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EDG Auto Starts
- All 4 start on LOCA (either div, either unit)
- 2 divisional: Loss BOP bus
- BOP bus U/V AND UAT U/V with UAT supply breaker open
- 1 single DG: Loss E-bus
- bus U/V OR M/S and x-tie breakers open
- AND DG in auto or not running
DG trips in AUTO
Low lube oil pressure
Generator Lockouts (diff, loss field, reverse power)
Barring Gear Engaged
Additional DG trips in manual
High lube oil temperature 190oF
High jacket water temperature 200oF
Low jacket water pressure 21 psig
What DG trips are bypassed on start?
For how long?
- For 45 seconds:
- Lube oil pressure
What does Jet Assist provide?
injects starting air directly into intake manifold during LOCA load sequencing
When does Jet Assist occur?
4 seconds duration from RHR pump start (t=10 - t=14) IF:
- DG running in AUTO
- output breaker closed
- run controls energized
- RHR pump breaker (same unit only) closed
DG Governor operation in AUTO
Isochronous 60 Hz w/varying load
NO load sharing capabilities!
DG Governor operation in Manual
Droop of 3Hz total
- allows load sharing
- must manually adjust speed with varying load
DG Mechanical governor
backs up AUTO governor, limiting to 61 Hz
If LOOP while full load testing, DG will swap to AUTO and mech gov will limit speed, but cannot take credit for mech gov reliability so DG not in "ready to load" condition
therefore DG INOP in manual
To swap DG from AUTO to MAN
expect up to 3Hz drop(full load)
must raise frequency or lower load to prevent EPA breaker trip (57.7Hz)
What are AUTO close permissives for DG output breaker?
- Bus undervoltage
- Bus stripped (except 480V E-bus feed)
- .75 second trip from AUTO start signal clear
- assuming (always req'd to close bkr)
- DG at rated speed and voltage
- Electrical lockouts clear
What is required to manually close DG output breaker?
sync scope on (local or same unit RTGB)
for opp unit, must have bus U/V
assuming (always req'd to close bkr)DG at rated speed and voltageElectrical lockouts clear
To close DG output breaker locally (ASSD)
local keylock switch in isolate
sync scope on AND Bus U/V
DG output breaker trips
- Electrical lockouts
- Any AUTO start .75 sec
- run controls de-energized (prevents reverse power)
DG indications: Red "NOT AVAILABLE" light indicates what condition?
Engine L/O relay tripped
DG indications: Green "NO LOAD" light indicates what condition
DG at rated speed and voltage
Diesel AUTO STOP pushbutton
Secures DG and energizes DG lockout relay
- must reset locally OR
- on an AUTO start (if no auto start previously present) OR
- when Emergency start pushbutton depressed
If EDG is running in manual and gets an AUTO start, what happens?
- DG output breaker opens
- E-bus strips
- Governor swaps to isochronous
- Tie back onto the bus ONLY if UV exists at 61Hz
How is a EDG Engine Lockout reset?
Depress reset pushbutton on (local) engine control panel
How is a Diesel Generator lockout reset?
reset at E-bus first using football switch, then reset Engine lockout locally
AUTO DG lockout reset
will reset 1 time for 1 second on an AUTO start signal or Emergency start PB used
What happens on a loss of DC power to DG engine control circuits?
Fuel rack cylinders reposition to the no-fuel position, but no trip signal
eventually trip on reverse power
DG control power comes from where?
ALWAYS ADDS UP TO 3
recieve annunciator if EITHER norm or alt power is lost
manual transfer (back of excitation cabinet) with mech interlock, must place DG back in auto after swapping
- normal same div, same unit
- alternate same div, opposite unit
What would you like to do?
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