25 kV Equipment Sizing Calculationv5_ (1).pdf

. DESIGN OF 25 KV OVERHEAD EQUIPMENT (OHE) SYSTEM FOR ELEVATED LINES AND POWER SUPPLY & SCADA FOR BOTH UNDERGROUND AND ELEVATED LINES INCLUDING CHECKING OF DESIGN OF RECEIVING SUBSTATION AND DESIGN VALIDATION OF DELHI MRTS PHASE III PROJECT – LOT I

25 KV TRACTION EQUIPMENT SIZING CALCULATIONS January, 18th 2013

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CONTENTS

1. INTRODUCTION ..................................................................................................................... 4 1.1. Reference documentation ................................................................................................ 4 1.2. Abbreviations ................................................................................................................... 5 2. TRACTION TRANSFORMERS .............................................................................................. 6 2.1. Power consumption of TSS’s ........................................................................................... 6 2.1.1. Normal operation (5 traction substations working) .................................................... 6 2.1.2. Failure cases .............................................................................................................. 7 2.2. Voltage in pantograph .................................................................................................... 11 2.2.1. Normal operation (5 traction substations working) .................................................. 11 2.2.2. Failure cases ............................................................................................................ 12 2.3. Conclusions .................................................................................................................... 13 3. BOOSTER TRANSFORMERS ............................................................................................. 15 4. 25 KV FEEDERS .................................................................................................................. 19 4.1. Rated current calculation (In) ......................................................................................... 19 4.1.1. Main track ................................................................................................................. 19 4.1.2. Depot Calculation ..................................................................................................... 20 4.2. Calculation with current in case of nominal overload of the transformer (Io) ................. 21 4.3. Voltage drop ................................................................................................................... 23 4.4. Short circuit criteria ........................................................................................................ 23 4.4.1. 4.4.2. 4.4.3. 4.4.4. 4.4.5. 4.4.6.

Simply Single Line Scheme ..................................................................................... 25 Equivalent Single Line Scheme ............................................................................... 25 Impedance Calculations ........................................................................................... 26 Calculation of the continuous current of short circuit (Isc) ....................................... 28 Calculation of the Maximum Current Asymmetric Short-Circuit (Is) ........................ 28 Rupture capacity and connection ............................................................................. 29

4.5. Conductor sizing ............................................................................................................ 29 4.5.1. Type of Conductor .................................................................................................... 29 4.5.2. Size of Conductor ..................................................................................................... 30 5. RETURN CABLES................................................................................................................ 35 5.1. Return cables ................................................................................................................. 35 5.2. Return conductor ............................................................................................................ 35 5.2.1. Rated current calculation (In) ................................................................................... 35 5.2.2. Voltage drop ............................................................................................................. 36 5.2.3. Short circuit criteria .................................................................................................. 36 6. INDUCED VOLTAGE CALCULATION ................................................................................ 36 7. CIRCUIT BREAKERS RATING ............................................................................................ 38

25 KV Traction Equipment Sizing Calculations

. 8. INTERRUPTERS RATING ................................................................................................... 39 9. CURRENT TRANSFORMERS RATING .............................................................................. 40

Annex 1. Technical data of 26/45 kV XLPE insulated copper cable used for calculation. Annex 2. Guide for calculation of cable capacity under short time operation currents. Annex 3. Technical data of aluminium cables used for calculation. Annex 4. Rolling stock data used for calculation

25 KV Traction Equipment Sizing Calculations

1. Introduction The present document aims to determine the rating of the equipment foreseen for the 25 kV traction network in the scope of the design of 25 kV Overhead Equipment (OHE) system for the Mukundpur – Gokulpuri – Shiv Vihar section (Line 7) including Mukundpur and Vinod Nagar Depots. 1.1. Reference documentation Comparative Study of various Schemes of underground ASS & Recommendations for DMRC Phase-III. DMRD. Edition Nov 2011. Ardanuy-Barsyl. Edition of 17/08/2012 DMRC Project Line 7. Detail Design Consultant. CCDD-1. Traction simulation sizing study Ardanuy-Barsyl. Edition of 17/08/2012

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1.2. Abbreviations DMRC

Delhi Metro Rail Corporation Limited

UG

Underground (Package, Station or Section)

ELV

Elevated (Package, Station or Section)

DPT

Depot

ASS

Auxiliary Substation

RSS

Receiving Substation

TSS

Traction Substation

PD

Propriety Development

TVF

Tunnel Ventilation Fan

TEF

Tunnel Emergency Fan

ECS

Environment Control System

S&T

Signal & Telecommunication

TR

Transformer

DG

Diesel Generator

CCB

Coupling Circuit Breaker

VDE

Association of German Electrical Engineers

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2. Traction Transformers The Traction Simulation Study for the Line 7 extension has been performed by M/s Ardanuy using RailPower software. In this chapter the results and main conclusions obtained from the study are included. 2.1. Power consumption of TSS’s Different alternatives have been simulated to get the power consumptions in transformers of the Tractions Substations. The values have been obtained taking into account these assumptions: Total Trip: Mukundpur – Shiv Vihar, 57.705 km, 37 stations. Rolling Stock with 6 coach compositions (DM-T-M-M-T-DM) and full loaded (1,800 people). Total weight of Rolling Stock is 371.25 Tons (Tare weight is 252 Tons, 42 Tons/car). It is assumed that up to 75% of the power generated by train braking is able to be regenerated in electrical power by the motors of the train (Regenerative braking performance will be 0.75). Braking force will be supplied by the train motor brakes until the maximum engine brake force for each speed is given. If it is necessary more braking force than the motor is able to generate, it will be provided by pneumatic brake. By default, it is considered a value of train power factor of 1. Auxiliary Power Consumption of trains (according to values provided by DMRC): 33 kVA/car (198 kVA whole train) Headway of 135 seconds between trains in same direction (what means 68 trains at same time in the system) 2.1.1.

Normal operation (5 traction substations working)

Maximum, average and RMS (maximum RMS value for integration period of 1 hour) power values for Traction Substations during the peak hour are shown in the following table.

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SIMULATED VALUES OF POWER CONSUMPTION IN TSS DH-KN INA VN-NG YMVH MKPR (KVA)

(KVA)

(KVA)

(KVA)

(KVA)

TRF1

TRF1

TRF1

TRF1

TRF1

MAX

19.630

37.103

24.233

32.028

19.422

RMS

12.114

17.219

16.388

17.006

12.625

AVG15 min.

11.146

13.556

15.625

14.875

10.773

AVG5 min.

11.478

14.640

16.072

15.431

11.067

Table 1. Simulated values of power consumption in TSS. Normal operation

According to these values, transformers with nominal power of 40/50 MVA are plenty dimensioned to feed the whole line present. The overload conditions that each transformer should be complied are: Overloads above 150% of nominal power (40 MVA) during less than 15 minutes in a 3 hour cycle. Overloads above 200% of nominal power (40 MVA) during less than 5 minutes in a 3 hour cycle. It can be seen the worst case (transformer more loaded) for this simulation is transformer of Dhaula Kuan TSS. There is not any instant in the simulation when the power is higher than 150% of nominal power (40x1,5 = 60 MVA), therefore both conditions of overloading are complied. 2.1.2.

