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Control Room B Test > Turbine/ Generator > Flashcards

Turbine/ Generator Flashcards

1
Q
  1. What are the eccentricity requirements before rolling the turbine?
A

Less than 3 mills

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2
Q
  1. What oil pumps should be in service before rolling the turbine?
A

SOB, BOP, EH pump, Air side seal oil pump, Hydrogen side oil pump, bearing lift pumps on H3.

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3
Q
  1. What sources supply Auto stop oil?
A

SOB below rated speed

Main shaft at 2/3 rated speed

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4
Q
  1. What are the minimum degrees superheat that you can have to roll the turbine?
A

100 degrees superheat

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5
Q
  1. What steam conditions are required for a cold start?
A

Must have 100 deg superheat, total steam temp less than 800 deg to limit stress applied during rotor heating

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6
Q
  1. What temperatures determine a cold start? Hot start?
A

Cold start: either the first stage metal temp or the IP blade ring temp is below 250 deg F
Hot start: both the first stage metal temp and the IP blade ring temp is above 250 deg F

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7
Q
  1. Name the turbine-generator trip relays? Where are they located?
A

Reverse power

2) Generator backup
3) Generator differential
4) Generator ground
5) Loss of excitation
6) Overexcitation
7) Negative sequence
8) Main power transformer differential
9) 6900 NS transformer fault pressure
10) 6900 NS transformer differential
11) 6900 NS ground
12) 4160 NS transformer fault pressure
13) 4160 NS transformer differential
14) 4160 NS transformer ground
15) Substation trip FK05
16) Under frequency

Located in the relay rooms for each unit, can also be seen on generator master page

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8
Q
  1. What are the transfer speeds for Unit #1 #2 and Unit #3?
A

H1 and H2 – 3425 RPM

H3 – 3500 RPM

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9
Q
  1. What temperature requirements have to be met before transferring from Throttle valve control to Governor valve control? Why?
A

Deep well temperatures left and right must be greater than or equal to saturation temperature at existing throttle pressure. This is to prevent water induction.

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10
Q
  1. What are the rotor stress limits?
A

+/- 75 degrees F

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11
Q
  1. What conditions require a Turbine heat soak?
A

If either first stage metal temp or IP blade ring temp is below 250 deg

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12
Q
  1. What is the purpose of a Rotor Warming Hold period during a cold start?
A

To evenly warm the rotor to a point where the first stage metal temp and the IP blade ring temp is above 250 deg F

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13
Q
  1. What is heat soak speed on Unit #1 ,#2 and Unit #3?
A

H1 and H2- 2170

H3- 2175

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14
Q
  1. Explain how to put the steam seals in service. When would you put them in service and what steam pressure and temperature do you need to put them in service?
A

Select “turbine aux.” page, start the gland steam condenser exhauster.
Open the HP and LP steam seal supply valves, use the HP steam seal bypass if necessary, to help achieve 3 psig.

Ensure 250 – 350 lbs throttle pressure and 25 degrees superheat before putting steam seals into service.

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15
Q
  1. Explain the following: Field breaker, , Voltage regulator test and on position and voltage adjuster.
A

Field Breaker - connects the PMG to the voltage regulator.
Voltage regulator test - in the “test” position the voltage adjuster is used to zero buck and boost for a bump less transfer.
Voltage regulator on – in the “on” position is used to control machine voltage. Voltage adjuster – with the voltage regulator in the “on” position, the voltage adjuster is used to adjust system voltage.

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16
Q
  1. Explain the following: MEL, KFL, OXP and MXL.
A

MEL-minimum excitation limiter-clamps voltage regulator which keeps voltage from going lower than a predetermined KVA
KFL-loss of field relay-trips the unit on loss of excitation maintained by system operations department, looks at generator output and trips unit above the steady state stability curve
OXP-over excitation protection- if excitation continues to increase, at 110% of rated rotor current OXP protective relay begins timing and will time out in 23 seconds at 110% rated generator current and trips the voltage regulator to base adjuster control, if excitation has not returned to normal level in 3 seconds after it times out it will trip the generator
MXL-maximum excitation limiter-prevents generator from overexciting by clamping the voltage regulator, it comes in before the OXP

