.3
Survey Symbols and Clearances
The survey data loaded into a project will have unique requirements for minimum code
clearances, classification and display. Within PLS-CADD\Distribution many of the commands
associated with these unique requirements are located within the menu selection Survey
Data/Survey Symbols and Clearances. Located within this menu are selections to Edit, Load,
Save or produce a report for the feature code table. There is also a button on the distribution
toolbar to launch the command to load a feature code (.fea) file. At the bottom of the Survey
Data/Survey Symbols and Clearances menu are three options that control the survey point
display settings for display of survey points. See section 6.1 of this manual for more information
on the general use of Feature Codes.
17.1.2.4
Surface Modeling
Within PLS-CADD/Distribution a Triangulated Irregular Network (or TIN) model of the XYZ
terrain is a surface can be created. Within the menu command Survey Data/Surface Modeling
are many of the same commands associated with working with TIN files in PLS-CADD. These
commands include display options for the TIN, creating and deleting TIN surfaces. The menu
command Survey Data/Surface Modeling/Add point at X,Y will add a XY point into the project
and use an elevation of Z based off of the TIN surface. The menu command Survey
Data/Surface Modeling/Surface Model Interpolation for Z=0 Survey Points, or XY Based
Structures... is a command that is used to bring a project down to an elevation of zero can be
used to help snap a project to a new or updated TIN surface. See Section 6.4 of this manual for
additional information on these commands.
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17.1.3
Structure Functionality
PLS-CADD/Distribution is intended to be utilized with PLS-POLE models, however Method 1
“stick” structures can be utilized if they have been prebuilt using the PLS-CADD program. Stick
structures cannot be created inside PLS-CADD/Distribution.
PLS-POLE models (.pol) can be built using PLS-POLE/Distribution that is provided with PLSCADD/Distribution. These structures are built using framesets from a prebuilt frameset
component library file. Guys and cables can also be installed from their respective component
library files or if defined in the framing library. All other components for a pole, such as crossarms, braces, davit arms and equipment, need to be included in the framing library in order to
be used in the limited version of PLS-POLE.
Structures are spotting using the features for spotting X,Y structures. Automatic spotting and
optimum spotting of structures is not available in PLS-CADD/Distribution.
17.1.3.1
Adding and Deleting Structures
Only XY Structures are allowed to be added within PLS-CADD/Distribution. The menu
commands located Structures/Add will provide options to add XY Structure, add XY structure
along line or add XY Structure at survey point. There are also
distribution toolbar that launch these same commands.
buttons in the
To delete structures the command Structures/Remove or similar button on in the distribution
toolbar can be used.
17.1.3.2
Modifying Structures
PLS-CADD/Distribution is provided with a version of PLS-POLE with limited capabilities that
only allows for the use of framesets from the frameset component library.
The menu command Structures/Modify or
button will open the Structure Modify dialog box
allows and allow for structure modifications to structure file name, height adjustment,
orientation, structure comments, counter weights and more.
Within the menu command Structures/Move are three commands that will help move XY
Structures. Structures/Move/Freehand or
button will allow you to move the structure to the
mouse coordinates selected. Structures/Move/On Snap... or
button will snap a structure to
a selected survey point. Structures/Move/XY Structure Along Line... or
button will move a
structure along a line defined by two entities.
Structures can also be rotated with two commands located within the Structures/Rotate menu
command. The command Structures/Rotate/Freehand or
button will allow a structure to
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graphically rotate using the mouse structure while Structures/Rotate/Bisect Points or
button will rotate a structure so the transverse face of the structure aligns with the bisector
between two selected points.
17.1.3.3
Structure Staking Table
The structure staking table is available within the menu command Structures/Staking Table....
See section 12.2.1 of this manual for additional details on this table.
17.1.3.4
Checking Structures
The analysis of M1 or M4 structures in PLS-CADD/Distribution is the same as in PLS-CADD
and the menu command Structures/Check can be used or the structure check button in the
distribution toolbar.
17.1.3.5
Customizing Structures
Customization of structures for site specific arrangements is available in PLSCADD/Distribution but is limited to adjusting guy anchor locations and rotating framesets.
Guy anchors included as part of frameset have limited options for customization. Whereas guy
anchors added to a pole model from the component library in PLS-POLE have more options for
customization. Whether a guy wire is added via a frameset or as an individual component will
determine the level of flexibility in customizing the guy anchor to fit site specific locations. The
command Structures/Customize Structure/Move Guy Anchor will create a site specific
structure and allow guy anchor locations to vary from structure to structure when using common
structure file and the guy anchor is added from the component library in PLS-POLE. Within the
Move Guy Anchor menu there are options to move a guy anchor and snap it to a survey point,
move it graphically with the freehand option, move in-line with wires, bisect the line angle or
extend the guys to the ground surface by selecting slope intersect with TIN.
Framesets included on the structures can be modified if PLS-CADD. Using these commands
will create a site specific structure file. The menu command Structures/Customize
Structure/Move Framing has commands to rotate a cross-arm perpendicular to a wire, rotate
graphically with the freehand selection or snap to a survey point. This command can also be
accessed thru the Entity Info menu.
17.1.4
Wire Functionality
PLS-CADD/Distribution uses the graphical method of stringing wires. This allows maximum
flexibility to string wires between any structures within the line model by clicking on each
structure in the order the wire will be strung. Once wires are strung in the model, the traditional
features are available for displaying wire at specific weather cases, colors, wind directions and
generating sag-tension reports and stringing charts.
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465
The ability to define circuits or to perform electrical or thermal calculations is not included in
PLS-CADD/Distribution.
17.1.4.1
Adding and Deleting Wires
Within PLS-CADD/Distribution the menu command Wires/Add Graphical... or
button on the
distribution toolbar will allow for graphical stringing of wires within a project. See Section
10.3.1.3 of this manual for additional information on the Graphical Stringing command. The
menu command Wires/Remove... or
button on the distribution toolbar will delete selected
wires from a model.
17.1.4.2
Modifying Wires
The menu command Wires/Modify or
button will open up the Section Modify dialog which
allows for review or edit properties of the suction such as to the wire file used, voltage, sagging
conditions and display conditions. All wire files used in PLS-CADD/Distribution will need to be
created or made available outside the program as there are no provisions to create or edit wire
files in PLS-CADD/Distribution.
17.1.4.3
Relocating Wires
The command Wires/Graphically Relocate Wires allows for graphically swapping wire
attachment points on a structure. The command can also help attach wires to structure
attachments if the wire is not previously attached to the structure. This command can also
detach a wire from a structure by dragging the wire attachment to the base of the structure.
17.1.4.4
Sagging Wires
The menu command Wires/AutoSag will automatically sag all wires in a project to meet the
Automatic Sagging criterion which is saved within the criteria file. The Automatic stringing
criteria will need to be established in the criteria file before it is loaded into the PLSCADD/Distribution model since criteria cannot be edited from the program. See section 7.3.7 for
additional information on the Automatic Sagging feature.
The command Wires/Graphical Sag... will allow for wires to graphically be sagged to match a
survey point or mouse coordinate. See section 10.3.2.1.4 for information about the graphical
sag command.
17.1.4.5
Wire Table
The menu command Wires/Table... provides opens up the Section Table where information on
the wires contained within the project is available and editable. See section 10.3.5 of this
manual for additional information on the Section Table.
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17.1.4.6
Checking Wires
The menu command Wires/Check... checks the cable tension against the limits defined within
the Cable Tensions criteria.
17.1.4.6
Checking Wire Clearances
The menu command Wires/Clearances has four commands to help check clearances from
model wires to various entities within the project.
To check vertical or minimum clearances from a selected wire to the TIN surface the menu
command Wires/Clearances/To Ground can be used. This function provides a graphical
measurement and interactively displays clearance distances within the status bar.
Clearance checks can be made between the energized portion of the wire system and the
models of supporting structures with Wires/Clearances/To Structure....Section 11.2.3.3
describes this feature in more detail.
Wires/Clearances/Between Sections... will enable the Sections Clearances dialog which will
allow for selection of cables and weather conditions to measure clearances between. See
section 11.2.3.2.1 of this manual for details on this function.
To check clearances between phases for galloping the following menu command can be
utilized, Wires/Clearances/Galloping Ellipses.... Section 7.3.15 and11.2.3.2.3 describes this
analysis in greater detail.
17.1.4.7
Stringing Chart
The menu command Wires/Stringing Chart has selections to create a stringing chart for a
single selected section or multiple sections. With a stringing chart the sag, tension, return wave
time or catenary constant numbers can be used by construction crews to match the condition of
a tension section in the field to that assumed in the design calculations. See section 11.2.4 for
additional details on construction stringing charts.
17.1.4
Reports and Design Checks
PLS-CADD/Distribution contains the same line design checks as the standard PLS-CADD
program. Checks and reports are available for wire usage, structure usage, clearance to survey
points and TIN, wire to wire clearances and wires to PLS-POLE structures. The summary
report, construction staking report and structure staking table are also available. Detailed
reports for bills of material, structure loads, thermal rating and a few others are not available in
PLS-CADD/Distribution. Details regarding all reports available in PLS-CADD/Distribution are
described in other sections of this manual.
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Comparison of PLS-CADD Standard and Distribution Editions
Standard
Distribution
Built in ruling span sag-tension
Built in finite element span sag-tension (SAPS program
required)
Import survey data and feature code file
Includes terrain modeling
Import criteria file
Modify/Edit criteria file
Alignment or XY based structures
Both
Create and spot M1 stick structures
XY only
Spot only
Create and spot M4 PLS-POLE structures*
Generate structure loading trees
Links to PLS-POLE for checking structures
Manual and automatic structure spotting features
Both
Manual only
Graphically string wires between any structures
Models all wires attached to a single structure
Utilize concentrated loads (i.e. marker balls, mid-span
SAPS required
taps, etc)
Full material management (Create, edit, report)
Report only
Allows vector and raster image attachments
Create Plan & Profile sheets
Check clearances to survey points and terrain model
Check clearances for vegetation grow-in and danger trees
Check wire clearance to PLS-POLE structures (including
guys)
Check clearance between wires
Create galloping ellipses
Create construction staking reports
Create stringing charts and offset clipping reports
Both
Stringing
only
charts
Export model to Google Earth
Conductor thermal calculations (IEEE, CIGRE, TNSP)
Electrical calculations
constants)
(EMF,
lightning,
electrical
* PLS-POLE program is not included as part of standard PLS-CADD program and must be
purchased separately. A limited version of PLS-POLE is included with PLS-CADD/Distribution.
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APPE7NDIX A.
NOTATION
ABS(*)
ARC
AR0
AT
BS
C
=
=
=
=
=
=
Ci
D
DENS
E
=
=
=
=
EF
EFCOMP
ETCOMP
ETMAT
GRFc
GRFs
h
H
h'
HS
HSMAX
HT
HTADJ
L
LA
LINS
LL
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
LR
=
LREF
LFT
LFV
LFW
NCL
NCR
=
=
=
=
=
=
absolute value of quantity inside parentheses
cross section area of core conductor material (mm2 or in2)
cross section area of outer conductor material (mm2 or in2)
total cross section area of conductor (mm2 or in2)
point at center of base of a structure
cable catenary constant = horizontal component of cable tension divided
by cable load per unit length (m or ft)
span chord length (m or ft)
cable diameter (mm or in)
ice density (weight per unit volume) (daN/dm3 or lbs/ft3)
modulus of elasticity of cable (ground wire or conductor)
(daN/mm2/100 or psi/100)
final cable modulus of elasticity (daN/mm2/100 or psi/100)
linearized composite modulus of elasticity (daN/mm2/100 or psi/100)
combined thermal expansion coefficient of composite cable (/100 deg)
thermal expansion coefficient of material MAT (/100 deg)
gust response factor for ground wires and conductors
gust response factor for structures
height of obstacle above ground (m or ft)
horizontal component of tension in cable (daN or lbs)
elevation difference between span ends (m or ft)
actual wind (horizontal) span (m or ft)
maximum allowable wind (horizontal) span (m or ft)
structure height - from ground to TOP point (m or ft)
ajustment of height of base of structure (m or ft)
longitudinal design load at structure attachment point (daN or lbs)
line angle or load angle (degrees)
length of insulator string (m or ft)
longitudinal reaction (tension) at right end of one cable in left span (daN
or lbs)
longitudinal reaction (tension) at left end of one cable in right span (daN
or lbs)
unstressed reference length of cable (used internally) (m or ft)
load factor for loads due to cable tensions
load factor for vertical loads
load factor for wind loads
number of subconductors in left bundle
number of subconductors in right bundle
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469
O
P
PC
PCP
Q
RS
S
SA
S
=
=
=
=
=
=
=
=
=
PFL
SPRL
SPRT
SQRT(*)
t
T
TEMP
TEMPC
TEMPREF
=
=
=
=
=
=
=
=
=
TEMPTEST
TL
TOP
TR
TS
UH
UI
ULT
UR
UV
UW
V
v'
VS
VSMAX
VSMIN
W
WA
VINS
W ICE
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
470
offset of point on ground - measured from center line (m or ft)
point on the ground
permanent cable elongation due to creep
permanent cable elongation due to common point load
air density factor used to relate wind velocity to pressure
ruling span (m or ft)
station of point on ground - measured along center line (m or ft)
insulator swing angle - positive if in direction of transverse axis (degrees)
structure orientation angle (relative to bisector or perpendicular to line)
(deg.)
type of terrain model - based on Station, Offset and elevation Z
design pressure for structure in longitudinal direction (Pa or psf)
design pressure for structure in transverse direction (Pa or psf)
square root of quantity inside parentheses
ice or snow thickness (cm or in)
transverse design load at structure attachment point (daN or lbs)
cable temperature (degrees)
temperature at which creep of cable is assumed to occur (degrees)
reference temperature at which unstressed length LREF defined
(degrees)
temperature at which experimental cable data were obtained (degrees)
transverse reaction at right end of one cable in left span (daN or lbs)
reference point at top of structure
transverse reaction at left end of one cable in right span (daN or lbs)
structure transverse axis
horizontal (transverse) force per unit length of cable (daN or lbs)
weight of ice (snow) per unit length of cable (daN/m or lbs/ft)
rated ultimate strength (tension) of cable (daN or lbs)
resultant force per unit length of cable (daN/m or lbs/ft)
vertical force per unit length of cable (daN/m or lbs/ft)
weight of cable per unit length of cable (daN/m or lbs/ft)
vertical design load at structure attachment point (daN or lbs)
span length in plane of catenary (m or ft)
actual weight (vertical) span (m or ft)
maximum allowable weight (vertical) span under some condition (m or ft)
minimum allowable weight (vertical) span under some condition (m or ft)
reference wind velocity (km/h or mph) at reference height
angle between wind direction and normal to span (degrees)
insulator dead weight (daN or lbs)
ice weight per unit length of cable (daN/m or lbs/ft)
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WCW
WLF
Wz
(x,y,z)
XYZ
(X,Y,Z)
ZE
α
β
ε
φ
σ
=
=
=
=
=
=
=
=
=
=
=
=
weight of counter-weight to reduce insulator swing (daN or lbs)
weather load factor which multiply all wind and ice loads
wind velocity at height z above the ground (m/s or mph)
structure local coordinate system to define top geometry
type of terrain model - based on global coordinate system
global coordinate system to define location of terrain point
force at end of catenary in direction opposite to UR (daN or lbs)
angle used in calculation of end span reactions
angle of swing of entire span
cable strain (elongation per unit length in percent)
component strength factor (usually <=1)
cable stress (daN/mm2 or psi)
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APPENDIX B.
REFERENCES
This Appendix includes some material that is referred to in the PLS-CADD manual. However,
references to codes and standards may not be up-to-date. For codes and standards used in our
software, we recommend that you consult our most current list which is available at:
http://www.powline.com/products/designcodes.html
Aluminum Association (1971), Stress-Strain-Creep Curves for Aluminum Electrical Conductors,
Aluminum Electrical Conductor Handbook, New York, NY.
ANSI/ASCE Standard 10-97 (1997), Design of Latticed Steel Transmission Structures.
ASCE - PCI (1997), Guide for the Design of Prestressed Concrete Poles, PCI Journal, Vol. 42,
No. 6, pp.94-134.
ASCE Manual 72 (1990), Guide for Design of Steel Transmission Pole Structures.
ASCE (1991), Guidelines for Electrical Transmission Line Structural Loading, ASCE Manual 74,
ASCE, New York, NY.
ASCE Manual 91 (1997), Design of Guyed Electrical Transmission Structures.
Avril C. (1974), Construction des Lignes Aériennes à Haute Tension, Editions Eyrolles, 61 Blvd.
St. Germain, Paris, France.
Batterman R.M. (1967), "ALCOA's Computer Program for Cable Sag and Tension Calculations,
Aluminum Company of America, Pittsburgh, PA.
Bellman R. (1957), Dynamic Programming, Princeton University Press, Princeton, N.J.
Bougue M. (1999), Lignes Electriques Aériennes à Très Haute Tension, INEO, 2, allée Jacques
Brel, 92240 Malakoff, France.
Carton T. and Peyrot A.H. (1992), "Computer-Aided Structural and Geometric Design of Power
Lines," IEEE Transactions on Power Systems, Vol. 7, No. 1, pp. 438-443, Feb. 1992.
CENELEC (2001), Overhead Electric Lines ..., Standard EN50341-1:2001, European
Committee for Electrotechnical Standardization, Brussels, Belgium.
472
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CIGRE Study Committee 22 (1977), "Permanent Elongation of Conductors - Predictor
Equations and Evaluation Methods," Working Group 05, Paper 22-77 (WG05)07, CIGRE, Paris,
France.
CIGRE Study Committee 22 (1991), "Loading and Strength of Overhead Transmission Lines,"
Working Group 06 (Line Reliability and Security) of CIGRE Study Committee 22, ELECTRA, No.
137, pp. 130-169.
CIGRE Study Committee 22 (2001), "Safe Design Tension with Respect to Aeolian Vibrations
Loading and Strength of Overhead Transmission Lines," Working Group 22.11.04, ELECTRA,
No. 198, Oct. 2001, pp. 28-43.
EPRI (1982), Transmission Line Reference Book - 345kv and Above, Second Edition, Electrical
Power Research Institute, Palo Alto, CA, USA.
EPRI (1988), TLOP/SAGT Manual, TLWorkstation Code, EPRI EL-4540, Vol. 6, Electrical
Power Research Institute, Palo Alto, CA, USA.
Forbes B., Bradshaw D. and Campbell F. (2002), "Finding Hidden Capacity in Transmission
Lines", Transmission and Distribution World, pp. 30-37, Sept. 2002.
GO95 (1969), Rules for Overhead Electric Line Construction, General Order No. 95, Public
Utilities Commission of California.
Harvey J.R. and Larson R.E. (1979), "Technique to Include Elevated Temperature Creep in
Condutor Sag-Tension Calculations," IEEE Transmission and Distribution Conference, April 1-9,
1979.
Hooper, Bryan (2003), “Vegetation Management Takes to the Air”, Transmission & Distribution
World, Sept. 2003.
IEC (2003), Design Criteria of Overhead Transmission Lines, IEC Standard 60826, International
Electrotechnical Commission, Geneva, Switzerland.