Failure cases

Feed extensions cases have been simulated, for failures of 1, 2, 3 and 4 TSS. The worst case for each type of operation (N-1, N-2, N-3 and N-4) has been simulated. The following list shows the worst case simulated for each operation mode (the worst case for each operation mode is the case where the electrical sector fed by 1 TSS is the longest): N-1 Case. Failure of TSS3 (INA): Dhaula Kuan will feed from Neutral Section in K.P 9+200 to Neutral Section in 34+935. N-2 Case. Failure of TSS1 (Mukund Pur) and TSS2 (Dhaula Kuan): INA will feed from dead end of the line (Mukund Pur Station) to K.P. 34+845.

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N-3 Case. Failure of TSS1 (Mukund Pur), TSS2 (Dhaula Kuan) and TSS3 (INA): Vinod Nagar will feed from dead end of the line (Mukund Pur Station) to K.P. 48,685. N-4 Case. Failure of TSS2 (Dhaula Kuan), TSS3 (INA), TSS4 (Vinod Nagar) and TSS5 (Yamuna Vihar): Mukund Pur will feed the whole line Simulations for feed extension cases have been realized taking into account the following headways: Case

Headway.

Case N-1

135 seconds

Case N-2

240 seconds

Case N-3

480 seconds

Case N-4

1,200 seconds

Table 2. Headway for failure cases

CASE N-1: FAILURE OF TSS3 (INA) In this case, Dhaula Kuan will be feeding from Neutral Section in K.P 9+200 to Neutral Section in 34+935. The rest of the line will be fed as normal operation case. FAILURE OF INA TSS

-0+680 MKPR TSS

9+200 SP

34+935 SP

17+045 DH-KN TSS

42+140 VN-NG TSS

48+775 SP

54+000 YMVH TSS

Figure 1 Case N-1. Failure of TSS3 (INA)

SIMULATED VALUES OF POWER CONSUMPTION IN TSS DH-KN VN-NG YMVH MKPR (KVA) (KVA) (KVA) (KVA) MAX

TRF1 19.630

TRF1 54.085

TRF1 32.028

TRF1 19.422

RMS

12.114

31.826

17.006

12.625

AVG15 min.

11.146

28.252

14.875

10.773

AVG5 min.

11.478

29.627

15.431

11.067

Table 3. Simulated values of power consumption in TSS. Case N-1

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The worst case for this simulation is the transformer of Dhaula Kuan TSS. In order to comply with criteria of overload above 150% during less than 15 minutes in a 3 hours cycle, the nominal power of this transformer will be dimensioned for 40 MVA. CASE N-2: Failure of TSS1 (Mukund Pur) and TSS2 (Dhaula Kuan) In this case, headway of 4 minutes has been taken into account. INA will be feeding from dead end of the line (Mukund Pur Station) to K.P. 34+845. The rest of the line will be fed as normal operation case. FAILURE OF MUKUND PUR AND DHAULA KUAN TSS

25+400 INA TSS

34+935 SP

42+140 VN-NG TSS

48+775 SP

54+000 YMVH TSS

Figure 2. Case N-2. Failure of TSS1 (Mukundpur) and TSS2 (Dhaula Kuan)

SIMULATED VALUES OF POWER CONSUMPTION IN TSS INA VN-NG YMVH (KVA) (KVA) (KVA) MAX

TRF1 52.217

TRF1 15.360

TRF1 16.613

RMS

26.356

11.453

8.412

AVG15 min.

23.080

9.207

6.581

AVG5 min.

25.082

10.494

7.366

Table 4. Simulated values of power consumption in TSS. Case N-2

The worst case for this simulation is the transformer of INA TSS. In order to comply with criteria of overload above 150% during less than 15 minutes in a 3 hours cycle, the nominal power of this transformer will be dimensioned for 40 MVA. CASE N-3: Failure of TSS1 (Mukund Pur), TSS2 (Dhaula Kuan) and TSS3 (INA) In this case, headway of 8 minutes has been taken into account. Vinod Nagar will be feeding from dead end of the line (Mukund Pur Station) to K.P. 48,685. The rest of the line will be fed as normal operation case.

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FAILURE OF MUKUND PUR AND DHAULA KUAN AND INA TSS

42+140 VN-NG TSS

48+775 SP

54+000 YMVH TSS

Figure 3. Case N-3. Failure of TSS1 (Mukundpur), TSS2 (Dhaula Kuan) and TSS3 (INA)

SIMULATED VALUES OF POWER CONSUMPTION IN TSS VN-NG YMVH (KVA) (KVA) MAX

TRF1 34.550

TRF1 10.473

RMS

19.605

4.864

AVG15 min.

16.523

3.668

AVG5 min.

17.910

4.201

Table 5. Simulated values of power consumption in TSS. Case N-3

The worst case for this simulation is the transformer of Vinod Nagar TSS. In order to comply with criteria of overload above 150% during less than 15 minutes in a 3 hours cycle, the nominal power of this transformer will be dimensioned for 40 MVA. CASE N-4: Failure of TSS2 (Dhaula Kuan), TSS3 (INA), TSS4 (Vinod Nagar) and TSS5 (Yamuna Vihar) In this case, headway of 20 minutes has been taken into account. Mukund Pur will be feeding the entire line. FAILURE OF DHAULA KUAN, INA, VINOD NAGAR AND YAMUNA VIHAR TSS

-0+680 MKPR TSS

Figure 4. Case N-4. Feeding from TSS1 (Mukundpur)

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POWER CONSUMPTION IN TSS MKPR (KVA) MAX

TRF1 22.458

RMS

10.910

AVG15 min.

8.854

AVG5 min.

9.768

Table 6. Simulated values of power consumption in TSS. Case N-4

In order to comply with criteria of overload above 150% during less than 15 minutes in a 3 hours cycle, the nominal power of the Mukumpur SST transformer will be dimensioned for 40 MVA. 2.2. Voltage in pantograph 2.2.1.

Normal operation (5 traction substations working)

Voltage in the train pantographs have been calculated considering Normal Operation of electrification system (5 Traction Substations working at same time). For this calculation the following has been taken into account: Value of lump impedance of the catenary system 25 kV feeding cable impedance Exit voltage at the electrical traction substations Exit current at the substations Current consumed by each train, which will correspond to the results of the simulations Location of the substations and neutral sections The voltages presented below are the maximum and minimum that can be produced on the pantograph with the foreseeable circulation graph (headway of 135 seconds).

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VOLTAGE IN TRAIN PANTOGRAPH

DIRECTION

MIN

MAX

AVG

(V)

(V)

(V)

MUKUNDPUR – SHIV VIHAR

26,563 27,939 27,332

SHIV VIHAR - MUKUNDPUR

26,517 28,150 27,341

Table 7. Voltage in train pantograph. Normal operation

For normal operation, minimum voltage in the line is 26,517 V, over the threshold established in the normative EN 50163 “Railway applications - Supply voltages of traction systems”, for traction systems of AC 25 kV (Umin1 = 19,000 V). 2.2.2.

Failure cases

Except in the case of N-1, the headway between trains should increase as shown below to assure that the voltage drop in the pantograph trains complies with the values established in norm EN 50163 (where Umin1 = 19,000 V): Case

Headway.

Case N-2

4 minutes

Case N-3

8 minutes

Case N-4

20 minutes

Table 8. Headway for N-2, N-3 and N-4 failure cases.

