ASIR CPS EXTENSION PROJECT

PAGE

TCE CONSULTING ENGINEERS LIMITED

i30421007-3CL-00008-P0B13.8kV BUS DUCT SIZING REPORTSHEET OF iOF 4

SAUDI ELECTRICITY COMPANY

EASTERN OPERATING AREA

Dammam, Saudi Arabia

GENERATION EXPANSION OF ARAR POWER PLANT

(CONTRACT NO :30421007/00)

DESIGN BASIS

FOR

13.8kV BUS DUCTSIZING

DOCUMENT NO. : 30421007-3CL-00008-P0BMARCH 2005

ENGINEERING CONSULTANTTCE CONSULTING ENGINEERS LIMITED

73/1, ST. MARKS 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. 009661-4631150

CONTENTSCLAUSE No.DESCRIPTIONPAGE No.

1.0INTRODUCTION2

2.0OBJECT3

3.0REFERENCES4

4.0ASSUMPTIONS / CONSIDERATIONS6

5.0SIZING CALCULATION7

6.0ANNEXURES

ANNEXURE-I - GE DRAWING NO-385A3302, SHEET 4.

ANNEXURE-II - GE ELECTRICAL DATA, GENERATOR-DWG NO-385A3308, SHEET 13.

ANNEXURE-III - GE ELECTRICAL DATA, GENERATOR-DWG NO-385A3308, SHEET 1 to 15.

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.

2.0 OBJECT:2.1 The object of this report is to determine the ratings of 13.8kV Bus Duct between Generator Terminals & Generator Circuit breaker panel and from Generator Circuit breaker panel to 13.8kV side of Generator Transformer to be installed at Arar Central Power Station, Saudi Arabia.

2.2 The following parameters are established through this report for 13.8kV Bus Duct:

Continuous Current rating.

Symmetrical and Asymmetrical current ratings of the Bus Duct.

BIL and Power Frequency withstand values.

Type of Conductor and Enclosure.

3.0 REFERENCES:

3.1 Cl.No.3.03 (16), Page 40 of 336 of PTS-1022 which states that Lot 13.8kV, 2500A, 3 phase Segregated Phase Bus Duct with required Tap Off connections between Generator and Generator Circuit Breaker Panel and from Generator Circuit Breaker Panel to Generator Transformer.

3.2 Cl.No.4.03.B, Page 90 of 336 of PTS-1022 which states that The short circuit rating of 13.8kV Generator Switchgear, Generator Bus Duct and 13.8kV Cables for Unit Auxiliary Transformer shall be 40kA for 3 seconds

3.3 Cl.No.6.03.G, page 188 of 336 of PTS-1022 which states that The HV and LV terminals shall be suitable for XLPE cable connection and brought out to an air insulated cable end box. At HV side, the cable end box shall be with Phase Segregated terminal arrangement

3.4 Data Schedule for Metal Enclosed Bus Duct: 4.16kV, 13.8kV or 34.5kV, Cl.No.4.3, Page 12 of 15 of SEC-EOAs specification vide which the material of bus duct enclosure is specified as Steel.

3.5 Data Schedule for Metal Enclosed Bus Duct: 4.16kV, 13.8kV or 34.5kV, Cl.No.4.4, Page 13 of 15 of SEC-EOAs specification vide which the material of bus duct conductor is specified as Copper.

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

3.7 SEC-EOAs Clarification Set No.05 dated 28th Dec 2003, A.119 vide which SEC-EOA has informed that the gas turbine output enhancement by intake air cooling will be limited to match the maximum generator rating at 50 Deg C.

3.8 Key One Line Diagram KA-667481 Rev-P0E

3.9 GE-Electrical Data, Generator-DWG No: 385A3308. Sheet-1 to15 & DWG No-385A3302, Sheet-4.

3.10 Item No.20, Page 6 of 16 of List of deviations from SEC-EOA Scope of work and Technical specifications acceptable to SEC-EOA vide which deviation was taken that Non Segregated phase bus duct from GT to Circuit breaker would be provided and Segregated busduct would be provided from Circuit breaker to Transformers.

