Diesel Generators (DG) Flashcards
(29 cards)
What’s the (DG) rated for?
-Electrically
•5,500kW continuous
•6,050kW intermittent (for 2hrs in a 24hr period)
-Mechanically
•7,670HP
What’s the purpose of the (DG’s)?
•To supply power to safe plant shutdown equipment in the event of (LOP) or (LOOP).
How fast should the DG turn on?
•10 seconds or less
The DG’s are designed to operate during/after a safe shutdown earthquake.
TRUE OR FALSE
•True
What ESFAS’s do the DG’s automatically start on?
•SIAS (Emergency mode)
•AFAS (Emergency Mode)
•LOP(Emergency mode)
•CSAS(Test mode)
CSAS will start in EMERG. if SIAS is already in
All ESFAS signals start both DG’s except for which one?
•LOP- only starts the affected trains Diesel.
Which switches are key locked on the DG’s control panels?
•Remote selector switch
&
•Emergency Mode Interlock defeat switch
Describe Remote selector switch
-3 positions
•OFF, Local, Remote
-OFF
•Disables all starts (Brings in alarm)
-Local
•Local start or automatic ESFAS start only
-Remote
•CR start or automatic ESFAS start only.
What will the Manual start and stop buttons do?
•Start and stop the DG in Test mode only
Describe Emergency Start Push buttons.
Will start DG in Emergency mode
•Simulated LOP
•Simulated ESF actuation
Describe Emergency Stop
And reset push button.
•Open the DG output breaker and stop the DG without 5min cooldown(alarms)
•Reset will clear the stop signal that’s engaged and allow the DG to be restarted.
Describe first out and system reset pushbutton’s
•Resets local alarms that are cleared
•Verify with CR that there are no automatic ESFAS signals in because when reset, the DG will start again
• “First Out” button makes the first trip alarm that tripped the DG flash at a different sequence so you know which one tripped it.
Describe Emergency Mode interlock defeat switch.
-2 position switch
-OFF
•Allows DG to start and run in EMERGENCY mode
-On
•Returns the DG to Test mode from emergency run condition
What ESFAS signals will automatically start the DG?
•LOP (Emergency mode) (Output breaker closes)
•SIAS (Emergency mode)
• AFAS (Emergency mode)
• CSAS (Test mode)
How does the DG operate in Emergency mode?
•Isochronous preset at 60Hz.
•Emergency mode light will be lit.
•Should always be considered to be in this mode.
How does the DG operate in Test mode?
•Operates in ‘Droop’ mode.
•Starts at whatever the speed and voltage potentiometer is at
What conditions have to be met for the DG output breaker to close automatically?
5 things
•DG @ rated speed 600rpm
•DG @ rated voltage 4.16kv
•No faults on normal or alt breaker
•Normal and Alt breaker OPEN
•LOP signal
How is the DG started?
•It’s started by stored compressed air called “Starting Air” which is at 250psi
What are subsystems of the Starting Air?
•Non-class
-Two redundant air compressors, per train
-Two coalescing filters and air dryers, per train
•Class
- Two redundant air receivers, per train
-Two redundant starting air control valves, per train
-Two redundant Air distributors per train
-20 starting air valves per train
-When does the air compressor start and stop?
-Where is it powered from?
•Starts when receiver gets to 240psig
•Stops when receiver gets to 250psig
•Powered from (NH)
Describe the flow path of the starting air starting at the compressors.
•Starts at Air compressors (3 stage)
•Intercooler/after cooler (Cools the air going to the different stages in the compressor)
•Starting unloader (relieves cylinder pressure when compressor stops)
•Air dryers (removed moisture by condensing the liquid in the air then discharging it
•Lastly, Receivers (Stored at ~250psig)
What powers the Air dryers?
•Non-class 480vac MCC
Describe Air Receivers on the Starting Air system
•Maintained @ 250psig
•Alarms if outlet valve is closed or if pressure drops below 185psig for 3min
What do starting air control valves do?
Directs air to either:
-Starting air headed (on diesel start)
Or
-Control air network
•80psig for Emergency trips & Fuel control cylinder
•37psig for test trips & temp control for intercooler heater core