In the following table, values of voltage in the train pantographs are shown for the different cases of feed extensions. VOLTAGE IN TRAIN PANTOGRAPH CASE

DIRECTION MIN (V) MAX (V) AVG (V)

CASE N-1: FAILURE TSS3

DW LINE

25,550

27,939

27,138

FEED FROM TSS2

UP LINE

25,681

28,150

27,134

CASE N-2: FAILURE TSS1 AND TSS2

DW LINE

19,737

28,054

26,979

FEED FROM TSS3

UP LINE

22,859

28,333

27,084

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VOLTAGE IN TRAIN PANTOGRAPH CASE

DIRECTION MIN (V) MAX (V) AVG (V)

CASE N-3: FAILURE TSS1,TSS2 AND TSS3

DW LINE

20,159

28,082

26,691

FEED FROM TSS4

UP LINE

23,337

28,130

26,800

CASEN N-4: FAILURE TSS2, TSS3, TSS4 AND

DW LINE

20,478

28,535

26,668

UP LINE

21,027

28,420

26,615

TSS5 FEED FROM TSS1

Table 9. Voltage in train pantograph. Failure cases

In N-1 situation, the minimum value of voltage in train pantograph is 25,550 V. This value is over the threshold established in the normative EN 50163 (where Umin1 = 19,000 V) In N-2 situation, the minimum value of voltage in train pantograph is 19,737 V. This value is over the threshold established in the normative EN 50163 (where Umin1 = 19,000 V) In N-3 situation, the minimum value of voltage in train pantograph is 20,159 V. This value is over the threshold established in the normative EN 50163 (where Umin1 = 19,000 V) In N-4 situation, the minimum value of voltage in train pantograph is 20,478 V. This value is over the threshold established in the normative EN 50163 (where Umin1 = 19,000 V) 2.3. Conclusions Main conclusions obtained for the study are summarized below: From electrical simulations, it can be deduced that 40/50 MVA transformers are sufficiently dimensioned to support headway of 135 seconds with the model of train considered and the 5 substations working at normal operation. There are no overloads exceeding 50% in any of the transformers of 40/50 MVA (nominal power value). From the simulations of failure of one of the Traction Substations (feed extensions cases) it can be deduced for the worst case will be failure of INA TSS. In this case the transformers of 40/50 MVA (Dhaula Kuan TSS) comply with the criteria of overload. With respect to drop voltage along the line, for cases simulated the voltages in train pantographs are over the threshold established in the normative EN 50163 “Railway applications - Supply voltages of traction systems” (where Umin1 = 19,000 V)

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From the simulations of failure of more than 1 Traction Substation (feed extension N2, N-3 and N-4) headway must be increased in order to reduce the number of trains and therefore maximum drop voltage along the OCS will be reduced complying with the values established in norm EN 50163 (where Umin1 = 19,000 V).

With these operation conditions and headways, it can be deduced that for the worst cases that all transformers will be plenty dimensioned for 40/50 MVA.

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3. Booster Transformers Currently, in existing lines of DMRC there are two kinds of Booster Transformers, with the following characteristics: Nominal Rating

Rated

Current

150 kVA

and 366 A at 409 V

280 kVA

500 A at 560 V

voltage

Overload rating (15 ms)

550 A

750 A

Impedance at full load at 0.15 ohm (Max)

0.15 ohm (Max)

75º Centigrade

Guaranteed max no load 225 W

350 W

losses

Guaranteed

max

load 4000 W

6500 W

losses Table 10. Booster transformers used in DMRC

The maximum current calculated for outgoing feeders for the main line in Line 7 is 439.58 A according to the electrical dimensioning of the Line 7 simulated with RailPower. This value of current is the RMS value corresponding to n-2 failure situation (Mukundpur TSS and Dhaula Kuan TSS failure) for the feeder cable to Down Line at Mukundpur side. Capacity of booster transformers will be calculated with the expression:

SBT

IRC UBT

Where: SBT = Capacity of the booster transformer (VA). UBT = Voltage in the booster transformer (V). IRC = Return current which cross the booster transformer (A) η = Performance of the Booster transformer

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Figure 5. Scheme of operation with Booster transformers

Considering that the voltage of the return conductor in the connection with rails is zero, the voltage of the booster transformer can be calculated according to the expression:

UBT

IRC (z RC LRC

z BT )

Where: UBT = Voltage in the booster transformer (V). IRC = Return current which cross the booster transformer (A) ZRC = Impedance per km of the return conductor (ohm/km) LRC = Length of return conductor between the adjacent connections of RC with the rail (km). ZBT = Impedance of the booster transformer (ohm) Calculating these parameters: IRC (A) η ZRC (ohm/km) LRC (km) ZBT (ohm/km)

439.58 0.85 0.119+j0.402 2.6

0.016+j0.078

From electrical dimensioning of the Line 7 (Maximum RMS value of case N-2) Typical value Calculated from catalogue Maximum distance between two adjacent RC to rail connections According calculated in annex 2 of Traction Simulation Sizing Study

UBT (V)

514.12

Calculated with previous data

Sa (kVA)

265.92

Calculated with previous data Table 11. Sizing of BT

Therefore, the Booster transformer of 280 kVA can be selected for the worst case. Nevertheless, taking into account the location of every BT along the line (distance to TSS) and the distances between adjacent BTs, and considering that every TSS feed the line with

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this value maximum of current, these parameters can be calculated for every booster transformer and therefore, accurate sizing of every booster transformer can be done. In the following table these calculations are shown:

BT

Ch.

imp. Return feeder (ohm/km)

imp. BT (ohm)

RC distance RC Voltage BT BT connection current (V) Power Power rail-RC (A) (BT (kVA) (kVA) (km) Voltage)

BT701 0+214

0.119+0.402i 0.016+0.078i

0.797

369.55

152.82

66.44

150

BT703 6+855

0.119+0.402i 0.016+0.078i

1.465

74.08

51.36

4.48

150

BT705 8+570

0.119+0.402i 0.016+0.078i

1.428

58.28

39.51

2.71

150

BT707 9+710

0.119+0.402i 0.016+0.078i

1.793

28.58

23.74

0.80

150

BT709 12+155 0.119+0.402i 0.016+0.078i

1.909

165.58

145.66

28.37

150

BT711 16+790 0.119+0.402i 0.016+0.078i

1.835

425.29

360.84

180.55

280

BT713 19+289 0.119+0.402i 0.016+0.078i

1.822

240.18

202.48

57.21

150

BT715 20+433 0.119+0.402i 0.016+0.078i

1.352

138.53

89.49

14.58

150

BT717 34+127 0.119+0.402i 0.016+0.078i

1.425

38.01

25.72

1.15

150

BT719 36+700 0.119+0.402i 0.016+0.078i

2.287

107.68

111.77

14.16

150

BT721 38+700 0.119+0.402i 0.016+0.078i

2.270

229.70

236.83

64.00

150

BT723 41+240 0.119+0.402i 0.016+0.078i

2.475

384.67

429.67

194.45

280

BT725 43+650 0.119+0.402i 0.016+0.078i

2.158

339.54

334.06

133.45

150

BT727 45+555 0.119+0.402i 0.016+0.078i

2.084

213.33

203.32

51.03

150

BT729 47+818 0.119+0.402i 0.016+0.078i

2.273

63.40

65.44

4.88

150

BT731 50+100 0.119+0.402i 0.016+0.078i

2.066

111.47

105.40

13.82

150

BT733 51+950 0.119+0.402i 0.016+0.078i

2.103

267.11

256.65

80.65

150

BT735 54+305 0.119+0.402i 0.016+0.078i

2.453

403.94

447.38

212.61

280

BT737 56+855 0.119+0.402i 0.016+0.078i

1.729

105.98

85.21

10.62

150

Table 12. Detailed calculation of Line 7 BTs (Up line)

