Diesel Generators

Question 1

What happens on a loss of PKA-M41, if DG A is paralleled to offsite power?

Answer 1

Loss of class control power to the DGs affects controls, starting circuit and electrical protection. The affected DG trips if it is running and its output breaker, if closed, will remain closed due to loss of control power. If paralleled with offsite power the generator will motorize.

Question 2

What are the automatic starts for the Diesel Generator?

Answer 2

SLAC

SIAS
LOP
AFAS
CSAS (DG not in Emergency Run unless SIAS present also, will start in Test mode)

Question 3

What is the rated speed, voltage, and load for the Diesel Generator?

Answer 3

600 RPM
The DG systems will supply 4160 VAC
60 Hz electrical power.
Each DG is rated for 5500 KW continuous output, and up to 6050 KW output (110% rated load) for 2 hours out of 24 hours.

Question 4

List the 5 conditions that must be met for the Diesel Generator to start in any mode:

Answer 4

• Overspeed reset
• Generator differential reset
• Low engine lube oil pressure reset
• Emergency stop pushbutton in reset position
• Mode control switch not in “off” (remote or local)

Question 5

What are the conditions necessary for the Diesel Generator Output Breaker to close?

Answer 5

Conditions necessary for the diesel generator output breaker to automatically close:
* LOP
* Diesel generator at rated speed and voltage
* No fault (86 Lockout) on the normal or alternate supply breaker
* Both normal and alternate supply breakers open
Conditions necessary for the diesel generator output breaker to be manually closed from the control room:
* Diesel generator at rated speed and voltage
* No fault on the normal or alternate supply breaker
* Alternate supply breaker open
* Sync key must be on.

Question 6

What are the Emergency Run trips?

Answer 6

• Overspeed Shutdown (660 rpm)
• Low Engine Oil Pressure Shutdown
  (Bypassed for 20 seconds when < 540 rpm)
• Generator Differential

Question 7

What is the fuel consumption rate of the diesel at full load?

Answer 7

• 6.55 gpm – fuel oil used at full rated load.

Question 8

What’s the power supply for the Fuel Oil transfer pumps?

Answer 8

PHA/PHB

Question 9

What’s the Tech Spec minimum level in the Fuel Oil Storage Tank?

Answer 9

≥ 80 % - 7 day supply at 100% rated output (~71,383 gallons)

Question 10

What’s the Tech Spec minimum level in the Fuel Oil Day Tank?

Answer 10

550 gallons (2.75’ or 55%) – minimum Tech Spec level (SR 3.8.1.4)

Question 11

What does the Jacket Water subsystem cool in the Diesel Generator?

Answer 11

Cools the engine cylinder jackets, main governor, and turbocharger

Question 12

What system is used to make-up to the Jacket Water subsystem?

Answer 12

Jacket Water Make-up (manual only)
o DW (normal source)
o Condensate Transfer System (CT) or a hose connection from Fire Protection System (Back-up)

Question 13

When is the Diesel Generator lube oil circulating pump and heater on? When does it turn off?

Answer 13

Running when DG is < 280 rpm. (Off > 280 rpm)
An electric heater controlled by a
temperature switch energizes at a low temperature (120°F decreasing) and de-energizes when temperature has been restored (135°F increasing).

Question 14

When does the Diesel Generator Essential Exhaust fan start and stop?

Answer 14

o Auto starts when DG starts, defeats the local HSs
* Auto Stops after DG stops and room is < 110°F

Question 15

When does the DG Control Equipment Room Essential AHU start?

Answer 15

o Auto starts when the essential exhaust fan starts
Auto Stops after DG stops and room is < 110°F

Question 16

How long can the Diesel Generator run without Spray Pond support?

Answer 16

15 minutes unloaded (output breaker open)
2.6 minutes loaded

Question 17

What is the motive force for the Diesel Generator turbocharger?

Answer 17

o DG exhaust spins the turbocharger
o Raises engine efficiency (more oxygen into the combustion chamber)

Question 18

What happens on Loss of non-class DC (NKN-D42 A DG / NKN-D43 B DG)?

Answer 18

• Loss of power to the DG Control Panel and DG alarms
• DG will trip if not in Emergency Run
  (Prevents manual DG start from B01 in MCR)
• DG can auto start for an emergency run or by Local Simulated ESFAS / LOP start pushbuttons.
• loss of indication
  * loss of test run functions

Question 19

What Diesel Generator output breaker trips are re-established when taking the DG to OVERRIDE?

Answer 19

o 3 DG output breaker trips are re-established (Overcurrent, Neutral Voltage, Negative sequence).
(Remaining test trips not enabled until DG is taken to stop.)
also re-establishes speed and voltage control

Question 20

If attempt to start the diesel and no response is observed, what is a likely failure?

Answer 20

Jacking gear not fully disengaged

Question 21

Diesel day tank at 2.75’ (550 gal), fuel oil transfer pump fails. How long will the diesel run at full load?

Answer 21

84 minutes (6.55 gpm use for a fully loaded diesel)

Question 22

When syncing the Diesel Generator, what action must be taken in a timely manner?

Answer 22

Pick up speed to ensure reverse power trip does not occur

Question 23

LCO 3.8.3 Diesel Fuel Oil, Lube Oil, and Starting Air requires how many days of Fuel Oil?

Answer 23

7 days

Question 24

What is the purpose of “Non-Fail Safe Air” ?

Answer 24

Non-Fail Safe Air is air that is always available and is needed to shutdown the DG.

It is also the air that is used to pressurize the trip
system. If non-fail safe air pressure is lost, the engine would have to be secured by manuallytripping the overspeed butterfly valve to take away combustion air or manually actuating the fuel shutoff linkage to secure fuel.

Question 25

What speed is the mechanical governor set to during normal operation? Is the mechanical or electronic governor normally in control?

Answer 25

608 rpm
electronic is normally in control, if it fails mechanical will maintain at set speed (608 rpm)