IEEE Std. 691 (1985), Trial-Use Guide for Transmission Structures Foundation Design.
IEEE Std. 738 (1993), IEEE Standard for Calculating the Current-Temperature Relationship of
Bare Overhead Conductors.
IEEE Std. 751 (1991), Trial-Use Guide for Wood Transmission Structures.
PLS-CADD – Version 16.0 © Power Line Systems, 2019
473
IEEE Std. 1283 (2002), IEEE Guide for Determining the Effects of High Temperature Operation
on Conductors, Connectors, and Accessories.
Kluge R. and Peyrot A.H. (1994), "Assessment and Upgrade of an Older Transmission Lines"
Proceedings of ASCE Structures Congress XII, Atlanta, GA, pp. 607-612, April 1994.
McDonald B. and Peyrot A.H. (1988), "Analysis of Cables Suspended in Sheaves," Journal of
Structural Engineering, ASCE, Vol. 114, No. 3, pp. 693-706, March 1988.
McDonald B. and Peyrot A.H. (1990), "Sag-Tension Calculations Valid for Any Line Geometry,"
Journal of Structural Engineering, ASCE, Vol. 116, No. 9, pp. 2374-2387, Sept 1990.
Motlis, Y., et. al. (1998), "Limitations of the Ruling Span Method for Overhead Line Conductors
at High Operating Temperatures," Report of the IEEE Task Force on Bare Conductor Sag at
High Temperature, Winter Meeting, Power Engineering Society, Tampa, Florida, February 1998.
NESC (2012), National Electrical Safety Code, ANSI C2-2012 or older editions, IEEE, New
York, N.Y.
Nigol O., and Barrett J.S. (1981), "Characteristics of ACSR Conductors at High Temperatures
and Stresses," IEEE Transactions on Power Apparatus and Systems, Vol. PAS-100, No.2,
Feb.1981, pp. 485-492.
Olbrycht L. (1982), "A Contribution to the Methods of Optimizing the Spotting of Transmission
Lines," Electric Power Systems Research, Vol. 5, pp. 163-171, Elsevier Sequoia, Netherlands.
Peyrot A.H and Goulois A.M. (1978), "Analysis of Flexible Transmission Lines", Journal of the
Structural Division, ASCE, Vol. 104, No. ST5, May 1978, pp. 763-779, May 1978.
Peyrot A.H. and Goulois A.M. (1979), "Analysis of Cable Structures", Computers & Structures,
Vol. 10, pp. 805-813, 1979.
Peyrot A.H and Brinker D. (1997), Transmission and Communication Structures, Section 30 of
Structural Engineering Handbook, Fourth Edition, Edited by E.H. Gaylord et. al., McGraw Hill,
New York, NY, pp. 30-1 to 30-20.
Peyrot A.H. (1991), "Computer-Aided Evaluation of Existing Transmission Lines," Transmission
and Distribution, pp. 58-63, June 1991.
Peyrot A.H., Peyrot E.M., and Carton T. (1992),"Interaction and Integration in Power Line
Design," IEEE Computer Applications in Power, Vol. 5, No. 4.
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Peyrot A.H., Peyrot E.M., and Carton T. (1993), "Computer-Aided Design of Transmission
Lines," Engineering Structures, Vol. 15, No. 4, pp. 229-237.
Peyrot A.H., Peyrot E.M. and Senouci A. (1993), "Optimization Methods for Transmission Line
Design," Engineering Structures, Vol. 15, No. 4, pp. 239-246.
PLS-POLE (1999 and later), Analysis and Design of Concrete, Steel or Wood Poles and
Frames, Power Line Systems, Madison, WI.
Portugal NNA (2001), National Normative Aspects (NNA) for Portugal, CENELEC Standard
EN50341-3-17, European Committee for Electrotechnical Standardization, Brussels, Belgium.
Rawlins, C.B. (1999), "Some Effects of Mill Practice on the Stress Strain Behavior of ACSR,"
IEEE Transactions on Power Delivery, Vol. 14, No. 2, pp. 602-629, April 1999.
REA (1992), Design Manual for High Voltage Transmissin Lines, REA Bulletin 1724E-200 (Sept.
1992), Rural Electrification Administration, US Government Printing Office, Washington, DC
20402.
Reding J. (1976). Multi-Constraint Variable Modulus Sag-Tension Program User's Manual,
Bonneville Power Administration, Portland, OR.
REE (2001), Red Electrica de Espana adaptation of National Normative Aspects (NNA) for
Spain, based on CENELEC Standard EN50341-3-1, Red Electrica Espanola, Madrid, Spain.
SAGSEC (1997), A Computer Program for the Exact Calculation of Sags, Tensions and Loads
in Multi-Span Systems, Power Line Systems, Madison, WI.
SAG-TENSION and LOADS (1990), Computer Programs for Determining Sags, Tensions and
Design Loading Trees for Transmission Structures, Power Line Systems, Madison, WI.
SAPS (1997), A Computer Program for the Nonlinear Structural Analysis of Power and
Communication Systems, Power Line Systems, Madison, WI.
Senouci A. (1991), "Optimum Spotting and Selection of Power Line Structures," PhD Thesis,
Dept. of Civil Engineering, University of Wisconsin, Madison, WI.
Ranero, I. (1990), "Automatic Minimum Cost Support Spotting by Computer, "Proceedings of
the 1990 CIGRE Conference, Paper 22-105, Paris, France.
PLS-CADD – Version 16.0 © Power Line Systems, 2019
475
Thrash R. et. al. (1994), Overhead Conductor Manual, Southwire Company, One Southwire
Drive, Carrolton, GA, 30119.
TOWER (2000 and later), A Computer Program for the Analysis and Design of Steel Latticed
Transmission Towers, Power Line Systems, Madison, WI.
UK NNA (2001), National Normative Aspects (NNA) for the United Kingdom and Northern
Ireland, CENELEC Standard EN50341-3-9, European Committee for Electrotechnical
Standardization, Brussels, Belgium.
Winkelman, P.F. (1959), "Sag-Tension Computations and Field Measurements of Bonneville
Power
Administration,"
AIEE
Paper
59-900,
June
1959.
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APPENDIX C.
FEATURE CODES FILE
All the information needed to describe the feature codes associated with terrain points and their
appearances on the screen or on paper drawings are contained in a single file. The feature
code file which is used for a particular project has the same name as the project with the
extension ".fea". Even though feature code files are ASCII (TEXT) files, their detailed format is
not described in this manual. Instead, these files should be prepared by entering or editing data
with Terrain/ Feature Code Data/ Edit as described in Section 6.1.
Profile Label Code
The profile label control code consists of a sequence of eleven binary digits (0 or 1), each
controlling the display of a text item next to each
occurrence of the feature code on all profile views. The
digit is equal to 1 if the item is to be displayed, 0
otherwise. The binary sequence is defined by checking
the proper items in the box of Fig. C-1. The box opens
when you double-click on the binary sequence in the
Feature Codes table. The binary sequence
corresponding to the data in Fig. C-1 is 00000000001.
For example, with the profile control code 01000000000
associated with feature code 401, the text "Marsh"
appears in the Demo line at each terrain point having
feature code 401.
Plan Label Code
This control code is similar to that for the profile views,
except that it applies to all plan views.
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Fig. C-1 Feature Code Labeling
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APPENDIX D.
XYZ TERRAIN FILE
All the information needed to describe an XYZ terrain model is included in a terrain file which
must be named Project.xyz if the name of the project is Project. The terrain file is an ASCII
(TEXT) file which can be created or edited with a variety of methods: 1) with any text editor
using the formats shown in Section D.1, 2) using our specialized XYZ terrain editor as shown in
Section D.2, 3) importing with or without translation from other ASCII files (Section D.3), 4)
importing with filtering from other ASCII files, etc. You will find a lot of useful information
regarding XYZ files and possible sources of data in technical notes listed under the title
Technical Notes / PLS-CADD/ Terrain and Other Data at:
http://www.powline.com/news.html
Fig. D.1 shows an overview of the
various options which you have to
load XYZ data into memory and save
an XYZ file. These options are
discussed in detail in this Appendix.
PROJECT XYZ FILE
ACTIVE POINTS
INACTIVE POINTS
REACTIVATE
FILTER
FILTER
DEACTIVATE
XYZ POINTS IN MEMORY
TEMPORARY FILE OF INACTIVE POINTS
INCOMING
FILTER
POINTS
TRANSLATOR
FILTER
POINTS THAT
ADDITIONAL
XYZ FILE
USER-DEFINED
XYZ FILE
XYZ ASCII FORMAT
ARBITRARY FORMAT
PASS THROUGH
Fig. D.1 Options for Loading and Saving XYZ Data
D.1
XYZ File Format
PLS-CADD can save XYZ files in either binary or ASCII format. The default format is binary and
this results in much smaller files and faster file/open and file/save operations. The disadvantage
of binary is that it is not human readable nor is it readable by programs other than PLS-CADD.
To save in ASCII format use File/Save As and change the Save as type to "ASCII XYZ Files".
The ASCII format for an XYZ file consists of one record per line formatted as shown below. A
record of that file, designated as R.* below, includes one or more data which must be separated
by blanks.
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Records
R.0
Header which includes:
TYPE= ' XYZ FILE ', VERSION= ' 4 ' or other, UNITS= ' US ' or ' SI '
SOURCE= ' PLS-CADD Version *** ', USER= ' Username ', FILENAME= ' '
Then for each terrain point a record that includes:
R.i
Description of terrain point (text string limited to 256 characters included within single
quotation marks)
x-coordinate ( m or ft ), y-coordinate ( m or ft ), z-coordinate ( m or ft )
Feature code (Integer)
Obstacle height, h ( m or ft ) - must input zero value if there is no obstacle
Optional surveyor note to appear on all profile views (this is a text string limited to 256
characters that must be included within single quotation marks, for example ' poor soil ')
Optional surveyor note to appear on all plan views (this is a text string limited to 256
characters that must be included within single quotation marks)
For example, the record { '12345' 1000. 500. 100. 200 0 ' ' ' Hydrant ' } will cause the word
"Hydrant" to be drawn on all plan views at the location of ground point 12345.
D.2
XYZ Terrain Editor
Fig. D.2 XYZ Terrain Data Editor (1 of 2)
You can create a new XYZ file manually by going through the following steps: 1) go to the Open
PLS-CADD Project dialog box with File/ New and type in the name of the XYZ file for your new
project, for example Newproj.xyz, 2) associate a feature code table to the project by loading an
existing feature code list with Terrain/ Feature Code Data/ Load FEA File or enter your own
list with Terrain/ Feature Code Data/ Edit, and 3) go to the Edit XYZ Data dialog shown in
Fig. D-2 with Terrain/ Edit/ Edit XYZ.
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You can edit the XYZ data of an existing project by going directly to the Edit XYZ Data dialog.
The data shown in the Edit XYZ Data dialog shows points currently in memory. When you load
an existing project with File/ Open, the active points (active and inactive points are discussed in
Section D.5) are loaded into memory (block labeled XYZ POINTS IN MEMORY in Fig. D-1) and
the inactive points (if any) are copied in a temporary file (block labeled TEMPORARY FILE OF
INACTIVE POINTS in Fig. D-1). Conversely, when you save a project with File/ Save, the XYZ
data in memory are saved to the active portion of the XYZ terrain file and the data in the
temporary file of inactive points are saved in the inactive portion of the XYZ terrain file. When
you edit data in the Edit XYZ Data dialog box, you can only operate on data in memory. When
you exit the dialog box, these data are in memory and can be seen in the Profile, Plan and 3-D
views, but they only get saved in the project XYZ file when you do a File/ Save. The basic EDIT,
OPEN and SAVE operations are identified as vertical arrows in Fig. D-1.
Once you are in the Edit XYZ Data dialog, click on the ADD button to add a new terrain point.
To edit a record, highlight it with the mouse and then
click on the Edit button.
You are taken to the dialog of Fig. D.2.1 where you pick
a Feature code from the list of available feature codes
(list comes from the Feature Codes table defined in
Section 6.1) and enter the particular point data. All items
should be self-explanatory.
You can sort the order of the points shown in Figure D.2
by different values by going to Terrain/Edit/Sort XYZ
Points/. Normally this should be left to the default sort
to optimize redraw selection.
Fig. D-2.1 XYZ Editor (2/ 2)
D.3
Importing and Translating
If you have XYZ data in the format (ASCII) described in Section D.1, these can be added to the
data already in memory using Terrain/ Edit/ Merge Points from External File/ Merge Points
From XYZ File. You have the option of adding (merging) all these points to those already in
memory or to only add those which pass through the filter. This is illustrated by the arrows
connecting the ADDITIONAL XYZ FILE block in Fig. D.1 to the XYZ POINTS IN MEMORY
block. The effects of the optional filtering are discussed in Section D.4.
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If you have XYZ data in ASCII files which do not follow our required format as described in
Section D.1, you can still add them to those in memory after translating them as shown by the
arrows between the USER DEFINED XYZ FILE block in Fig. D.1 and the XYZ POINTS IN
MEMORY block. In such cases you will need to go through a translator using Terrain/
Edit/Merge Points from External File/Merge XYZ Points from User Defined XYZ file. After
opening the file to merge, say Merge.fil, you are taken to the dialog box of Fig. D.3. Unless you
are re-using some previously determined translation parameters by clicking on the Load
settings button, you should specify these parameters by clicking on the Import format button.
You will be taken to the User Terrain Import dialog box of Fig. D.5. The User Terrain Import
dialog box gives you several import options for the file being imported including the options to
use a point filter, set the survey data coordinates units (feet or meters), etc. If you have a
coordinate system defined in your project as described in Section 6.2.1 then you can also define
a coordinate system for the data you are importing and if it is different the program will
automatically reproject the data being imported into the project coordinate system.
You can also choose
to bring in data in
decimal degrees for
latitude and longitude if
you check the option
below the coordinate
system
which
will
reading the northing
and easting value as
longitude and latitude
and
automatically
convert the data to a
XYZ point in the
defined
project
coordinate system.
By clicking on the
button corresponding
Fig. D.3 User Terrain Import
to a particular item you
are taken to the dialog box of Fig. D.6 where you describe how to locate the start and end of the
item in each record of the file Merge.fil. There are several delimiter options for doing this. To
help you select the proper options, the selected items in Merge.fil are displayed in red between
square brackets in the lower part of the dialog box of Fig. D.3-2. As you OK your options in that
dialog box you are returned to the dialog of Fig. D.3-1 where your selected options are
displayed on the corresponding button.
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For example, terrain data in the format
shown below can be translated to the
standard XYZ format with the settings in
Fig. D.3-1. These import parameters can
be saved for future use as an *.imp file
using the Save Settings button. These
settings can then be loaded in the User
Terrain Import dialog box using the Load
Settings button in Fig. D.3.
Fig. D.3-1 Universal Translator for User Defined XYZ File
Data before import:
Standard XYZ format:
sidewalk 900. 300. 100. ,Description, $plan comment
'Description' 100. 300. 900. 200 0. 'sidewalk' 'plan comment'
Fig. D.3-2 Setting Import Field Delimiters
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D.3.1
Importing XYZ data from the Internet
If XYZ data is not available there is a feature in PLS-CADD the menu command
Terrain/Edit/Merge Points from External File/Merge Points from Internet... will download
and import topographic information from the internet. The topographic data is from NASA's
Shuttle Radar Topography Mission (SRTM) and can provide topographic information for projects
within 56 degrees south and 60 degrees north of the equator. Information about the SRTM
topographic data can be found at https://www2.jpl.nasa.gov/srtm/. The exception to this that for
Puerto Rico USGS NED (https://www.usgs.gov/core-science-systems/national-geospatialprogram/national-map) has been used because it is a better dataset and this was requested for
help in reconstruction efforts for damage from Hurricane Maria. Figure D.3-2 shows the dialog
box for the Internet Terrain Import and the table below describes the options for this function.
Fig. D.3-2 Setting Import Field Delimiters
Available options for this dialog are described below:
Feature Code For Imported
Points
Selection of feature code to place imported survey points in
Import Extents
Wherever intersect project will import survey data defined by
a rectangle covering all entities within a project.
Within X of Alignment will import survey points within a
specified offset from the alignment.
Current Plan View Extents will import survey points within the
current plan view.
Inside rectangle will import survey points defined by
coordinates of the lower left and upper right extents of a
rectangle.
This feature is showcased in the video on our website titled Download XYZ Point Data From
Internet and located https://www.powerlinesystems.com/videos and the Power Line Systems
YouTube channel.
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D.3.1.1
Organizing User LiDAR for use with Importing XYZ data from the Internet
The Internet terrain import function reached via Terrain/Edit/Merge Points from External
File/Merge Points from Internet... requires data to be stored as degrees of longitude and
latitude in WGS 84 datum and elevation in meters. This is stored in a compressed LAS file in
the LAS zip (LAZ) format. Power Line Systems has hosted SRTM data but users could organize
their own LiDAR data so that it can be imported in a similar manner.
The Terrain/Edit/Merge Points from External File/Merge Points from Internet... command
can be used to help automatically load the appropriate LiDAR within a project. The files must be
organized so that data is stored in tiles where each tile covers one degree of longitude and
latitude. No assumptions are made regarding spacing of points inside a tile which may be
irregular and possibly have gaps (e.g. for a large lake). Each tile covers one degree of longitude
and latitude starting from a whole number.
The file name encodes this information. In the file name t_LONG_LAT.laz where LONG and
LAT are the longitude and latitude of the lower left of the tile. The data in the file cover from
(LONG, LAT) to (LONG+1, LAT+1) degrees.
In addition to this file the program will also attempt to open a t_LONG_LAT.txt file and display
the contents to the user whenever data from the corresponding t_LONG_LAT.laz file is
imported. This text file should be used to describe the source of the data, licensing terms, limits
of accuracy, etc.
To make PLS-CADD use your data instead of the data it serves from the internet you will need
to override the “Path to use for Merge Points From Internet Cache” within File/Preferences... as
shown in Figure D.3-3.
Fig. D.3-3 Settings for Path to use for Merge Points
from Internet Cache
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D.4
Importing and Filtering
XYZ terrain files with hundreds of thousands or millions of points may be too large to be loaded
in memory or it may be inefficient to have that many points in memory at once because the
speed of some calculation and display functions is adversely affected. Therefore, as you read a
very large file, you should be able to filter
YMAX
(i.e. not import) points which:
OMIN
SMAX
1)
2)
3)
4)
5)
D
B
SMIN
are inside or outside a domain
described by minimum and
C
maximum values of X, Y, Z, and
OMAX
H.
A
are inside or outside a domain
described by minimum and
YMIN
maximum stations and offsets
XMAX
XMIN
have or do not have a particular
Fig. D.4 Keeping Points inside Grayed Area
feature code
are one of "n" points appearing in a sequence of "m" points in the XYZ file
are within n meters (or ft) of a previous point with the same feature code.
E
By making several passes over terrain files with the right combination of filtering techniques, you
can work with very large XYZ files. While memory issues are not a big issue with 64 bit
machines, prudent use of the filter can be useful in removing unnecessary points from a project.