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17
Q
  1. Explain the operation of the auto synchronizer.
A

The auto synchronizer will engage at 3602rpm, once engaged the voltage will auto adjust to match the incoming and running voltages. When the scope reaches midnight it will close in the generator breaker and the unit will be online. The generator breaker will then need to be red flagged

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18
Q
  1. What is the purpose of the synchroscope?
A

It allows operator to see when generator frequency is matched to system frequency

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19
Q
  1. When looking at the synchroscope, what does incoming and running mean?
A

Incoming – is the voltage the generator is putting out

Running – is the voltage from the system

20
Q
  1. What is the reason for matching voltages when synchronizing the Generator breaker?
A

To ensure a bump less transfer, ensure all 3 phases are in sync, and, prevent excessive VAR flow

21
Q
  1. What effect does generator speed have on the synchroscope?
A

The generator speed affects frequency. If generator frequency is higher than the system, then the synchroscope rotates clockwise.
If generator frequency is lower than the system, the synchroscope rotates counter-clockwise. The bigger the gap in frequencies the faster the synchroscope turns.

22
Q
  1. What is the reason for a syncro accepter?
A

Ensures that generator freq & system freq are matched so that you do not sync out of phase

23
Q
  1. Explain the operation of putting the generator on line after recalling 3602.
A

Notify marketers that we will be coming online shortly

  1. Generator Master Page Close in field breaker and ensure you see a “NAC”
  2. Close in VR control switch
  3. Observe generator voltage increases to approximately 24KV (do not let voltage exceed 25KV. Open field breaker if voltage increases past 25KV)
  4. Increase voltage with the voltage adjuster to 24KV if needed
  5. Place voltage regulator mode control switch to “auto” once the “Ready to
  6. Transfer” light is backlight
  7. Unlock generator breaker
  8. Place the synchro scope for the generator breaker in the “auto” position
    The controller will RAISE or LOWER the exciter voltage to bring the Generator voltage to that of the system (The Generator voltage must be within +/- 0.5% of the system voltage in order for the auto synchronization relay to operate. It will also increase or decrease the speed for frequency matching)
  9. The Generator breaker should close automatically if the above conditions are met.
  10. Red flag the Generator Breaker control switch
  11. Generator will now be online
  12. Verify a minimum of 5-10mw
  13. When the Generator breaker closes, the Turbine Master will automatically reject to manual to align its output to coincide with valve position rather than turbine speed
  14. Adjust and maintain the unit VARS at zero with the voltage regulator until the unit is at approximately 150 MW
24
Q
  1. After coming online, what is the best way to control rotor stress?
A

Monitoring steam pressure and temperature, ensure rotor stress does not exceed +75° or -75° by opening and closing governor valves

25
Q

Explain throttle pressure.

A

A measurement of steam pressure at the throttle valves

26
Q
  1. Explain MW control operation
A

The boiler master, turbine master and fuel/ air are in auto, governor valves modulate to control MW set point

27
Q
  1. Explain swapping from the FW/Drum pressure control to #3 feed water inlet.
A

At 30 to 50 MW’s with 800 to 1000 lbs. of pressure, ensure that the piddle valve and SUBFP are in auto, open #3 heater inlet and observe that the piddle valve closes and suspends to auto

28
Q
  1. Explain changing load and rate in operator auto.
A

In operator auto-fuel, air, turbine master, boiler master, and water must all be in auto.
Go to the LMCC page and click the HOLD button.
Click on the MW target button and type in your change, and then press enter.
Click on your MW/min button and type in the rate of change, then hit enter, Then hit GO

29
Q
  1. Explain how the turbine is controlled in turbine manual mode.
A

The turbine master control station can be put in manual and the up and down arrows can be used to control the governor valves/throttle valves

30
Q
  1. What valves are controlled when in turbine manual?
A

In speed control the throttle valves will control until transfer speed and in load control the governor valves will control

31
Q
  1. How do you get back to operator auto mode from turbine manual?
A

Fuel and air, boiler master and turbine master all in auto

32
Q
  1. Describe the procedure for going to boiler follow.
A

Take turbine master to manual

33
Q
  1. What is OPC and how does it work?
A

Over speed Protection Controller – prevents turbine over speed so that turbine trip is avoided. Above 103% rated speed, the OPC will close the governor and intercept valves. The intercept valves are modulated by speed to remove trapped steam in the reheater. The governor valves stay closed until the speed has been reduced to synchronous speed.

