purple line traction power study report-rev4

8/19/2019 Purple Line Traction Power Study Report-rev4

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TRACTION POWER SYSTEM

SIMULATION – PRELIMINARY

REPORT

OCTOBER 31, 2013 – REV: 4

2012.01.06.TP.PE.11.TPSSStudy Report-04


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Traction Power System Simulation Report Revision: 4

October 31, 2013Page 1

Revision History

Revision Date Description

Draft 2/3/2012 Initial Issue for PMC Review

1 3/30/2012 Revised per PMC review comments dated 3/7/12.

2 4/10/2012 Changed report title to “Preliminary Report”; Misc minor

editorial changes.

3 6/14/2013Updated study report with revised track alignment data and

substation locations

4 10/31/13

Baseline condition AW3 load at 5 minute headway;

Add recovery operation with one track at AW4 load at 3

minute headway for four consecutive trains;

Q09 TPS location at 508+50

Change Log and Comments

Section Description of Change/Question Answered Name Date

1.2 Added descriptions on how the 18 substations were

determined.JGY 3/30/12

3.6 Added OCS conductor allowable ampacity for

reference.JGY 3/30/12

Misc Misc. minor editorial changes JGY 3/30/12

Misc Misc minor editorial changes JGY 4/10/12


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Table of Contents

1 Executive Summary .......................................................................................................... 5

1.1 Objectives ..................................................................................................................................................... 5

1.2 Basic requirements ....................................................................................................................................... 5 1.3 List of substations......................................................................................................................................... 6

1.4 Summary of findings .................................................................................................................................... 6

1.4.1 Train voltages ........................................................................................................................................... 6

1.4.2 Maximum rail potential ........................................................................................................................... 7

1.4.3 Ratios of rectifier load RMS current/rating ............................................................................................. 7

1.5 Conclusions ................................................................................................................................................... 7

2 Introduction ....................................................................................................................... 8

2.1 Main parameters .......................................................................................................................................... 8

2.1.1 Running rails ............................................................................................................................................ 8

2.1.2 Substation rectifier units ......................................................................................................................... 8

2.1.3 Train consists and operational headway ................................................................................................. 8

2.1.4 Train stops ............................................................................................................................................... 9

2.2 Methodology ................................................................................................................................................ 9

2.2.1 Simulation runs ........................................................................................................................................ 9

2.2.2 Train dispatching.................................................................................................................................... 10

3 Simulation Results ...........................................................................................................11

3.1 Substation power demands (average kW) ................................................................................................. 11

3.2 Rectifier load current (RMS amps)/ rating ratios ....................................................................................... 12

3.3 Substation feeder current (RMS amps) ...................................................................................................... 13

3.4 Train voltage plots...................................................................................................................................... 16

3.4.1 Normal operations ................................................................................................................................. 17

3.4.2 Contingency operations ......................................................................................................................... 18

3.4.3 Recovery operations .............................................................................................................................. 19

3.5 Rail potential plot ....................................................................................................................................... 20




3.6 OCS current plot (RMS amps) ..................................................................................................................... 24




4 Appendix A – List of Reference Document ....................................................................28


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List of Figures

FIGURE 1. TRAIN VOLTAGE PLOT – NORMAL OPERATIONS ....................................................................................... 17

FIGURE 2. TRAIN VOLTAGE PLOT – CONTINGENCY OPERATIONS ............................................................................. 18

FIGURE 3. TRAIN VOLTAGE PLOT –

RECOVERY OPERATIONS .................................................................................... 19 FIGURE 4. RAIL POTENTIAL PLOT – NORMAL OPERATIONS ....................................................................................... 21

FIGURE 5. RAIL POTENTIAL PLOT – CONTINGENCY OPERATIONS ............................................................................. 22

FIGURE 6. RAIL POTENTIAL PLOT – RECOVERY OPERATIONS .................................................................................... 23

FIGURE 7. OCS CURRENT – NORMAL OPERATIONS ................................................................................................... 25

FIGURE 8. OCS CURRENT – CONTINGENCY OPERATIONS .......................................................................................... 26

FIGURE 9. OCS CURRENT – RECOVERY OPERATIONS ................................................................................................. 27

FIGURE 10. OCS SEGMENTS ........................................................................................................................................ 31

FIGURE 11. SINGLE LINE DIAGRAM FOR THE TRACTION POWER SYSTEM ................................................................ 34

FIGURE 12. VEHICLE TRACTIVE EFFORT CURVE .......................................................................................................... 37

List of Tables

TABLE 1. LIST OF SUBSTATIONS .................................................................................................................................... 6

TABLE 2. LIST OF SIMULATION RUNS AND RECTIFIER CAPACITIES (MW) ................................................................... 9

TABLE 3. SUBSTATION POWER DEMANDS IN KW (0 MINUTE OFFSET) ..................................................................... 11

TABLE 4. SUBSTATION RECTIFIER RMS LOAD CURRENT /RATING RATIO .................................................................. 12 TABLE 5. POSITIVE FEEDER LOAD CURRENTS (RMS AMPS) ....................................................................................... 13