In order to filter points on input you should use either the Terrain/ Edit/ Merge Points from
External File/Merge Points from XYZ file or Terrain/ Edit/Merge Points from External
File/Merge XYZ Points from User Defined XYZ file command. If you select the filtering option,
you are taken to the Point Deactivator/ Deleter dialog box (we will call it the Filter box) of Fig.
D.4-1. The filter box is shown schematically in the lower left portion of Fig. D.1 where the short
stubs in the right of the filter box indicate various options regarding what to do with points which
are not allowed to pass through the filter.
For example, assume that you have a very large terrain file Large.xyz which includes points in
the entire area of Fig. D.4 but you wish to add to your current Project.xyz file only one out of ten
points in the greyed area. This can be done with settings similar to those shown in Fig D.4-1.
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With the settings in Fig. D.4-1, points
which do not pass through the filter
are thrown out (deleted), but they
remain in the original Large.xyz file.
This is true for all the What to do
with points deactivated/deleted
options at the bottom of the dialog
box, i.e. the file you are importing
points from will not be affected
regardless of the option which you
select.
The points which are filtered out can
be written to files or discarded,
depending on the option you select
at the bottom of the Filter dialog box
in Fig. D.4-1.
If you select Deactivate points (keep
in ..) the filtered-out points are
written to a temporary file (block
labeled TEMPORARY FILE OF
INACTIVE POINTS in Fig. D-1) and
Fig. D.4-1 Filter Parameters
are appended to the inactive portion
of the project XYZ file upon saving the project. The concept of active and inactive points is
described in Section D.5.
If you select Delete points and write them to separate XYZ file, the filtered-out points are saved
to a separate XYZ file which you select by clicking on the button at the bottom of the Filter
dialog box. Default name is "a.xyz" as shown in Fig. D.4-1.
If you select Export points to selected XYZ file then the filtered out points are not removed from
the project but the point list is written to a separate XYZ file.
If you select Delete points and append them to separate XYZ file, the filtered-out points are
added to the points already existing in a separate XYZ file which you select by clicking on the
button at the bottom of the Filter dialog box.
When writing or appending these deleted points to a separate XYZ file you can choose whether
to write it to a binary or ASCII XYZ file with the radio buttons at the bottom of the dialog box.
If you select Delete points the filtered-out points are discarded.
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D.5
Deactivating, Reactivating or Deleting Points
When you deal with large numbers of terrain points, you should be aware of a number of
different functions available for shuffling points between files and memory. The number of points
that can be stored in a file can be extremely large, in the millions. However, the number of
points which can reside in RAM and be displayed is limited not only by the size of that memory
but also by the fact that large number of points degrade the performance of all computing and
display functions. It is generally a good idea to limit the number of points in memory to around
100,000 unless working on a high performance machine. With newer 64 bit machines the
memory limitations have been eliminated. The following tech note details memory management
in PLS-CADD for 32 bit computers.
http://www.powline.com/products/memory.html
We covered the concept of filtering points on input in Section D.4. However, there is another
useful concept which is that of deactivating points. Suppose for a moment that you have been
able to bring into memory a very large number of points, but that at some stage in your design
you do not wish for all these points to be in memory. What you can do is segregate the points
between active and inactive points. Active points will be kept in memory and thus they will be
displayed and you will be able to edit them with Terrain/ Edit/ Edit XYZ. Inactive points will be
removed from memory and thus will not be displayed and you will not be able to edit them
unless re-activated. Active points can be de-activated and inactive points can be re-activated.
Deactivating points is done with one of the Terrain/ Edit/ Deactivate, Delete or Export Points
commands which will send all points in memory through the same filter which was discussed in
Section D.4. You should select the Deactivate points (keep in current XYZ ...) option in the lower
portion of the Point Deactivator/ Deleter filter dialog box in Fig. D-8. Points which pass through
the filter will remain in memory as the active points. Those which do not pass are labeled
inactive points and are sent to a temporary file (TEMPORARY FILE OF INACTIVE POINTS in
Fig. D-1). As mentioned before, when you save your project with File/ Save, the points in
memory are stored in the active portion of the Project.xyz file, and the points in the temporary
file of inactive points are stored in the inactive portion of the Project.xyz file which is appended
after the list of active points. This is shown schematically in Fig. D-1. Therefore, once saved
from PLS-CADD, a Project.xyz file contains both its active and inactive points. Therefore it is
always complete regardless of the active or inactive status which you assign to its points.
If you load a project which includes deactivated terrain points in its XYZ file, these can be
reactivated with the Terrain/ Edit/ Reactivate Points command. As shown in the top right of
Fig. D-1, the inactive points will be read in and optionally passed through the filter which you
can configure to let all points be reactivated or only a subset of them.
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Graphical selection of Extents in Point Deactivator/ Deleter dialog box:
You can also graphically specify the extents of the terrain to filter using the Terrain/ Edit/
Deactivate, Delete or Export Points command while in one of the views. In this menu you can
select the Non-Graphical method discussed in section D.4 but you can also select items
graphically inside or outside of a user defined fence, polygon, dxf or shp file, or a planar feature.
If you select the Fence or Polygon option you will draw the fence or polygon and when all points
have been graphically selected you can hit the enter key and the dialog box will appear asking
what to do with the points and whether to apply the command to the selected points or the
unselected points. You can also choose in the dialog box to show an additional point selection
criterion which is the same filter as shown in Fig. D-8 and these selection criteria will be applied
to the graphically selected points. The same option is available if using the dxf or shp file
except you will select the object out of the dxf or shp file that contains the points in question.
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D.6
Break Lines File Format
Break lines were described in Section 6.5. A BRK file is an ASCII file which consists of records,
each record being terminated by a Carriage Return (CR or Enter). A record, designated as R.*
below, includes some data which must be separated by blanks.
Records
R.0
Header which includes:
TYPE = 'BRK FILE'
VERSION = '1'
UNITS = 'US' or 'SI'
SOURCE = 'PLS-CADD Version 4.57'
; comments
Then for each break line segment a record that includes:
R.i
x-coordinate of origin of segment (m or ft)
y-coordinate of origin of segment (m or ft)
z-coordinate of origin of segment (m or ft)
x-coordinate of end of segment (m or ft)
y-coordinate of end of segment (m or ft)
z-coordinate of end of segment (m or ft)
Two break line segments are made part of the same break line string if the x-,y-, and zcoordinates at the end of one segment are identical to those at the origin of the other.
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D.7
Import of .LAS Files
You can import .LAS files directly into an existing PLS-CADD model by using the Terrain/ Edit/
Merge Points From External File/ Merge Points From LAS Files command. A LAS file is an
ASPRS (www.asprs.org) standard point classification file which has some predefined standard
feature codes for points. The ASPRS standard limits the user to 32 feature codes but PLSCADD allows you to import up to 256 different feature codes for compatibility with other
programs that do not follow this standard. Figure D.7-1 below shows the LAS Import Options
dialog box that appears when using this command.
Figure D.7-1 LAS Import Options
The top of the dialog box shows a report with information about the .LAS file that is being
imported. On the left side of the dialog box the user can access several features and tools that
can be used with the import. You can choose whether to use a point filter on import similar to
Figure D-8 or use the standard 32 feature codes or use the extended 256 feature codes. Also
you can choose the data’s coordinate system and units so it can be reprojected into the project
coordinate system if necessary. The table portion of the dialog allows you to match the .LAS file
feature class to a PLS-CADD feature code for import. You can also select whether to import
points from the LiDAR class in the file by selecting Yes or No in the column. The LAS import
also will work with geographic coordinates (degrees of longitude and latitude). To use this
feature selecting the coordinate system EPSG:4326 on import within the LAS Coordinate
System selection in the menu command Terrain/Edit/Merge Points from External File/Merge
Points from LAS/LAZ Files.... The .LAS import supports LAS 1.4 files and also the ability to
read LAZ compressed files.
The import settings can be loaded and saved using the two buttons in the lower left hand corner
of the dialog. These settings are saved in a .lmp file.
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D.8
Creation of XYZ or PFL Points from DXF or Shapefile Attachment
You can import xyz point data directly into PLS-CADD by importing the points directly from a
DXF or Shapefile that is already attached to the project by the method described in Section
6.6.1. The Terrain/ Edit/ Merge Points From External File/ Create XYZ or PFL Points from
DXF Attachment dialog box is shown in Figure D.8-1 below. This command will create XYZ or
PFL points from a DXF attachment at regular intervals along a DXF or Shapefile entity as well
as inside its surface if the element is a planar closed polyline, surface of a solid, or a face.
The top of the dialog box allows
you to pick the feature code to
use for the points extracted from
the file. You can choose to use
one feature code for all points
extracted from the DXF, use the
text layer name from the DXF for
feature code description, or use
the integer layer name from the
DXF as the feature.
In the second section of the
dialog box you can select where
to create points in the DXF file.
You can choose whether to
create the points at vertices,
along edges, in surfaces of solids
and faces, or planar closed
polylines. It also gives you the
opportunity to enter the interval
you wish to create points and
Fig. D.8-1 Extract Points From DXF File
whether to recurse through
blocks/cells to extract points inside these items.
The points will be created based on the DXF or Shapefile attachment selected in the list in the
dialog box.
The bottom of the dialog box gives you the option to extract all elements in the selected file or
the user can interactively extract points from individual elements selected with the mouse after
hitting the OK button.
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D.9
Creation of XYZ Point Data from KML or KMZ files
You can create xyz point data from
KML or KMZ files by merging these
files into the program using the
Terrain/Edit/Merge Points from
External File/Merge Points from
KML/KMZ Files command.
After
picking the KML/KMZ file that you
would like to import the feature code
selection dialog shown in Fig. D.9-1
will appear.
Fig. D.9-1 KML/KMZ Import dialog
In this dialog you are able to select the feature code that you would like for the imported points.
You can choose whether to use the point filter upon import of the points and /or create an
alignment based on each linestring entity in the file. The third selected in the figure above will
place the contents of any name and/or description entities in the Plan Comments for the xyz
points created. The bottom option will use the elevation from the TIN as the Z value for points
created from the KMZ file.
D.10 Merge Points from Raster Attachments
You can create xyz point data from raster attachments that contain elevation data in the pixels
such as GeoTiff images. To do so you must first have the raster image attached in the Plan
view of the project and then go to Terrain/ Edit/ Merge Points from External File/ Merge
Points from Raster Attachment and select the raster image from the list of attached files. This
will bring up the Select Feature Code for New Points dialog similar to Figure D.9-2 above where
you can select the feature code for the imported points and whether to use the point filter upon
import.
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APPENDIX E.
PFL TERRAIN FILE
All the information needed to describe a PFL terrain model is included in a terrain file which
must be named Project.pfl if the name of the project is Project. The terrain file is an ASCII
(TEXT) file which can be created or edited with one of the following methods: 1) with any text
editor using the formats shown in Section E.1, 2) using our specialized PFL terrain editor as
shown in Section E.2, or 3) saving the terrain as a PFL file after creating an alignment on top of
an XYZ terrain model (see Section 6.3).
E.1
PFL File Format
A PFL file consists of records, each record being terminated by a Carriage Return (CR or
Enter). A record, designated as R.* below, includes one or more data which must be separated
by blanks.
Records
R.0
Header which includes:
TYPE= ' PFL FILE '
VERSION= ' 4 ' or other
UNITS= ' US ' or ' SI '
SOURCE= ' PLS CADD Version *** '
USER= 'Username'
FILENAME= ' '
Then for each terrain point a record that includes:
R.i
Description of terrain point (text string limited to 256 characters included within single
quotation marks)
Station - cumulative distance along line ( m or ft )
Offset - distance from center-line - positive to the right of line on top view ( m or ft )
Elevation or z-coordinate ( m or ft )
Line angle LA , positive if clockwise (in seconds - 3600 seconds in one degree)
Feature code (Integer)
Obstacle height, h ( m or ft ) - must input zero value if there is no obstacle
Optional surveyor note to appear on all profile views (this is a text string limited to 256
characters that must be included within single quotation marks, for example ' poor soil ')
Optional surveyor note to appear on all plan views (this is a text string limited to 256
characters that must be included within single quotation marks)
For example, the record { '12345' 1000. 0. 100. 23. 200 0 ' ' ' Hydrant ' } will cause the
word "Hydrant" to be drawn on all plan views at the location of ground point 12345.
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E.2
PFL Terrain Editor
Fig. E-1 PFL Terrain Data Editor (1 of 2)
You can create a new PFL file manually by going through the following steps: 1) go to the Open
PLS-CADD Project dialog box with File/ New and type in the name of the PFL file for your new
project, for example Newproj.pfl, 2) associate a feature code table to the project by loading an
existing feature code list with Terrain/ Feature Code Data/ Load FEA File or enter your own
list with Terrain/ Feature Code Data/ Edit, and 3) go to the Edit PFL Data dialog shown in Fig.
E-1 with Terrain/ Edit/ Edit PFL.
You can edit the PFL data of an existing project by going directly to the Edit PFL Data dialog.
Once you are in the dialog of Fig. E-1, click on the ADD button to add a new terrain point. To
edit a record, highlight it with the mouse and then click on the Edit button.
You are taken to the dialog of Fig. E-2 where you pick a Feature code from the list of available
feature codes (list comes from the Feature Codes table defined in Section 6.1) and enter the
particular point data. All items should be self-explanatory.
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Fig. E-2 PFL Terrain Editor (2 of 2)
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APPENDIX F.
STRUCTURE FILE
All information needed to describe the geometry of a structure and check its strength is
contained in a single file for Method 1, 2 or 3 structures or in a basic file and its associated
component libraries for Method 4 structures. This Appendix describes how to create and edit
these files.
F.1
Method 1, 2 or 3 Structures - Direct Editing
New models for Method 1, 2 or 3 structures are created using Structures/ Create New
Structure. Existing models can be edited with Structures/ Edit structure or by clicking on the
Edit button once you have selected a structure with Structures/ Modify .
For example, let's look at the Demtan1.110 pole used as Structure #7 in the Demo line. If you
select it with Structures/ Modify and click on the Edit button, the Structure Data Editor table
of Fig. F-1 will appear. The data in the Structure Data Editor table include a complete
description of the structure model.
General data at the top of the editor include:
Description:
Your designation for the structure
Height (ground to top of structure):
Structure height as shown in Fig. 8.2.1
Embedment length:
If your structure is a pole, this optional value is used for reporting purposes only, but does not
affect the geometry of your pole above the ground.
Lowest wire attachment point height above ground:
This value is automatically computed from the value of the height of the structure minus the
distance from the top of the structure to the lowest wire attachment point (from all the data
entered in the table). For the example in Fig. F-1, 62 ft is the difference between 110 and the
distance from the bottom of the suspension insulator of Set #8 - Phase 1 to the top of the
structure (40 + 8).
Then for each set and phase, the data described in Sections F.1.1. to F.1.3 are needed:
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Figure F-1 Structure Data Editor
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F.1.1 Top Geometry Information
The first twelve columns of the Structure Data Editor (Fig. F-1) table include required top
geometry information for all insulator types. For each cable attachment point you need to enter:
Set # and Phase #:
See Section 8.2.1 for definitions
Dead End Set:
Yes:
if the attachment point is the end of a tension section. This is
always the case for Strain insulators and for dead-end Clamps.
No: if the attachment point is not the end of the tension section. This is
always the case for Suspension and 2-Part insulators. It is
assumed to be the case for a Clamp if the structure is very flexible
longitudinally at the clamp attachment point or for a flexible Post
insulator.
Set Description:
Your description of the set. This is an important item as it is displayed in
the Attachment set pick list of the Section Stringing dialog box which you
reach with Sections/ Add or by clicking on the Edit Stringing button at
the bottom of the Section/ Modify dialog box.
Insulator Type:
Clamp:
Strain:
Suspension:
2-Part:
Insulator Weight:
attachment device that has no weight and no dimension
dead-end insulator in line with conductor
Post:
linear insulator fixed at its
base to the structure and supporting conductor at its tip:
unless braced, such insulators are subjected to bending
moments.
insulator hanging from a structure and providing
longitudinal flexibility to the conductor attachment point
insulator made of two suspension parts coming
together at the conductor attachment point, for example Vstrings (see Fig. F-3).
Self explanatory. For 2-Parts, it is the weight of the first part (Side 1).
Insulator Wind Area: The transverse wind load applied to the insulator attachment point to the
structure is equal to the transverse load received from the attached cable
plus the design transverse wind pressure times this Wind Area. For 2Parts, it is the wind area of the first part (Side 1).
Insulator length:
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Attachment Transverse Offset:
Horizontal distance “x”, in local “x,y,z” coordinate system (see Fig. 8.2-1), from vertical axis of
structure to:
Actual location of clamp for Clamps
Structure attachment point for Strains and Suspensions
Conductor attachment point (tip) for Posts
Structure attachment point of first part (Side 1) for 2-Parts
Attachment Dist. Below Top:
Vertical distance “y”, in local “x,y,z” coordinate system (see Fig. 8.2-1), from top of structure to:
Actual location of clamp for Clamps
Structure attachment point for Strains and Suspensions
Conductor attachment point (tip) for Posts
Structure attachment point of first part (Side 1) for 2-Parts
Attachment Longitudinal Offset:
Horizontal distance “z”, in local “x,y,z” coordinate system (see Fig. 8.2-1), from vertical axis of
structure to:
Actual location of clamp for Clamps
Structure attachment point for Strains and Suspensions
Conductor attachment point (tip) for Posts
Structure attachment point of first part (Side 1) for 2-Parts
Min. Req. Vertical Load:
You can specify the minimum vertical load that should be applied
to an insulator (a positive value is down):
No Uplift: insulator is not capable of supporting upward vertical
loads
No Limit: insulator is capable of supporting unlimited vertical load
Typed value: insulator is only capable of support downward
vertical loads larger than this value. For example, if you type -100,
the insulator is capable of 100 lbs of uplift.
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F.1.2
Data Needed Only for Suspension and 2-Part Insulators
The following data in the 13-th column of the table of Fig. F-1 are only needed for Suspension
and 2-Part insulators. When you click on a cell in the Allowable Suspension Swing Angles and
2-Part Load Angles (min, max for 4 conditions) column, the dialog box of Fig. F-2 opens.
For Suspension insulators,
you need to enter the
maximum
and
minimum
allowable swing angles for the
four design swing conditions
described in the Criteria/
Insulator Swing & Uplift
menu (see Section 7.3.17)
For 2-Part insulators, you need
to enter the maximum and
minimum allowable load angles
LA for the four design
conditions described in the
Criteria/ Insulator Swing &
Insulator menu (see Section
7.3.17). With 2-Part insulators,
the load angle LA (measured
from vertical to the direction of
Fig. F-2 Allowable Angles for Suspensions and 2-Parts
the load and positive if
counterclockwise as shown in Fig. F-3) is often limited in design to avoid putting one side in
compression, or if some compression is allowed, to avoid too much curvature in the
compressed string. The load angle limits, LAMIN and LAMAX are illustrated in Fig. F-3.
When you OK the dialog box of Fig. F-2, the selected limits are shown in the Allowable
Suspension Swing Angles and 2-Part Load Angles (min, max for 4 conditions) column of the
dialog box of Fig. F-1.