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According to these calculations it can be sized the booster transformers: Up line Booster Transformer

Dn line

Capacity (kVA)

Booster Transformer

Capacity (kVA)

BT701

150

BT702

150

BT703

150

BT704

150

BT705

150

BT706

150

BT707

150

BT708

150

BT709

150

BT710

150

BT711

280

BT712

280

BT713

150

BT714

150

BT715

150

BT716

150

BT717

150

BT718

150

BT719

150

BT720

150

BT721

150

BT722

150

BT723

280

BT724

280

BT725

150

BT726

150

BT727

150

BT728

150

BT729

150

BT730

150

BT731

150

BT732

150

BT733

150

BT734

150

BT735

280

BT736

280

BT737

150

BT738

150

Table 13. Line 7 BTs (Up and down lines)

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4. 25 kV Feeders Dimensioning of 25 kV feeders has been developed according to the worst criterion of following ones: Maximum admissible current for conductors will be taken into account in order to select the cable according to the maximum calculated current in normal conditions. Voltage drop will be calculated in order to maintain minimum voltage above the minimum voltage required for operation, which is 19 kV, according to EN. Conductors must withstand mechanical and thermal loads during a short circuit. Firstly, the value of currents foreseen in all of these cases is calculated. With all of these values of currents, the size of the conductors which compose the feeders are checked. 4.1. Rated current calculation (In) 4.1.1.

Main track

The maximum current calculated for feeding of the main line in Line 7 can be obtained from “Power Consumption Assessment” for the electrical dimensioning of the Line 7: Mukundpur – Shiv Vihar. According to results given by the software, the worst case regarding currents is when Mukundpur TSS and Dhaula Kuan TSS fail. In such case, INA TSS must feed the section fed by these two substations in normal operation. FAILURE OF MUKUND PUR AND DHAULA KUAN TSS

25+400 INA TSS

34+935 SP

42+140 VN-NG TSS

48+775 SP

54+000 YMVH TSS

Figure 6. Worst case from the current values point of view. Case N-2.

In this case, according to the results given by the software, the currents in each outgoing feeder from Mukundpur substation are:

Case AVG RMS MAX

F1 DOWN LINE

F1 UP LINE

F2 DOWN LINE

F2 UP LINE

353.69 439.58 1152.14

339.30 384.58 774.55

162.07 192.75 364.55

86.84 160.73 349.99

Table 14. Current in feeder cables obtained in Traction Simulation Study in case N-2

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Where F1 are the feeders which feed the Mukundpur side and F2 are the feeders which feed the Shiv Vihar side of OHE. Therefore, the feeders must be sized for an In of 439.58 A. In the chapter 4.5 the conductors of feeders are sized according to this value of current. 4.1.2.

Depot Calculation

For Depot, the following cases have been considered: Starting up of one train. Several trains in stabling tracks consuming auxiliary power (33% of trains stabled in depot). The maximum current obtained between these two situations will be considered for sizing the feeder cables from TSS to Depot. Current in the starting up For the starting up of the trains, the maximum current consumed by one train is 240 A according to rolling stock data received (annex 4). It is considered that only one train is starting up at depot at the same time. Current because of auxiliary power consumption The power required by auxiliaries of the rolling stock (6 cars) is 198 kVA. In Mukundpur Depot there are 18 stabling track with capacity for 36 trains formed by 6 cars. Considering that 33 % of the trains will be consuming maximum power at the same time, the current through the feeder will be:

In

n Sa U n min

Where: n = number of trains consuming auxiliary power at the same time Sa = apparent power of auxiliaries of the rolling stock (6 cars) in kVA. Unmin = minimum admissible voltage in kV.

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Unmin (kV)

19

Minimum admissible voltage

n

12

33% of total capacity of stabling tracks

Sa (kVA)

198

According to Rolling Stock data

In (A)

125.05

Calculated with previous data

Table 15. Current in feeder cable in Mukundpur Depot. Case of 12 trains with auxiliary power consumption

In Vinod Nagar Depot there are 45 stabling track with capacity for 45 trains formed by 6 cars. Considering that 33 % of the trains will be consuming maximum power at the same time, the current through the feeder will be:

In

n Sa U n min

Where: n = number of trains consuming auxiliary power at the same time Sa = apparent power of auxiliaries of the rolling stock (6 cars) in kVA. Unmin = minimum admissible voltage in kV. Unmin (kV)

19

Minimum admissible voltage

n

15

33% of total capacity of stabling tracks

Sa (kVA)

198

According to Rolling Stock data

In (A)

156.31

Calculated with previous data

Table 16. Current in feeder cable in Vinod Nagar Depot. Case of 15 trains with auxiliary power consumption

Therefore the maximum current considered to size the feeder cable to Mukundpur and to Vinod Nagar Depot will be given by the starting up of train case. In the chapter 4.5 the conductors of feeders are sized according to these values of current. 4.2. Calculation with current in case of nominal overload of the transformer (Io) In the previous chapter, the nominal current in the worst case of overload has been determined according to results given by “Power Consumption Assessment”. However, traction transformers must have an overloading capacity of traction transformer of 50%loading for 15 minutes and 100% overloading for 5 minutes, after the transformer has attained steady temperature on continuous operation at full load, with interval between two successive overloading of 3 hours. 25 KV Traction Equipment Sizing Calculations

21

Therefore, in case of the maximum overload of the transformer, the current will be bigger than obtained by calculations, because the transformer capacity has been selected in order to fulfill this overloading requirement. Taking this into account, the capacity of the transformer considered for calculations must be of 40 MVA. The maximum current given by the transformer in overload situation can be obtained by:

So Un

Io With:

So = apparent power in kVA in 50% and 100% overload. Un = nominal voltage in kV. Therefore, the currents will be: Un (kV)

25

25

Sn (kVA)

60000

80000

In (A)

2400

3200

Table 17. Currents given by traction transformer in overload cases

These currents will pass through 4 feeders existing in the substation (up and down, Mukundpur and Shiv Vihar sides). The quantity of the total current which goes for every feeder will not be the same. To make the calculation, the same percentages which have been obtained in the Power Consumption Assessment calculation have been considered. In the case of failure n-2, these percentages are: RMS

%

F1 DN

439.58

37%

F1 UP

384.58

33%

F2 DN

192.75

16%

F2 UP

160.73

14%

Table 18. RMS values of current in every feeder cable of INA TSS. N-2 case

Taking these percentages into account, the most loaded feeder in the overload situation will take the 37% of the total current. Therefore, the feeder must be dimensioned for withstand 888 A during 15 minutes and 1184 A for 5 minutes.

