Tit Sec(Eoa) Arar e d Gtsizing A

SPEC. NO.SECTION

PAGE

TCE CONSULTING ENGINEERS LIMITED

iTITSEC(EOA)ARAR-ED001DESIGN BASIS FOR GENERATOR TRANSFORMERSHEET OF iOF 4

SAUDI ELECTRICITY COMPANY

EASTERN OPERATING AREA

Riyadh, Saudi Arabia

GENERATION EXTENSION OF ARAR POWER PLANT

(CONTRACT NO :30421007/00)

DESIGN BASIS

FOR

GENERATOR TRANSFORMER

DOCUMENT NO. : TITSEC (EOA)ARAR-ED001, REV. A

JUNE, 2004

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.

1.0INTRODUCTION1

2.0OBJECT2

3.0SIZING3

4.0CONCLUSIONS6

ANNEXURE 1GTG GUARANTEED OUTPUT1

ANNEXURE 2SEC-EOAs CLARIFICATION No.05 DATED 28th DECEMBER 20033

ANNEXURE-3GENERATOR CAPABILITY CURVES.3

ANNEXURE-4GENERATOR TECHNICAL DATA SCHEDULE1

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 scope of this document is the sizing of the GeneratorTransformer for proposed Gas Turbine Unit#7 and Unit#8 to be installed at Arar Central Power Station, Saudi Arabia.

2.2 Reference Documents:

Gas Turbine Guaranteed Output enclosed as Annexure1

SEC-EOAs clarification vide A.114 & A.119 of Clarification No.05 dated 28th December 2003 on sizing of Generator Transformer enclosed as Annexure2

Generator Capability Curves enclosed as Annexure3

Generator Technical Data Schedule (page-1) submitted as part of proposal document under Section 4.3.2: Technical Data Schedules (TD-6) enclosed as Annexure-4

CL.No.9.01 (3) of SEC-EOAs specification for Generation expansion of Arar Power Plant, PTS-1022 (page 336 of 336).

SEC-EOAs specification requirements for Generator Transformer defined under Cl.No.3.03 (1), page 37 of 336 of PTS-1022.

SEC-EOAs site conditions specified under Cl.No.4.01, page 70 of 336 of PTS-1022.

SEC-EOAs Amendment No.--- dated ------ regarding Maximum Site Ambient Temperature.

( Al-Toukhi may please enter the Amendment No. and date above as the same is not available with TCE )

IEC 60076 (Latest Edition)

IEC-60354 (Latest Edition)

3.0 SIZING

INPUT DATA

3.1 Generator Parameters:

Guaranteed Average Unit Gross Power Output at 50 Deg C site ambient temperature

(Refer Annexure-1)60160 kW, under site conditions.

Generator Maximum Continuous Output at 15 Deg C site ambient temperature

(Refer Annexure-4)81920 kW

(Al-Toukhi to get this confirmed from GE before submitting the calculations to SEC-EOA)

Generator Maximum Continuous Output at 50 Deg C site ambient temperature corresponding to a Generator liquid temperature of 54 Deg C

(as per Generator Capability curve: Generator output as function of Liquid Temperature attached as Annexure-3)64500kW

Rated Voltage13.8kV

Rated Frequency60 Hz

Power Factor0.8

Generator Capability CurvesSee Annexure3

3.2 Generator Transformer Parameters:

(as defined under Cl.No.3.03 of PTS-1022 (page 37 of 336) for Main Offer)

Rated MVA (for Main offer)40/50MVA

Type of CoolingONAN/ONAF

Rated Voltage13.8/132kV


Power Factor0.8

Impedance 14% on 40MVA base

Tap Changer type and rangeOn Load Tap Changer with +/-10% range with RTCC and without AVR

3.3 132 kV Network main characteristics

Rated Voltage132 kV

Rated Maximum System voltage145kV


Rated short time withstand current

(refer to Dwg no.KT-808215 issued alongwith SEC-EOAs Bid document)40 kA rms for 1 sec

3.4 Site Conditions for Guaranteed Gross Output in kW: (Refer Annexure1)

Maximum Ambient Temperature

(Refer Cl.No.4.01.1 of PRS-1022)50(C

Minimum Ambient Temperature-5(C

Relative Humidity100%

Altitude600 meters above sea level

NOTE: Al-Toukhi to confirm the Maximum and Minimum site ambient temperatures since the specification received by us indicate the Maximum Site ambient as 55 Deg C and Minimum Site ambient as 5 Deg C.