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B
BL
A
AL
C
LA
LA
LA
C
MAX
MIN
B
UP
B
A
C
C
C RIGHT
LEFT
DOWN
A
Fig. F-3 2-Part Insulators (also V Strings)
F.1.3 Data Needed Only for 2-Part Insulators
WARNING: 2-Part insulators (which include V-strings) are not allowed on Method 3 structures.
This is because the behavior of these insulators can be nonlinear which makes them
incompatible with the linear theory used to relate loads to forces and moments in the structure
components.
When you select 2-Part in the Insulator Type column of Fig. F-1, the last nine columns become
available for data entry.
2-Part insulators include two sides (parts) attached to the structure at points A and B as shown
in Fig. F-3. Examples of 2-Part insulators are V-strings (top part of Fig. F-3 or line A-CDOWN-B at
the bottom left) and horizontal V's (line A-CRIGHT-B at the bottom right of the figure).
Side A (or Side 1 or First Part) of a 2-Part insulator is attached at Point A and Side B (or Side 2
or Second Part) is attached at Point B. Each side has its own length (AL for Side A and BL for
Side B), weight, and wind area (from which wind load on each side can be determined). From
given positions of A and B and given lengths AL and BL, the position of the common Point C
where the load is applied is determined automatically. Since there are mathematically two
possible positions of Point C (see lower left and lower right portions of Fig. F-3), you need to tell
the program which one you want. This is done by telling the program if you want Point C to be
the lower (bottom) or upper position, or in the case where AB is vertical, or near vertical, if you
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want the right or left position. You tell the program this by entering “Yes” in the "2-Part Bottom/
Right" column of Fig. F-1 if you want the lower or rightmost of the two solutions, or “No” if you
want the upper or leftmost solution. You will be provided with either the coordinates of Point C
or its displayed position to check your selection.
To fully define the geometry of a 2-Part insulator, you will need to enter the Weight, Wind Area,
Length, Transverse Offset, Distance Below Top and Longitudinal Offset of the second part (Side
2) in the appropriate columns, just as you did for the first part (Side 1) in Section F.1.1.
When you use the structure programs PLS-POLE and TOWER to model Method 4 structures
(not the Method 1 and Method 2 structures discussed in this section), each part is modeled by
either a straight bar (if the part is capable of carrying compression) or a cable (if it cannot carry
compression). Therefore, the way in which a 2-Part insulator transfers loads to its structure
attachment points depends on the ability of each side to carry compression. You specify that
ability by specifying whether each side is "Tension Only" or not. This information is generally not
needed for Method 1 or Method 2 structures (unless you select Levels 2, 3 or 4 modeling - see
Appendix N), as these structures are checked by allowable wind and weight spans. However,
for consistency among all structure modeling methods in PLS-CADD, you can specify whether
Side 1 and Side 2 of your 2-Part insulators are Tension Only or not in the two columns before
the last column of the table of Fig. F-1.
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F.1.4 Creating or Editing Structure Strength
Clicking on the Structure Strength button at the
lower left of dialog of Fig. F-1 takes you to the
Strength Definition box of Fig. F-4 where you
select among the basic Allowable Spans method
(Method 1), the Interaction Diagram method
(Method 2), and the Critical Component method
(Method 3).
Fig. F-4
F.1.4.1
Strength by Method 1
If you select Allowable Spans, you
are taken to the dialog box of Fig. F5 where input data are:
Description of limits of validity:
This is very important alphanumeric
information that reminds the user
that the allowable spans listed below
are not pure strength properties of
the structure but depend on the
design criteria, number and types of
conductor attached, etc.
Fig. F-5 Allowable Spans Table (Method 1 Structures)
For each line angle:
Maximum wind span: Self. expl.
Maximum weight span Condition 1 (usually extreme Wind):
Maximum allowed weight span (VSMAX1 in Fig. 8.3-1) for the first load case selected in the
Weight Span Criteria dialog box (see Fig 7.3-5) which is reached with Criteria/ Weight Spans
(Method 1) menu (see Section 7.3.10).
Maximum weight span Condition 2 (usually Cold without ice nor wind):
Maximum allowed weight span (VSMAX2 in Fig. 8.3-1) for the second load case selected in the
Weight Span Criteria dialog box.
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Maximum weight span Condition 3 (usually extreme Ice or Ice with some wind):
Maximum allowed weight span (VSMAX3 in Fig. 8.3-1) for the third load case selected in the
Weight Span Criteria dialog box.
Minimum weight span:
Minimum allowed weight span (VSMIN in Fig. 8.3-1) for all the load cases selected in the Weight
Span Criteria dialog box. This number can be negative if uplift is permitted. Minimum weight
spans are indirectly checked by the maximum allowed swings or load angles defined in the
dialog box of Fig. F-2.
The largest line angle included in the first column of the Allowable spans table is the largest
line angle at which the structure is allowed to be located. If the structure is part of the list of
structures to be considered in optimum spotting, it will not be tried for any line angle larger than
the largest angle shown in the table. If a dead-end structure is also to be used for large line
angles, make sure that there is data for the large angles in the table. Allowable wind and weight
spans for angles not shown in the table are calculated by simple linear interpolation between
provided values.
Edit Single Side Limits:
If you click on the Edit Single Side Limits button in the lower left corner of the dialog box of
Figure F-5 it will bring up a dialog box for single side limits for wind and weight span which will
allow you to dictate a percentage of the total allowable wind and weight span that may come
from a single side of a structure. You can rapidly apply single side limits to existing structures
by using the Structures/ Available Structure List/ Batch Modify of Single Side Wind &
Weight Span Limits function.
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F.1.4.2
Strength by Method 2
If you select Interaction
Diagram, you are taken
first to the dialog box of
Fig. F-6 where you define
a list of angle ranges for
which interaction diagrams
will be defined. The angle
ranges should be entered
in ascending order. To
add an angle range, enter
a value in Maximum Angle
(larger than the upper limit
of the previous range) and
click on the Accept
button.
Then, for each angle
range in Fig. F-6, you will
need to define a diagram
for a series of load cases.
To do so, you select an
Angle Range in the dialog
of Fig. F-6 and click on the
Edit button. You will be taken to the box of Fig. F-7.
Fig. F-6
The actual interaction diagram is shown for each of the load cases you enter in the tables for
your reference. Figure F-6 shows all interaction diagrams for all load cases and all angle
ranges. Figure F-7 shows the interaction diagrams associated with all load cases for just the
selected angle range. Figure F-8 shows the single interaction diagram for the selected load
case and selected angle range.
The same Edit Single Side Limits option that is described in section F.1.4.1 for Method 1
structures is also available for Method 2 structures and is input in the dialog in Fig. F-6 above.
The same batch modify option is also available.
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Each row in the dialog box of Fig.
F-7 represents a load case that
should match exactly that in the
corresponding
row
of
the
Interaction Diagram Criteria
table (see Fig 7.3-6) which is
reached with Criteria/ Interaction
Diagram (Method 2) (see
Section 7.3.11). The number of
points listed in each row of Fig. F7 is automatically determined
after you define a diagram in the
subsequent table (Fig. F-8) as
described next (it is the number of
non-blank rows in the table of Fig.
F-8).
Once you select a load case (row)
in Fig. F-7 and click on Edit, you
are taken to the Structure
Interaction Diagram dialog box
of Fig. F-8 where you enter the
following data:
Figure F-7
Description of limits of validity:
This is very important alphanumeric information that reminds the user that the allowable wind
and weight spans listed in the following table are not pure strength properties of the structure
but depend on the design criteria, number and types of conductor attached, etc.
Please see the technote at http://www.powline.com/products/windwgt.html for a discussion on
allowable wind and weight spans versus real structure models.
Allowable Wind and Weight Spans:
You enter as many pairs of allowable wind and weight span points as are necessary to describe
your interaction diagram for the particular combination of weather case and line angle range
(see Fig. 8.3-2 for an example with 9 points). Figure F-8 below shows an example with 13
points. The points are connected in the order they are entered in the table.
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Figure F-8 Interaction Diagrams
F.1.4.3
Strength by Method 3
As mentioned in Section 8.3.3 we recommend that you do not use Method 3 structures any
more. Therefore, we do not describe the various tables where you enter the data for Method 3
structures. However, these should be self-explanatory, should you need to use them.
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F.1.5 Assigning Structure Material
Clicking on the Material button at the bottom of the dialog of Fig. F-1 takes you to the Structure
File Material List dialog of Fig F-9 where you simply type in the Stock Number and the Quantity
of whatever parts or assemblies make up the structure. As soon as you type in a valid part or
assembly number, its description appears in the grey area of the dialog. You can also right click
on a stock number of an item in either the part or assembly tables at the bottom of the dialog
box and choose to Add to Structure File Material List to populate the table.
Fig. F-9 Structure File Material List
You may directly edit the parts table by entering data in the middle table. To edit the
assemblies the user will need to visit the Structures/Material/Parts and Assemblies File/Edit
Assemblies table.
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F.1.6 Batch saving multiple structures
Clicking on the Multiple Save button at the bottom left of the dialog of Fig. F-1 lets you define a
complete family of structures each having the same top
geometry, the same strength model, and the material list, but
with different Heights (height HT in Fig. 8.2-1).
You are taken to the Batch Save dialog shown in Fig. F-10
where you define the Number of structures in the family,
their Structure file name extensions, their Heights above
ground and, if they are direct embedment poles, their
Embedded lengths.
For example, if the name of the structure file used to develop
some direct embedded pole data in the dialog of Fig. F-1 is
TanPole, then the data in Fig. F-10 will generate five
Fig. F-10 Multiple Save
structure
files
named
TanPole.060,
TanPole.065,
TanPole.070, TanPole.075 and TanPole.080. The five generated poles will have total lengths
(from base to top) of 60, 65, 70, 75 and 80 ft, actual heights HT above ground (HT defined in
Fig. 8.2-1) of 52, 56.5, 61, 65.5, and 70 ft, and embedment lengths of 8, 8.5, 9, 9.5 and 10 ft,
respectively.
If parts have been assigned to the original TanPole file, you may have to edit the Stock Number
of the pole shaft in each of the Tanpole.060 to TanPole.080 files to account for different shaft
lengths. However, the various parts and assemblies which make up the arms, insulators and
hardware need not be changed.
F.2
Method 1 or 2 Structures - Using Structure Programs
Files for Method 1 and Method 2 structures can be created automatically by our structure
programs PLS-POLE (for concrete, steel and wood poles and frames) and TOWER (for steel
latticed towers). Because these models are created by our structure programs which know their
detailed geometry, they are displayed accurately (see discussion in Section 8.4.2) in PLSCADD instead of being shown as stick structures.
Older versions of our TOWER program could create Method 3 structure files automatically for
linear towers, but this capability has been abandoned in more recent versions (Version 5 and
newer).
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F.3
Method 4 Structures
Method 4 structures are checked by direct link to our structure programs PLS-POLE and
TOWER. Being specialized programs for transmission or distribution structures, these programs
let you create structure models with the minimum amount of effort. You should consult their
user's manuals to see how Method 4 models are created or edited.
The structures modeled by PLS-POLE and TOWER can have almost any conceivable
configuration. They can be single concrete, steel or wood poles, guyed or unguyed. Or they can
be multipole structures (frames) made up of any arrangement of concrete, steel or wood poles
connected by a wide assortment of davit arms, cross arms, braces or guys. Or they can be steel
latticed towers, self-supporting or guyed.
COMPONENT
MODEL
ANALYSES
DATA BASES
MATERIAL PROPERTIES
MATERIAL LIST ESTABLISHED
AUTOMATICALLY
STEEL ANGLES
STEEL ROUNDS
BOLTS
GUY CABLES
DESIGN CHECK OPTION
STRUCTURE IS ANALYZED
FOR GIVEN LOADS
POLE SHAFTS
WOOD
STEEL
CONCRETE
AUTOMATIC WHEN LINKED
TO PLS-CADD
DAVIT ARMS
CROSS ARMS
BRACES
INSULATORS
POSTS
STRAIN
SUSPENSION
2-PARTS
SWINGING BRACKETS
EACH COMPONENT HAS
UNIQUE STOCK NUMBER
STRUCTURES ARE
ASSEMBLED FROM
COMPONENTS IN
DATA BASES
FINITE ELEMENT MODEL
IS DEVELOPED
AUTOMATICALLY
MULTIPLE HEIGHT MODELS
ARE GENERATED
AUTOMATICALLY
DEFLECTED SHAPE
WITH COLOR CODING
OF PERCENT USE IS
DISPLAYED
ALLOWABLE SPANS OPTIONS
ALLOWABLE WIND AND
WEIGHT SPANS OR
THEIR INTERACTION
DIAGRAMS ARE
DETERMINED FOR
GIVEN LOAD CRITERIA
Fig. F-11 Assembling Structure from It’s Components
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PLS-POLE and TOWER let you build a structure model by selecting components from data
bases and assembling them into a finished structure as shown in Fig. F-11. Assembling the
components into a structure is very simple and does not generally require any special
knowledge of structural analysis principles. Once the structure is assembled, the program
automatically generates its finite element representation for analysis purposes. In the case of a
structure family made up of poles of different classes and lengths but sharing the same top
geometry, the entire family can automatically be generated from the model of one of its member
structure.
If the structure is made up of standard components described by unique stock numbers, then its
model contains a complete description of these components.
When the structure model is used by PLS-CADD, then a complete parts list for the entire line
project can be established, thus automating cost estimates and linking to work order systems.
The parts, components or subassemblies can be shown automatically on PLS-CADD Plan &
Profile drawings.
Similar to the Method 1 structures if you go to Structures/ Modify and select a PLS-POLE or
TOWER structure and hit Edit the model will open in the appropriate program for editing. If you
do a Save As in either of the structure programs and change the name of the structure file PLSCADD will not automatically switch the structure in the line model. However if you select the
structure button in the Structures/ Modify dialog after making the new file the program will
detect the change of the structure name via use of Save/ As in the structure editor and offer
options to change to the newly saved name.
F.3.1
Linear vs. nonlinear analysis
The analysis of the finite element model automatically created by PLS-POLE or TOWER can
either be linear or nonlinear. With the linear option, the secondary effects of the structure
displacements, i.e. the so-called P-Delta effects, are ignored. With the nonlinear option, all
forces and moments are in equilibrium in the structure deformed state, i.e. P-Delta effects are
accounted for. While the nonlinear option takes care of all geometric nonlinearities, linear
material properties are still used in all programs. This is consistent with all current code-based
design procedures for transmission structures.
The elastic buckling of a structure is an extreme case of P-Delta effect. When running in
nonlinear mode, buckling is detected.
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APPENDIX G.
GROUND WIRE OR CONDUCTOR FILE
All the information needed to describe the geometrical, electrical, mechanical and thermal
properties of a ground wire or conductor is contained in a single file. A cable file is an ASCII
(TEXT) file which should be created/ edited with the cable editor described in Section 9.2. This
appendix provides additional information regarding cable modeling and data.
Files containing the properties of hundreds of commonly used conductors and ground wires can
be downloaded from Power Line Systems web site at: http://www.powline.com/files/cables.html
or through the web download option in many of the menus as described in Section 5.8.
G.1
Stress-elongation and Creep-elongation Coefficients from Test Data
For
an
homogeneous
conductor (made of a
single material), the
five
polynomial
coefficients
a0
through a4 in Eq. 9-3
and
the
five
coefficients
c0
through c4 in Eq. 9-8
can be determined
automatically
from
simple test data. This
can also be done for
bi-metallic
conductors if one
assumes that these
Fig. G-1 Test Results for Test data Conductor
conductors behave as
a homogeneous component, i.e. when the outer and core materials are considered as a single
composite material rather than separate materials. In this case the thermal expansion coefficient
of the outer strands should be a composite coefficient for both materials and the core properties
are not considered (i.e. the "b" and "d" coefficients and the core thermal expansion coefficient
are not needed).
Fig. G-1 shows some assumed test data for a fictitious conductor named Testdata. The data
consist of 8 pairs of tension vs. initial elongation data and 6 pairs of tension vs. creep elongation
data. The creep elongation is the assumed elongation beyond the initial elongation if the tension
is maintained for a period of ten years. The first data line in Fig. G-1 should be small but
nonzero numbers (for example .001) to indicate that the elongations are near zero when the
tension is near zero. The table in Fig. G-1 is accessed by clicking on the Generate Coefficients
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button at the bottom of the Cable Data dialog box opened with Sections/Cable Files/Edit
Existing Cable File... (see Fig. G-2). In Fig. G-2, the cross section area, outside diameter, unit
weight, ultimate tension, and test temperature of the entire cable as well as the thermal
expansion coefficient of the outer strands should be entered before clicking on Generate
Coefficients. In the case of a composite cable, the outer strands are assumed to represent the
entire cable, i.e their thermal expansion coefficient should be a weighted average of the
expansion coefficients of the outer and core materials.
When you OK the data in Fig. G-1, PLS-CADD runs regressions between the pairs of tensioninitial and tension-creep data points to determine the polynomial coefficients shown in Fig. G-2.
After returning from the menu of Fig. G-1 to that of Fig. G-2, you should input the value of the
Final modulus of elasticity of the outer strands. This value should be equal to, or close to, the
stress-strain coefficient A1.
After saving the cable data generated by the above procedure, you should always make sure
that the derived stress-strain and stress-creep models are correct. This is best done graphically
with the Sections/Cable Files/Edit Existing Cable File... and choosing the Graph Cable
Properties command. Fig. G-3 shows the data in Fig. G-1 as small squares and the
corresponding curves derived from the polynomial coefficients and final modulus of elasticity in
Fig. G-2.
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Figure G-2 Conductor From Test Data
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Fig. G-3 Graph of Data in Figs. G-1 and G-2
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G.2
Linear Conductor Example
This example is provided to show you how simple a conductor or ground wire model can be if
you accept the simplifying assumptions of linear elastic behavior and nominal creep. The
nominal creep in the example is assumed to be a constant 0.0005 permanent strain elongation,
or equivalently, the strain caused by a 21.5 degrees Celsius shift in temperature (0.0005 = 21.5
x 0.0000231).
Fig. G-4 shows the data for the simple example and Fig. G-5 shows a graph of the same data
Fig. G-4 Linear Elastic Cable with Nominal Creep
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Fig. G-5 Graph of Cable in Fig. G-4
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G.3
Improved Linear Conductor Example
This example is provided to show you how the improved linear cable model for a conductor or
ground wire behaves if you accept the simplifying assumption of linear elastic behavior and
nominal creep proportional to the creep weather case tension. For more information on the
improved linear cable model please see the technote at :
http://www.powline.com/technotes/Improved_Linear_Cable_Model.pdf
Figure G-6 Improved Linear Cable Model
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Figure G-7 Graph of Improved Linear Cable Model in Figure G-6
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APPENDIX H.
DEMO LINE EXAMPLE
This appendix describes a short fictitious line, Demo, which we have referred to many times in
this manual. This line is not a real design. In fact, it violates several of its own design criteria. It
is only provided for you to quickly experiment with the many features of PLS-CADD. As you
load the Demo line by selecting Demo.xyz with File/ Open, all the files associated with the
Demo line (feature code file Demo.fea, design criteria file Demo.cri, etc) are loaded
automatically. All these files are included on the PLS-CADD distribution diskettes. Fig. H-1
shows a Plan and a Profile view for the line.