25 KV Traction Equipment Sizing Calculations

22

In the chapter 4.5 the conductors of feeders are sized according to these values of current. 4.3. Voltage drop Voltage drop calculated in Traction Simulation Study for Line 7 has already into account the length of the feeders which feed main tracks from TSS’s. Therefore, they are suitable according to this criterion. Regarding feeder to Depots, voltage drop must be calculated according to expression:

U

L I

R

j X

Where: L = Length of the conductor (km) I = Current of the conductor (A) R = conductor resistance ( /km) X = conductor reactance ( /km) The voltage drop will be: Feeder

Mukundpur Depot

Vinod Nagar Depot

L (km)

1.2

1.7

Distance from drawings

I (A)

240

240

From chapter 4.2

R (Ω/km)

0.0754

0.0754

Calculated from catalogue

X (Ω/km)

0.115

0.115

Calculated from catalogue

ΔU (V)

39.60

56.10

Calculated with previous data

Table 19. Voltage drop calculation for feeder cables in depots

4.4. Short circuit criteria When sizing and selecting equipment, and electrical components must be taken into account in accordance with VDE (Association of German Electrical Engineers) determinations, not only due to permanent loads the current and voltage, but surges caused by short circuits. Short-circuit currents are usually several times higher than nominal therefore cause high dynamic and thermal overloads. The short circuit currents traversing land can also be the cause of contact stresses and unacceptable interference. Short circuits can cause the destruction of equipment and components or cause damage to people if the design does not take into account the maximum short-circuit currents.

25 KV Traction Equipment Sizing Calculations

23

For calculation of short circuit currents will follow the guidelines VDE 0102, and 2/11.75 1/11.71 parts. Two methods exist to perform the calculation, one, the absolute impedance calculation, and the other, the dimensionless impedance calculation or per unit. It has been selected the calculation per unit method for this design. The “per unit method” simplifies the calculation when there are two or more levels of voltage and interest the effective value. It also presents other advantages: Manufacturers specify the impedances in percent of the nominal values given in the plates. The impedances per unit of the same type of apparatus are very close values, although their ohmic values are very different. If you do not know the impedance of a device, you can select from tabulated data that provide reasonably accurate values. The impedance of a transformer unit is equal in the primary than in the secondary and is not dependent on the type of connection of the windings. To follow the method per unit must establish two arbitrary values, such condition all others. Normally the base values chosen are: A [MVA] power for the entire circuit B [kV] to a voltage level For a different voltage level, the voltage value of the base has to be multiplied by the transformation ratio of the transformer which separates the two levels. In calculating circuit currents requires knowledge of the temporal variations since the short circuit occurs until it reaches the permanent short-circuit current. As in practice as quickly as possible short circuit current by circuit breakers or other devices, knowledge of temporal variations of the short-circuit current is only necessary to select and size the equipment and components in some cases. The parameters involved in the calculation of the short circuit currents are: I"k: is the rms value of the symmetrical short-circuits current, is the moment when the short circuit occurs. From this value the following currents are determined. Is: Maximum current asymmetric short, is the maximum instantaneous value of the current, which occurs after the short circuit occurs. Also known as peak value or impulse current. This value may know electrodynamics forces.

25 KV Traction Equipment Sizing Calculations

24

Isc: Permanent Short Circuit Current, is the rms value of the symmetrical short-circuit current, which endures after completion of all transients. Used to determine the thermal stress on machinery. Ia: balanced current court, is the rms symmetrical short-circuit current flowing through a switch on the instant you start separating contacts. Used to determine the performance characteristics of the switch off apparatus. This design will be carried out calculations phase short circuits, and these, short circuit away from the generator. Thus one must take into account that VDE 0102 values permanent short circuit current (Icc) and cutting the symmetrical current (Ia) coincide with the current value of the symmetric initial short circuit current (I"k). 4.4.1.

Simply Single Line Scheme

The following diagram shows only those different voltage levels, and the status of power transformers and substation different outputs, in order to perform the calculation of short circuit currents: TT 220 kV/25 kV 40 MVA Ucc=13.8%

CIT

TSS OHE FEEDER TO UP LINE

FEEDER TO DN LINE

FEEDER TO FEEDER TO UP LINE DN LINE

Figure 7. Simply Single Line Scheme.

4.4.2.

Equivalent Single Line Scheme

To obtain the equivalent circuit simply replace the transformer by its respective impedance. The short circuit in the feeder cables will have its maximum value just outside of the substation, as the absence lead length the short circuit effect is not reduced by the line

25 KV Traction Equipment Sizing Calculations

25

impedance. The impedances for conductors and switchgear are negligible and will not be included in the schemes or calculations. The equivalent circuit is reflected in the figure below. The figure also marked the possible points where it can happens different electrical short circuits.

Figure 8. Equivalent circuit.

4.4.3.

Impedance Calculations

To perform the calculation method impedances adapted per unit it has to be fixed, first, arbitrary baseline values. These values determined for each element in intensity per unit. Values are taken as basis: SB = 20 MVA UB = 220 kV The table shows the values per unit based on an equal basis for all power system substations. UB (kV)

220

25

SB (MVA)

20

20

90,9

800

IB (A)

Table 20. Short circuit current per unit based calculation

Observations of the table: SB = Apparent power kVA basis for the entire system, arbitrary value.

25 KV Traction Equipment Sizing Calculations

26

UB = Voltage basis for each kV voltage level is obtained by multiplying the transformation ratio between two voltage levels. IB = current per unit A for each voltage level is obtained from the equation:

I

1000 S U

Values in percent transformers having its reference voltage circuit (Ucc). The short-circuit impedance (ZCC) approximately matches the value shorted reagent (Xcc), so the error made by omitting the resistance is minimal and does not affect the final results ZCC ≈ Xcc With the results of the baseline values for each voltage level it is possible to calculate the impedance by referring to the power unit base. The generic equation for this calculation is:

Z ( pu)

Z cc S B 100 S N

where: Zcc impedance circuit is in percent. SB is the power base. Sn is the rated power of the electrical machine. The equivalent impedance of the network is obtained as follows: Z net

SB S cc

where: SB is the power base. SCC is the short-circuit power of the network (given by electrical company). The results are shown in the following table: Component Characteristics NET RT

Scc = 8800 MVA Sn = 40 MVA Zcc = 13.8%

Impedance per unit referred to SB = 20 MVA ZN = 0,0023 pu ZRT = 0,069 pu

Table 21. Impedance per unit calculation

25 KV Traction Equipment Sizing Calculations

27

4.4.4.

Calculation of the continuous current of short circuit (Isc)

As mentioned above permanent short circuit current (Icc) is equal to the symmetrical initial

I k"

current (I"k) and cutting the symmetrical current (Ia). I cc

Ia

The calculation uses the equation of the Law’s Ohm using values per unit: icc

u z eq

Where u = 1 when calculating per unit, and zeq the calculated value in the table above for each point. Then the resulting values are multiplied by the base value of current, as the voltage level, obtaining the absolute value of the constant intensity at each point shorting: I cc

icc I B

Short-

Equivalent

circuit

Impedance

Point

[pu]

A

ZeqA = 0,0023

iccA = 434,78

IB = 90,9

IccA = 39521,74

B

ZeqB = 0,069

iccB = 14,49

IB = 800

IccB = 11592

Short-circuit current [pu]

Permanent Base current [A]

short-circuit current [A]

Table 22. Short circuit continuous current calculation

4.4.5.

