Sizing of cable tray rev. D.pdf

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SIZING OF CABLE TRAY

LPG - I UNIT

FOR

NEW PROPANE GAS COMPRESSOR

ONGC CONTRACT NO.

MR/MM/LSTK/AB/OTP/PGC(R)/2009/Y15BC09001/PC-6039

OF

OIL AND NATURAL GAS CORPORATION LIMITED

MUMBAI, INDIA

CONSULTANT

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SIZING OF CABLE TRAY

CONTENTS

1. SCOPE

2. BASIS & ASSUMPTIONS

3. CABLE TRAY /LADDER SPECIFICATION 4. TRAY SIZING CALCULATION

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SIZING OF CABLE TRAY

1.

SCOPE

This calculation covers the Sizing of Cable Tray with respect to Cable Data consideration required for all equipment of “New Propane gas compressor” project at LPG-1 plant, Uran complex of Oil & Natural Gas Corporation limited (ONGCL). The panels for all the equipment are considered to be located in existing LPG-1 substation. Power supply will be from new PMCC to be located in the LPG-1 substation.

2.

BASIS & ASSUMPTIONS

2.1 Electrical Design Basis for New Propane Compressor (Doc. No. section C2.8 of 6867-00-50-50-DB-01 rev. B, clause no.7.2 & 14.2 “Cable laying philosophy”).

2.2 Cable Data as per Cable Schedule doc. no. 6972-010-50-50-CSH-0021. 2.3 Cables are considered to be laid in single layer.

2.4 Spare capacity of 10 % is considered for cable trays (as per ‘Design Philosophy for Electrical Facilities’ clause no. 7.2.5 of cabling system).

2.5 Refer ‘Design Philosophy for Electrical Facilities’ Cl.no: 7.2.8 of cabling system – for cable tray design related to loading.

2.6 Cable data for sizing of cable trays have been selected based on the Standard chart of “Polycab” make Copper & aluminium conductor, XLPE insulated, armoured cable conforming to IS 7098 part-1/1988.

3.

CABLE TRAY /LADDER SPECIFICATION

3.1 Refer Standard Specification no. 6-51-0082 rev. 2, Clause no.3.1 & 4.1 of “Cable Trays & Laying”. 3.2 Cable ladders are recommended for sizes above 300mm.

3.3 Cable trays shall comply with the requirements specified in EIL installation standard (7-51-0333). 3.4 HT Power, LT Power and control cables shall be laid in separate trays wherever trays are used. 3.5 Refer to NEC table 318-9 for the maximum fill area for multicore cables.

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SIZING OF CABLE TRAY

4.

TRAY SIZING CALCULATION:

4.1

CABLES FROM LPG-1 S/S TO NEW PROPANE GAS COMPRESSOR

4.1.1 Cable tray from LPG-I to New Propane gas compressor shed (New Propane gas Compressor)

(Copper conductor up-to 16 mm2).

Sum of total Diameter for LT Power cables = 468 mm. With spare capacity of 10%, size required = 516 mm Recommended tray size for single layer of LT cables:

Select from the Standard Cable tray sizes available = 1no. X 600 mm. Cables are touching to each other.

For cable tray drawing refer annexure II (b)

LT Cable size No. Overall Dia. (mm) Total length of Tray required (mm) 3c x 4 mm² 7 15.0 7 x 15 = 105.0 4c x 6 mm² 5 18.0 5 x 18 = 90.0 3c x 70 mm² 1 30.0 1 x 30 = 30.0 3c x 95mm² 3 33.0 3 x 33 = 99 3c x 185 mm² 2 45.0 2 x 45 = 90 3.5c x 35 mm² 1 26.0 1 x 26 = 26 3.5c x 50 mm² 1 29.0 1 x 29 = 28 Total: 468 mm

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SIZING OF CABLE TRAY

4.1.2 Cable tray from LPG-I to New Propane gas compressor shed (New Propane gas Compressor)

(Copper conductor up to 16 mm2).

Sum of total Diameter for LT Power cables = 436.2 mm. With spare capacity of 10%, size required = 480 mm Recommended tray size for single layer of LT cables:

Select from the Standard Cable tray sizes available = 2no. X 300 mm. Cables are touching to each other.