The line consists of
variety
of
different
structure
types
and
models. It starts going
east with a single 345 kV
KIWI flat circuit at a
dead end latticed tower
DEMDED1.80 (Fig. H-2).
Just to the right of the
first tower, a separate
138 kV DRAKE circuit
starts on a dead end
pole DEMDED2.40 (Fig.
H-3). Then both circuits
are
supported
by
tangent
steel
poles
DEMTAN1.* (Fig. H-4)
and are dead-ended on
a
latticed
tower
Fig. H-1 Demo Line
DEMDED4.TOW
located at the first 90 degrees line angle. The line continues south beyond the first line angle
and then goes east again after the second line angle. Between the two line angles it is
supported by two tangent latticed towers DEMTAN2.TOW (Fig. H-5).
All structures in the Demo line for which you do not see an outline below the ground line in the
Profile view are modeled by the basic allowable spans method (Method 1). Those for which you
see outlines were modeled either by the TOWER or PLS-POLE programs (Method 4). You may
want to look at the properties of any structure with Structures/ Edit Structure or, better, with
Structures/ Modify followed by a click on the Edit button at the bottom of the Structure Modify
dialog box.
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Fig. H-3 DEMDED2.40
Fig. H-2 DEMDED1.80
1
3
2
10'
6
6 '
8 '
4
7
8 '
6 '
5
8
6 '
8 '
20'
T
Fig. H-4 DEMTAN1*
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Fig. H-5 DEMTAN2.TOW
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APPENDIX I.
I.1
CONCEPTS OF RULING, WIND AND WEIGHT SPANS
Ruling Span
The PLS-CADD 3-dimensional line
S1
S2
S3
S4
S5
model
includes
a
detailed
representation of all cables in all
spans. Sag and tension calculations
C5
can be performed rapidly by clicking
C4
OR
C3
F
C2
on a particular cable in a particular
D
E
C1
span. Each cable is part of a
C
A
B
"tension section", i.e. a collection of
VS
spans with horizontal components of
cable tension which are nearly equal
Fig. I-1 Section Tension
or related. In Fig. I-1, the conductor
is dead-ended at points A and F, and is in suspension at points B, C and E. If the conductor is
also in suspension at support D, it is part of a single tension section. This is because all
suspension insulators move freely as they try to equalize the horizontal components of tension
in all the spans. If point D cannot move, i.e. it is a dead-end point, then the conductor is part of
two separate tension sections, one between A and D, and the other one between D and F. For
the purpose of tension calculations, a cable behaves as a unit over an entire tension section. As
weather and cable conditions vary continuously over the life of the line, the suspension
insulators forever swing back and forth trying to equalize the tensions.
In actual lines with suspension and dead-end (strain) insulators, tension sections are clearly
defined. They start at a dead-end, pass under suspension insulators and end at the next deadend. In lines with post insulators, the identification of a tension section is not always
straightforward. If the post insulators and their supporting structures are flexible, they will move
longitudinally as they attempt to equalize the tensions in adjacent spans. A flexible post is
therefore not different from a suspension insulator for the purpose of defining a tension section.
However, if a post insulator and its supporting structure are very rigid, they may act as dead
ends and the assumption that the tensions on both sides are nearly equal or related cannot be
supported.
As described in Section 7.1.1, PLS-CADD provide four analysis levels for a tension section.
With Level 1 (Ruling span method), it is assumed that the suspension and post insulators are
perfectly flexible and therefore that the horizontal component of tension is equal in all the spans
of the tension section. That horizontal component of tension is calculated for a fictitious span,
the ruling span, which duplicates the behavior of the entire tension section. When you deal with
a situation where the ruling span assumptions are not applicable (this is discussed in Section
I.1.1), advanced finite element modeling with Levels 2, 3 or 4 can be used. With Levels 2, 3
and 4, increasingly accurate structural analyses of the tension section are performed inside
PLS-CADD using the same finite element algorithms (Peyrot and Goulois, 1978) which are
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used in our popular SAGSEC and SAPS programs. These analyses can account for the various
levels of flexibility provided by post insulators, poles and frames, as well as nonuniform loads on
the spans. Appendix N discusses many of the assumptions of finite element modeling.
For a Level 1 analysis, the ruling span is a single fictitious level span, with length determined by
the formula:
RS
=
SQRT( {S14/C1 + S24/C2 + . . + Sn4/Cn} / {C1 + C2 + . + Cn} )
Si
Ci
=
=
(I-1)
where:
length of span i (horizontal projection)
chord length of span i
For a single span between dead ends, the ruling span is S * S / C, i.e. it is shorter than S for an
inclined span.
It can be shown that the horizontal tension in a tension section under any combination of
weather and cable conditions can be estimated by replacing the entire tension section by its
ruling span. The ruling span of Eq. I-1 is used in PLS-CADD to make all tension calculations.
The ruling span method is actually an approximation which has its limits of validity as discussed
in Section I.1.1.
Eq. 1-1 is an improvement over the classical equation for ruling span where Ci is taken equal to
Si. The improvement accounts for the effect of spans with unequal end elevations. In PLSCADD, the ruling span is computed with Eq. I-1. Other ruling span equations have been
proposed (Avril, 1974; Bougue, 1999).
PLS-CADD continuously and automatically keeps track of tension sections. The ruling span and
tension calculations are done so rapidly that you seldom realize that complex computations are
being performed behind the scene.
For example, if there is a suspension insulator at point D in Fig. I-1, the horizontal component of
tension of the entire cable between points A and F is calculated by dealing with a single ruling
span of length:
RS = SQRT( {S14/C1+S24/C2+S34/C3+S44/C4+S54C5} / {C1+C2+C3+C4+C5} )
If there is a dead-end support at point D, the tension calculation for the cable between points A
and D is performed with a ruling span of:
RSL = SQRT( {S14/C1+S24/C2+S34/C3} / {C1+C2+C3} )
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and that for the cable between points D and F is performed with a ruling span of:
RSR = SQRT( {S44/C4+S54/C5} / {C4+C5} )
I.1.1
Limits of Validity of the Ruling Span Concept
While it is an approximation, the ruling span concept (Level 1 modeling) is one of the most
useful concepts in transmission line design. However, you should be aware that it has its limits
of validity and that alternate calculation methods (Levels 2, 3 or 4) should be used when your
application falls outside these limits.
I.1.1.1 Situations Where the Ruling Span Concept Works Well
Fortunately, the ruling span concept works well in the great majority of design situations. This is
why all preliminary designs can be based on this concept. Once the spotting from a preliminary
design has been completed you should take a second look at unusual situations where this
concept may not be valid.
Fundamental to the validity of
the ruling span concept are the
assumptions that: 1) all spans
are subjected to the same
weather load per unit length,
and
2)
the
horizontal
component of tension is the
same in all the spans within a
given tension section. It is as
though
the
spans
were
supported by roller supports, as
shown in Fig. I-2.a. There are
other underlying assumptions,
such
as
parabolic
approximations, but these are
R
(a)
SA
SA
IL
CA
(b)
VP
LP
D1
SA1
CA
D2
D3
usually not as critical as the
assumption
of
constant
horizontal tension in the tension section.
LIMB
CA1
(c)
(d)
V
Fig. I-2 Cable Support Conditions
In most practical situations, intermediate supports within a tension section include post or
suspension insulators.
Post insulators are obviously not ideal roller supports. Depending on their longitudinal flexibility,
on the flexibility of the support to which they are attached, and on the magnitude of the
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longitudinal movement required for tension equalization, post insulators may or may not be
considered as good tension equalizers. In general, posts are used on flexible poles where we
assume that they function as roller supports. However, in the case of short stiff posts mounted
on longitudinally stiff supports (for example a longitudinally guyed pole), you should be
concerned about their ability to equalize tensions.
Even suspension insulators are not always good tension equalizers. Figure I-2.d shows a
suspension insulator as it swings to the right to attempt equalization of the span tensions. LP is
the longitudinal insulator displacement, IL is the insulator length, LIMB is the longitudinal
imbalance (i.e. the difference between the tension in the right span and that in the left span),
and V is the vertical conductor load. Neglecting the insulator weight, statics dictates that LIMB /
V = LP / VP. Or, if we accept that VP is approximately equal to IL for small longitudinal
displacements, LIMB is approximately equal to (V / IL) x LP. The ratio of vertical load to
insulator length, V / IL, is the apparent longitudinal stiffness of the suspension insulator. For a
suspension insulator used at a running line angle, Fig. I-2.d is still valid if you replace V by the
resultant of the vertical and transverse loads. That resultant is generally much larger than the
vertical load. Therefore, small vertical loads and long insulator lengths facilitate tension
equalization, while large vertical loads, line angle situations and short insulator lengths make it
more difficult for the tensions to equalize. For example, assume that a 50 cm suspension
insulator (IL = 50 cm) is vertically plumb at the everyday temperature but swings LP = 10 cm at
high temperature as it attempts to equalize tension. Assume further that the insulator supports
a large weight span resulting in substantial vertical load V = 2,500 daN. For this situation, LIMB
= (2,500 / 50) x 10 = 500 daN. This tension imbalance is certainly significant and can result in
sag problems if it is not accounted for.
If suspension insulators are attached to longitudinally flexible structures, the longitudinal
displacements of the attachment points (for example D1, D2 and D3 in Fig. I-2.c) will help
equalize the tensions.
Short suspension links or clamps commonly used to attach ground wires may be poor tension
equalizers.
In summary, for relatively uniform spans supported by flexible post insulators, or by long
suspension insulators not subjected to large vertical loads, or by long suspension insulators not
subjected to large transverse loads at running angles, the ruling span is a good approximation
from which reliable sag calculations can be obtained.
I.1.1.2 Situations Where the Ruling Span Concept Does Not Work Well
For situations with widely differing span lengths in hilly terrain or with running angles, the ruling
span may give quite erroneous results. This is illustrated in Fig. I-3 for a 138 kv line supported
by wood H-Frames. The top left of Fig. I-3 shows, at scale (i.e. without amplification of the
vertical scale), the six spans of the tension section. The lower left part of the figure shows, with
vertical scales amplified by a factor of 10, the cable sags of the third span at high temperature.
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The higher cable positions were determined with the ruling span concept (Level 1 modeling)
and the lower positions were based on a Level 4 analysis. The Level 1 and Level 4 models
were such that all structures and all suspension insulators were vertically plumb for the 60 deg.
F (16 deg. C) everyday condition after creep, i.e. the two models had identical geometries at
everyday condition. At high temperature, however, you can see a difference in conductor sag of
about 8 ft in the third span, resulting in a vertical clearance violation not detected by the ruling
span approach. The right portion of Fig. I-3 shows the positions of Structure #3 for the everyday
and hot conditions, respectively. You should note that the frame is very flexible longitudinally. Its
longitudinal movement at high temperature happens to be of similar magnitude as that of the
longitudinal insulator swing.
With the much simpler modeling of the tension section with Level 3, we found almost identical
sags at high temperature as those produced with Level 4. Levels 2 and 3 are more appropriate
than Level 4 for everyday design situations.
Fig. I-3 High Temperature Sags Using Ruling Span Vs. Level 4 Model
Ruling span can also give inaccurate results for the reported wind span, weight span, structure
loads, and swing angles when looking at angle structures since all values are based upon the
undeformed shape of the insulator. An angle structure’s undeformed insulator is such that the
insulator is hanging straight down but in reality it will move due to tension on the line and the
angle such that the wire attachment point can vary by several feet horizontally and vertically
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depending on the length of the insulator. This movement can cause the values for the angle
structure and its adjacent structures to be in error since the wind span, weight span, structure
loads, and swing angles are based on a different wire attachment on the angle structure. The
only way to competently report these values is to use finite element sag tension which takes the
deformed position of the insulator into account in the model.
In addition to becoming inaccurate for spans with widely differing lengths and end elevations
(Avril, 1974; Bougue, 1999; Motlis, 1998), the ruling span method is obviously not applicable to
the many situations of unbalanced ice, residual longitudinal loads from broken conductors or
insulators, loads resulting from adding or removing slack in the spans (for example when
removing or adding conductor length through splicing operations), loads resulting from motion of
the structures at their base, etc. For such applications, as well as other situations where the
ruling span concept is not applicable, alternate wire models (Level 2, Level 3 or Level 4) are
available as described in Section 7.1.1 and Appendix N.
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I.2
Wind Span
Fig. I-4 shows a top view, an elevation
view and a view down the line of two
B C
C
TOP VIEW
A
spans adjacent to tangent Structure B.
The two spans are level spans with
B
equal end elevations. When the wind
HS
blows perpendicular to the line, both
WIND
spans swing out away from the wind in
shapes which are symmetrical about
A
B
C
ELEVATION
T
the centers of the spans (see top view).
Because of the symmetry, the
VIEW DOWN
transverse wind load TL transferred to
THE LINE
VS
Structure B by a single cable can be
calculated as the product of the
Fig. I-4 Spans With Equal End Elevations
horizontal load per unit length of cable,
UH, times the length HS of cable between the most swung out points in the spans, i.e. TL = UH
x HS. HS is often called wind span or horizontal span.
Because the length of cable between the
most swung-out points is very close to
the horizontal distance between these
points, traditional power line design
practice defines as wind span for a
particular structure the average of its two
adjacent spans. The definition is also
applied to angle structures.
C
A
B
TOP VIEW
C
B
HS
WIND
B
T
C
ELEVATION
A
When the spans adjacent to Structure B VIEW DOWN
VS
have unequal end elevations (see Fig. I- THE LINE
5), the cable in a span still blows out
Fig. I-5 Unequal End Elevations
symmetrically about the center of the
span as viewed from the top. However, the length of cable actually blown upon by the wind is
closer to the average of the chord lengths Ci of the adjacent spans than to the average of the
horizontal spans Si.
Wind span reported by PLS-CADD: For reasons discussed above, the wind span reported by
PLS-CADD and used for the check of a structure with either Method 1 or Method 2 (Allowable
spans methods) is the average of the chord lengths and not the average of the spans
themselves.
When computing transverse wind loads on a structure with Structures/ Loads/ Report or when
checking a structure with either Method 3 or Method 4 (Critical components or full analysis),
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PLS-CADD does not rely on the wind span concept but uses the more exact procedure
described in Appendix J. The more exact procedure will yield results slightly different from the
traditional wind span approach for spans with unequal end elevations.
I.3
Weight span
Returning to Figs. I-4 and I-5, and looking at the elevation views, one can see that the vertical
load VL transferred by a single cable to Structure B is the product of the vertical load per unit
length of cable, UV, times the length VS of cable between the low points in the elevation views,
i.e. VL = UV x VS. VS is often called the weight span or vertical span. For level spans (Fig. I-4)
the weight span is equal to the wind span.
For inclined spans (Fig. I-5) the distance between the low points in adjacent spans has no
relationship to the wind span. That weight span changes with different weather and cable
conditions. Therefore, a weight span can only be defined for a particular combination of weather
and cable conditions. This is why PLS-CADD requires that weather and cable conditions be
specified when weight spans are calculated for structure checks by either Method 1 (Basic
allowable spans method) or Method 2 (Allowable spans interaction diagram method). When
wind is blowing on inclined spans, it is actually difficult to locate the low points in the elevation
view. For a given cable tension, the location of the low point in the elevation view depends on
the swing angle of the entire span (see discussion about swung-out catenary in Section J.2). In
addition, the length of cable between low points may be substantially different from the
horizontal distance between these points. Therefore, one should clearly understand the
assumptions behind any weight span calculation. Since weight spans are an indirect measure of
vertical loads through the equation VL = UV x VS, the validity of a particular method for
calculating weight spans should be judged by the ability of the method to predict correct vertical
loads.
Traditional weight span: With traditional hand calculations and some computerized versions of
these calculations, the effect of the span swing angle is neglected. A catenary template
corresponding to the resultant load per unit length of cable is drawn in the vertical plane and the
horizontal distance measured between low points is taken as the weight span.
Weight span based on arc length between low points in vertical plane: The first option available
in PLS-CADD is similar to the traditional method in that it assumes that the cable lies in a
vertical plane. The weight span is then calculated as the actual length of cable between the low
points, not the horizontal projection of that length. While the arc length method is an
improvement over the traditional method for level spans and inclined spans without wind, both
methods give erroneous results for inclined spans subjected to wind. You can see the
magnitude of the error by getting two separate weight span reports for a particular structure, one
after selecting the "arc length" method with Criteria/ Weight span model, and the other after
selecting the "exact" method. Providing you with the ability to compare traditional and exact
calculations is one of the reasons we still support the "arc length" method in PLS-CADD. This
should help you understand why lines which were designed with weight spans based on the
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traditional or "arc length" methods are often shown to be overloaded when analyzed by the
"exact" method described below. Unless you are on fairly flat terrain, you should use the "exact"
weight span method for spotting optimization (Section 14).
Exact weight span: With this second option available in PLS-CADD, the effect of the span swing
angle is fully accounted for. The weight span is based on an accurate calculation of vertical load
VL divided by the vertical load per unit length of cable. The procedure for calculating VL is
described in Appendix J. This option requires slightly more computer time but is more accurate.
With this option, vertical loads VL and weight spans VS are always compatible, since V = UV x
VS.
In summary, the weight spans reported by PLS-CADD and used for the check of a structure
with either Method 1 or Method 2 (Allowable spans methods) can be based on either one of
two assumptions. You chose your assumption with Criteria/ Weight span model.
When computing vertical loads on a structure with Structures/ Loads/ Report, when checking
a structure with either Method 3 (Critical components) or Method 4 (Full analysis), or when
checking an insulator swing or an uplift condition, PLS-CADD does not rely on the weight span
concept, but always uses the more exact procedure described in Appendix J.
When a structure supports cables of
different sizes with different installation
tensions, you can get a report on the
weight spans of each individual cable
set with Lines/ Reports/ Wind &
Weight Span Report. However, for
purpose of checking a structure with
strength described by Method 1 or
Method 2 (Allowable spans), PLSCADD uses the weight span of the
heaviest cable at
the average
attachment height of its set. For spotting
optimization, it uses the weight span of
the lowest conductor of a designated
cable set.
VS 1 +
VS 2 +
VSL 3 -
1
VSR 3 +
2
VS 3 +
VS 4 3
5
4
Fig. I-6 Cold Weight Spans in Hilly Terrain
The weight span concept can be used to quickly detect uplift conditions at a particular structure
from the shapes of the cables. Consider the cold configuration of the cable in Fig. I-6, i.e. that
most likely to create severe uplifts. The weight spans VS at each structure are indicated. The
cable shape in Span 1-2 shows a low point. In any of the other spans, the low point is actually
outside of the span. However, the definition of weight span to estimate vertical load still holds
algebraically, i.e. VS = VSL + VSR, where VSL = distance from structure to low point in
catenary of left span, positive if low point is to left of structure and VSR = distance from
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structure to low point of catenary in right span, positive if low point is to the right of the structure.
For example, VS3 is a positive quantity (vertical load down) because VS3 = VSL3 (a negative
quantity) + VSR3 (a larger positive quantity). VS4 is a negative quantity, indicating uplift at
Structure 4.