Calculation of the Maximum Current Asymmetric Short-Circuit (Is)

Also called surge current is the maximum value and its value is given by the equation:

IS

x

2 I cc

Where “x” is a factor which depends on the relationship between the effective resistance and the reactance of the circuit impedance. As the resistive value is unknown, take x = 1.8 which is an accepted value for these cases. Thus, following the above equation using a value x = 1.8, the impulse current in each shortcircuit point will be the value shown in the following table:

25 KV Traction Equipment Sizing Calculations

28

Maximum Current

Short-circuit

Permanent SC

point

current (kA)

A

IscA = 39.52

IsA = 100.60

B

IscB = 11.59

IsB = 29.50

Asymmetric SC (kA)

Table 23. Maximum Short-Circuit Asymmetric Current calculation

4.4.6.

Rupture capacity and connection

For the election of the switches are fundamental two variables: Breaking capacity (or power off). Is defined by cutting symmetrical current (Ia). It is expressed in MVA

Sr

Un Ia

Connection capacity (or power connection). Is defined by the maximum asymmetric short circuit current (IS). It is expressed in MVA

Sc

Electric Point

Cutting Symmetrical Current (kA)

Un Is

Breaking Capacity

Surge Current

(MVA)

(kA)

Connection Capacity (MVA)

A

IaA = 39.52

SrA = 8694.4

IsA = 100.60

ScA = 22132

B

IaB = 11.59

SrB = 289.75

IsB = 29.5

ScB = 737.5

Table 24. Breaking and connection capacity calculation

4.5. Conductor sizing 4.5.1.

Type of Conductor

Medium Voltage Cables are manufactured with XLPE insulation. It is very remarkable features cables, both losses in the dielectric, thermal and electrical resistivity and dielectric strength.

25 KV Traction Equipment Sizing Calculations

29

Being able to work at a service temperature of 90°C, these cables have the possibility of transmitting more power than any current wire section. In addition, its smaller size makes it more manageable cable, easier to install, lighter and easier to transport. Type

Single pole

Simple Nominal Voltage

26 kV

Nominal voltage between phases

45 kV

Maximum voltage between phases

52 kV

Voltage pulses

250 kV

Maximum permanent temperature allowable in the conductor Screen

90ºC

Copper

Isolation

Polyethylene (XLPE)

Envelope

Polyvinil Chloride (PVC) Table 25. Conductor characteristics

4.5.2.

Size of Conductor

The feeders will be installed into canalization from the TSS to the viaduct. On the viaduct they will be installed on the parapet, supported by brackets. In case of the feeders of Depots, they will be into canalization from the TSS to the depot FP and from the FP to OHE. Therefore, the lower admissible current will occur when the cables are laid down buried into canalization. According to supplier’s information, the admissible nominal current for an underground copper cable 1x240 mm2 is 501 A (see annex 1), when it is buried at 1.2 m depth, with ground temperature of 25ºC and a ground thermal resistivity of 1 K·m/W. Considering that in the worst case, the groud temperature will reach the 40ºC it will be needed to consider a deration factor of 0.88. Therefore, the maximum nominal current of 1x240 mm2 copper cable will be 440 A. 4.5.2.1. Permanent current In case of main tracks, maximum average current will be 439.58 A per feeder, so 219.79 A per each 240 mm2 cable in permanent operation. Therefore this 240 mm2 cable is valid with a safety factor of 2. 25 KV Traction Equipment Sizing Calculations

30

In case of Depots, maximum nominal current will be 240 A, so one copper cable of 240 mm2 can withstand this current with a safety factor of 1.8. 4.5.2.2. Short time operation current Regarding short time operation currents caused by overloading of the transformer, the capacity of one conductor is given by expression:

IKB

I Z fkB (annex 2, chapter 18.6.5, expression 18.122)

Where: -

IKB is the admissible current for short time operation

-

Iz is the admissible current for permanent operation

-

fkB is overloading factor, given by 2

In IZ

1 fKB

tb

e (annex 2, chapter 18.6.5, expression 18.126)

tb

1 e Where: -

In is the initial current before the overload (nominal current)

-

tb is the duration of the overload

-

τ is time constant of the cable (1/5 of the time taken from the curve to almost reach the permissible final temperature). It is given by the expression:

q IZ

B

2

(annex 2, chapter 18.6.2, expression 18.117)

Where: -

q is the cross section of the conductor

-

B is a constant related with the conductor properties, environment temperature and the maximum temperature admissible for the cable permanent operation. It is given by the expression:

B

c

1

0 20

c (annex 2, chapter 18.6.2, expression 18.118) 20

20 c

25 KV Traction Equipment Sizing Calculations

31

Where: -

Θc is the final temperature in the cable by overload current

-

Θ0 is the initial temperature in the cable before the overload

-

χ20 is the conductivity of the conductor. For copper 56·106 1/Ω·m

-

c is the specific heat of the material. For copper 3.45·106 J/K·m3

-

α20 is the heat transferring factor. For copper 0.00393 K-1

Therefore, the admissible currents for100% and for 50% of overload in the cable will be: 100% overload

50% overload

Source of data

θc (ºC)

90

90

θ0 (ºC)

50

50

5,60E+07 0,00393 3,45E+06 240 440

5,60E+07 0,00393 3,45E+06 240 440

In (A)

219.8

219.8

tb (s)

300

900

6,06E+15 1803,18 2.268 998.12

6,06E+15 1803,18 1.469 646.58

Admissible temperature for un XLPE cable Initial temperature in the cable before the overload From Annex2 table 18.37 From Annex2 table 18.37 From Annex2 table 18.37 Cross section of the cable Chapter 4.5.2 of this document Nominal current in each cable of feeder (Half of RMS value 439.58A, obtained from Traction simulation study) Duration of overload: 5 minutes (300s) and 15 min (900s) for 100% and 50% of overload. Calculated with previous data Calculated with previous data Calculated with previous data Calculated with previous data

χ20 (1/Ωm) α20 (1/K) c (J/Km3) q (mm2) Iz (A)

B (A2s/m4) τ fkB IkB (A)

Table 26. Short time operation capacity calculation for 240 sqmm copper cable

Therefore, one 240 mm2 cable is able to withstand 998.12 A for 5 minutes and 646.58 during 15 minutes. According to calculated in chapter 4.2 of this document, the feeder cable (2 cables of 240 mm2) must be dimensioned for withstand 888 A during 15 minutes and 1184 A for 5 minutes, so each cable of 240 mm2 should be able of withstand 444 A during 15 minutes and 592 A for 5 minutes. Therefore, 240 mm2 cables are able to withstand the overload currents with safety factors of 1.45 and 1.68.

25 KV Traction Equipment Sizing Calculations

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4.5.2.3. Short circuit current Regarding of the maximum short circuit current supported by the cable, it can be obtained as it is shown in the following figure. As it can be seen in this figure, short circuit current considering duration of fault of 3 s is 19 kA, higher to short circuit current calculated in chapter 4.4.4. Therefore, copper conductor of 240 mm2 selected is valid for this application.

