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POWER PLANT OPERATION- OBJECTIVE TEST

Time: 1Hr.Total Marks: 50

Instructions :

1) Answer all questions in attached answer sheet only2) Do not write anything on question paper. Please return the question paper before you leave

examination hall.

PART IMultiple Choice (marks 1.5x10)

1. For medium volatile Bituminous coal required fineness is-a) 60% pass through 200 mesh

b) 80% pass through 200 meshc) 70% pass through 200 mesh

d) 90% pass through 200 mesh

2. A boiler is purged in order to-a) Warm up the gas passes

b) Cool down the gas passes

c) Remove deposits from metal surfaces as they coold) Remove combustible gases and dust from the boiler

3. For generator synchronization, sequence of operation is-a) Main breaker on - Voltage develops - Field breaker on - synchroscope on - Turbine speed 3000

rpm.

b) Turbine speed 3000 rpm - Field breaker on - Voltage develops - Synchroscope on - Main breakeron.

c) Turbine speed 3000 rpm - Synchroscope on - Main breaker on - Field breaker on - Main breaker on- Voltage develops.

d) Voltage develops - Turbine speed 3000 rpm - Field breaker on - Main breaker on - Synchroscopeon.

4. One of the functions of HP bypass system is to control-a) Main steam temperature before ESV

b) Hot reheat steam pressure before IV

c) Main steam pressure as per the set pointd) Hot reheat steam temperature.

5. dn/dt protection provided in KWU governing system operates when-

a) Turbine acceleration (dn/dt) falls below 108 rpm/min. due to inadequate TSE margins during raisingof speed from 600 to 3000 rpm

a) Turbine is overspeeded by 10%

b) Reverse power protection is operated

c) None of the above

6. Critical speed of turbine shaft is the-a) Speed at which overspeed protection operatesb) Normal running speedc) Speed at which natural frequency of rotor matches which causes heavy bearing vibrationsd) Speed which is caused by uneven heating

7. During turbine start-up, following control is used-

a) Load control

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b) Pressure control

c) Speed controld) Any of the above

8. To start vacuum pulling of the turbine which one of the following conditions should be fulfilled-

a) One circulating water pump in serviceb) One boiler feed pump in service

c) One circulating water pump and one condensate extraction pump is in service

d) Starting oil pump in service

9. Fuel Air dampers open in proportion to-

a) Furnace windbox differential pressure

b) Fuel flow in particular elevationc) Fuel flow to boiler in total

d) FD discharge pressure

10. What would be the first action to relight up the boiler when flame failure occurs in the furnace-a) Igniters should be switched on immediately

b) Oil burners should be put into arrest drop in steam pressurec) Coal fire should be established so that steam temperature may not drop

d) The furnace should be purged before restarting the fire.

PART-IIWrite True or False (marks 1.5x10)

1. Boiler trips on reheater protection when turbine trips & HP bypass valves do not open

2. When X6 criterion is fulfilled, generator can be synchronized

3. Low capacity PRDS is in service during plant operation at lower loads (less than 50% load)

4. Before charging & warming of steam lines drain valves should be opened

5. Generator with static excitation trips on 1st rotor earth fault

6. Field barker can be closed only when TG speed is 3000 rpm

7. EBD valve opens automatically when drum level is high

8. One of the permissive of BFP is Discharge valve closed

9. If reheat temperature falls, burners are tilted downward

10. Before condenser vacuum pulling operation, turbine should be running on barring gear

PART IIIFill in the blanks (marks 1x10)

1. Temperature of coal air mixture at outlet of mill is maintained at ________ Deg. C.

2. SH outlet pressure at rated load will be around ________ kg/sq.cm. and temperature ______ Deg. C.

3. Turbine hot start procedure is followed if turbine metal temperature is greater than _____ Deg.C.

4. __________ is the chemical used for removal of oxygen in feed water.

5. When HP heater level goes very high, heaters are _________ from _______ & _________side

6. Oxygen content in flue gas at rated load should be between _______ to ______%.

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7. During cold start-up, KWU turbine soaking is performed at _______ & ______rpm

8. Air ingress in condenser will cause __________in temperature of condensate

9. The available NPSH at the installation of a pump is less than required NPSH, then ___________takesplace

10. Turbine trip is reset by bringing ______________ to 0% position.

PART IV

Match the Pairs (marks 1x10)

1 HP Bypass station A High DM make-up consumption

2 Purging permissive B 210 MW GT type of cooling

3 Main steam temperature high C HFO/LO Trip valve closed

4 Drum metal temperature < 100 deg. C D Turbine load above 20MW

5 Drum level very high E High excess air

6 OFWF F Single pair of oil guns in service

7 Load control active G Boiler & Turbine trip

8 Deaerator level very low H Build up of suitable MS parameters while plant start-up

9 Boiler tube failure I Turbine load above 100MW

10 HP heaters are cut-in J BFP trip

POWER PLANT OPERATION- SUBJECTIVE TEST

Time: 1Hr.Total Marks : 50

Note: i) Question one is compulsoryii)solve any two questions from rest of the questions

Q1) Explain Why? (short answers) 30

a) Boiler light-up can not be performed without purging operation

b) SCAPH should be charged during cold light-up

c) Fire is killed of during IBD blow down

d) Hp bypass pr. Set point is kept higher than MS pr. During normal operation of turbine

e) HP-LP bypass capacity is restricted to 60%

f) PRDS has low capacity & high capacity lines

g) H2 purity should be more than 98%

h) Generator frequency should be slightly higher than grid frequency while synchronization

i) Reverse power protection is basically for turbine protection

j) Recirculation valve open is the permissive for BFP start-up

Q2) List out with significance 3 protections of boiler & 3 protections of turbine. (10 each)

Q3) List out various purge permissives.

Q4) Write stepwise procedure of boiler light-up.

Q5) Write stepwise cold rolling of turbine to rated speed.

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Q6) Explain in brief manual synchronization procedure for generator

POWER PLANT OPERATION APPRAISAL- OBJECTIVE TEST

Roll No. Name ______________________ Marks Obtained

I) Multiple Choice (marks 1.5x10)

a b c d a b c d1 6

2. 7

3 8

4. 9

5 10

II) True or False III) Fill in the blanks (marks 1x10)

( marks 1.5x10)

T F

1

2

3

4

5

6 7

8

9

10

IV) Match the Pairs (marks 1x10)

A B C D E F G H I J

1

2

3

1 ---------------75-77---------------------------------

2 -----------------150---------------------------540---

3 ---------------------350-------------------------------

4 ------------------HYDRAZINE-----------------------

5 -----------------5-----------10-------------------------

6 -----------------3.5----------4-------------------------

7 -----------------600-----------3000------------------

8 ---------------INCREASE IN TEMP.--------------

9 -----------------CAVITATION-----------------------

10 -----------------SLLD----------------------------------

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4

5

6

7

8

9

10