If counterweights are used on a structure they will be added to the weight span that is calculated
for the structure. This will impact the weight spans displayed in the Lines/ Reports/ Structure
Usage and Lines/ Reports/ Wind & Weight Span Report. These reports will contain a
comment column that will alert you when a counterweight impacts the weight span. If you do
not wish for the counterweights to impact the weight span, F1/ Custom / Under Development/
Compatibility Options/Include insulator counterweight in weight span (version 12.10 and
earlier did not)...and disable the option.
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APPENDIX J.
SPAN END REACTIONS
As described in Section 7.1.1, PLS-CADD provides you with four modeling levels to analyze
conductors and ground wires. This section describes how the cables are displayed and how
reactions at the ends of a span are calculated depending on the method which you chose.
J.1
Level 1 Modeling - Ruling Span Method
With the Ruling Span method, the horizontal component of tension, H, is determined for each
weather case with the ruling span as described in Section I.1. This tension is assumed to exist
in all the spans of the same tension section. The resulting equilibrium of each span is then
determined as described below.
J.1.1 Cable in its Plane
The equilibrium configuration of a span is
always a "catenary". The catenary lies in
the plane defined by the chord length of
the span and the resultant wire load per
unit length, UR (defined in Section 7.2.3),
which is assumed to have constant
magnitude and direction at any point along
the cable in a given span. UR is based on
the direction of the chord (a straight line),
even though actual points along the cable
are below the chord. Without wind, UR is
vertical and oriented downward. With wind,
UR is not vertical and it defines the swing
angle β of the span plane.
T
ZE
x
V
E
H
v'
UR
h'
O
y
A
a
C
Fig. J-1 Cable as a Catenary
Fig. J-1 shows the catenary shape for a cable in span O - E. The shape is entirely defined by its
catenary constant C and the end attachment points O and E. The catenary constant is the ratio
H / UR, where H is the horizontal component of tension and UR the load per unit length of
cable. H is constant throughout the span.
The equation of the catenary is simplest if given in a coordinate system centered at the distance
C below the low point. In that system:
y
=
C Cosh [ x / C ]
(J-1)
The vertical component of the tension, V, at any point along the catenary is:
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V
=
H Sinh [ x / C ]
(J-2a)
and the corresponding tension (resultant of H and V) is:
T
=
H Cosh [ x / C ]
(J-2b)
The mid-span sag (measured from the chord ) is the one given in all reports. It is calculated as:
SAG
=
C ( Cosh [ h' / 2C ] - 1 ) SQRT { 1 + ( v' / 2C Sinh [ h' / 2C ] )2 }
(J-3)
For given horizontal and vertical projections of the span, h' and v', respectively, and a given
catenary constant, the low point on the catenary can be located a distance "a" from the origin of
span, by the following procedure:
1)
Translate the coordinate system to point O. At this point, "a" is unknown, but it will be
determined by the procedure.
v'
2)
to:
C Cosh [ (h' - a)/ C ] + C Cosh [ - a / C ]
(J-4)
Make use of the identity Cosh[x+y] + Cosh[x-y] = 2 Sinh[x] Sinh[y] to transform Eq. J-4
v'
3)
=
=
2 C Sinh [ (h'/ 2 - a)/ C ] Sinh [ h'/ 2 C ]
(J-5)
Solve Eq. J-5 for the argument of the Sinh function, { (h'/ 2 - a)/ C }:
(h'/ 2 - a)/ C = Sinh-1 [ v'/ (2 C Sinh [ h'/ 2 C] ]
(J-6)
or
a
=
h'/ 2 - C Sinh-1 [ v'/ (2 C Sinh [ h'/ 2 C]) ]
(J-7)
4)
Noting that the inverse function Sinh-1 [x] = Log [ x + SQRT( 1 + x2) ], the distance "a"
can be determined in term of the span projections, h' and v'.
The vertical component of tension V can be expressed as the product of H by the slope of the
catenary (derivative of Eq. J-4) at point E:
V=
H Sinh [ (h' - a) / C ]
(J-8)
which can be transformed to:
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V=
UR { C Sinh [ h' / 2 C ] SQRT( 1 + ( v' / (2 C Sinh [ h' / 2 C ]))2 )
+ (v' / 2) Cosh [ h' / 2 C] / Sinh [ h' / 2 C] }
(J-9)
The force V in Eq. J-9 is opposite to the direction of the vector UR. Since UR is not always
vertical and we want to reserve the notation V for vertical force in the rest of this Appendix, we
will use the notation ZE for the variable V in Eq. J-9. ZE is a local force, in the sense that it is
defined relative to the load per unit length UR. Therefore:
ZE
=
V in Eq. J-9
(J-10)
J.1.2 Swung-out Catenary
Consider now Fig. J-2. Part (a) is an
isometric view of relevant quantities in a
span starting at Point O and ending at
Point E. Part (b) is a view toward the
end of the line. Without wind, the cable
in the span lies entirely in the vertical
plane passing through points O, B, and
E. With wind blowing in the span
transverse direction the entire span
swings out by the angle β which is
defined by the direction of the resultant
load per unit length UR. Point B is just
below E at the elevation of O. Point A is
the projection of B onto the swung out
plane of the catenary.
ZE sin β
ZE cos β
β
ZE
H
H
E
cos α
v'
T
E
β
β
v
A
A
T
β
WIND
UH
h'
h
L
α
B
B
V
UR
UV
β
O
Fig. J-2 Isometric and End View of Swung-out Span
For a given weather condition, the forces H and ZE are first determined in the plane of the
catenary. Then they are projected in the vertical, transverse (perpendicular to vertical plane
through span chord) and longitudinal (horizontal force in vertical plane through span chord)
directions at the end of the span to get the end reactions at point E:
534
VE
=
ZE Cos [ β ] + H Sin [ α ] Sin [ β ]
(J-11)
TE
=
ZE Sin [ β ] - H Sin [ α ] Cos [ β ]
(J-12)
LE
=
H Cos [ α ]
(J-13)
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J.2
Levels 2, 3 and 4 Modeling - Finite Element Method
With finite element modeling (see Section 7.1.1 and Appendix N), a single wire model (Level 2)
or a model including all the wires between nearby dead end structures (Levels 3 and 4) is
developed internally. The models are used to display the cables under the desired weather
cases and to determine the horizontal components of tension, H, in each span. The horizontal
component of tensions in each span are used to determine design loads following the same
procedures as those used for the ruling span method and described in Sections J.1.1 and J.1.2.
This was done to have a single way of calculating structure design loads and insulator swings,
regardless of whether horizontal tensions come from a Level 1, 2, 3 or 4 analysis.
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APPENDIX K.
FILES OVERVIEW
This appendix gives an overview of the various files accessed by PLS-CADD and suggests a
system of directories in which to keep these files organized. It also describes how to back-up all
the files pertaining to a given project.
K.1
Project View
Fig. K.1 Project View
Each time you load an existing project, your line is displayed in a Profile view (maximized), a
Plan view, a 3-D view and P&P sheets views (all three minimized at the bottom of the screen).
It is also described in a Project view, also minimized at the bottom of the screen. Fig. K-1
shows a typical Project view. A Project view includes a tree representation of the various
categories of files which make up a project. It generally shows the order in which the data
should be prepared. Closing the Project view closes the project and gives you an opportunity to
save any change you may have made.
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In order to view sub-branches of a particular branch, you need to double-click on the icon
displayed next to the "+" sign at the origin of the branch or sub-branch. Clicking on these icons
toggles between displaying or hiding the sub-branches.
Right-clicking on an item will display a context menu related to that item. For example you can
right-click on any one of the files shown in the Project window and you will be presented with a
menu that generally lets you do something with that file.
Most files in the Project view are named after the project. For example, the name of the project
in Fig. K-1 is "dtm2". Reading from the top of Fig. K-1 lets you know the following:
The terrain model consists of points in file dtm2.xyz. These points have feature codes already
defined in file dtm2.fea. The file dtm2.num stores the P.I. data that was generated when defining
the alignment. Terrain constraints (excluded zones etc.) specified on the alignment for spotting
optimization are stored in the dtm2.con file. A TIN model derived from the terrain points (see
Section 6.4) is stored in file dtm2.tin.
Attached to the terrain model is an imported CAD plan view drawing stored in file planbch.dxf.
Also attached to the terrain model are digitized photographs in files north.bmp and south.bmp.
These various graphics attachments can be seen in Fig. 6-22 of Section 6.6.
Attached to each P&P sheet is an imported CAD background drawing showing page borders
and common project titles or data (see Fig. 13.1-4 of Section 13.1). The page background is
stored in file PAGEPLS.dxf. Also attached to each P&P sheet is a company logo stored in file
Power.bmp.
Display parameters for the automatic drawing of the P&P sheets (Section 13.2) are stored in file
dtm2.pps.
Design criteria for the project are stored in file dtm2.cri.
The master parts list referred to by the project is named Partfile.prt. Its location is defined in the
Preferences menu available from File/ Preferences.
Linking of the master parts list to an ODBC database is defined in the dtm2.dbc file.
The Available Structures List in file dtm2.str includes all the structure files actually used in the
"dtm2" project and all the structure files made available for optimization through the Structures/
Available Structure List menu. Next to the name of each individual structure file is the number
of such structures spotted in the project.
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The Cables list includes all the conductor or ground wire files actually used in the project.
Finally, the file dtm2.don contains the spotting, stringing and sagging information for one line
built on the dtm2.num alignment. There could be more than one line designed on the same
alignment. Each line design includes a staking list consisting of actually spotted structures and
sagged sections.
Double-clicking on the Structures icon opens a detailed list of all structures in the line. Method
1, Method 2 or Method 3 structures have their strength and insulator swings checked instantly
and reported as a percent use of allowable. This dynamic structure strength and insulator swing
checking is carried out continuously during idle computing cycles and does not interfere with
whatever else you are doing. Dynamic checking currently does not apply to Method 4 structures
which are checked by linking to PLS-POLE or TOWER. However, if you want to check all
structures in a line, including Method 4 structures, this can be done at any time with the Lines/
Reports/ Structures usage command. The results of dynamic checking are indicated by green
G's for structures which are OK, red N's for structures with inadequate strength or swings, and
blue U's for unchecked structures (Method 4). Double-clicking on any structure in the list will
bring that structure to the center of all opened windows (Plan, Profile, 3-D or Sheets) where you
can easily select it for further checking or modification.
By double-clicking on the Sections icon you can open the detailed list of sections as well as see
the results of dynamic checking of these sections. The dynamic checking indicates the percent
of permissible tension used. Similar to what you can do with structures, double-clicking on any
section will center that section in any opened view.
K.2
Files and Directories
Fig. K-1 shows how the files that make up a particular project can be displayed in the Project
view. If some of the files are shared by several projects, it is essential that they be accessible in
well organized libraries or sub-directories. For example, Fig. K-2 shows a sample directory
structure, where one may keep all needed PLS-CADD data. All files reside in sub-directories of
the Train directory. These files often include a required extension, ".ext", which describes the file
type.
In Fig. K-2, the Cables directory contains the library of cable properties files (see Section 9 and
Appendix G).
The Criteria directory contains the master design criteria files (with required ".cri" extension)
from which individual project criteria can be copied (see Section 7).
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Fig. K.1 Possible File Organization Under Train Directory
The Features directory contains the master feature codes files (with required ".fea" extension)
from which individual project feature codes can be copied (see Section 6.1 and App. C).
The Parts directory contains the parts and assemblies files which must have the ".prt" extension
(see Section 8.5 and Appendix M).
The Plots directory contains the master drafting parameters files (with required ".pps" extension)
from which individual project page parameters can be copied. These parameters define page
size, page layout, scales, text size and placement, etc. as described in Section 13.2.
The Temp directory is used to store all temporary files written by PLS-CADD or the various
Structure programs. This directory should never be located on the network for performance
reasons and also to prevent file collision with other users.
The Struct directory contains the structure files. There is one file for each structure type and size
(see Appendix F). PLS-CADD users may need to access hundreds or thousands of structure
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files. Therefore, it is essential that the sub-directories used to store the files have easily
identifiable names. For example, in the directory structure of Fig. K-2, all wood poles to be
checked by the allowable span method (see Section 8.3.1) are listed under the Wpoles/
Method1 heading. All the steel poles to be checked by direct analysis (see Section 8.3.4) are
under the Spoles/ Method4 heading. These sub-directories can further subdivided into voltage
categories, unguyed or guyed types, etc.
All of the directories listed above contain files which can be shared across projects. Individual
projects reside in the Projects directory which include the project-specific files. For example, the
Projects directory could include all of the "dtm2.*" files described in Fig. K-1. Generally, for a
specific project, the Projects directory includes the following files:
Project.xyz or Project.pfl includes information about surveyed points and obstacles (see
Sections 6.2 and 6.6 or Appendices D and E)
Project.num includes information related to the alignment (see Section 6.3). It is
generated automatically and is not accessible to the user.
Project.tin includes data on the triangulated (TIN) model of the terrain (see Section 6.4).
It is generated automatically and is not accessible to the user.
Project.don stores information about structure locations, types, and materials, as well as
cable installation conditions. "*.don" files are generated automatically by the commands
described in Section 10 and should not be edited by the user. A "*.don" file is unique to a
line design and has a pointer to the appropriate "*.xyz" or "*.pfl" terrain file. However,
different "*.don" files can describe different lines defined on top of the same terrain.
When this is the case, the lines can be superimposed as described in Section 5.4.6.4.
Project.con contains information on terrain constraints such as prohibited zones, extra
cost zones, required structures or structure locations, etc. (see Section 14.2). It is only
needed for optimum spotting.
Project.str contains the list and costs of the structures allowed for optimization (see
Section 14.3).
Project.opt contains the optimization parameters as defined in Section 14.4.
Upon using the command File/ Save, all of the project files "Project.*" listed above are saved. In
addition, the project criteria, feature codes and drawing parameters are automatically saved in
the Projects directory under the Project.cri, Project.fea and Project.pps names.
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A project generated by the PLS-CADD/ LITE option (see Section 15) is saved under the
Project.loa file name. Project.loa includes all the data defined in the dialog of Fig. 15.1-1. The
".loa" extension is required.
K.3
Project back-up
As first discussed in Section 5.3, you can use File/ Backup to save all the information
pertaining to a project in a single file. File/ Backup is quite different from File/ Save.
File/ Save stores all the Project.* files describing the 3-D line model in the Projects directory,
but it has no effect on the structure and cable files which reside in separate structure and cable
libraries. The structure and cable files are referred to by the model, but are external to it.
Structure and cable libraries are shared across projects. Feature code, criteria, and sheet
parameter files which are imported from their libraries to build the model are also not affected by
File/ Save. If any change is made to the structure and cable files in their respective libraries
after you use File/ Save, then these changes will affect your project when it is re-loaded at a
later time.
Fig. K.3 Restoring Backup File
File/ Backup compacts all the information pertaining to the 3-D line model into a single file, say
Project.bak. Project.bak includes all the files saved by File/ Save plus all the structure and cable
files actually used in the model. Therefore, any change in the structure and cable libraries will
not affect the structures and cable information stored in Project.bak. Project.bak is a complete
record of the information available at the time a project is backed-up. That information can be
restored on the same or another computer with File/ Restore Backup. Project.bak includes not
only files but also the complete directory structure. Upon restoration, the entire file and directory
structure will be recreated. Because the single file Project.bak contains all the information
needed to recreate a project, it greatly simplifies the archiving of projects and the transfer of
project data from one computer to another.
When you use File/ Restore Backup, you are given the opportunity to change the names of the
directories in which the various files are kept. This is done in the Directory Mapping dialog box
shown in Fig. K-3. This is very convenient when you transfer a project from one computer,
where for example the project resides somewhere on the D: drive, to another computer where
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the project, including all its structure and cable files, will reside somewhere on the C: drive. With
the data in Fig. K-3, a project made up of files in six different directories will be restored into the
single directory C:\temp\PROJ1.
We strongly recommend that you archive completed projects with the File/ Backup command
and that you make periodic backups of your project to insure against system failure, user error
or file corruption.
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APPENDIX L.
PLS-CADD AND STRUCTURE PROGRAMS LINKAGES
Our
transmission
structure
programs
PLS-POLE
and
TOWER
(Structure
programs) can be
used in support of
PLS-CADD and viceversa. The different
possible
linkages
between the programs
are discussed in this
appendix and shown
schematically in Fig.
L-1.
STRUCTURE
FILES
MODEL
M1
M2
BASIC ALL.
SPANS
INTERACT.
ALL. SPANS
PROGRAMS
PLS-CADD / LITE
SINGLE STRUCTURE
WITH
RADIATING WIRES
LOADS /
CRITERIA
LOADING
CRITERIA
CREATE LOADS FILES
PLS-CADD
FULL LINE MODEL
M3
M4
CRITICAL
COMPONENTS
DETAILED
MODEL
CREATE STRUCT. FILES
EDITING
CHECK BY DIRECT
LINK
STRUCTURES
PROGRAMS
TOWER
PLS - POLE
( POLES & FRAMES )
VECTOR LOADS
( . LCA )
FOR CHECK
WIRE LOADS
( . LIC )
FOR ALL. SPANS
Fig. L-1 PLS-CADD to Structures Programs Linkages
PLS-CADD and PLS-CADD/ LITE can export load files to the Structure programs in vector
loads (.LCA) or wire loads (.LIC) formats. These formats are discussed in the Structure
programs manuals.
PLS-CADD can pass control to a Structure program for a structure strength check by direct link
(Method 4). Stress and deflected geometry results are returned to PLS-CADD.
Files for structures to be checked by Method 1 (Basic allowable spans), Method 2 (Interaction
diagrams between allowable spans), or Method 3 (Critical components) can be created / edited
by PLS-CADD or generated automatically by the Structure programs.
Files for structures to be checked by Method 4 (Analysis by direct link) have to be edited by a
Structure program.
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APPENDIX M.
MATERIAL HANDLING
PLS-CADD includes powerful functions to manage material databases and generate a variety of
part or assembly lists. These databases and functions were first discussed in Sections 8.5 and
12.3. PLS-CADD's material handling capabilities are an important factor in improving your
productivity.
M.1
Linking Parts List to Commercial Databases
PLS-CADD has the ability to share material information with any ODBC compliant database
such as Microsoft Access, SQL Server, Oracle, IBM DB2, etc. Such databases include
ODBC drivers that enable communication with PLS-CADD. Assume that you have ODBC
drivers for Microsoft Access and wish to create a new parts table in PLS-CADD and populate
it with data from an Access database. The five step process (M.1.1 to M.1.5) required to
achieve that goal is explained below.
M.1.1
Create a Parts Table in PLS-CADD
Once in PLS-CADD, go to the File/ Preferences menu and click on the Part/Assembly Library
button under Setting for Project to select a file name for your parts, say C:\partfile.prt. This file
will contain at a minimum a table with 11 columns. The default columns including the stock
number, item description, material unit cost, etc. are discussed further in section 8.5.3 of the
manual. You can add columns to that table with Structures/ Material/ Parts and Assemblies
File/ Setup. For example, you may wish to add a column for Manufacturer Name and Catalog
Number. You can look at the still empty parts table you have just formatted by selecting
Structures/ Material/ Parts and Assemblies File/ Edit Parts.
