Diesel Generators (DG)

Question 1

What’s the (DG) rated for?

Answer 1

-Electrically
•5,500kW continuous
•6,050kW intermittent (for 2hrs in a 24hr period)

-Mechanically
•7,670HP

Question 2

What’s the purpose of the (DG’s)?

Answer 2

•To supply power to safe plant shutdown equipment in the event of (LOP) or (LOOP).

Question 3

How fast should the DG turn on?

Answer 3

•10 seconds or less

Question 4

The DG’s are designed to operate during/after a safe shutdown earthquake.

TRUE OR FALSE

Answer 4

•True

Question 5

What ESFAS’s do the DG’s automatically start on?

Answer 5

•SIAS (Emergency mode)
•AFAS (Emergency Mode)
•LOP(Emergency mode)
•CSAS(Test mode)
CSAS will start in EMERG. if SIAS is already in

Question 6

All ESFAS signals start both DG’s except for which one?

Answer 6

•LOP- only starts the affected trains Diesel.

Question 7

Which switches are key locked on the DG’s control panels?

Answer 7

•Remote selector switch
&
•Emergency Mode Interlock defeat switch

Question 8

Describe Remote selector switch

Answer 8

-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.

Question 9

What will the Manual start and stop buttons do?

Answer 9

•Start and stop the DG in Test mode only

Question 10

Describe Emergency Start Push buttons.

Answer 10

Will start DG in Emergency mode
•Simulated LOP
•Simulated ESF actuation

Question 11

Describe Emergency Stop
And reset push button.

Answer 11

•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.

Question 12

Describe first out and system reset pushbutton’s

Answer 12

•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.

Question 13

Describe Emergency Mode interlock defeat switch.

Answer 13

-2 position switch

-OFF
•Allows DG to start and run in EMERGENCY mode

-On
•Returns the DG to Test mode from emergency run condition

Question 14

What ESFAS signals will automatically start the DG?

Answer 14

•LOP (Emergency mode) (Output breaker closes)

•SIAS (Emergency mode)
• AFAS (Emergency mode)
• CSAS (Test mode)

Question 15

How does the DG operate in Emergency mode?

Answer 15

•Isochronous preset at 60Hz.
•Emergency mode light will be lit.
•Should always be considered to be in this mode.

Question 16

How does the DG operate in Test mode?

Answer 16

•Operates in ‘Droop’ mode.
•Starts at whatever the speed and voltage potentiometer is at

Question 17

What conditions have to be met for the DG output breaker to close automatically?
5 things

Answer 17

•DG @ rated speed 600rpm
•DG @ rated voltage 4.16kv
•No faults on normal or alt breaker
•Normal and Alt breaker OPEN
•LOP signal

Question 18

How is the DG started?

Answer 18

•It’s started by stored compressed air called “Starting Air” which is at 250psi

Question 19

What are subsystems of the Starting Air?

Answer 19

•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

Question 20

-When does the air compressor start and stop?
-Where is it powered from?

Answer 20

•Starts when receiver gets to 240psig
•Stops when receiver gets to 250psig
•Powered from (NH)

Question 21

Describe the flow path of the starting air starting at the compressors.

Answer 21

•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)

Question 22

What powers the Air dryers?

Answer 22

•Non-class 480vac MCC

Question 23

Describe Air Receivers on the Starting Air system

Answer 23

•Maintained @ 250psig
•Alarms if outlet valve is closed or if pressure drops below 185psig for 3min

Question 24

What do starting air control valves do?

Answer 24

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

Question 25

How does the starting air distributor work?

Answer 25

•The air distributor is a timing device that distributes air in the correct sequence to the starting air valves
•Driven by the cam shaft

Question 26

How does the turbocharger interface with the starting air system?

Answer 26

•Warm air from the turbo is piped to the starting air header to prevent condensation.

Question 27

Describe the turning gear on the diesel.

Answer 27

•Uses 250psig supply and steps it down to 100psig
•Manually moved into position and interlocked with the ‘Starting air solenoid valve’ to prevent the Diesel from starting.

Question 28

How long can the Diesel Fuel oil storage/supply system provide oil for Both Diesel Generators?

Answer 28

•It can provide fuel to both diesels for 7 days of continuous use.

Question 29

What does the ‘Fuel Oil Storage’ system consist of?

Answer 29

•Storage tank
•Transfer Pump
•Supply header strainers
•Fuel oil day tank