For cable tray drawing refer annexure II (c)

LT Cable size No. Overall Dia. (mm) Total length of Tray

required (mm) 12P x 1.5mm2 2 29.7 2 x 29.7 = 59.4 6P x 1.5 mm2 8 21.6 8 x 21.6 = 172.8 10C x 2.5mm2 3 21 3 x 21 = 63 6C x 2.5mm2 4 15 4 x 15 =60 3C x 2.5mm2 4 14 4 x 14 = 56 3C x 4 mm2 1 15 1 x 15 = 15 2C x 2.5mm2 2 12 2 x 12 =24 Total: 436.2 mm

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SIZING OF CABLE TRAY

4.1.3 Cable tray from Panel no. 19 in LPG-I to New Propane compressor 6.6kV HT motor

Sum of total Diameter for HT Power cables = 80 mm. With spare capacity of 10%, size required = 88 mm

Select from the Standard Cable tray sizes available = 1no. X 300 mm.

For cable tray drawing refer annexure II (a)

HT Cable size No. Overall Dia. (mm) Total Diameter (mm)

3c x300mm² 1 80.0 1 x 80 = 80.0

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SIZING OF CABLE TRAY

4.2

CABLE TRAY FROM LPG-1 S/S TO LPG-2 S/S

4.2.1 Single core cable

Sum of total Diameter for HT Power cables = 492 mm. With spare capacity of 10%, size required = 542 mm

Select from the Standard Cable tray sizes available = 1no. X 600 mm. Spacing between cables is 80 mm after trefoil connection

For cable tray drawing refer annexure I (a)

LT Cable size No. Overall Dia. (mm) Total length of Tray

required (mm)

1C X 300 mm2 12 41 12 x 41 =492

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SIZING OF CABLE TRAY

4.2.2 Control cable (run through 4’’ GI conduit)

Sum of total diameter for control cables = 42 mm. Sum of total diameter for HT Cables =160 mm. Total diameter of control and power cables is 202 mm (42 + 160).

With spare capacity of 10%, size required = 223 mm.

Select from the Standard Cable tray sizes available = 1no. X 300 mm

For cable tray drawing refer annexure I (b)

LT Cable size No. Overall Dia. (mm) Total length of Tray

required (mm)

10C X 2.5 mm2 2 21 2 x 21= 42

Total: 42 mm

LT Cable size No. Overall Dia. (mm) Total length of Tray

required (mm)

3C X 300 mm2 2 80 2 x 80= 160

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SIZING OF CABLE TRAY

5.

TRAY SIZING VERIFICATION:

5.1

CABLES FROM LPG-1 S/S TO NEW PROPANE GAS COMPRESSOR

5.1.1 Cable tray from New PMCC to Field Equipment (New Propane gas Compressor)

5.1.1.1 LT Cables laid on 600mm tray are as follows:

Run Core Size - mm2 Overall Diameter (mm) Weight of Cable

-kg/km 7 3 4 15 545 X 2.45 5 4 6 16.5 740 X 1.45 1 3 70 30 1350 X 0.35 3 3 95 33 1655 X 1.05 2 3 185 45 2835 X 0.7 1 3.5 35 25 910 X 0.35 1 3.5 50 28 1125 X 0.35 TOTAL 7316

5.1.1.2 LT Cables laid on 2 NOS. 300 mm tray are as follows

Run Core Size - mm2 Overall Diameter (mm) Weight of Cable

-kg/km 2 12P 1.5 29.7 945 X 0.7 8 6P 1.5 21.6 740 X 0.78 3 10 2.5 21 665 X 1.05 4 6 2.5 15 620 X 1.13 4 3 2.5 14 435 X 1.07 1 3 4 15 545 X 0.35 2 2 2.5 12 385 X 1.25

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SIZING OF CABLE TRAY

5.1.2 Cable tray from Panel no. 19 to New Propane compressor 6.6kV HT motor

HT Cables laid on 1no. 300 mm tray are as follows:

Run Core Size - mm2 Overall Diameter (mm) Weight of Cable

-kg/km

1 3 300 80 7140 X 0.35

TOTAL 2499

5.2

CABLE TRAY FROM LPG-1 S/S TO LPG-2 S/S

5.2.1 HT Cables laid on 600 mm tray are as follows:

Run Core Size - mm2 Overall Diameter (mm) Weight of Cable

-kg/km

12 1 300 41 1840 X 3

TOTAL 5520

5.2.2 Control Cables along with HT Cables laid on 300 mm tray are as follows:

Run Core Size - mm2 Overall Diameter (mm) Weight of Cable

-kg/km

2 3 300 80 7140 X 0.5

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SIZING OF CABLE TRAY

Conclusion:

Thus the Cable tray size selection meets all the requirements of:-a) Spare Capacity (10%)

b) Allowable fill area (as per NEC table)

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