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As a PCO, list your top 3 priorities in day to day operation of the Unit?
Safety of plant personnel, environmental compliance, asset protection.
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Purpose of economizer recirculation valves and
when are they used?
They are used during low FW flow conditions (startup or shutdown)
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What position should the Turbine Oil Pump controls be in
prior to startup?
All pumps should be in Auto-start position. the oil pump key switch should be in the Normal position.
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What should turbine oil temp be on TG? How is temp increased?
90-100 deg F. Run the Auxiliary oil pump
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What is the purpose of the IDF and FDF HEA
relays?
Arms the trip scheme on the fans. Loss of either FDF or IDF will trip corresponding FDF or IDF.
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Why blow APH soot blowers during startup?
To remove any oil residue from APH baskets when firing igniters.
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We fire to maintain 950 deg f on gas entering the superheater
during startup.
Why?
During startup there is very little flow through the Superheater, and no flow through the Reheater. Limiting the gas temperature will protect the tubes.
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What is steady state eccentricity? How is it determined?
Eccentricity that has remained at a normal value for at least an hour. You can use 01S to determine what the normal value has been in the past.
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If there is a field on the generators (turning gear) and the
shaft stops, what should be a PCOs first action?
Open the field breakers.
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The turbine has been rolled and trips before being tied to the line will the field breakers trip?
No because the field breaker sequential trip will not be armed until the unit is tied to the line. (The operator will have to open the field breakers)
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Once turbine has been rolled, what should be the turbine oil temperature setpoint and why?
115 deg F. This will ensure that the cooling water valve will close, allowing the turbine oil temperature to increase as turbine speed increases
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What should the minimum turbine oil temperature be before exceeding 3000 rpms?
100 deg F
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Why monitor turbine drain temperatures during startup?
To ensure the drains are open and you have flow through them
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Describe process for tieing generators to the system. (GCBs, MOD, ACC, Frequency,and Voltage)
Receive instructions from ACC to open GCBs, close MOD, match generator frequency and voltage to system frequency and voltage, close GCBs.
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When can voltage regulators be placed in automatic during
startup?
After manual voltage adjusters have brought the voltage up to a point that the automatic voltage adjusters are in range.
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Why roll the turbines in full arc admission? When and how is the transfer made to partial arc?
In order to evenly heat the nozzle block. Around 20 MW close control valves until mw load start to decrease. Open stop valve bypass wide open which will allow main stop valves to open.
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Describe the process of swapping station service from SSS to
RSS.
Unit must be stable. Sync the A 4160v RSS breaker, close the A 4160v RSS breaker, at this time the A 4160v SSS breaker will open. Clear the amber light,Turn sync switch off. Then follow this same sequence for B 4160v bus, and both A & B 600v busses.
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What are the limiting factors in increasing load and drum
pressure?
Temperatures and water chemistry limitations.
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What equipment should be checked before beginning the
shutdown process?
All three turbine oil pumps and both turning gear motors.
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Which sootblowers should be blown during the shutdown
process?
Blow all retracts that are in service, multiple times if necessary.
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Describe the process for swapping station service from RSS to
SSS?
Unit must be stable. Sync the A 4160v SSS breaker, close the A 4160v SSS breaker, at this time the A 4160v RSS breaker will open. Clear the amber light, Turn sync switch off. Then follow this same sequence for B 4160v bus, and both A & B 600v busses.
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What are hot and cold drop outs and when would each be used?
- Hot drop out - closing the SSS breakers with the RSS breakers closed, this would be used when the unit is still tied to the line.
- Cold drop out - opening the RSS breakers before closing the SSS breakers, this would be used when the unit is not tied to the line.
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Describe the process for taking the unit offline?
Run mw load to zero by closing control valves, trip turbine, and reverse power relay will operate and open the GCBs.
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Describe the operation of the reverse power relay.
?
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Describe the actions taken for cooling the drum and boiler.
Increase air flow as much as possible while still maintaining opacity within limits.Fill drum to + 15 inches (transmitter high range). Then drop surge tank level 10 inches.
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When cooling the boiler when should air preheaters be taken
off?
When the boiler outlet gas reaches 300 deg F.
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What are some of the effects of a boiler tube leak?
Decreased drum level, increased FW flow, increased makeup flow, and temperature splits across the boiler.
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Describe pco actions in the event of a FDF or IDF trip
Trip the fire. Reduce load to 5-10 megawatts. Purge the furnace and establish the fire. Increase load to the limit of one set of fans. Troubleshoot fan trip.
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Describe pco actions in the event of an air preheater trip?
?
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Describe pco actions in the event of a high or low drum level.
?
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Describe pco actions in the event of a BFP trip.
?
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Describe pco actions in the event of a pulverizer fire.
Close hot air damper, which will allow the cold air damper to open. Increase feeder speed as much as possible in an attempt to smother the fire. Open firewater valve if applicable. After all evidence of the fire has disappeared, isolate pulverizer and inspect for damage
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How does turbine oil temperature effect bearing vibration?
?
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What are the potential sources for turbine water induction?
?
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What are potential causes of condenser low vacuum?
?
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What actions should be taken in the event of a CWP trip?
?
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What actions should be taken on loss of a main seal oil pump?
?
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If hydrogen purity is dropping, what action should be taken?
?
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What should be the operator action in the event of a DCS loss
of communication?
?
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What are the potential causes of a high feedwater heater level?
?
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What are the boiler trip points for superheat temperatures?
- 1050 degrees Fahrenheit for 15 minutes
- 1060 degrees Fahrenheit for 3 minutes
- 1070 degrees Fahrenheit for 10 seconds
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What is the boiler trip point for reheat temperatures?
?
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What is the boiler trip point for main steam pressure?
?
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Explain how the prewarming circuit works?
?
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Explain the steps of isolating a feedwater heater.
?
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Explain the steps of isolating a Boiler Water Circ Pump.
?
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Explain the BE BTB/BT/Valve transfers.
?
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Explain the Waterwall Ramp.
The process of increasing waterwall pressure as temperature increases not to exceed temperature limitations. As waterwall temperature increases, the waterwall pressure set point increases. The BE valves close to increase waterwall pressure. This causes feedwater flow to decrease. The feedwater valve will open to increase feedwater How. The BFP speed will increase at this time in order to bring feedwater valve position back to set point. This will increase waterwall pressure.
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Explain the Superheat Pressurization Ramp
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By what means will the FGD Bypass Damper open ?
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List the potential sources for SSS for Units 1-5.
- The normal alignment for Units 1-4 is from the Bessemer line (A transfomer).
- The alternate alignment for Units 1-4 is from the Leeds #2 line (B transformer).
The normal alignment for Unit 5 is from the County Line Road line through Atransformer to A bus, and from the Yellow Dirt line through B transformer to B bus.
- The alternate alignment for Unit 5 can be either County Line
- Road (A transformer) feeding both A and B busses, or Y ellow Dirt line (B transformer) feeding both busses.
The Combustion Turbine can be aligned to either Leeds #2 line or County Line Road line.(Leeds #2 is normal)
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