TABLE 6. NEGATIVE FEEDER LOAD CURRENTS (RMS AMPS) ..................................................................................... 15

TABLE 7. LIST OF STATION LOCATIONS ...................................................................................................................... 29

TABLE 8. LIST OF TRAFFIC SIGNAL AND PEDESTRIAN CROSSING LOCATIONS ........................................................... 29

TABLE 9. LOCATION OF TRACK CROSS-BONDS RELATIVE TO SUBSTATIONS ............................................................. 32

TABLE 10. CONDUCTOR RESISTANCES FOR 1 MESSENGER // 1 CONTACT WIRE ...................................................... 33

TABLE 11. SYSTEM VOLTAGE LEVELS .......................................................................................................................... 35

TABLE 12. DC VOLTAGE REGULATION FOR RECTIFIER ............................................................................................... 35

TABLE 13. VEHICLE ASSIGNED WEIGHTS .................................................................................................................... 36


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1 Executive Summary

This revision of the report details the findings from the simulation study of the Purple Linetraction power system between Bethesda and New Carrollton.

The study takes into account the latest development in Design Criteria, Design Build Technical

Requirements, track alignment, substation locations and the light rail vehicle data.

1.1 Objectives

The simulation analysis is based on the MTA Red / Purple Line Design Criteria (Reference 2)

and the Design Build Technical Requirements (Reference 10). The objective of this study is to

confirm that the proposed traction power system configuration can meet the requirements of the

Design Criteria and the Design Build Technical Requirements.

1.2 Basic requirements

The basic requirements of the criteria are summarized as follows:

The system should be able to support 2-car train operation at AW3 load at 5 minute headway.

Under normal operation, at least 90% of all train voltage observations during simulation shallbe above the minimum vehicle voltage for full performance, i.e., 650V.

Rectifier load should be within its 100% rating for normal operation.

The maximum rail potential should be equal to or less than 50V.

Under contingency operation (substation outage for single-rectifier substations; or rectifierunit outage for two-rectifier substations), train voltages should be at or above 525V.

Rectifier load should be within its 150% rating for 2 hours for contingency operation.

The maximum rail potential should be equal to or less than 75V.

Recovery Service of four sequential maximum length trains operating at maximum allowablespeeds with AW4 loads at normal LRV performance levels at three minute headways at anylocation on the Mainline with simultaneous service of maximum length Trains at five minuteheadways on the other track (Reference 10). The performance requirements are the same as incontingency operation listed above.


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1.3 List of substations

In the previous study as detailed in the report revision 2, it was determined that 18 substations

were needed in order to meet the design criteria.

According to the latest site surveys and drawings, the locations of substations are listed in the

following table. The number of rectifier units for the substations are also listed in the same table.

Table 1. List of substations

Name RectifiersLocationchainage

Location(miles from

SOL)

Distance tonext sub(miles)

Q01 2x2MW 120+29 0.38 0.90

Q02 1x2MW 168+00 1.29 1.04

Q03 1x2MW 222+66 2.32 0.85

Q04 1x2MW 267+59 3.17 1.01

Q05 1x2MW 321+00 4.19 0.95

Q06 1x2MW 371+00 5.13 1.01

Q07 1x2MW 424+15 6.14 0.72

Q08 1x2MW 462+00 6.86 0.88

Q09 1x2MW 508+50 7.74 0.83Q10 1x2MW 552+50 8.57 0.87

Q11 1x2MW 598+50 9.44 1.11

Q12 1x2MW 657+25 10.55 1.04

Q13 1x2MW 712+00 11.59 0.86

Q14 1x2MW 757+50 12.45 0.94

Q15 1x2MW 807+00 13.39 0.82

Q16 1x2MW 850+50 14.21 0.99

Q17 1x2MW 903+00 15.21 0.93

Q18 2x2MW 952+00 16.14 0.21

Note: SOL=Start of Line at 100+00

A schematic diagram for the proposed traction power system is shown in Figure 11 in AppendixB.

1.4 Summary of findings

1.4.1 Train voltages

The system meets the requirements for train voltages

Under normal operation condition, the occurrence of train voltages below 650V is 0.28%

of all train voltage observations during simulation, i.e., 99.72% of all observed train

voltages are above 650V. The minimum train voltage identified is 622V (see Fig. 1).

Under all contingency operation conditions, all train voltages are above 525V. Theminimum train voltage identified is 568V (see Fig. 2).

Under recovery operation conditions, all train voltages are above 525V. The minimum

train voltage identified is 603V (see Fig. 3).


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1.4.2 Maximum rail potential

The system meets the requirements for rail potential limit

Rail potential is less than 50V under normal operation. The maximum rail potential

identified is 39V (see Fig. 4).

Rail potential is less than 75V under all contingency operation conditions. The maximumrail potential identified is 61V (see Fig. 5).

Rail potential is less than 75V under all recovery operation conditions. The maximum railpotential identified is 42V (see Fig. 6).

1.4.3 Ratios of rectifier load RMS current/rating

The system meets the requirements for rectifier load/rating ratios

All rectifier loads are within 100% continuous rating under normal operation. The

maximum ratio identified is 54% (see Table 4).

