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KORBA/FARAKKA 1x500 MW PROJECTADDENDUM TO ST47050

Page 1 of21. Clause 7.1.1. of ST 47050 to be read as follows:

Instruments in HPSU:Pressure transmitter is to be provided at the discharge of each CF pump and alsoin the CF header. All pressure transmitter to be 'SMART' type with HART

protocol.-All filters to be equipped with differential pressure switches along with local

indication for clogging. ,-' Suitable pressure switches and gauges to be provided in HPSU.

-Resistance temperature detector to be provided for measuring the temperature inthe tank.

C -Suitabl~ level gauges & switches to be provided on the CF tank for level

measunng.Contact rating of all the switches to be furnished.Number & type of instruments shall be subject to BHEL approval. Completeinstrument list showing range, model no. and set point of various instrumentsshall be furnished for BHEL approval.

2. Clause 7.1.2 ofST 47050 to be read as follows:Interface with BHEL's System:Signals from the instruments shall be processed in BHEL's system & commandsfrom BHEL's control system shall go for controlling the motors, fans etc in theHPSU and also the Pilot valves, Servo-valves and TSVs in the valve actuators.Supplier is to furnish the recommended operation logics for the entire systemenabling BHEL to develop suitable control schemes.For operation of LPBP and water injection control valves, BHEL shall supply J:7.5 mA / ::!:: 30 mA signal to servo-valves/ proportional valves from its DCS.

f' In case vendor system is not able to accept this signal, 4-20 mA demand signal'-- can be furnished by BHEL. In such a case suitable positioner shall be supplied by

the vendor for interfacing with servo-valve / proportional valve.Necessary software for calibration / parameterization of the positioner shall alsobe supplied.

3. Cv test requirement referred in Clause 10.0 of ST 47050 stand modified asfollows:(a) Cv test will be carried out for LP Bypass valve and test report will be

submitted for review. The Cv test can be carried out physically on the valve orthrough computer simulation.

(b) In case test report is already available which is not more than 5 years old, thesame shall also be acceptable.

(c) In case the offered valve is already in successful operation using the samevalve body, seat and trim combination as of the offered valve, the vendor mayfurnish the name of project, data sheet, cross sectional drawing of that valvefor review in lieu of the Cv test report.

4, Vendor may offer Servo-valve/ proportional valve as per their standard practice.

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KORBA/FARAKKA 1x500MW PROJECTADDENDUM TO ST47050

Page 2 of 2

5. For quick closing of stop valves,2 nos solenoid operated Poppet valves (TSV's)shall be supplied. Solenoid shall be with single / double coils as per supplierpractice. All solenoids shall be rated for 25V::t 5V.

6. Power supply requirements for all 3 phase motors shall be 415V::t10% AC.

7. Hydraulic accumulators shall be provided on the hydraulic system to ensurepositive supply of oil to hydraulic actuators even when hydraulic oil pumps arenot available. Accumulators shall be adequately sized to ensure supply for at leasttwo complete stroking operation of all connected actuators.

08. Provide oil system with 100% redundant pumps, motors, accumulators and

control cubicles.

9. Provide LP bypass valves with gland cooling arrangement, preferably using spraywater, as per manufactureI; standard practice. Further graph oil packing rings orequivalent arrangement to be provided for valve glands.

10. Provide warming up arrangement for LP bypass valves and associated piping.

11. Seat tightness of LP bypass valves shall be equivalent to block valve tightnessconfirming to MSS SP61.

12. 2x100% coolers and ensure all surface coming in contact with control fluid shallbe stainless steel. -

C 13. Control fluid purifying unit to purify at least 6 % of total fluid discharge in thesystem per hour on a continuous basis along with 2xl00% capacity AC drivenpurification pumps(for fluid circulation thru purification pumps)

14 Duplicate filters at downstream of all pumps alongwith differential pressureswitches for alarm .

15 Ensure surfaces of reservoir in contact with fluid to be stainless steel with2x 1 00% vapour extraction fans etc.

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NTPC QUALITY PLAN

MANUFACTURING QUALITY PLAN

MANUFACTURERS NAME & ADDRESS:

ITEM:____________________________________________ SUB-SYSTEM:____________________________________

QP NO.____________ REV.______________ DATE:_____________ PAGE _____OF.____

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AGENCY SL

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TYPE OF

CHECK

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REFERENCE DOCUMENT

ACCEPTANCE NORMS

FORMAT OF

RECORDS

D* M C N

REMARKS

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