M.1.2
Identify or Create a Corresponding Table in Database
In
order
to
download data
from
the
database into
PLS-CADD,
you
should
have a table or
query in the
database which
has
some
columns
that
match those in
the PLS-CADD
parts table. For
example, Fig.
Fig. M-1 “Test” Query Defining Data Needed for Parts File
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M-1 shows a query, named "Test " and defined in Microsoft Access, that will produce a table
with some of the column information needed in the PLS-CADD parts table.
M.1.3
Create an ODBC Data Source
You should now use the MS-Windows Control Panel ODBC option or the program named
ODBC Administrator to: 1) select a single ODBC reference name for your data source, say
PARTS, 2) specify the name and location of the database that will be referred to as PARTS,
and 3) specify the ODBC driver. PARTS is now an ODBC data source which can be used to
access the original database.
M.1.4 Create the Link Between the ODBC Data Source and PLS-CADD
You will then create links between columns of the table or query in the data base and the
columns in the PLS-CADD parts table. This is done by selecting Structures/ Material/ Parts
and Assemblies File/ Configure Parts Database while in PLS-CADD or by using the stand
alone program PLS-DB. The dialog of Fig. M-2 will open.
The bottom half of Fig. M-2 shows the
various tables and queries that are
included in the data source PARTS.
"Test" in the lower part of Fig. M-2 is
the name of the query defined in Fig.
M-1. In order to create the mapping,
you select one of the column names
under "Test", then you double-click in
the appropriate row of the Map To
column in the top part of the Figure.
The linkage is saved in a file named
Projectname.dbc.
Fig. M-2 Mapping Between Table Columns
M.1.5 Download the database
The last step is to download the database information into the PLS-CADD parts table (see Fig.
M-3). This is done with the Structures/ Material/ Parts and Assemblies File/ Download Parts
List command. While the linkage described in Section M.1.4 only needs to be defined once,
downloading may be performed frequently to reflect updated information. Periodic downloading
can also be automated, but this is an advanced feature you should contact us to discuss if it is
necessary.
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Fig. M-3 Downloaded Query of Fig. M-1 in PLS-CADD
M.2
Linking Assemblies List to Commercial Databases
Unlike a part list,
assemblies must
be stored in the
Power
Line
Systems format
documented
below if they are
to be imported
with the built in
Structures/
Material/ Parts
Fig. M-4 Assemblies Data in Database
and
Assemblies File/ Download Assemblies from Database command. This format is also used
when the Structures/ Material/ Parts and Assemblies File/ Upload Assemblies to Database
command is invoked to write assemblies into the database. The PLS format "flattens"
assemblies into four columns as shown in the Microsoft Access table of Fig. M-4. Data in each
column are described below:
"PLS ASSEMBLY STOCKNO" - contains the assembly stock number (VARCHAR, max 40
chars)
"PLS ASSEMBLY DESC" - contains the assembly description (VARCHAR, max 255 chars)
"PLS ASSEMBLY PART STOCKNO" - contains the stock number of a part in the assembly
(VARCHAR, max 40 chars)
"PLS ASSEMBLY PART QUANTITY" - contains the number of these parts in the assembly
(DOUBLE PRECISION FLOATING POINT)
A row contains a single part for an assembly. An assembly will have as many rows as it has
parts. In each row the PLS ASSEMBLY STOCKNO and PLS ASSEMBLY DESC fields will be
duplicated and must be the same for all parts in the same assembly.
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Note that Oracle will not accept column names that have spaces in them. So, for Oracle the
columns names may have underscores instead of spaces.
For example,
“PLS_ASSEMBLY_STOCKNO” instead of “ PLS ASSEMBLY STOCKNO” will be required.
M.3
Exporting Staking and Material Tables to Commercial Databases
As described in Section 12.3, design summary information is available in two staking tables.
The staking tables, like all other tables in PLS-CADD, may be exported to an ODBC compliant
database via the Database Export context menu which appears when you select the entire
table (by clicking on its upper left corner). You can also export portions of a table (by dragging
over selected columns). Before exporting a table to a database, you should already have
created the database and corresponding ODBC data source as described in Section M.1.3. To
export the table, click on Database Export, select the appropriate ODBC data source from
those listed in the Select Data Sources dialog and either accept the suggested table name or
override it by typing a new table name, say Tablename. The contents of your PLS-CADD table
(or the portion you selected) will then be copied into a newly created table named Tablename in
your database. If the table already exists you will be given the option to replace it with the new
table from PLS-CADD or cancel the operation.
M.4
To Learn More About Links Between PLS-CADD, GIS and Databases
For more information
regarding how PLSCADD
integrates
with
GIS
and
databases, you can
download technical
notes and videos on
the subject from our
web site.
Fig. M-5 Web site Material on Database Links
A good place to start is:
http://www.powline.com/products/data.html
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547
M.5
Project Lifecycle and Material Status
Using PLS-CADD and its ability to track the status of material and multiple line designs in the
Lines/Edit menu, you can track projects throughout their lifecycle from a new line to
modifications proposed on an existing. Below is an example of how to use these capabilities
For example start with a design called Preliminary Design. For this example we will focus on
structure 26 to see some possible material functions. While the functions below will focus on
one individual structure they can apply to the line as a whole. Going to Lines/Edit we see our
Preliminary Design as shown in Figure M-6. All items have a status of New since the project
has not been built yet.
Figure M-6 Preliminary Design
When a Lines/Reports/Bill of Material is run for structure 26 the following appears:
Bill of Material of New Items
Stock
Number
Unit Material
Total
Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
------------------------------------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each
845.00
845.00 548.00
548.00 1393.00
2-60
2-60 Wood Pole
2.00
Each
718.00
1436.00 487.00
974.00 2410.00
7NO8DAMPER
Damper for 7 NO. 8 ALWD
4.00
Each
20.00
80.00
20.00
80.00
160.00
DOVEDAMPER Damper for Dove Conductor
6.00
Each
20.00
120.00
20.00
120.00
240.00
TM-4A OHGW Suspension Assembly
2.00
Each
42.00
84.00
27.00
54.00
138.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
110.00
330.00
71.00
213.00
543.00
Material Subtotal
Labor Subtotal
Total
Description
Quantity
2895.00
1989.00
4884.00
Now assume some further refined survey data requires structure 26 to be changed from a 60'
pole to a 65' pole structure. You would first make a new design in the Lines/Edit dialog and call
it Final Design and then change the structure file from a 60' pole to a 65' pole. The Lines/Edit
menu would appear as shown in Figure M-7.
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Figure M-7 Final Design
When a Lines/Reports/Bill of Material is run for structure 26 on the Final Design the following
appears:
Bill of Material of New Items
Stock
Number
Description
Quantity
Unit Material
Total
Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
------------------------------------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each
845.00
845.00 548.00
548.00 1393.00
2-65
2-65 Wood Pole
2.00
Each
1001.00
2002.00 605.00 1210.00 3212.00
7NO8DAMPER
Damper for 7 NO. 8 ALWD
4.00
Each
20.00
80.00
20.00
80.00
160.00
DOVEDAMPER Damper for Dove Conductor
6.00
Each
20.00
120.00
20.00
120.00
240.00
TM-4A OHGW Suspension Assembly
2.00
Each
42.00
84.00
27.00
54.00
138.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
110.00
330.00
71.00
213.00
543.00
Material Subtotal
3461.00
Labor Subtotal
2225.00
Total
5686.00
The difference between the Bill of Material on the Preliminary Design and the Final Design can
be shown by running the Lines/Reports/Bill of Material Delta report and selecting the
preliminary design as the reference project and the Final Design as the Design Project. The
report for entire line taking into account the change on structure 26 would be as follows:
Bill of Material Delta of New Items
Stock
Number
Description
Count
Count Quantity
Unit
in
in
Delta
of
Reference
Design
Measure
---------------------------------------------------------------------------2-60 2-60 Wood Pole
32.00
30.00
2.00
Each
2-65 2-65 Wood Pole
6.00
8.00
-2.00
Each
Next assume the project is completed and was built to the specifications in the Final Design.
You would then want to make a new design in the Lines/Edit dialog and call it As-Built. In actual
projects you may define these projects with further information in its title like project numbers
and dates. Figure M-8 shows the Lines/Edit dialog with a copy of the Final Design labeled as
As-Built 1.
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549
Figure M-8 As-Built 1
Once the design has been copied you will want to take all of the items marked as New and
change their status to Existing using the Structures/Material/Global As-Built command.
Figure M-9 shows the Global As-Built dialog box with all of the items checked to convert to
Existing. Since there are no retired or transferred items to dismiss the bottom of the dialog can
be left with its default settings as shown.
Figure M-9 Global As-Built
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After leaving this dialog all items are now set to a status of Existing.
The new
Lines/Reports/Bill of Material for the As-Built 1 design for structure 26 would be as follows.
Notice that the heading on the report is Bill of Material of Existing Items instead of New Items.
Bill of Material of Existing Items
Stock
Number
Description
Quantity
Unit Material
Total
Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
------------------------------------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each
845.00
845.00 548.00
548.00 1393.00
2-65
2-65 Wood Pole
2.00
Each
1001.00
2002.00 605.00 1210.00 3212.00
7NO8DAMPER
Damper for 7 NO. 8 ALWD
4.00
Each
20.00
80.00
20.00
80.00
160.00
DOVEDAMPER Damper for Dove Conductor
6.00
Each
20.00
120.00
20.00
120.00
240.00
TM-4A OHGW Suspension Assembly
2.00
Each
42.00
84.00
27.00
54.00
138.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
110.00
330.00
71.00
213.00
543.00
Material Subtotal
3461.00
Labor Subtotal
2225.00
Total
5686.00
Now suppose that a new thermal upgrade project requires that structure 26 must be changed
out with taller 70' poles instead of the existing 65' poles. The first step in the process would be
to make a new design in Lines/Edit copied from the As-Built 1 design. For this example we will
call the new design Thermal Upgrade as shown in figure M-10.
Figure M-10 Thermal Upgrade
After making a copy of the As-Built 1 design, the Thermal Upgrade Project is identical to the AsBuilt 1 project. The next step in the process would be to change out the structure file for
structure 26 using the Structures/Modify dialog for one with 70' poles. Anytime an item is a
structural element then a new structure file should be created to reflect the new design. Figure
M-11 shows the Structure Modify dialog box after changing the old structure file for the new
structure file in the upper left hand corner.
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551
Figure M-11 Structure Modify
Once you OK out of the Structure Modify dialog box the program will prompt where to retire the
existing items from the old structure file. You have the option to place them in the Structure
Specific Material List or the Line Specific Material List or not at all. If the structure is being
replaced but not removed then we recommend placing the retired items in the structure specific
material list. Figure M-12 shows this dialog.
Figure M-12 Where To Retire Existing Items
After closing the Where to Retire Existing Items dialog you can go to Structures/Modify and
check the option to see the Items in the Structure File as shown in Figure M-13. These items all
have defaulted to the New status which means they are being added to the project. The
structure specific items at the top of the dialog box are set to the status of Retired since they
were removed from the project. The one item left with a status of Existing is the dampers which
were added manually to the structure specific material list. The user would want to change the
status of the dampers to Transferred manually if they were going to be reused as shown below.
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Figure M-13 Structure Specific Material List with Retired and Transferred Items
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553
Once this is complete the Lines/Reports/Bill of Material for Structure 26 would be as shown
below. This report shows the New, Retired, and Transferred status items and not the Existing
status items since Existing Items were not selected in the Bill of Material dialog box.
Bill of Material of New Items
Stock
Number
Description
Quantity
Unit Material
Total
Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
------------------------------------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each
845.00
845.00 548.00
548.00 1393.00
2-70
2-70 Wood Pole
2.00
Each
1130.00
2260.00 620.00 1240.00 3500.00
TM-4A OHGW Suspension Assembly
2.00
Each
42.00
84.00
27.00
54.00
138.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
110.00
330.00
71.00
213.00
543.00
Material Subtotal
3519.00
Labor Subtotal
2055.00
Total
5574.00
Bill of Material of Retired Items
Stock
Number
Description
Quantity
Unit
Labor
Total
Total
of
Unit
Labor
Cost
Measure
Cost
Cost
-----------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each 256.00 256.00 256.00
2-65
2-65 Wood Pole
2.00
Each 250.00 500.00 500.00
TM-4A OHGW Suspension Assembly
2.00
Each
11.00
22.00
22.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
33.00
99.00
99.00
Labor Subtotal
877.00
Total
877.00
Bill of Material of Transferred Items
Stock
Number
Unit Labor
Total
Total
of
Unit
Labor
Cost
Measure
Cost
Cost
----------------------------------------------------------------------------------7NO8DAMPER
Damper for 7 NO. 8 ALWD
4.00
Each 30.00 120.00 120.00
DOVEDAMPER Damper for Dove Conductor
6.00
Each 30.00 180.00 180.00
Labor Subtotal
Total
Description
Quantity
300.00
300.00
After the project is complete you would want to As-Built the project by first creating a new
design under the Lines/Edit dialog called As-Built 2. This is shown in Figure M-14.
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Figure M-14 As-Built 2
Then you would want to make sure all items in the project have a status of Existing by
converting the status of certain units or by dismissing items or certain status. The
Structures/Material/Global As-Built dialog can be used to accomplish this. As shown in Figure
M-13 you have some items that have been transferred, retired, and added as new. The first
thing you would want to do is dismiss any retired items from the structure specific material list so
you would check these options at the middle of the dialog box as shown in Figure M-15. Next
you would want to convert the transferred items to a status of existing. You can do this by
leaving the Change to Existing radio button checked in the middle of the dialog box. The last
thing is to convert all of the New items to a status of Existing in the structure file material list. By
leaving the structure file material list checked on in the dialog box it will change these items
status also.
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555
Figure M-15 Global As-Built
Once this is complete the Structure Specific Material List and the Structure File Material List for
structure 26 would appear as shown in Figure M-16 with all items marked with a status of
Existing and all Retired status items removed.
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PLS-CADD – Version 16.0 © Power Line Systems, 2019
Figure M-16 Structure Specific Material List after Global As-Built
The Lines/Reports/Bill of Material for structure 26 would appear as below after the As-Built:
Bill of Material of Existing Items
Stock
Number
Description
Quantity
Unit Material
Total Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
-----------------------------------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each
845.00
845.00 548.00
548.00 1393.00
2-70
2-70 Wood Pole
2.00
Each
1130.00
2260.00 620.00 1240.00 3500.00
7NO8DAMPER
Damper for 7 NO. 8 ALWD
4.00
Each
20.00
80.00 20.00
80.00
160.00
DOVEDAMPER Damper for Dove Conductor
6.00
Each
20.00
120.00 20.00
120.00
240.00
TM-4A OHGW Suspension Assembly
2.00
Each
42.00
84.00 27.00
54.00
138.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
110.00
330.00 71.00
213.00
543.00
Material Subtotal
Labor Subtotal
Total
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3719.00
2255.00
5974.00
557
Now that the user has an As-Built 2 line complete, suppose a maintenance project requires the
replacement of one of the poles in an H-Frame due to rot. You will start with As-Built 2 and
make a copy of the line called Pole Replacement as shown in Figure M-17.
Figure M-17 Pole Replacement
You can go to the Structure Specific Material List for structure 26 and display the items in the
Structure File Material as shown in Figure M-18.
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PLS-CADD – Version 16.0 © Power Line Systems, 2019
Figure M-18 Structure Specific and Structure File Material List
You can double right click on the stock number of the wood pole item to be replaced from the
Structure File Material List which brings up the menu shown in Figure M-19 where you can
select to Add to Structure Specific Material List as Replaced Item which will copy the item up to
the Structure Specific Material List as a Retired status unit and as a New status unit as shown in
Figure M-20. Replacing the pole in the structure also requires a transfer of the existing frameset
TH-1GX. This can also be copied up to the Structure Specific Material List with an item status
of Transferred.
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Figure M-19 Replace Pole in Structure File Material List
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Figure M-20 Pole Replacement
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561
Once this is complete the Lines/Reports/Bill of Material for New, Retired, and Transferred
items on structure 26 would appear as below:
Bill of Material of New Items
Stock
Number
Description
Quantity
Unit Material
Total
Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
------------------------------------------------------------------------------------------------2-70 2-70 Wood Pole
1.00
Each
1130.00
1130.00 620.00 620.00 1750.00
Material Subtotal
1130.00
Labor Subtotal
620.00
Total
1750.00
Bill of Material of Retired Items
Stock
Number
Description
Quantity
Unit
Labor
Total
Total
of
Unit
Labor
Cost
Measure
Cost
Cost
------------------------------------------------------------------------2-70 2-70 Wood Pole
1.00
Each 260.00 260.00 260.00
Labor Subtotal
260.00
Total
260.00
Bill of Material of Transferred Items
Stock
Number
Unit
Labor
Total
Total
of
Unit
Labor
Cost
Measure
Cost
Cost
-------------------------------------------------------------------------TH-1GX TH-1GX Frameset
1.00
Each 592.00 592.00 592.00
Labor Subtotal
Total
Description
Quantity
592.00
592.00
Once the work is completed on the pole replacement you can As-Built the project by going to
Lines/Edit and copying the Pole Replacement project and renaming it As-Built 3 as shown in
Figure M-21. Then you can use the Structures/Material/Global As-Built command to dismiss
or convert all items to a status of Existing. For this particular project the pole being changed out
is accounted for in the Structure File Material List. So the Retired and New unit for the pole in
the structure specific material list will need to be dismissed. The dialog for the Global As-Built
would need to appear as shown in Figure M-22 which has the dismiss
transferred status items as well as dismissing new and retired pairings from the Structure
Specific Material List checked on.
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Figure M-21 As-Built 3
Figure M-22 Global As-Built
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563
The resulting Lines/Reports/Bill of Material for Structure 26 would just have Existing status
items as shown below:
Bill of Material of Existing Items
Stock
Number
Unit Material
Total
Labor
Total
Total
of
Unit Material
Unit
Labor
Cost
Measure
Cost
Cost
Cost
Cost
------------------------------------------------------------------------------------------------------------TH-1GX
TH-1GX Frameset
1.00
Each
845.00
845.00 548.00
548.00 1393.00
2-70
2-70 Wood Pole
2.00
Each
1130.00
2260.00 620.00 1240.00 3500.00
7NO8DAMPER
Damper for 7 NO. 8 ALWD
4.00
Each
20.00
80.00
20.00
80.00
160.00
DOVEDAMPER Damper for Dove Conductor
6.00
Each
20.00
120.00
20.00
120.00
240.00
TM-4A OHGW Suspension Assembly
2.00
Each
42.00
84.00
27.00
54.00
138.00
TM-1B-69 69 KV Suspension Assembly
3.00
Each
110.00
330.00
71.00
213.00
543.00
Material Subtotal
Labor Subtotal
Total
Description
Quantity
3719.00
2255.00
5974.00
This is just an example of how PLS-CADD can be used to track project status throughout its
lifecycle as well as provide a means to track labor and material costs through many project
scenarios.