All rectifier loads are within 150% 2-hour rating under all contingency operationconditions. The maximum ratio identified is 73% (see Table 4).

All rectifier loads are within 150% 2-hour rating under all recovery operation conditions.The maximum ratio identified is 73% (see Table 4).

1.5 Conclusions

The system configuration presented in this report conforms to the design criteria and the design

build technical requirements.


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2 Introduction

2.1 Main parameters

The main parameters for the simulation models are listed as follows.

The vehicles are based on 95 feet length per car. Maximum operation speed is 55 mph

(Ref.1 as listed in Appendix A);

Traction power is supplied by DC rectifiers at 750V nominal voltage (Ref.2);

The OCS has 6 segments, using Fixed Termination Single Contact Wire (FTSCW) and

Auto-Tension Simple Catenary (ATSC) as shown in Reference 7.

o In OCS Segments 1,2,3,4,6, OCS) has either one messenger wire of 500kcm

hard drawn copper or one parallel feeder cable of 500kcm hard drawn copper,

plus one contact wire of 350kcm hard drawn copper (Ref.7); The operating

temperature of the OCS is at 75oC, with the contact wire 30% worn as the worst

case (Ref.2).

o In OCS Segment 5 of the OCS, 2x1000 kcmil copper feeders will be used pertrack for electro-magnetic interference mitigation (Ref.7), plus one contact wire of

350kcm of hard drawn copper. The feeders will be connected to the contact wire

through risers.

2.1.1 Running rails

Running rails are of 115 RE rails. The working temperature of the rails is at 60oC, with 10%

worn as the worst case (Ref.2).

Both rails are used for traction return current on each track. The running rails on the two tracks

are assumed to be cross-bonded at approximately 2000’ intervals.

2.1.2 Substation rectifier units

Each substation is assumed to have 1x2000kW rectifier unit, which is the standardized size forMTA LRT rectifiers (Ref.2). The two end-of-line substations are equipped with 2x2000kWrectifier units each.

The dc no-load voltage is at 795V and the nominal load voltage at 750V, giving an inherentvoltage regulation of 6%. With a minimum short circuit capacity of 100MVA for the ac supply,2.2% extra regulation is added to the overall regulation.

2.1.3 Train consists and operational headway

Trains consists are based on 2-car trains (Reference 3 as listed in Appendix A).

In normal operation, the minimum headway is 5-minutes for weekday peak period operations,with train weight at AW3 (Reference 10).

Recovery Service of four sequential maximum length Trains operating at maximum allowablespeeds with AW4 loads at normal LRV performance levels at three minute headways at any


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location on the Mainline with simultaneous service of maximum length Trains at five minuteheadways on the other track. (Reference 10).

2.1.4 Train stops

Train stops and dwell times are according to Scenario 2 as contained in the reference 8

(Simulation study report Rev4).

In addition to regular passenger stops, all traffic signal stops and pedestrian crossing stops arealso included in the simulation model.

In practical operation, a train may not necessarily stop at every traffic signal, depending on thestatus of the signal and timing. There is a degree of randomness on where each train might stopwhen it encounters a traffic signal. By including all traffic signal stops, the model captures theworst case loads for the traction power system.

2.2 Methodology

Simulations have been carried out to assess the traction power system performance under both

normal operation, contingency operation and recovery operation conditions.

2.2.1 Simulation runs

Simulation runs and the number of rectifiers in service in each run are listed in the following

table.

Table 2. List of simulation runs and rectifier capacities (MW)Substation

NameNormal Outage-1 Outage-2 Outage-3 Outage-4 Outage-5 Outage-6

Q01 4 2 4 4 4 4 4

Q02 2 2 0 2 2 2 2

Q03 2 2 2 0 2 2 2

Q04 2 2 2 2 0 2 2

Q05 2 2 2 2 2 0 2

Q06 2 2 2 2 2 2 0

Q07 2 0 2 2 2 2 2

Q08 2 2 0 2 2 2 2

Q09 2 2 2 0 2 2 2

Q10 2 2 2 2 0 2 2

Q11 2 2 2 2 2 0 2

Q12 2 2 2 2 2 2 0

Q13 2 0 2 2 2 2 2

Q14 2 2 0 2 2 2 2

Q15 2 2 2 0 2 2 2

Q16 2 2 2 2 0 2 2

Q17 2 2 2 2 2 0 2

Q18 4 4 4 4 4 4 2

Note- Highlighted cells indicate substations in contingency operation. For recovery operation,

substations are in normal configuration.


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Contingency conditions are defined as follows:

For Q01 and Q18 substations, 1 rectifier unit is out of service while the other rectifier

remains in service. DC bus and feeders also remain in service.

For all other substations, the rectifier, dc positive bus and positive feeders are all

taken out of service. The section break bypass switches are closed at the affectedsubstations so that electrical continuity of the OCS conductors is maintained on each

track while the two tracks are not electrically connected in parallel.