25 KV Traction Equipment Sizing Calculations

33

2

Current (kA)

Section of conductor (mm ) Duration (s) Figure 9. Short circuit capacity of 240 sqmm copper cable

25 KV Traction Equipment Sizing Calculations

34

5. Return Cables 5.1. Return cables In front of substations, rails will be connected to substation by means of 3.3 kV cables. Their aim is to carry the return traction current from rails to substation, so they must withstand the same current than 25 kV feeders. Therefore they will be made up of the same number of cables and cross section, as the 25 KV feeders. 5.2. Return conductor One all aluminium conductor with a nominal cross section of 233 sq.mm and a copper equivalent of 140 sq.mm will be used as Return Conductor. Dimensioning of this return conductor has been developed according to the worst criterion of following ones: Maximum admissible current for conductors will be taken into account in order to select the cable according to the maximum calculated current in normal conditions. Voltage drop will be calculated in order to maintain minimum voltage above the minimum voltage required for operation, which is 19 kV, according to EN. Conductors must withstand mechanical and thermal loads during a short circuit. 5.2.1.

Rated current calculation (In)

In the Return current system foreseen, the return conductor must carry the same current as catenary. Therefore it must be dimensioned for carrying the same current calculated in the chapter 4.1.1., (439.58 A). The maximum admissible current for one all aluminium conductor (AAC) with a nominal cross section of 233 sq.mm is 584 A in the following conditions (annex 3): Environmental temperature: 40ºC Solar radiation 900 W/m2. Wind: 0.6 m/s Maximum conductor temperature: 80ºC Frequency: 50Hz Applying a deration factor of 0.9 to take into account the solar radiation and other deration factor of 0.89 to take into account that the worst environmental temperature will be 50ºC, the maximum admissible current will be 467.78 A, so the conductor selected is valid for the nominal current.

25 KV Traction Equipment Sizing Calculations

35

In stations, return conductor will be made by means a 233 sq.mm stranded aluminium conductor, with insulated sleeve. It will be laid under platforms. 5.2.2.

Voltage drop

Voltage drop calculated in Traction Simulation Study for Line 7 has already into account the characteristics of return conductors, so it is not needed any additional calculation. 5.2.3.

Short circuit criteria

Regarding of the maximum short circuit current supported by the Return conductor, it can be obtained by means of following expression:

Where: I: Short circuit current (A) t: Short circuit duration (s) K: parameter which depends of kind of conductor (Cu or Al) and of its isolation. In present case with aluminium conductors, K = 94 will be assumed (jump of temperature from steady temperature to short circuit temperature minimum), so worst scenario has been assumed. S: cross section of the conductor (mm2) Therefore, the minimum section required to withstand the short circuit current calculated in chapter 4.4.4 will be: I (A)

11600 0.25

t (s)

Calculated in chapter 4.4.4 of this document Short circuit duration (estimated as conservative value)

K 2

S (mm )

94

Value for aluminium conductor

61.7

Calculated with previous data

Table 27. Return conductor sizing under short circuit current criteria

Therefore, aluminium conductor of 233 mm2 selected is valid as return conductor. 6. Induced Voltage Calculation According to IEC 60287-1-3:2002, induced voltage per unit length in a conductor can be determined by the following expression:

25 KV Traction Equipment Sizing Calculations

36

E

2

f M I 10

3

V km

Where: f: is the frequency of the nominal voltage waveform I: is the maximum permanent current main conductor M: is the mutual inductance between two conductors arranged in parallel given by the expression:

M

0,46 log

2 Dm Dp

mH km

where: Dm: is the distance between the two conductors Dm Dp: is the equivalent diameter of conductor induced D p

D d' 2 4 S

For cable 26/45kV XLPE, Cu 240 Sqmm the characteristics are: d = 18.3 mm d' = 20.1 mm D = 38.5 mm Screen = 16 mm2

Figure 10. Cross section of XLPE insulated cable

The maximum drop voltage in case of the end of the cable being earthed is given by the expression:

25 KV Traction Equipment Sizing Calculations

37

V

E L

where: E: induced voltage per unit length in a conductor L: Length of conductor According to this length in each case, the drop of voltage will be obtained per each feeder: Dhaula

Mukundpur

Kuan

INA

Vinod Nagar

Maujpur

Rajouri

Kashemere

Garden

Gate

f (Hz)

50

50

50

50

50

50

50

I (A)

219.79

219.79

219.79

219.79

219.79

219.79

219.79

Dm (mm)

8

8

8

8

8

8

8

Dp (mm)

4.514

4.514

4.514

4.514

4.514

4.514

4.514

M (mH/km)

0.252

0.252

0.252

0.252

0.252

0.252

0.252

E(V/km)

17.46

17.46

17.46

17.46

17.46

17.46

17.46

L (km)

1.5

1.5*

1.2

0.7

2.1

1.1*

2.75*

∆V (V)

26.19

26.19

20.94

12.22

36.65

45.41

48.01

(*) Length obtained earthing the sheath cable in it center point Table 28. Induced Voltage Calculation

Therefore, in all cases the voltage in the sheath can be lower than touch voltage by earthing the cables in one end or in their center point and no sheath voltage limiters will be required. 7. Circuit Breakers rating Circuit breakers are foreseen in the outgoing feeders in traction substations (TSSs), and in depot’s Feeding posts, installed in the incoming feeder from TSS and in the incoming feeder from main tracks. In any case, circuit breakers must be able to actuate in short circuit conditions. Therefore, for the election of the circuit breakers are fundamental two variables: Breaking capacity (or power off). Is defined by cutting symmetrical current (Ia). It is expressed in MVA Connection capacity (or power connection). Is defined by the maximum asymmetric short circuit current (IS). It is expressed in MVA

25 KV Traction Equipment Sizing Calculations

38

These variables have been calculated in the chapter 4.4.6 of these documents, and, regarding 25 kV circuit breakers they are: Cutting Symmetrical Current: Ia = 11.59 kA Breaking Capacity: Sr = 289.75 MVA Surge Current: Is = 29.5 kA Connection Capacity: Sc = 737.5 MVA Regarding voltage, they must able to withstand nominal values foreseen in the traction system: Rated voltage: 25 kV Maximum service voltage (permanent): 27.5 kV Therefore, the characteristics required for the circuit breakers foreseen in Mukundpur and Vinod Nagar Depot Feeding posts, as well in feeders of Rajouri Garden FP, Dhaula Kuan FP and Welcome FP will be: Rated voltage

kV

25

Maximum service voltage (permanent)

kV

27.5

Service frequency

Hz

50

Number of phases

1

Erection

Outdoor

Rated current

A

2000

3 sec. Short time current

kA

25

Symmetrical breaking capacity

kA

25

Rated peak withstand current

kA

40

Table 29. Circuit Breakers characteristics

8. Interrupters rating Interrupters foreseen in the OHE have to be able to operate under load conditions. According to calculations shown in the chapter 4.1 the maximum nominal current through each feeder is 439.58 A.

