Control Oil Flashcards
What is the purpose of the CO system?
provide pressurized hyd fluid for operation of the main steam control valves, stop valves, combined intermediate valves and electrohydraulic control system
When is the transfer filtering pump used?
when fluid reservoir is being filled or drained of for bypass filtering of reservoir fluid when the hydraulic pumps are shut down
What is the cooling water for control oil hyd coolers?
TC
what system powers main hyd pumps?
NG
What happens if power is lost to hydraulic pumps?
turbine will trip on low oil pressure
What system powers the filter pump motor?
NH
What does NN do for the CO system?
power to the EHC control cabinet
How is the hyd oil cooler affected by a loss of IA? operator actions?
TC control valves will fail open to the hyd oil coolers
Operator will have to throttle open the bypass around the temp control vavle and then isolate the control valve. Also goes to the CO reservoir dryer/conditioner
What is the capacity of the hydraulic fluid reservoir?
800 gallons of EHC fluid
What maintains the temp of the reservoir and how is it controlled?
2 electric fans operated automatically
Why is the reservoir also equipped with temp controllers?
they control position of the hyd fluid coolers cooling water inlet valves such that the hydraulic fluid entering the reservoir is 115F
Reservoir heater/fan controls, what happens when the switch is taken to START?
Fans will start but heaters will not energize regardless of reservoir temp
Reservoir heater/fan controls, what happens when the switch is taken to AUTO?
If temp is less than 85F the fans will start and the heaters will engage.
Fans and heaters run until reservoir goes above 85F and the heater will deenergize and fans will continue to run for 10 mins after
When reservoir heater/ fan control goes to stop what happens?
everything stops
What is the capacity of the main hydraulic pumps?
100% each
how do the pumps respond to system demand changes?
The pump will vary its stroke to meet flow demand and maintain constant pressure.
The pump will stroke to 0 delivery when dead headed.
what is the purpose of the auxiliary pump mounted into the main pump housing?
takes suction on the control oil reservoir and supplies cooling and lubrication to the main pump
What is the auto start for the standby main hydraulic pump?
system pressure falls below 1300psi
where are the pumps normally operated from and where are they located?
control room and 100’ turbine building
how much nitrogen is in the accumulators?
1000psig
What is the purpose of the accumulators?
provide an immediate 200% reserve of fluid for transient flow requirements
What is the capacity of the 2 hydraulic fluid coolers and what cools them?
100% capacity each
cooled by TC
What temp range does the hydraulic fluid cooler maintain the fluid at?
100-125F
What temp would sound an alarm in the control room?
130F high and 85F low
What is the purpose of the air dryer? How does it perform its function?
remove moisture from the hyd fluid reservoir
IA pushes thru the alumina
alumina blue good/ pink bad
What kind of pump is the transfer filter pump?
rotary positive displacement pump
How does the transfer filter pump operate to move fluid?
Fluid captured between vanes in low pressure in large region and forces thru higher pressure and small area
What uses do I have for the transfer filter pump?
used to provide control oil flow thru the fuller earth filters for oil purification when hyd pumps are secured.
Used periodically during power unit operation for bypass filtering of fluid in the reservoir or when adding fluid to the reservoir
What is the purpose of the fullers earth filters?
maintain control oil in neutral pH level by neutralizing acids and absorbing water
maintain chlorine content
What is neutralization?
chem reaction that stops an evens an ionic charge
How do we prevent overpressurization of the fullers earth filters?
relief valves set at 75psig
one relief valve is located downstream of both the hyd fluid pump and FCV-27 to ensure overpressure protection is available regardless of the pumping source
When is the fullers earth filtering system normally in service?
when turbine is in service.
What 2 important tasks are accomplished by the low pressure air purge in the stealth EHC system?
extracts moisture and excludes other contaminants
how much of the rated discharge air of the membrane of the EHC system is used to transport moisture?
5-20%
What is the purpose of the recirc tank
5 gallon tank that does batch mode purification independent of the rest of the system
Used during caking after replacing fuller earth filter elements, which allows the saturation of the filter media to ensure the media will fulfill its filtering function
What are the 4 configurations associated with CO-V204?
closed, discharged, recirc to fluid reservoir and discharge to recirc tank
Where can I test the auto start of the main hydraulic fluid pumps?
locally at the CO skid and is coordinated with the main control room during system startup before turbine is reset
What pressure will the turbine trip at?
1100psig 2 out 3 logic
how much fluid flow is thru the fuller earth filters for continuous cleanup during normal operation?
5% or 2.5 gallons
how is the system affected by loss of IA?
reservoir temp control valves fail open due to loss of air to the controllers
CO oil reservoir conditioner dryer lose air supply
EHC dryer will lose air supply