3.5 Sizing of the Generator Transformer

As per SEC-EOAs specification requirement (refer Section 4.3.1.2), the Generator Transformer must be sized to cater to the following conditions:

3.5.1As per Cl.No.9.01 (3) (page 336 of 336) of SEC-EOAs specification PTS-1022, the Generator Transformer MVA rating shall be decided by the Bidder on the basis of following criteria.

i) Generator Maximum Continuous Rating.

ii) Unit Capacity addition due to installation of air intake cooling system in future. The air intake cooling system will be operative in summer.

iii) Load power factor within the boundary of Generators Reactive Capability.

3.5.2SEC-EOA clarified vide A.114 (page 5 of 11), Clarification No.05 dated 28th December 2003 that the inlet cooling system requirement is limited to the provision in the inlet air ducting and it has no impact on the sizing of the Generator Transformer, 132kV Cables etc.

3.5.3Further, SEC-EOA clarified vide A.119 (page 8 of 11), Clarification No.05 dated 28th December 2003 that, in future, the Gas Turbine Power output enhancement by intake air cooling will be limited to match with the maximum Generator rating at 50 Deg C. Therefore, there is no need to consider any reserve capacity to be in built into the sizing of Generator and downstream electrical equipment.

3.6Sizing Criteria & Calculation

3.6.1At site conditions, the Generator Transformer must be capable of evacuating the Gross Power output of the Gas Turbine Generator at reference ambient temperature.

As mentioned in Cl.No. 3.1 above,

The guaranteed Gross Power output of GTG Unit=60.16MW

at 50(C under site conditions.

3.6.2The Generator Transformer shall match with the Maximum Continuous Rating of Generator at 50 Deg C maximum site ambient conditions.

As mentioned in Cl.3.1 above,

The Maximum Continuous Rating of

=64.50MW

Generator at 50 Deg C site ambient conditions.

=80.625MVA

at 0.8 P.F

3.6.3The ONAF rating of the Generator Transformer is matched with the Maximum Continuous Rating of Generator at ambient temperature of 50(C since as per IEC 76-2, part-2, Clause 3, page 9 of IEC76-2, the Power figure for the alternative with the highest cooling capacity is the rated power of the transformer.

Rating of Generator Transformer

=81MVA

at 50 Deg C site maximum ambient conditions

and at ONAF cooling.

3.6.4The ONAN rating of the Generator Transformer is selected to be 80% of ONAF rating of Transformer. This rating has been considered based on Cl.No.3.03 (1) of PTS-1022 (page 37 of 336) wherein the Generator Transformer rating was specified as 40/50MVA for ONAN/ONAF conditions.

Rating of Generator Transformer

=80% of 81MVA

at 50 Deg C site maximum ambient conditions

and at ONAN cooling.

=64.8MVA

3.6.5 As per Table-1 of IEC-60076 part-5, the minimum value of Impedance for Transformers with two separate windings having a rated power of 63.001MVA to 100MVA shall be 12.5%.

Impedance of Generator Transformer

=12.5%.

selected at 65MVA base.

3.6.6The On Load Tap Range of +15% to -10% is selected to ensure operation of Generator Transformer within the boundary of Generator reactive capability (refer to Reactive Capability curve of Generator attached as Annexure-3)

4.0 CONCLUSION

Summarising the above, the sizing of the Generator Transformer results in the data listed below.

Rated Power (ONAN/ONAF)65/81 MVA.

Ref. Temperature50C Maximum Ambient at site conditions.

No load Voltage Ratio (HV/MV)132/13.8 kV, (with On Load Tap Changer of +15% to - 10% in steps of 1.25% on 132kV winding.)


CoolingONAN / ONAF

Vector Group SymbolYNd11

Impedance voltage at principal tap (at 65MVA base rating, at ref. Temperature of 75(C)12.5%

The above rating as obtained in Section 3.0 is considered adequate & the following specific confirmations will be obtained from the GeneratorTransformer supplier:

i)The ratings indicated above are the final ratings as required at site conditions at 50 Deg C Maximum ambient temperature.

ii)The Generator Transformer supplier shall consider the necessary correction factors as per IEC to take into account the effect of altitude, ambient pressure, relative humidity and ambient temperature while designing the transformer.

iv) The Generator Transformer supplier shall confirm that the Transformer capability curve will be always equal to or greater than the Gas Turbine Generator capability curve for the entire range of operating ambient temperature.

v) The temperature rises shall be in accordance with IEC-60076 duly considering the Site conditions specified under Cl.No.4.01.1 (page 70 of 336) of PTS-1022.

EMBED Word.Picture.8

A 28-06-2004GLSJHSRSJH

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FILENAME : TIT-SEC(EOA)-ARAR-E-D-GTSIZING-A

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