All contingency conditions are covered by 6 simulation runs listed in the above table, labeled

Outage-1 through Outage-6. Each contingency run covers 3 substations that are in

contingency conditions. The substations with contingency conditions in each contingency

run are separated by five substations that are in normal operation. In this way, the effect of

one contingency on another in the same run is minimized. The number of simulation runs is

minimized while the accuracy of the simulation results is not compromised.

Recovery operations are covered by 2 simulation runs:

EB trains with AW3 weight and 5 minute headway; WB trains with AW4 weight and 3

minute headway

EB trains with AW4 weight and 3 minute headway; WB trains with AW3 weight and 5

minute headway

By assigning a regular headway of three minutes at AW4 weight, these two runs cover all

recovery operation conditions that will have four sequential trains operating at three minute

headway at all location throughout the line.

2.2.2 Train dispatching

Under each condition, train dispatching from the two ends of the track are simulated withdifferent time offsets, so that trains on the two tracks may meet at different locations and theworst cases of power demands can be captured. The simulation results in this report reflect thefollowing offsets:

WB train is dispatched at the same time as EB train (0 minute offset)

WB train is dispatched 0.5 minute later than EB train (0.5 minute offset)

WB train is dispatched 1 minutes later than EB train (1 minute offset)

WB train is dispatched 1.5 minutes later than EB train (1.5 minute offset)

WB train is dispatched 2 minutes later than EB train (2 minute offset)

WB train is dispatched 2.5 minutes later than EB train (2.5 minute offset)


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3 Simulation Results

3.1 Substation power demands (average kW)

The average power demands in kW for both normal operation and contingency operation are

listed in the following table (peak hour service, 0 minute offset).

Table 3. Substation power demands in kW (0 minute offset)Substation

NameNormal Outage-1 Outage-2 Outage-3 Outage-4 Outage-5 Outage-6

Q01 642 566 929 698 659 569 566

Q02 656 695 0 823 696 707 697

Q03 599 612 780 0 871 674 624

Q04 737 753 777 959 0 1023 807

Q05 871 935 900 920 1104 0 1203

Q06 910 1199 999 943 966 1224 0

Q07 893 0 1282 994 926 962 1207

Q08 976 1337 0 1329 1057 1011 1068

Q09 1,024 1116 1353 0 1379 1100 1065

Q10 998 1045 1081 1373 0 1286 1080

Q11 936 1053 986 1030 1262 0 1266

Q12 904 1259 1010 953 1006 1274 0

Q13 888 0 1195 964 937 1014 1232

Q14 934 1200 0 1223 1008 979 1020

Q15 923 981 1216 0 1242 991 945

Q16 847 862 919 1183 0 1096 862

Q17 833 836 849 900 1087 0 892

Q18 738 739 743 759 814 1173 652

Total 15,311 15,187 15,020 15,052 15,014 15,085 15,186

Maximum 1,024 1,337 1,353 1,373 1,379 1,286 1,266

Note - Highlighted cells indicate substations in contingency operation

Power demands for other headway offsets are similar as those listed above. They are not listed

in this report for brevity.


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3.2 Rectifier load current (RMS amps)/ rating ratios

The ratios of rectifier load current (RMS amps in peak hour service) over the rated current are

listed in the following table.

Table 4. Substation rectifier RMS load current /rating ratio

Substation Power Rating(kW)

Current Rating(A)

Normal (alloffsets)

Outages (alloffsets)

Recovery (alloffsets)

Q01 4,000 5,333 18% 32% 21%

Q02 2,000 2,667 33% 42% 40%

Q03 2,000 2,667 31% 45% 38%

Q04 2,000 2,667 40% 54% 45%

Q05 2,000 2,667 45% 63% 59%

Q06 2,000 2,667 47% 63% 64%

Q07 2,000 2,667 44% 65% 61%

Q08 2,000 2,667 49% 68% 70%

Q09 2,000 2,667 54% 72% 73%

Q102,000 2,667 53% 73% 72%

Q11 2,000 2,667 48% 65% 63%

Q12 2,000 2,667 45% 65% 61%

Q13 2,000 2,667 45% 63% 59%

Q14 2,000 2,667 48% 64% 61%

Q15 2,000 2,667 47% 64% 61%

Q16 2,000 2,667 45% 63% 57%

Q17 2,000 2,667 47% 59% 55%

Q18 4,000 5,333 19% 34% 24%

Maximum 54% 73% 73%

The above table indicates that the rectifiers have sufficient capacities to support the normaloperation, all the contingency operation conditions and the recovery operations. The system

meets the requirements of the design criteria in terms of rectifier ratings.


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3.3 Substation feeder current (RMS amps)

Feeder name designations in the simulation model are according to the single line diagram

shown in Figure 11 in Appendix B. A typical substation feeder numbering is shown in the

diagram below.

For each simulation, an RMS load current for each feeder in each substation is derived from thesimulation results. These include both positive feeders and negative feeders. The maximumvalues from all the simulation runs are summarized for each feeder, which represent the worstcase load for the feeder.

The following table lists positive feeder load currents.