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M.6
Project Estimator
PLS-CADD can also perform estimates on projects without preparing a full line design using the
Project Estimator tool accessed through either File/ New/ Project Estimator for a completely
new project or you can use it with an existing project by going to Lines/ Project Estimator or
access it through the Project Estimator button on the Lines/ Edit dialog box. Figure M.6-1
below shows the Project Estimator dialog box. The Project Estimator dialog box has 11 tabs for
entering various items concerning the estimate and reporting on the estimate.
Figure M.6-1 Project Estimator
At the top of the dialog box the user can enter general data about the line such as the Line
Length and Right of Way Width and the Right of Way Area will update accordingly based on this
input. The first three tabs are the Wires Estimate, Structures Estimate, and Line-Specific
Material Estimate. The Wires Estimate tab concerns the wire data for the project. You can
choose to populate this manually or you can import the information from an existing project
using the Import Data from Existing Project button at the bottom of the dialog box. If you
choose the Import Data button you can choose to import data for any of the tabs from any
project by telling the program the .don file and line name to import. The Structures Estimate tab
pulls information from the existing file you have imported or you can choose to load a .str file of
structures to consider for the estimate. Then you can enter the quantity of each structure type
to use in your estimate by selecting total quantity of structures in the line or the number of
structures per mile (km) that is applied to the line length in the General Data tab. The LineSpecific Material Estimate tab is similar to the Line Specific Material List described in Section
8.5.4.2.
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565
The next six tabs are generic estimate categories where you can enter items to be considered in
the estimate and choose a fixed unit if you want to enter a known quantity on the project or you
can choose one of the other units such as per mile, per hour, per acre, % project, etc. If the unit
picked is related to the line length then the program will automatically use the value in the
General Data tab if 0 is entered for the quantity. If a nonzero value is entered in the quantity
column then this value is used for the calculation of the cost. The Project Overhead tab gives
you the ability to add a percentage adder for different items in each of the tabs for items like
sales tax, contingency, profit, and insurance. This percentage will be added to the total of the
items in the tab category selected. The names of these tabs can be customized using the View/
Edit Customizations/ Dialog Strings table.
The last tab is the Reports tab shown in Figure M.6-2 which gives you control over the reporting
functionality of the project estimator.
Figure M.6-2 Reports Tab
The reports tab gives a report similar to the Bill of Material report discussed in Section 8.5.6 and
throughout Appendix M. The basis of this report can be either the data entered in the estimate
tab or the actual design in the project by selecting the appropriate radio button in the Material
items to include in Report section of the dialog box. You can also choose whether to include the
other tab categories in the report by checking the appropriate boxes. This estimate feature can
be a powerful tool to obtain total project estimate for an entire line.
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APPENDIX N.
FINITE ELEMENT ANALYSIS OF WIRE SYSTEM
This appendix discusses the many assumptions that are used when you select the finite
element method for modeling the wire system (Level 2, Level 3 or Level 4 modeling). Wire
modeling levels were initially described in Section 7.1.1. While the finite element analysis is
automated and gets all of its data from the 3-D line model that you have developed in PLSCADD, you should be aware that the analysis is actually performed by our SAPS finite element
code. Therefore, you must own a SAPS license if you are going to exercise one of the finite
element modeling options.
When you select finite element instead of the ruling span for the analysis of the wire system the
analysis is performed automatically and all results are displayed in PLS-CADD exactly as if you
were using the more basic ruling span approach. Despite having SAPS do all the analysis work
for you, you never need to leave PLS-CADD due to the tight integration between PLS-CADD
and SAPS.
While all the assumptions used by the SAPS program are listed in its user manual, some are
described in this appendix to make sure that you understand the fundamental differences
between our finite element analyses and the simplified approach of the ruling span.
N.1
General Considerations
N.1.1 Major Differences Between the Ruling Span Assumption and a Finite Element
Analysis
Most line design work can be done with the ruling span method. The assumption behind that
method is that, for a given weather case, the horizontal component of tension is the same in any
span of a tension section and that it can be predicted by subjecting a single imaginary span, the
ruling span, to that weather case. The length of the ruling span is determined as shown in
Section I.1. Because of its simplicity and sufficient accuracy in most situations, the ruling span
method is the basic method used in PLS-CADD for modeling the wire system. It is extremely
efficient in term of calculation time, resulting in almost instantaneous line display and
calculations of structure loads when any design parameter is changed. Because the ruling span
is a single span, it is fairly easy to consider its nonlinear material characteristics (see curves in
Figs. 9.1-1 to 9.1-4) and the fact that each material of a bi-metallic cable has its own behavior.
With the advent of powerful computers, it is now possible to make a more accurate analysis of
the wire system by finite element methods, where each span or each portion of a span is
modeled by an accurate 3-dimensional cable element (see Fig. N-1).
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567
In PLS-CADD, we use a well proven element
and efficient solution algorithms which have
been used for more than twenty years in our
finite element program SAPS (SAPS, 1997)
and other commercial programs. The element
and the solution algorithms are fully described
in the references (Peyrot and Goulois, 1978;
Peyrot and Goulois, 1979). The original
algorithms have been considerably improved
over the years, including the ability to handle
cable nonlinear material characteristics. A
finite element analysis does not have the basic
limitation of the ruling span that horizontal
tensions are the same in all spans of a tension
JFZ
RADIAL ICE
JFY
JFX
WIND
WX
J
IFX
IFY
WY
I
IFZ
Z
Y
X
GLOBAL
section. In fact, it is capable of accurately
Fig. N-1 3-D Cable Element
determining displacements of all conductor
attachment points including the possible interaction between different cables when the
supporting structures are flexible. With a finite element analysis, tensions vary in every cable of
every span.
As mentioned before, the
TYPICAL USES OF WIRE MODELING LEVELS
main advantages of the
LEVEL 1 LEVEL 2
LEVEL 3
LEVEL 4
finite element approach
OCCASIONAL
RARE
BEST
GLOBAL DISPLAY OF ENTIRE LINE
over the ruling span
INDIVIDUAL TENSION SECTION
method are that it can
OK
OK
BEST
AT VERY HIGH TEMPERATURE
determine the effects on
INDIVIDUAL TENSION SECTION
the wire system of: 1) the
AFTER SLACK REALLOCATION
OK
BEST
NO
OR STRUCTURE MOVE AFTER
WITH
application of nonuniform
WITH
CLIPPING ALL INSULATORS
STIFF
FLEXIBLE
loads on the spans, for
IMPOSSIBLE STRUCT. STRUCT.
IF STRUCTURE CONNECTED TO
example full ice on certain
SECTION AS DESCRIBED ABOVE
spans and reduced ice on
WIND, UNIFORM ICE, AND
BEST
OK
OK
NOMINAL LONGITUDINAL LOADS
others,
2)
structure
LONGITUDINAL LOADS WHICH ARE
flexibilities and interactions
OK
BEST
REQUIRED BY CODE TO BE
NO
WITH
WITH
between the wires, and 3)
CALCULATED BY PROCEDURE THAT
FLEXIBLE
STIFF
ACCOUNTS FOR INSULATOR SWING IMPOSSIBLE
structure
displacements,
STRUCT. STRUCT.
AND STRUCTURE FLEXIBILITY
changes of insulator clip
Fig. N-2 Levels Recommended for Typical Applications
locations and additions/
subtractions of cable length in the spans: the ruling span method is not capable of handling
these effects. The finite element method will also produce more accurate sags at high
temperature when tensions are not identical in all the spans. The main shortcomings of the finite
element method are that: 1) it may be compute intensive and 2) it may result in a model that is
too large for the computer to handle or that is numerically unstable.
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Fig N-2 summarizes typical modeling applications and the best modeling method for these
applications.
For the global display of an entire line (in the Line Display Options dialog of Fig. 5.4-4a), we
recommend that you always use Level 1. Even with that choice, PLS-CADD will automatically
promote the display to Level 2, 3 or 4 for tension sections where you have clipped insulators.
You can also use Level 2, but you should be aware that all spans not supported by suspension
insulators (for example ground wire spans or spans supported by post insulators) may be
displayed as if their end points were fixed, i.e. as if every span was dead-ended.
For the display of a particular tension section supported by suspension insulators and subjected
to very high temperatures (say in excess of 200 degrees F), we recommend Level 2 (in the
Section Modify dialog of Fig. 5.4-4a).
Once the insulators supporting a section have been clipped (check box at the lower left of the
Section Modify box), it can only be displayed with Level 2, 3 or 4. We recommend Level 2 if
you have stiff structures (latticed towers) and Level 3 if you have flexible structures (poles and
frames).
For the calculation of structure loads (in the Structure Loads Criteria table of Fig. 7.3-10) we
recommend Level 1 for loads from uniform extreme wind or ice. You should only use Level 2 or
3 if your code or specification requires that you determine unbalanced longitudinal loads by
using a procedure that takes into account insulator swings and possible structure flexibility. You
should note that the choice of method can be made load case by load case, i.e. you will have
some load cases determined by the ruling span method (Level 1) and others by the finite
element method (one of the Levels 2, 3 or 4, depending on your selection in the dialog box of
Fig. N-5) .
Please note that Level 4 is not recommended, unless you are an advanced user and have a
special condition requiring detailed investigation.
N.1.2 Nonlinear Cable Model for Conductors and Ground Wires
Finite element calculations assume that each cable in each span has three fixed unstressed
lengths: one unstressed length to predict its initial behavior, another to predict its behavior after
creep and a third one to predict its behavior after heavy load. Unstressed lengths are discussed
in Section N.4.
N.1.2.1
Linearized Cable Model Used in Stand-alone SAPS Program
In the stand-alone version of SAPS, cable elements are required to have a linear stress-strain
behavior as illustrated in Fig. N-3. However, that limitation, which existed in the earlier versions
of PLS-CADD which exported models to SAPS, no longer exists when SAPS is used as the
analysis engine of PLS-CADD, as discussed in Section N.1.2.2.
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In a linear stress-strain model, the slope of the stress-strain line is the modulus of elasticity,
EFCOMP. Temperatures T larger than the reference temperature of zero degree shift the stress
strain curve to the right by the amount ETCOMP x T, where ETCOMP is the composite thermal
expansion coefficient.
When needed for a stand-alone SAPS
analysis, the composite modulus of
elasticity EFCOMP and the composite
thermal expansion coefficient ETCOMP
can be calculated from properties in the
cable file as:
STRESS
σ
EF
AT ZERO
DEGREE
COMP
1
AT TEMPERATURE
T DEGREES
ET
COMP
X T
ELONGATION

0
Fig. N-3 Linear Stress-strain Behavior
EFCOMP =
EFO + EFC
Eq. N-1
ETCOMP =
( EFO X ETO + EFC X ETC ) / ( EFO + EFC )
Eq. N-2
where the cable file data (see Section 9.2) are:
EFO
=
final modulus of "outer" material x area of outer material / total area
EFC
=
final modulus of "core" material x area of core material / total area
ETO
=
thermal expansion coefficient of "outer" material
ETC
=
thermal expansion coefficient of "core" material
N.1.2.2
Nonlinear Cable Model when SAPS is used as the analysis engine of
PLS-CADD
When SAPS is used as the analysis engine of PLS-CADD, i.e. whenever you select Level 2, 3
or 4 for modeling your wires, an accurate nonlinear cable model is automatically used such as
described in Section 9.1.
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At each temperature T for which an analysis has to be done, SAPS uses the appropriate Initial,
After Creep or After Load curve as depicted in Fig. N-4. These curves are identical to those
shown in Fig. 9.2-4. In Fig. N-4, the curve labeled INITIAL is the assumed behavior if you select
Initial FE (Level 2, 3 or 4) for display or for the calculation of loads. The curve labeled AFTER
CREEP is the assumed behavior if you select Creep FE. The curve labeled AFTER LOAD is the
assumed behavior if you select Load FE. In some cases the AFTER CREEP curve is to the left
of the AFTER LOAD curve (as displayed in Fig. N-4), while in other cases it is the opposite. If
you select Max Sag FE for display purposes, sag calculations will be based on the curve
furthest to the right.
The relative positions of the
three Initial, After Creep and
After
Load
curves
are
determined automatically by
PLS-CADD depending on your
sagging parameters and the
weather cases causing creep
and
permanent
load
deformations.
STRESS
BEHAVIOR AT TEST
TEMPERATURE , T
BEHAVIOR AT
TEMPERATURE T
TEST
ELONGATION
Fig. N-4 Nonlinear Stress-elongation for Finite Element Model
N.1.3 Insulator Modeling
Another improvement of the finite element approach over the ruling span is that insulators can
be modeled accurately. Strain and suspension insulators are modeled as heavy cables (see for
Example the left pane of Fig. N-7). Therefore, the effect of heavy strain insulators at the end of
slack spans (for example at take-off substation structures) is accounted for. This complex
problem cannot be addressed with the ruling span.
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N.2
Selecting Finite Element for Display and for Calculating Structure Loads
If you wish to see particular tension sections or your entire line when analyzed by finite element
(Level 2, 3 or 4) instead of the more common ruling span approximation (Level 1), all you need
to do is select Initial FE, Creep FE, Load FE or Max Sag FE instead of Initial RS, Creep RS,
Load RS or Max Sag RS in the Line Display Options dialog of Fig. 5.4-4a or in the Section
Modify dialog of Fig. 5.4-5.
If you wish to have structure loads calculated by finite element (Level 2, 3 or 4) instead of the
more common ruling span concept (Level 1), all you need to do is select Initial FE, Creep FE, or
Load FE instead of Initial RS, Creep RS, or Load RS in the Cable Condition column of the
Structure Loads Criteria table of Fig. 7.3-10-a. Note that selecting a finite element analysis
instead of using the ruling span can be done load case by load case, i.e. you may decide to only
use the more time consuming finite element analysis for some unbalanced ice calculations while
using ruling span for all your other load cases.
Note: If you select Clip Insulators at the bottom of the Section/ Modify dialog box, PLS-CADD
will automatically promote RS cable conditions to FE conditions when doing calculations for the
section.
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N.3
Selection of Level and Default Stiffness Parameters
Levels 2, 3 and 4 modeling make use of parameters entered in the Criteria/ SAPS Finite
Element Sag-Tension dialog box (see Fig. N-5).
If you select a finite element analysis for displaying cables or calculating structure loads (as
described in Section N.2), this will be done with Level 2 if you check L2 Finite element analysis
of single section .... in the SAPS Finite Element Sag-Tension box. It will be done with Level 3
if you check L3 Finite element analysis of system of sections interconnected by stiffness
matrices, and it will be done with Level 4 if you check L4 Finite element analysis of system of
sections interconnected by full structure models.
The Insulator Chaining Option allows modeling of insulators supported by other insulators in all
levels of SAPS analysis. By checking this option it allows for the flexibility or movement of all
insulators in the chain to be taken into account when doing a Level 2 or 3 analysis. This is
always the case with a Level 4 analysis. In order for the chaining of insulators to work all
insulators in the chain must be assigned a set and phase number in PLS-POLE or TOWER. If
you do not have a set and phase assigned a warning message will let you know you have
chained insulators with no set and phase assigned and only the insulator with the wire attached
will be taken into account in Level 2 or 3. The chaining of insulators can be used to model
swinging angle brackets on a structure by using a suspension insulator attached to the tip of a
2-part insulator with compressive capacity.
With Level 2, the default stiffnesses are infinitely rigid unless older legacy stiffnesses are
enabled at the bottom of the dialog of Fig. N-5 by going to File / Preferences and enabling in
the Settings section of the dialog. This is no longer recommended to be used with the modern
version of the program. The default infinitely rigid stiffness values used in Level 2 can be
overridden at each individual attachment point in the dialog box of Fig. N-6 (accessed through
Section/ Modify).
With Level 3, the stiffnesses entered in the lower part of the SAPS Finite Element SagTension dialog box are only applied to structures which are not Method 4 structures, i.e.
structures which are not modeled with our PLS-POLE or TOWER programs. For Method 4
structures, the stiffnesses of all structure attachment points and their interactions are
determined automatically for each structure by PLS-POLE or TOWER in the form of a structure
flexibility matrix.
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Fig. N-5 Parameters for Levels 2, 3, and 4 Modeling
With Level 4, each structure is modeled in its entirety and becomes part of a gigantic structural
model of the tension section (and possibly the two adjacent tension sections). When Level 4 or
Level 3 is selected the program includes all of the tangent structures in the two adjacent tension
sections and the shared deadend and analyzes them with the selected flexibility, either L3 or L4,
and the unshared deadends not shared with the target section are modeled as fixed (L2). Take
for example the simple four structure line with three sections shown in Fig. N-5a. If reporting a
sag and tension report on section number one between structure 1 and 2, structures 1 and 2 are
flexible while structures 3 and 4 are fixed as shown in Fig. N-5b. If reporting a sag and tension
report on section number two between structures 2 and 3, structures 2 and 3 are flexible and
structures 1 and 4 are fixed as shown in Fig. N-5c. If reporting a sag and tension report on
section number three between structures 3 and 4, structures 3 and 4 are flexible and structures
1 and 2 are fixed.
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Because Level 4 is extremely expensive in term of computer time and memory demands, you
will have the option to treat all latticed towers (which are normally rigid) at Level 3 or to treat all
non-guyed structures at Level 3. That last option recognizes the fact that guyed structures have
unique non-symmetrical behavior not amenable to the concept of a flexibility matrix. The next
option is to condense all tower models such that all their joints which do not move significantly
are considered fixed: this will reduce the size of your complete model considerably. The last
option will allow the software to use Level 2 modeling for display and insulator swing
calculations which allows structure loads to be Level 4 while the display and swing use the
Level 2 analysis. This option will speed up the processing time when using Level 4 analysis.
This setting is an optional value and is saved within the .CRI file.
The L3 and L4 Options for Structure Loads allows you to limit the number of spans from a
structure where you are having loads computed. For example if you left the number of spans to
0 it would only account L3/L4 analysis (deflection considered) for the one structure being
evaluated. All other structures would be modeled L2 (no deflection considered). If you input 1
for the number of span it would consider a L3/L4 analysis (deflection considered) on the
structure being evaluated and the adjacent structures and all other structures would be modeled
L2 (no deflection considered). This can be a requirement of some codes and it can also speed
up the L3/L4 analysis of a model depending on the number of spans selected.
The Jumper Options portion of the dialog box of Figure N-5 allows you to enable the ability to
model jumpers at dead end structures between sections as discussed in Section 10.3.8.
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Fig. N-5a Simple Line Model
Fig. N-5b Section 1 Sag Tension
Fig. N-5c Section 2 Sag Tension
Fig. N-5d Section 3 Sag Tension
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N.4
Unstressed Cable Lengths
The finite element analysis requires that the physical length of each cable in each span (at a
reference temperature of zero degree Celsius and under no tension) be known and be invariant
when the system is subjected to various weather cases. Such lengths are called the unstressed
lengths.
Fig. N-6 Wire Lengths and Attachment Stiffness
Unless you lock them (by checking Clip Insulators at the bottom of the Section Modify box of
Fig. 10.3-3) unstressed lengths are calculated each time they are needed with the assumption
that all spans of a tension section have identical horizontal cable tension for the combination of
cable Condition, Temperature and Horizontal Tension specified in the Sagging portion of the
Section Modify dialog box. This implies that all suspension insulators are perfectly vertica