4.0 ASSUMPTIONS/CONSIDERATIONS:

The following assumptions are made for purpose of 13.8kV Bus Duct sizing calculations.

4.1 13.8kV side of Unit Auxiliary Transformer is specified to be connected with 13.8kV Cables as indicated under Cl.No.3.2 & Cl.No.3.3 above. In line with Key One Line Diagram Drawing No:KA-667481-Rev-P0E, the tap off point from Generator Circuit Breaker, towards unit auxiliary transformer is provided through cables and hence no bus duct tap off link is provided in the 13.8kV bus duct between the Generator Transformer and Generator circuit Breaker.

4.2 Voltage Transformers, Surge Arrestors and Surge Capacitors are proposed to be located as part of 13.8kV Generator Switchgear / GLAC. Hence, no separate tap offs are considered from 13.8kV Bus Duct towards Voltage Transformers, Surge Arrestors and Surge Capacitors.

5.0 SIZING CALCULATION :

5.1 Continuous Current rating of Main Bus Duct:

a) GT Unit Output at 50 Deg C under

site conditions

=60.160MW.

Generator continuous rated output

at 50 Deg C under site conditions

=65.2 MW.

(The Ambient Temperature 50 Deg C corresponds to a cooling water temperature of 56 Deg C as per GE Drawing No: 385A3302, Sheet no-4.

As per the curve given by GE vide drawing no: 385A3308, Sheet-13, at 56 Deg C liquid Temperature, the generator out put is 65.2MW)

(TIT may please obtain the confirmation from GE that the Generator output is 65.2MW at 50 Deg C Ambient temperature before submission of this report to SEC since we have assumed that Cooling water temperature is same as Generator liquid temperature)

c)Generator rated current at 50 Deg C

under site conditions at 13.8kV

0.8 power factor

=3409.81 Amps.

The Continuous current rating of 13.8kV Bus Duct should not be less than the Generator rated current at 50 Deg C since SEC-EOA has clarified that the gas turbine output enhancement by intake air cooling will be limited to match the maximum generator rating at 50 Deg C.

Further, as per Cl.No.4.2.1 of 24SMSS-1 Rev.2, the next standard continuous current rating of Bus Duct is 4000A.

d)Hence, the Continuous current rating of

Bus Duct at 50 Deg C

=4000 Amps.

5.2Other parameters of the 13.8kV Bus Duct are tabulated below:

Sl.No.ParameterUnit13.8kV Main Bus DuctReference

1 Type of Bus Duct from Generator Terminals to Generator Circuit breaker panel

Non Segregated Phase Bus Duct As per Cl.No.3.10 above

2 Type of Bus Duct from Generator Circuit breaker panel to 13.8kV side of Generator Transformer

Segregated Phase Bus Duct As per Cl No.3.1 above

3 Nominal Voltage rating KV13.8As per Cl.No.4.2 of 24SMSS-1 Rev .2

4 Continuous Current rating at 50 Deg C Amps4000As per Cl No.5.1 above

5 Conductor material

CopperAs per Cl No.3.5 above

6 Enclosure material

Aluminium As per Cl.No.3.6 above.

7 Basic Insulation levelkV95As per Cl.No.4.2 of 24SMSS-1 Rev .2

8 Power Frequency withstand voltage kV36As per Cl.No.4.2 of 24SMSS-1 Rev .2

9 Short circuit withstand (Symmetrical) current for 3 seckA (r.m.s)40(Min 38.70kA as per Cl No.4.9 of System Study report for Arar)

10 10Peak withstand currentkA (peak)108.10

As per Cl No.4.9 of System Study report for Arar

11Short circuit withstand (Asymmetrical) current kA 60.1As per Cl No.4.9 of System Study report for Arar

EMBED Word.Picture.8

P0B

23-03-2005MPSR

P0A

24-08-2004DGSR

REV NO . DATEPREPARED BYCHECKED BYCLEARED BYAPPROVED BY

FILENAME : 13.8kV Bus Duct Sizing for Arar dated 23.03.2005

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