Table 5. Positive Feeder Load Currents (RMS Amps)

Substation Feeder NameMaximum – Normal Op

Maximum – Contingency

Op

Maximum – Recovery Op

Q01 EB1-Feeder 397 478 514

Q01 EB2-Feeder 369 464 475Q01 WB1-Feeder 185 274 250

Q01 WB2-Feeder 196 299 265

Q02 EB1-Feeder 263 306 331

Q02 EB2-Feeder 296 349 375

Q02 WB1-Feeder 391 440 499

Q02 WB2-Feeder 390 448 499

Q03 EB1-Feeder 287 361 360


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Op


Q03 EB2-Feeder 287 375 358

Q03 WB1-Feeder 279 339 380

Q03 WB2-Feeder 272 351 369

Q04 EB1-Feeder 391 468 472

Q04 EB2-Feeder 400 498 492

Q04 WB1-Feeder 252 318 346

Q04 WB2-Feeder 271 351 372

Q05 EB1-Feeder 357 448 533

Q05 EB2-Feeder 341 454 525

Q05 WB1-Feeder 417 509 620

Q05 WB2-Feeder 403 518 612

Q06 EB1-Feeder 319 428 515

Q06 EB2-Feeder 322 417 518

Q06 WB1-Feeder 435 550 656Q06 WB2-Feeder 435 536 659

Q07 EB1-Feeder 354 466 555

Q07 EB2-Feeder 348 473 551

Q07 WB1-Feeder 334 457 545

Q07 WB2-Feeder 340 476 552

Q08 EB1-Feeder 396 521 560

Q08 EB2-Feeder 395 518 561

Q08 WB1-Feeder 418 540 690

Q08 WB2-Feeder 431 550 703

Q09 EB1-Feeder 390 499 584

Q09 EB2-Feeder 376 493 560Q09 WB1-Feeder 487 601 777

Q09 WB2-Feeder 483 609 754

Q10 EB1-Feeder 413 535 565

Q10 EB2-Feeder 427 523 578

Q10 WB1-Feeder 474 601 710

Q10 WB2-Feeder 467 567 695

Q11 EB1-Feeder 395 506 586

Q11 EB2-Feeder 382 499 565

Q11 WB1-Feeder 390 503 577

Q11 WB2-Feeder 383 495 566

Q12 EB1-Feeder 305 440 483

Q12 EB2-Feeder 314 444 491

Q12 WB1-Feeder 375 516 598

Q12 WB2-Feeder 369 501 587

Q13 EB1-Feeder 370 482 545

Q13 EB2-Feeder 358 462 525

Q13 WB1-Feeder 356 476 550

Q13 WB2-Feeder 362 463 556

Q14 EB1-Feeder 436 524 550


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Op


Q14 EB2-Feeder 440 535 558

Q14 WB1-Feeder 402 484 575

Q14 WB2-Feeder 379 474 550

Q15 EB1-Feeder 439 549 632

Q15 EB2-Feeder 430 541 621

Q15 WB1-Feeder 320 414 498

Q15 WB2-Feeder 352 465 543

Q16 EB1-Feeder 434 545 597

Q16 EB2-Feeder 431 520 598

Q16 WB1-Feeder 319 424 462

Q16 WB2-Feeder 305 390 427

Q17 EB1-Feeder 378 459 549

Q17 EB2-Feeder 358 424 524

Q17 WB1-Feeder 413 494 549Q17 WB2-Feeder 422 488 565

Q18 EB1-Feeder 295 439 423

Q18 EB2-Feeder 264 393 379

Q18 WB1-Feeder 309 456 417

Q18 WB2-Feeder 278 409 376

Maximum 487 609 777

Of all the positive feeders, the maximum is 487A under normal operation, 609A for contingencyoperation and 777A for recovery operation.

The following table lists negative feeder load currents.

Table 6. Negative Feeder Load Currents (RMS Amps)

Substation Feeder NameMaximum -Normal Op


Op


Q01 EB1-Return 551 739 671

Q01 WB1-Return 419 620 482

Q02 EB1-Return 422 541 499

Q02 WB1-Return 530 643 687

Q03 EB1-Return 441 618 533

Q03 WB1-Return 426 604 549

Q04 EB1-Return 660 842 707

Q04 WB1-Return 431 629 526

Q05 EB1-Return 626 855 825

Q05 WB1-Return 610 842 836

Q06 EB1-Return 594 813 814

Q06 WB1-Return 673 888 941

Q07 EB1-Return 598 877 849

Q07 WB1-Return 590 856 841


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Table 6. Negative Feeder Load Currents (RMS Amps)

Substation Feeder NameMaximum -Normal Op


Op


Q08 EB1-Return 697 939 917

Q08 WB1-Return 666 912 1,011

Q09 EB1-Return 714 963 943

Q09 WB1-Return 737 983 1,067

Q10 EB1-Return 710 965 917

Q10 WB1-Return 756 1,010 1,055

Q11 EB1-Return 650 876 885

Q11 WB1-Return 659 887 904

Q12 EB1-Return 598 859 806

Q12 WB1-Return 613 877 855

Q13 EB1-Return 634 871 825

Q13 WB1-Return 627 864 828

Q14 EB1-Return 664 856 852

Q14 WB1-Return 674 878 905Q15 EB1-Return 677 898 924

Q15 WB1-Return 611 833 825

Q16 EB1-Return 686 912 897

Q16 WB1-Return 553 781 694

Q17 EB1-Return 660 812 805

Q17 WB1-Return 626 793 805

Q18 EB1-Return 528 826 682

Q18 WB1-Return 501 800 630

Maximum 756 1,010 1,067

Note - The above list includes all simulated headway offsets

Of all the negative feeders, the maximum is 756A under normal operation, 1010A forcontingency operation and 1067A for recovery operation.