34
Q
  1. What conditions should be met to run an over speed test?
A
35
Q
  1. What are the turbine runbacks?
A

Low drum level, loss of main or startup boiler feed pump, loss of set of fans

36
Q
  1. Explain what conditions must be met to run a governor and throttle valve test. How do you run this test?
A
  1. Run tests at low load (160-200 MW)
  2. Place Boiler Master in Manual
  3. Place in Single Valve Mode
  4. Throttle pressure between 1700-1800 PSI

RUN TEST
1. Go to LMCC page and select TV/GV overlay
2. Select Left or Right side. Governor valves will close then Throttle Valves will close then reopen then the governor valves will
Reopen. (Test can be aborted at any time by pressing Abort Test)
3. Repeat steps for other side
4. When tests are complete place Boiler & Turbine Masters back in Auto

37
Q
  1. What would you do if the load started varying while running the T.V. and G.V. test?
A

Abort test immediately

38
Q
  1. Explain how to run the reheat stop and intercept valve test.
A

Run test at low loads (160 - 200 MW).
2 Single valve mode.
3 Throttle pressure (1700 - 1800 psi).
4 Boiler master in manual.

Test procedure:

  1. Go to LMCC screen and select RV/IV overlay
  2. Select Left or Right side and press button. Intercept valve closes then reheat valve closes then reheat valve opens then intercept valve opens (Tests can be aborted at any time by depressing the abort button)
  3. Repeat steps for other side
  4. When test is complete place Boiler & Turbine Masters in auto
39
Q
  1. When running the reheat stop and intercept valve test, which valve closes first and opens first?
A

Intercept closes first

Reheat Stop opens first

40
Q
  1. Explain Boiler follow mode?
A

The turbine master is in manual and the boiler master in auto, the boiler will automatically makes adjustments when you make adjustments to the turbine controls.

41
Q
  1. Explain Turbine follow mode?
A

With the boiler master in manual, fuel, air and turbine master in auto. The turbine follows boiler changes to maintain throttle pressure

42
Q
  1. What will happen to the boiler controls if you get a 1st stage pressure transmitter differential alarm?
A

Boiler master, fuel and air all trip to manual

43
Q
  1. How can an operator request turbine follow mode?
A

Place the boiler master in manual.

44
Q
  1. What will happen to the combustion controls if you get a throttle pressure transmitter differential alarm?
A

Fuel and air controls will trip to manual.

45
Q
  1. How far will the turbine run back if you lose a set of fans on the boiler?
A

210 MW

46
Q
  1. In the event of a turbine/boiler trip, what are approximately 5 things that you would need to take care of quickly?
A
  1. Drum level.
  2. Purge Boiler.
  3. Swap to start up station power.
  4. Ensure SOB and BOP are running.
  5. Ensure field breaker has tripped.
  6. Ensure generator breaker has tripped and is locked out.
  7. Establish purge on BCP’s.
  8. Clean out coal mills using deluge system.
47
Q
  1. On a normal shut down, explain the procedure for taking the generator offline.
A

Reduce load to (30 MW).

  1. Ensure voltage regulator is in the “on “position.
  2. Zero vars.
  3. Manually drive control valves closed with turbine master control station.
  4. Ensure MW’s go to zero.
  5. At the end of 10 seconds all throttle, reheat, and governor valves should trip closed. If not raise valve position back up and reestablish load (determine why valves did not close).
  6. Unit should trip on one of the reverse power relays. (The reverse power relays are there to assure that there is no steam flow through the turbine before opening the generator breaker).
  7. If after 2 to 5 minutes the unit does not trip on reverse power, the turbine should be raised back up to minimum load until problem is detected. (Generator should not be tripped until it is determined there is no power flow from the generator).
  8. The only time that the generator breaker should open first is on an electrical fault, or manually in an under-frequency situation where the reverse power relays cannot operate after the turbine has been tripped.
  9. Never open the generator breaker by hand unless it’s an emergency and the unit is going to be damaged

Control Room B Test (12 decks)

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