EDGS Flashcards
What are the EDG Auto Starts?
- Load Shed (Loads to Bus)
- SI (does not load to bus)
If an EDG auto starts on a Load Shed, does it load to the TBUS?
Yes, it loads to the TBUS
If an EDG auto starts on a SI without a load shed, does it load to the TBUS?
No it does not auto load to the TBUS
What are the EDG Auto Trips (With DC Power)?
- Bearing Temp High
- Incomplete Start
- Gen Phase Overcurrent
- CO2 Actuation
- Fuel Oil Press Low
- Lube Oil Press Low
- Air Chest Press high
- Neutral Overcurrent
- Gen Phase Differential
- Electronic Overspeed (110%)
What are the EDG Trips available Without DC Power?
- Mechanical Overspeed (112% of 514 RPMs)
- Worthington/Manual Fuel Valve (MFV)
What are the only EDG TRIPS available after the EDG Auto Starts on an SI or Load Shed? (With 250 VDC Available)
- Gen Phase Differential
- Electronic Overspeed (110%)
- Manual Push Button
The starting Air Receivers are sized to do how many EDG starts?
Each tank has enough air to start the EDG 2 times and still have 100# for control air, even tho operability only requires 1 start
What are the EDG Starts?
- CR Control Switch
- Local Push Button
- Load Shed (loads to bus)
- SI (does not load to bus)
- Worthington/Manual Starting Air Valve (allows start during loss of 250VDC control power)
How do the starting air valves fail on a loss of 100# ctrl air?
Fail as is
What happens on a failure of the electronic governor?
EDG will speed up until Mechanical Governor takes over
set point for mech governor is 60.8-61 hz
Where does the field flash come from on a fast speed start?
From the 1kV inverter
Where does the field flash come from on a slow speed start?
From residual magnetism
From 1kV loads IF button is used to flash the field
What are the 1KV inverter Loads?
- Field Flash (Fast Start) (Slow Start if button is pushed)
- Bearing Temp Monitor (SG-40)
- Speed Transmitters
- Local/Remote Control Transfer Relays
How long does the Throttle Control Cylinder (TCC) extend for on a EDG Trip and why?
TCC will extend for 2 minutes on trip to prevent re-start of EDG
Will a EDG start with a loss of 100 psi Ctrl Air?
NO!
TCC extends on loss of 100 psi control air
it will trip if running, also
What causes Load Shed to be disabled?
EDG output breaker control switch is in close or lockout
When do run relays energize to allow power to bus?
At 95% running speed
start aux equip, input to load cons and provide interlocks/permissives
If an emergency start signal initiates at any time during the slow start, what will happen?
The slow start circuit automatically drops out and an emergency start takes place (Fast Speed)
Why do we have slow speed start circuitry?
It is easier on the EDG
Are the EDG trip relays energize or de-energize to trip?
Energize to Trip
Are the EDG start relays energize or de-energize to run?
De-Energize to run
(1 per bus – want to run if lost power)
Why is the EDG considered Inop during a surveillance?
Because the Load Shed signal is deactivated
When the TCC extends, what is it doing?
Forces the fuel racks closed
Per TS 3.8.3 (Diesel Fuel Oil), what quantity of fuel oil is required for operability for each fuel oil storage tank?
≥ 46,000 gal of fuel.
Per TS SR 3.8.1.6, what is the requirement regarding EDG air receiver pressure?
Each air receiver is ≥ 190#
Only 1 start per SAR is necessary for operability
What does TS 3.8.1 (AC Sources, Operating) require in regards to how many EDGs must be Operable??
2 EDGs operable M 1-4 and opposite Unit EDGs to support ESW when cross-ties are open
How is ctrl air designed to fail on a loss of 250V DC?
so that control air will be available to the TCC
What is the auto trip available with a loss of 250V DC?
Mechanical Overspeed
(112% of 514 rpms)
What supplies power to the EDG 1Kv inverter
250v DC Charger/Battery (Train Specific)
What loads sequence on during a load shed if there is NOT a SI?
CCW pump
ESW pump
MDAFW pump
NESW pump
What loads sequence on during a load shed WITH a SI?
CCP
SI pump
RHR pump
CCW pump
ESW pump
MDAFW pump
CTS pump (Starts when Phase B active)
NESW pump (Starts/Then Trips if CTS/Phase B active)
If you have a load shed without a SI, will your CCP auto restart?
No!! It will need to be manually restarted
What does TCC do when the HEA trips?
Extends [Fuel Racks close]
Will a loss of 1 Jacket Water Pump make the EDG INOPERABLE?
NO
If BOTH are lost, then INOP
What powers the Normal and Alternate ESW cooling supply valves?
ABD-A and ABD-D (Train Specific)
will be repowered upon EDG start
What is the minimum level allowed per TS for a EDG Fuel Oil Day Tank?
≥ 101.4 gal of fuel oil
Will the loss of 1 Fuel Oil Transfer Pump make the EDG INOPERABLE?
NO!
If BOTH are lost, then INOP
Will the loss of HVAC make the EDG INOPERABLE?
YES
What ventilation is required by TS LCO 3.8.1 for an EDG to be OPERABLE?
Supply Fan, Exhaust Fan and Cabinet Fan
When is speed droop in effect?
When EDG is paralleled
When is the field flash disabled during a fast speed start?
80% Speed
How often can you use the 14 Day AOT for planned EDG Outages?
1 time per cycle, per EDG
If an EDG suddenly goes INOP, can you decide to apply the 14 day AOT?
YES! The 1x per cycle is only applicable to the preplanned maintenance activities.
What is the bases behind the minimum level in the EDG Day Tank?
Min level means 70 gal of usable fuel oil to ensures adequate FO for >15 mins of DG operation at full load
What is the bases behind the minimum level in the EDS FOSTs?
1 EDG supplies 1 train, 7 days at full load
How is a reverse power condition prevented when closing the EDG output breaker during a surveillance?
Ensure that the synchroscope is rotating slowly in the ‘FAST’ (clockwise) direction prior to closing the breaker. This causes the DG to be slightly faster than the Grid causing it to pick up some load thus preventing a reverse power trip
While paralleled to the grid, what could rising amps on all 3 phases of the EDG mean? What should be done?
Rising current is caused by a failure of the voltage regulator. Transferring the Voltage regulator to manual and reducing current will prevent excessive reactive loads and reduce heating.
What happens to an EDG in standby if a CO2 discharge occurs in the EDG CD room?
The CO2 actuation signal trips the 87X relay. It must be reset or the EDG will not start when needed
In the event that an INOPERABLE DG is restored to OPERABLE status prior to completing the actions of TS 3.8.1 for Condition B.4.1 or B.4.2 (common cause determination), is there still a 24 hour constraint as imposed while in Condition B?
NO! The continued evaluation will be performed by the corrective action program to evaluate the common cause
If the EDG is being running due to an SI signal, can it be stopped with the normal control switch in the control room
Not unless SI has been reset, or the switch is help in stop. There is still a standing signal.