480V Bus Duct Sizing for Arar Dated 01.03.2005

TCE CONSULTING ENGINEERS LIMITED 30421007-3CL-00009-

480V BUS DUCT SIZING REPORT

SHEET i OF i OF 4

SAUDI ELECTRICITY COMPANY EASTERN OPERATING AREA Dammam, Saudi Arabia GENERATION EXPANSION OF ARAR POWER PLANT (CONTRACT NO :30421007/00) DESIGN BASIS FOR 480V BUS DUCT SIZING DOCUMENT NO. : 30421007-3CL-00009-P0B MARCH 2005

ENGINEERING CONSULTANT TCE CONSULTING ENGINEERS LIMITED 73/1, ST. MARK’S ROAD BANGALORE 560 001 INDIA

CONTRACTOR: AL-TOUKHI COMPANY FOR INDUSTRY & TRADING P.O. BOX 497, RIYADH 11411, KINGDOM OF SAUDI ARABIA

TEL. 00966-1-4633660 : FAX. 00966–1-4631150

P0B 01.03-2005

MP

SR

P0A 24-08-2004

DG

SR

REV NO . DATE

PREPARED BY

CHECKED BY

FILENAME : 275167646.doc

CLEARED BY

APPROVED BY TCE FORM 032 R1

TCE CONSULTING ENGINEERS LIMITED 30421007-3CL-00009-

480V BUS DUCT SIZING REPORT

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CONTENTS

CLAUSE No.

DESCRIPTION

PAGE No.

1.0

INTRODUCTION

2

2.0

OBJECT

3

3.0

REFERENCES

4

4.0

ASSUMPTIONS / CONSIDERATIONS

5

5.0

SIZING CALCULATION

6

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480V BUS DUCT SIZING REPORT

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1.0

INTRODUCTION:

1.1

Al-Toukhi company for Industry & Trading has been awarded turnkey contract for Open Cycle Gas Turbine based CPS extension project at Arar of Saudi Electric Company-Eastern Operation Area (SEC-EOA), Saudi Arabia.

1.2

The project consists of design, engineering, procurement, installation, testing and commissioning of two (2) Nos. 60.16MW @ 50C, PG7121 (EA) model Gas Turbine Generator unit of GE make along with associated Generator Transformer and other balance of plant electro-mechanical equipment.

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480V BUS DUCT SIZING REPORT

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2.0

OBJECT:

2.1

The object of this report is to determine the ratings of 480V Bus Duct from secondary of 4.16kV/480V Station Auxiliary Transformer to 480V Station Switchgear to be installed at Arar Central Power Station, Saudi Arabia.

2.2

The following parameters are established through this report: 

Continuous Current rating.



Short circuit withstand and peak withstand current ratings of the Bus Duct. Type of Conductor and Enclosure.



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480V BUS DUCT SIZING REPORT

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3.0

REFERENCES:

3.1

Cl.No.3.03 .8 (a), Page 39 of 336 of PTS-1022 which states that “Two (2) nos. 480V, 3 ph, 4 wire, 3500A, Non Segregated Phase Bus Duct runs connecting LV Auxiliary Transformers #T-201 & T202 to the new 480V Station Switchgear”.

3.2

Cl.No.2.0, page 1 of 4 of Data Schedule for “Metal Enclosed Bus Duct 480V” vide which the Short time current withstand capability is defined as 50kA for 1 sec.

3.3

Cl.No.2.0, page 1 of 4 of Data Schedule for “Metal Enclosed Bus Duct 480V” vide which the Continuous current rating at site conditions is specified as 3500A.

3.4

Cl.No.3.0, Page 2 of 4 of Data Schedule for “Metal Enclosed Bus Duct: 480V” of SEC-EOA’s specification vide which the material of bus duct enclosure is specified as Steel.

3.5

Cl.No.3.0, Page 2 of 4 of Data Schedule for “Metal Enclosed Bus Duct: 480V” of SEC-EOA’s specification vide which the material of bus duct conductor is specified as Copper.

3.6

SEC-EOA’s Clarification Set No.04 dated 10 th Dec 2003, A.53 vide which SEC-EOA has informed that Aluminium enclosure also is acceptable for Bus Duct.

3.7

Document No.30421007-3CL-00001-P0E: Unit Auxiliary & Station Auxiliary Transformer sizing report.

3.8

Key One Line Diagram KA-667481-Rev-P0E

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4.0

480V BUS DUCT SIZING REPORT

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ASSUMPTIONS/CONSIDERATIONS: The following assumptions are made for purpose of 480V Bus Duct sizing calculations.

4.1

The 4.16kV/480V Station Auxiliary Transformer rating is considered as 3000kVA as per Document No.30421007-3CL-00001-P0E: Unit Auxiliary & station auxiliary Transformer Sizing report.

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480V BUS DUCT SIZING REPORT

5.0

SIZING CALCULATION :

5.1

Continuous Current rating of 480V Bus Duct:

5.2

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a) 4.16kV/480V Station Auxiliary Transformer rating =

3000kVA.

b) Rated secondary current of 4.16kV/480V Station Auxiliary Transformer =

3609 Amps.

c) Hence, the continuous current rating of Bus Duct selected at 50 Deg C & site conditions =

4000 Amps.

Other parameters of the 480V Non Segregated Phase Bus Duct are tabulated below:

Sl.No. Parameter 1

Type of Bus Duct

2

Nominal Voltage rating

3

Continuous Current rating at 50 Deg C

4

Conductor material

5

Enclosure material

6

Short circuit withstand (Symmetrical) current for 1 sec

Unit

kV

Amps

kA (r.m.s)

480V Bus Reference Duct Non As per Cl No.3.1 Segregated, above 3 phase, 4 wire Bus Duct As per Cl.No.2.0 of SEC-EOA’s 0.480 data schedule for 480V Bus Duct As per Cl No.5.1 4000 above As per Cl No.3.5 Copper above As per Cl.No.3.6 Aluminium above 65 As per Cl.No3.8 (45.7kA as above and as per per System Cl.No.4.12 of Study report for System study Arar report for Arar) ISSUE P0B

TCE CONSULTING ENGINEERS LIMITED 30421007-3CL-00009-

480V BUS DUCT SIZING REPORT

Sl.No. Parameter

7

Peak withstand current

Unit

kA (peak)

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480V Bus Duct

Reference

137 (113.6kA as per Cl.No.4.12 of System study report for Arar)

As per System Study report for Arar

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