3.4 Train voltage plots

The following figures show the instantaneous train voltages (between pantograph and return

rails) across the system for the duration of simulation.

These figures indicate that:

There are instants when train voltages are below 650V under normal operations but the

frequency of such occurrence is below the specified limit of 10% of all observed train

voltage, per the Design Criteria. All train voltages are above 525V under all contingency operation conditions.

All train voltages are above 525V under all recovery operations.

The system meets the requirements of the design criteria in terms of train voltages.


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3.4.1 Normal operations

Figure 1. Train voltage plot – normal operations


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3.4.2 Contingency operations

Figure 2. Train voltage plot – contingency operations


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3.4.3 Recovery operations

Figure 3. Train voltage plot – recovery operations


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3.5 Rail potential plot

The following figures show the instantaneous rail potential (with respect to remote ground)

across the system for the duration of simulation.


Rail potential is within 50V across the system under normal operations.

Rail potential is within 75V across the system under all contingency operation conditions.

Rail potential is within 75V across the system under all recovery operation conditions.

The system meets the requirements of the design criteria in terms of rail potential.


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Figure 4. Rail potential plot – normal operations


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Figure 5. Rail potential plot – contingency operations


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Figure 6. Rail potential plot – recovery operations


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3.6 OCS current plot (RMS amps)

The following figures show the RMS currents in the OCS along the tracks across the system.

The RMS value for each location on each track is computed from the instantaneous currents

through the OCS conductors in the duration of simulation.


The maximum OCS RMS current in the system is 735A under normal operation.

The maximum OCS RMS current in the system is 1033A under all contingency operation

conditions.

The maximum OCS RMS current in the system is 1183A under all recovery operation

conditions

According to Reference 5, allowable ampacity for 500kcm messenger is 810A and for 350kcm

contact wire 650A, making a total ampacity of 1460A (continuous current rating) for the OCS

(based on 75oC conductor temperature, 25oC ambient temperature, wind velocity of 2

feet/second, under sun light).

If the contact wire is 30% worn, its cross-sectional area is reduced to 245kcm and its ampacity

is reduced to 520A. The total OCS ampacity is reduced to 1330A. This is sufficient to support

normal operations, contingency operations and recovery operations. (Ampacity for 245kcm is

not given in reference 5, as it is not a standard size. Using the ampacity of 530A for a 250kcm

contact wire, the ampacity of 245kcm contact is calculated to be 524A. It is rounded down to

520A.)


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Figure 7. OCS current – normal operations


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Figure 8. OCS current – contingency operations


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Figure 9. OCS current – Recovery operations


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Table 8. List of traffic signal and pedestrian crossing locations

