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Max. Marks: 100 Time: 2:00 Hours

QUESTION PAPEER ON

POWER PLANT OPERATION

FOR EXECUTIVE TRAINEES

Q1: encircle the correct choice out of the four options infollowing questions. Each carries 2 marks.01. During boiler start-up, drum vents are closed at a drum pressure of: -

a. 0.2 kg/cm b. 2.0 kg/cmc. 10.0 kg/cm d. 20.0 kg/cm

02. Warm start-up of turbine refer to the condition when HP Cylinder innercooling temperature is: -

a. Less then 150C but greater then 100C.b. Between 150C and 335C.

c. Between 335C and 500C.d. Between 500C and 1000C.

03. Minimum air flow to be maintained during boiler start-up is: -a. Depends upon flue gas oxygen.b. 25% of the total air flow at BMCR.c. 50% of the total air flow at BMCR.d. 90% of the total air flow at BMCR.

04. During turbine shutdown or tripping, while coasting down the barring geartakes auto start at: -

a. Standstill (Zero rpm). b. 36 rpmc. 250 rpm. d. 2750 rpm.

05. During boiler start-up, which equipment is run first just after drum filling: -a. B.C.P. b. FD Fanc. ID Fan d. Air Heater

06. What is the desired drum presser for starting cold rolling of turbine:-a. 20.0 Kg/cm b. 60.0 Kg/cmc. 30.0 Kg/cm d. 100.0 Kg/cm

07. At normal operating pressure, hydrogen purity in generator casing shouldbe:-a. > 50% Hydrogen in air. b. > 90% Hydrogen in air.c. >76% Hydrogen in air. d. >98% Hydrogen in air

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08. What is a must condition before taking the first FD fan in service: -a. At least one coal mill should be in service.b. At least one oil gun should be firing.c. At least one soot blower purge air fan should be in service.d. At least one I. D. Fan should be in service.

09. Type of cooling used for G.T.at Rihand is: -a. Oil Forced Air Forced (OFAF) b. Oil Forced Water Forced (OFWF)c. Oil Natural Air Natural (ONAN) d. Oil Natural Water Forced

10. Which of the following equipment stops in auto while turbine run up frombarring speed to 3000 rpm: -a. AC Jacking oil pump. b. Air side AC Seal Oil Pump.c. AC Lub Oil Pump. d. All the above.

11. Which of the following will not cause a boiler tripping while unit is at 500MW: -

a. Loss of two coal mills. b. Loss of two ID Fans.c. Loss of two FD Fans. d. Loss of two BCPs.

12. The following can not be indicated by the Capability curve trivectormetermeter: -

a. Reactive Power b. Power Factorc. Load Angle d. Frequency

13. During turbine start-up, you are about to run AEP for condenser vacuumpulling. Which of these equipments do you expect not to be running bynow:-

a. C.E.P. b. Flame Monitor Purge air fanc. B.F.P. d. Coal Mill

14. All turbine side leg drains, chest pre-warming drains and chest drains areclosed:-

a. Soon after leg chargingb. Just after completion of vacuum pulling.c. After ensuring that HP-LP bypass is in service.d. After unit synchronization.

15. What is the immediate activity to be done on TG side after completion of legcharging:-

a. Close turbine drains.b. Put the turbine gland sealing steam system on warm-up.c. Start vacuum pulling.d. Run the second C.E.P.

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Q.2: Write the answer to these question in a few lines. Each question carry

3 marks.

1. What is the very first activity done while shutting down the boiler, when the unit is

operating at 500MW ?

2. what is the pH of boiler water ? What is done to maintain the pH value ?3. While establishing generator seal oil system, Which side ( air or gas ) is sealed first

and why?4. What is accepted as the signal of completion of warm-up of turbine gland sealing

steam system?

5. At how much unit load is 11KV Unit Bus load is transferred onto Unit Transformerwhile load raising?

6. What does G.C.M. do?

7. What is the purpose of CBD? Why CBD operation is required during boiler start-up?

8. Where do the stator cooling water actually flow to cool the stator winding?9. What is the function of hydrogen dryer? How much is the duration of its one cycle?

10. After shutting down the turbine, What is the criteria to stop barring gear safety?

Q.4: White the answer to these question in short. Each question carry 5

marks.

1. What is the significance of `Soot blower purge air fan? During boiler start-up when itis taken in service?

2. What is the function of ESP? When are ESP fields charged during boiler start-up?

3. What do you mean by drum DT?

4. What steps are taken in removing silica from boiler drum?5. What are the necessary conditions for synchronization?

6. Draw an approximated capability curve of generator. Mark the boundaries accordingto the operational limitations they impose.

7. What are the components cooled by hydrogen gas?

8. What is the function of vacuum breaker vlave?