25 KV Traction Equipment Sizing Calculations

39

Catenaries for up and down tracks are paralleled in SSP’s along the track. Therefore, the interrupters will be dimensioned for the total current of the two tracks: In= 439.58 + 384.58 = 824.16 A. Regarding voltage, they must able to withstand nominal values foreseen in the traction system: Rated voltage: 25 kV Maximum service voltage (permanent): 27.5 kV Therefore, the characteristics required for the interrupters foreseen in the switching posts of Line 7 will be: Rated voltage

kV

25

Maximum service voltage (permanent)

kV

27.5

Service frequency

Hz

50

Number of phases

1

Erection

Outdoor

Rated current

A

2000

Table 30. Interrupters characteristics

9. Current Transformers rating Current transformers will be used in depot’s Feeding post for current measuring and protection. Therefore, they must be rated for the nominal current foreseen in depots which is 240 A according to calculations included in chapter 4.1.2. In addition, current transformers will be used in feeders in: Rajouri Garden FP Dhaula Kuan FP Welcome FP Regarding voltage, they must able to withstand nominal values foreseen in the traction system: Rated voltage: 25 kV Maximum service voltage (permanent): 27.5 kV 25 KV Traction Equipment Sizing Calculations

40

Therefore, the characteristics required for the current transformers in OHE part will be: Voltage / earth insulation

kV

27.5

Frequency

Hz

50

Erection

Outdoor

Insulation withstand voltage (permanent)

kV

36

Core 1

600/1, 5P10, 20VA Protection class

Core 2

600/1, 5P10, 15VA Protection class

kA

20 / 40

Secondary Core

Withstand Over-current (1s /peaks)

Table 31. Current transformers characteristics

25 KV Traction Equipment Sizing Calculations

41

ANNEX 1. TECHNICAL DATA OF 26/45 KV XLPE INSULATED COPPER CABLE USED FOR CALCULATION.

25 KV Traction Equipment Sizing Calculations

media tensión

anexo b

DATOS TÉCNICOS DEL CABLE VOLTALENE H 26/45 kV (conductor de cobre) RHZ1

CARACTERÍSTICAS DIMENSIONALES (Valores aproximados) 1 x sección conductor (Cu)/sección pantalla (Cu) (mm2)

26/45 kV 1x35/16 1x50/16 1x70/16 1x95/16 1x120/16 1x150/16 1x185/16 1x240/16 1x300/16 1x400/16 1x500/16 1x630/16 1x800/16 1x1000/16

Código

20117861 20117862 20117863 37011335 20052424 20992340 20013787 20084553 20001742 20117864 37011342 20106569 20117865 20117866

∅ conductor (mm)

7 8 9,7 11,4 12,6 14,1 15,9 18,3 20,5 23,1 26,3 29,6 34,1 38,7

∅ aislamiento (mm)

∅ pantalla (mm)

∅ cable (mm)

Peso (kg/km)

Radio de curvatura estático (posición final) (mm)

24,9 25,8 27,6 29,2 30,5 30,9 32,7 35,1 37,8 38,9 42 45,4 49,9 53,5

26,9 29,2 31 32,6 33,9 34,3 36,1 38,5 41,2 42,3 45,4 48,8 53,3 56,9

34,4 35,4 37,2 38,7 40 40,4 42,2 44,6 47,3 48,4 51,5 54,9 60 63,6

1320 1460 1720 2010 2290 2520 2910 3500 4180 4910 6020 7410 9490 11550

550 566 595 619 640 646 675 714 757 774 824 878 960 1018

Radio de curvatura dinámico (durante tendido) (mm)

688 708 744 774 800 808 844 892 946 968 1030 1098 1200 1272

CARACTERÍSTICAS ELÉCTRICAS 26/45 kV Tensión nominal simple, Uo (kV) Tensión nominal entre fases, U (kV) Tensión máxima entre fases, Um (kV) Tensión a impulsos, Up (kV) Temperatura máxima admisible en el conductor en servicio permanente (ºC) Temperatura máxima admisible en el conductor en régimen de cortocircuito (ºC)

26 45 52 250 90 250

(Valores aproximados) 1 x sección conductor Intensidad máxima (Cu)/sección pantalla admisible enterrado* (Cu) (mm2) (A) 26/45 kV 1x35/16 1x50/16 1x70/16 1x95/16 1x120/16 1x150/16 1x185/16 1x240/16 1x300/16 1x400/16 1x500/16 1x630/16 1x800/16 1x1000/16

171 202 248 297 338 381 431 501 565 644 731 824 921 1007

Intensidad máxima admisible al aire** (A)

Resistencia del conductor a 20 ºC (Ω/km)

Reactancia inductiva (Ω/km)

Capacidad (µF/km)

174 207 258 314 361 411 472 558 640 743 860 984 1132 1269

0,524 0,387 0,268 0,193 0,153 0,124 0,0991 0,0754 0,0601 0,047 0,0366 0,0283 0,0221 0,0176

0,159 0,152 0,144 0,136 0,132 0,125 0,121 0,115 0,112 0,106 0,102 0,098 0,095 0,090

0,135 0,144 0,161 0,175 0,186 0,209 0,226 0,249 0,275 0,341 0,375 0,411 0,460 0,546

*Condiciones de instalación: una terna de cables directamente enterrada o bajo tubo a 1,2 m de profundidad, temperatura de terreno 25 ºC y resisitividad térmica 1 K·m/W. **Condiciones de instalación: una terna de cables al aire (a la sombra) a 40 ºC. NOTA: valores obtenidos para una terna de cables al tresbolillo y en contacto. Para el cálculo de la reactancia inductiva con los conductores en cualquier disposición aplicar la fórmula (A) de la página 214. IMPORTANTE: Para los valores concretos de intensidades máximas según los conexionados de pantalla se ruega contactar con Prysmian.

201

ANNEX 2. GUIDE FOR CALCULATION OF CABLE CAPACITY UNDER SHORT TIME OPERATION CURRENTS.

25 KV Traction Equipment Sizing Calculations

ANNEX 3. TECHNICAL DATA OF ALUMINIUM CABLES USED FOR CALCULATION.

25 KV Traction Equipment Sizing Calculations

Prysal Aluminio

Características Técnicas Cables según norma IRAM 63003

Sección nominal

Formación

Diámetro

Masa

exterior

aprox.

Carga de rotura calculada

aprox.

Resistencia

Intensidad

eléctrica máxima

de corriente

a 20oC y

admisible (1)

c. c. 2

mm

N° x mm

mm

kg/km

kg

ohm/km

A

10

7 x 1,35

4,1

27

195

2,7842

78

16

7 x 1,70

5,1

43

302

1,7558

104

25

7 x 2,15

6,5

70

457

1,0977

139

35

7 x 2,52

7,6

95

594

0,7990

171

50

7 x 3,02

9,1

135

827

0,5563

215

70

19 x 2,15

10,8

190

1242

0,4025

265

95

19 x 2,52

12,6

260

1611

0,2930

324

120

19 x 2,85

14,3

335

2061

0,2291

380

150

37 x 2,25

15,8

405

2648

0,1877

431

185

37 x 2,52

17,7

510

3137

0,1496

498

240

37 x 2,85

20,0

650

4013

0,1170

584

300

61 x 2,52

22,7

840

5172

0,0907

687

400

61 x 2,85

25,7

1075

6615

0,0709

804

500

61 x 3,23

29,1

1381

8247

0,0552

942

625

91 x 2,96

32,6

1732

10645

0,0439

1087

800

91 x 3,35

36,9

2218

13234

0,0343

1266

1000

91 x 3,74

41,1

2764

15995

0,0275

1445

1265

91 x 4,21

46,3

3503

20268

0,0217

1657

(1) Para conductor expuesto a una radiación solar de 900 W/m², considerando una emisividad de 0,6, al nivel del mar y viento de 0,6 m/seg, temperatura ambiente de 40º C, temperatura máxima admisible de 80°C y una frecuencia de 50 Hz.

Acondicionamientos: Bobinas de madera

31

ANNEX 4. ROLLING STOCK DATA USED FOR CALCULATION

25 KV Traction Equipment Sizing Calculations