StationCode Station Name

locationchainage

location ftfrom SOL

locationmiles from

SOL

C14 Piney Br Rd/Univ 449+95 34,995 6.628

C15 Univ/Seek 459+45 35,945 6.808

C16 Univ/Carroll 470+95 37,095 7.026

C17 Univ/Merrimac 477+70 37,770 7.153C18 Univ/Lebanon 484+45 38,445 7.281

C19 Univ/Langley Plaza 486+95 38,695 7.329

C20 Univ/Tak-Lan TC 489+95 38,995 7.385

C21 Univ/New Hampshire 494+95 39,495 7.480

C22 Univ/TakLan Crossrd 499+70 39,970 7.570

C23 Univ/14th Ave 504+95 40,495 7.670

C24 Univ/15th Ave 516+45 41,645 7.887

C25 Univ/Riggs Road 524+95 42,495 8.048

C26 Univ/Guilford Road 535+20 43,520 8.242

C27 Univ/23rd Ave 548+20 44,820 8.489

C28 Univ/24th Ave (N) 555+20 45,520 8.621

C29 Univ/West Park 563+20 46,320 8.773

C30 Univ/Adelphi 593+70 49,370 9.350

C31 Pres Dr/Campus 601+95 50,195 9.507C32 Pres Dr/Valley 615+20 51,520 9.758

C34 STOP SIGN Ped 1 626+95 52,695 9.980

C35 STOP SIGN Ped 2 630+20 53,020 10.042

C36 STOP SIGN Ped 3 635+20 53,520 10.136

C37 Campus/Regents 640+45 54,045 10.236

C38 Rossboro/Baltimore 653+20 55,320 10.477

C40 Paint Pkwy/Rossboro 664+20 56,420 10.686

C41 Paint Pkwy/PaintTrl 673+45 57,345 10.861

C42 Paint Pkwy/MFRI 680+45 58,045 10.993

C43 Paint Pkwy/Metro 692+95 59,295 11.230

C44 River Road/Rivertch 732+95 63,295 11.988

C45 River Road/Haig 744+45 64,445 12.205

C46 River/Kenilworth 759+95 65,995 12.499

C47 Kenilwth/Rittenhse 772+45 67,245 12.736

C49 Riverdale/Mustang 811+95 71,195 13.484

C50 Riverdale/64th Ave 820+45 72,045 13.645

C51 Riverdale/On Ramp 825+45 72,545 13.740

C52 Riverdale/Off Ramp 830+20 73,020 13.830



C55 Vets Pkwy/Glenridge 886+70 78,670 14.900

C56 Vets Pkwy/Annapolis 903+20 80,320 15.212

C57 Vets Pkwy/Ellin 921+95 82,195 15.567

C58 Ellin/Hanson Oaks 934+95 83,495 15.813


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5.2 Traction Power System Data

5.2.1 OCS Segments

OCS segments are shown in the following figure.

Figure 10. OCS segments

5.2.2 Locations of track cross-bonds

At this stage, the precise locations of track cross-bonds have not been determined. A nominal

spacing of 2000’ between cross-bonds is assumed, per Design Criteria Chapter 15 - Signaling

(Reference 9). The following table lists the locations of the cross-bonds relative to substations

based on this assumption. Also listed in the table are the distances between adjacent cross-

bonds or between cross-bonds and their nearest substations.


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Table 9. Location of track cross-bonds relative to substations

TPS/BondLocations Chainage

Distance toprevious

location (ft)TPS/BondLocations Chainage

Distance toprevious

location (ft)

SOL-Bond_00 100+00 Z-Bond_12 523+17 1,467

Q01 120+29 2,029 Z-Bond_13 537+83 1,467

Z-Bond_01 144+14 2,385 Q10 552+50 1,467

Q02 168+00 2,386 Z-Bond_14 575+50 2,300

Z-Bond_02 186+22 1,822 Q11 598+50 2,300

Z-Bond_03 204+44 1,822 Z-Bond_15 618+08 1,958

Q03 222+66 1,822 Z-Bond_16 637+66 1,958

Z-Bond_04 245+12 2,246 Q12 657+25 1,959

Q04 267+59 2,247 Z-Bond_17 675+50 1,825

Z-Bond_05 285+39 1,780 Z-Bond_18 693+75 1,825

Z-Bond_06 303+19 1,780 Q13 712+00 1,825

Q05 321+00 1,781 Z-Bond_19 734+75 2,275

Z-Bond_07 337+66 1,666 Q14 757+50 2,275

Z-Bond_08 354+32 1,666 Z-Bond_20 782+25 2,475

Q06 371+00 1,668 Q15 807+00 2,475

Z-Bond_09 388+71 1,771 Z-Bond_21 828+75 2,175

Z-Bond_09A 406+42 1,771 Q16 850+50 2,175

Q07 424+15 1,773 Z-Bond_22 868+00 1,750

Z-Bond_10 443+07 1,892 Z-Bond_23 885+50 1,750

Q08 462+00 1,893 Q17 903+00 1,750

Z-Bond_11 485+50 2,350 Z-Bond_24 927+50 2,450

Q09 508+50 2,300 Q18 952+00 2,450

EOL-Bond_25 963+14 1,114

As shown in the above table, a total of 26 cross bonds are assumed, including one at each end

of the line: SOL (start of line) and EOL (end of line).

It is further assumed that the distance between two adjacent cross-bonds, or between one

cross-bond and its nearest substation return connection, should not exceed 2500’. Based on

this assumption and the distance between adjacent substations, the number of cross-bonds is

determined.

Where there is only one cross-bond between two adjacent substations, the cross-bond is

located at the mid-point within the feeding section.

Where there are two cross-bonds between two adjacent substations, the cross-bondsare located at ⅓ and ⅔ points with the feeding section.


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5.2.3 Conductor Resistances

Conductor resistances are listed in the following tables.

Table 10. Conductor resistances for 1 messenger // 1 contact wire

Conductor Type

R values no wear at given temp Temp coeff Working temp CWorking temp, no

wearWorking temp, with wear

Ohms/mi Ohms/kft

tempC forgiven

value

RefSource

Tempcoeff

1/C

ReferenceSource

Workingtemp C

ReferenceSource

Tempdiff C

Ohms/mi

% wear(X-

section

arealoss)

ReferenceSource

Ohms/mi

messenger500kcm HD

copper0.11616 0.02200 20 0.00377 75 MTA DC 55 0.1402 0% 0.14000

contact 350kcmHD copper

0.16099 0.03049 20Service

Wire Co.catalog

0.00377 75 MTA DC 55 0.1944 30% MTA DC 0.27767

OCS=Messenger// contact wire

0.06747 0.01278 75 MTA DC 0.0815 0.09307

running rail 115# steel (1 rail,

AREMA avg R)0.05390 0.01021 20

calc from AREMA

chemcomp

0.003611 60 MTA DC 40 0.0617 10% MTA DC 0.06854

running rail 115# steel (2 rails//, AREMA avg R)

0.02695 0.00510 0.03084 0.03427

For segment 5, where 2x1000 kcmil copper cables are used to run in parallel with the contact wire, the resultant OCS resistance is0.03113 Ohms/mile, in comparison with 0.09307 Ohms/mile for other segments where only 1x500 kcmil messenger or cable is usedin parallel with the contact wire.

