EDG - .5

Question 1

EDG Fuel specs.

Answer 1

Each EDG has two fuel oil storage tanks – 26,500 gallons each. Seven days at 4200KW requires 50,000 gallons of fuel.

Question 2

EDG Rating

Answer 2

1. Rated – 4430KW @ 0.8Pf 5538KVA
2. 110% Overload (4873KW) can be maintained for 2 out of 24 consecutive hours
3. 120% Overload (5316KW) can be maintained for 30 minutes.

Question 3

Auto-start signals.

Answer 3

1. LOP - Both incoming feeder voltages <92% AND
   Bus voltage <70%.
2. Degraded Voltage - Both incoming feeders <92% for 20 seconds.
3. LOCA - Core Spray logic
   RPV Level -129” OR
   Drywell Pressure 1.68psig OR Manual Core Spray Initiation

Question 4

EDG BKR Close permissive.

Answer 4

1. Diesel ready for Load - Frequency >57Hz (95%)
   Voltage >3950V (95%)
2. Switchgear - Both Normal and Alternate feeder breakers open
3. Bus voltage <70%
4. DG Lockout Relays reset

Question 5

Regular Lockout Relay (86R)

Answer 5

1. Generator differential o/c
2. Low Lube Oil Pressure
3. Overspeed (engine)
4. Bus differential o/c
5. Emergency Stop PBs

Question 6

Backup Lockout (86B)

Answer 6

1. Generator Differential o/c
2. Generator Phase o/c

Question 7

Test Lockout (86T)

Answer 7

1. Reverse Power
2. Bus Overcurrent
3. Low field current
4. Over-excitation

Question 8

What occurs when the Regular and Backup relays actuate?

Answer 8

1. Trip and lockout the diesel engine
2. Trip and lockout the EDG breaker
3. Enable EDG breaker failure protection

Question 9

What occurs when the EDG test lockout relay actuates?

Answer 9

1. Trip and lockout diesel generator breaker
2. Enable diesel generator breaker failure protection
   (Test Lockout is B/P on an emergency start)

Question 10

Breaker failure protection

Answer 10

1. Trips the diesel
2. Trips the normal and alternate feeder breakers.

Question 11

The following occurs to the EDG when a LOCA occurs:
(Not the sequencer)

Answer 11

1. All NORMAL Stops disabled (Emergency stops still work)
2. Test Lockout Relay disabled
3. Governor shifts to Isochronous (60Hz) and speed control is disabled (10C651)
4. Voltage Regulator shifts to Isochronous (4160V) and voltage control is disabled (10C651)
5. Opens EDG output breaker if running in TEST

Question 12

Local Engine Control Switch positions & functions.

Answer 12

1. Remote – Control from remote engine control panel or the control room.
2. Local – Control Locally, all auto starts disabled.
3. Maintenance – Control locally, all auto starts and excitation disabled.

Question 13

How do you enable the remote Generator EMERGENCY TAKEOVER and what automatic action is taken away?

Answer 13

1. Enables control of diesel and breaker from remote generator and engine control panels
2. Diesel will not respond to a LOCA (LOP responds to < 70%bus voltage signal only)

Question 14

What type of valve controls EDG LO Makeup operation, and how can you operate this valve in the case of a loss of power?

Answer 14

LO Makeup to the sump is controlled by a solenoid valve that fails close on a loss of power. It can be overridden locally with a control knob at the base of the valve.

Question 15

EDG S/U Sequence:
0 RPM

Answer 15

1. Cranking cycle timer initiate
2. SACS cooling water valve opens
3. Low Air start pressure alarms lockout

Question 16

EDG S/U Sequence:
95 RPM

Answer 16

Starting air shutoff

Question 17

EDG S/U Sequence:
>365 RPM

Answer 17

1. Starting air shutoff
2. Field flash (again)
3. Low Lube oil pressure trip enabled
   (indication after 7 sec TD)

Question 18

EDG S/U Sequence:
>125 RPM

Answer 18

1. Starting air shutoff (redundant)
2. D/G Room Recirc fan armed
3. Engine run timer starts
4. JW &LO Hi Temp alarms disabled
5. Motor driven fuel oil pump armed
6. Motor driven rocker arm prelube pump armed
7. LO Keep Warm heater shutdown
8. JW Keepwarm pumps and heaters shutdown
9. Generator Space heater shutdown
10. Exciter field flash circuit activated
11. Low starting air low pressure alarm re-activated
12. Cranking timers de-energized
13. “Diesel Running Not Loaded” light energized

Question 19

EDG S/U Sequence:
>3950Vac
and >57Hz

Answer 19

EDG Ready to load permissive

Question 20

Diesel Ready for Auto Start

Answer 20

1. Remote/Local/Maintenance in Remote
2. Normal/Emergency Takeover in Normal
3. Shutdown relay not energized
4. Diesel Generator Lockouts reset
5. Barring Device not engaged
6. Start Failure relay not energized
7. 125VDC control power available (If control power is not available, EDG will not start)

Question 21

EDG Recirc Fan Trips

Answer 21

1. Overcurrent
2. Undervoltage
3. CO2
4. Low Flow

Question 22

When can an EDG be paralleled with another power source?

Answer 22

When in Test.

Question 23

Anti-pumping circuit operation

Answer 23

IF a LOP were to occur within 2 seconds of a diesel breaker closure the breaker may not reclose after it trips due to the anti-pumping circuit. The operator will have to press the trip pushbutton and then close the breaker.

Question 24

EDG Start time criteria.

Answer 24

EDGs are expected to start and reach rated voltage within 10 sec. 13 sec are allowed due to signal processing time.

Question 25

SACS thru EDG HX Flow path.

Answer 25

Air Intercooler then Jacket Water then Lube Oil.

Question 26

Why is the Rocker Arm LO system separate?

Answer 26

Rocker Arm LO system is separate to prevent fuel oil contamination of the MLO system. Makeup to the Rocker Arm LO system is provided from the MLO system.

Question 27

Purpose of starting air system.

Answer 27

Provides air for (1) Starting, (2) Control, and (3) Shutdown

Question 28

Woodward Governor mechanical vs electrical.

Answer 28

Mechanical governor set higher than electrical. Electrical fails high and mechanical will take over.

Question 29

Emergency start signal vs normal stop signal

Answer 29

On a normal stop signal with the engine still coasting down and emergency start signal will still start the diesel.

Question 30

Emergency stop vs start PB.

Answer 30

On an emergency stop depressing the start PB will vent the air receivers to atmosphere.

Question 31

How many starts does each air receiver tank capable of?

Answer 31

5

Question 32

What must be done after a lockout?

Answer 32

The ENGINE RESET pushbutton must be pressed PRIOR to resetting the lockout.