5.2.4 Single Line Diagram

Single line diagram for the system is shown in the following figure, including both positive and negative circuits.


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Figure 11. Single line diagram for the traction power system


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5.2.5 Voltage Levels

The traction power system voltage levels are listed in the following table (Reference 1).

Table 11. System voltage levels

Maximum sustained supply voltage 900 VDC

Nominal supply voltage 750 VDCMinimum voltage for full performance 650 VDC

Minimum sustained supply voltage 525 VDC

Regeneration cut-off 900 VDC

5.2.6 Rectifier voltage regulation

The inherent regulation of the rectifier equipment is at 6%. When the ac supply impedance isadded (with minimum short circuit capacity at 100MVA for the ac supply), the total regulation isat 8.2%. Calculations are detailed in the following table.

Table 12. DC voltage regulation for rectifierNominal voltage 750 VnomNo-load voltage 795 Vdo

Voltage drop 45 Vdc

% regulation 6% Based on Vnom

Rectifier rating 2000 kW

Rectifier full load current 2667 Amp

Rectifier transformer rating 2200 kVA

Supply voltage (no-load, line-line) 13200 Vac (line-line)

Supply voltage (no-load, phase) 7621 Vac (line-neutral)

Minimum supply short circuit capacity at TPSS 100 MVA

Supply short circuit current (phase) 4374 Amp, ac RMS

Rectifier full load current at supply voltage (phase) 96 Amp, ac RMS

AC supply voltage regulation 2.2%

Total dc voltage regulation 8.2% Based on Vnom

DC voltage drop total 60.25 Vdc

DC voltage at full load current 734.75 Vdc

Equivalent DC resistance of converter & supply 0.0226 Ohms

5.2.7 Feeder cables and track cross-bonds

Substation feeder cables are assumed to be of 2x1000 kcm copper for each feeder circuit, with

300’ length from dc bus to the OCS connection. The lump resistance for each feeder circuit is

1.65 milli-Ohms.

Each negative feeder circuit is assumed to be of 4x1000kcm copper. With 300’ from the dc

negative bus to the track connection, the lump resistance for each circuit is 0.825 milli-Ohms.

For substation Q07, the length of the feeder cables is assumed to be 64 0’, due to the distancebetween the substation location and the sectionalization gaps. The resultant feeder resistancesare 3.52 milli-Ohms for each positive feeder circuit and 1.76 milli-Ohms for each negative feedercircuit.


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For track cross-bonds at each location, 2x1000 kcmil copper cables are assumed, with a

maximum length of 100’. The resultant circuit resistance is 0.55 milli-Ohms.

5.3 Vehicle Data

5.3.1 Vehicle Weight

The vehicle used for simulation is based on the 95 feet car. The vehicle and passenger weights

are listed in the following table (Reference 1).

Table 13. Vehicle Assigned Weights

AssignedWeight

WeightClass

Load detailsfor 1-car for 2-cars

lb kg lb kg

(Ready torun)

AW0Maximum empty

operating weight lb105,500 47,897 211,000 95,794

(Seatedload)

AW1 AW0 weight plus seated

load of 72 passengersand one operator

116,742 53,001 233,484 106,002

(Designload)

AW2

AW1 load plus 106standees at 2.7 ft

2 of

suitable standing spaceper standee

133,066 60,412 266,132 120,824

(Crush load) AW3


2 of


141,228 64,118 282,456 128,235

(Structuraldesign)

AW4


2 of


149,390 67,823 298,780 135,646

Note - From Reference 1.

It is assumed that the vehicle’s rotational weight is 10% of AW0 weight.

AW3 weight is used in simulation for normal operation and contingency operation; AW4 weight

is used for recovery operation.

5.3.2 Power conversion efficiency

Power conversion efficiency is at 0.85 for both auxiliary power converter and propulsion unit

(Ref.6).

5.3.3 Auxiliary Load

The onboard auxiliary load is assumed to be 80kW per car on the pantograph side (Ref.1).

5.3.4 Maximum Acceleration Rate, Braking Rate and Jerk Rate

The maximum acceleration rate is 3.0 mph/s. The maximum Braking rate is 3.0 mph/s. The jerk

rate limit is 1.5 mph/s/s.


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5.3.5 Maximum Operating Speed

The maximum operating speed is 55 mph [89 km/hr].

5.3.6 Vehicle Characteristic Curves

The following figures show the vehicle characteristic curves that accompany Reference 1.

Figure 12. Vehicle tractive effort curve

In the traction power system load flow study, regenerative braking power is utilized only for

onboard auxiliary loads. This produces the worst case power demand and energy consumption.

The maximum line draw per vehicle is 1650 amperes, including both propulsion and auxiliary

loads.

purple line traction power study report-rev4

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