Systems Exam 1 - Emergency Diesel Generators Flashcards
(36 cards)
EDG Emergency Start Signals
→BO
→SI
→SI Sequencer
→CR Emergency Start H/S
→Local Emergency Start H/S (with RLMS in Local)
EDG Normal Start Signals
→CR Normal Start H/S
→Local Normal Start H/S (with RLMS in Local)
How does air receiver tank pressure affect EDG Emergency Start capability?
→Engine will rotate with air until > 200 rpm or pressure in both receivers < 150 lbs.
→Emergency start blocked if air receivers < 150 lbs.
(can still try normal start below 150 lbs)
What automatic protective features does EDG have after Emergency Start?
Automatic protective features are disabled except:
—>mechanical overspeed (115%)
—>generator differential (86-1 lockout).
How are full automatic protective features restored to EDG after Remote Manual Emergency Start?
→RLMS to LOCAL
→CR DG Emergency HS to STOP
→RLMS to REMOTE
Automatic Voltage Regulation
→AVR will maintain voltage within 0.5% of setpoint, normal mode of operation
→If in isochronous mode and high voltage (7100 V) occurs, then AVR replaced with Magnetics
→If not in AVR mode, then the DG is INOP
What are the FO Storage Tank Tech Spec Minimum Volumes?
→Modes 1-6 for both
→FO Storage Tank Min volume 86,000 gal for 7 day supply
→FO Storage Tank Min Volume 74,600 gals for 6 day supply
Air Receiver Tank Pressure Limits
(both TS and Admin)
When does the low pressure alarm come in?
Tech Spec: ≥180 lbs
Admin: ≥184 lbs
Alarm: < 210 lbs
Day Tank Tech Spec Minimum Volume
1440 gal
(37” or 62%)
Note: EDG will actually run for ~2.8 hours based on 8-12 gpm fuel use
Which EDG components receive Operator Lockout on Blackout (BO)?
1) Pre-Lube Pump
2) Aux LO Pump
3) Aux JW Pump
4) Air Compressors
Which EDG components receive Auto Lockout on Safety Injection (SI)?
1) Pre-Lube Pump
2) Aux LO Pump
3) Aux JW Pump
4) Air Compressors
5) Waste Drip Tank Pump
6) FO Booster Pump
7) Keep Warm Pump
EDG Pneumatic Trips
1) Hi bearing Temperature ≥ 228°F
2) Return Line Lube Oil Temperature ≥ 200°F
3) Lube Oil Pressure at Turbochargers ≤ 15 psig (Left Bank or Right Bank)
4) Lube Oil Pressure at header ≤ 30psig
5) Hi Vibration on a Turbocharger (Left or Right Bank)
6) Engine Hi Vibration
7) Crankcase Hi pressure ≥ 1.5 psig
8) JW Return ≥ 200°F
First two always active. The rest are on a 60 sec time delay after normal start before active.
EDG 86-2 Trips
1) Reverse Power (86-2)
2) Loss of Field (86-2)
3) Negative Sequence (86-2)
4) Time Overcurrent (86-2)
5) Ground Overcurrent (86-2)
6) Over excitation (86-2)
7) Neutral Voltage (Gen ground) (86-2)
8) High Gen Bearing Temp > 190°F (86-2)
Which trips can’t be overridden with an emergency diesel start?
Phase to Phase Fault or Phase Differential (86-1)
Mechanical Overspeed (115%)
(must be manually reset at overspeed pivot lever)
DG Output Breaker Trips
(assuming RLMS in Remote)
→SI and either normal or alternate feeder breaker are closed.
→86-2 for the bus or generator without an emergency start.
→86-1
→Engine shutoff cylinders are pressurized to shutdown the engine
→Breaker HS to TRIP or PULLOUT
DG Output Breaker Trips
(from HSP)
→Breaker control is transferred with normal or alternate feeder breaker closed.
→86-2 for the bus or generator without an emergency start.
→86-1
→Engine shutoff cylinders are pressurized to shutdown the engine
→Breaker HS to TRIP or PULLOUT
If breaker is tripped from the RSP must transfer control back to the CR and then back before the breaker can be reclosed from the RSP, because of anti-pumping circuit
How long must the EDG be able to run, per Design Basis?
Each EDG must be able to operate for 7 days at rated speed and voltage with full load, after which it must still retain its 10 second start and load capability.
When do starting air admission valves close after a Normal start?
Normal Start: valves close 5 secs after start signal or when engine speed reaches >200 rpm
When do starting air admission valves close after an Emergency start?
Emergency Start: valves will not close until receiver pressure is < 150 psig or engine speed ≥ 200 rpm
(starting air banks are supplied from separate receivers)
When does the Aux Jacket Water Pump auto start?
(Unit Difference)
Unit 1:
Engine Speed > 200 rpm
JW Pressure ≤ 10 psig
Unit 2:
Engine Speed > 200 rpm
JW Pressure ≤ 7 psig
When does the “Ready to Load” red light illuminate?
READY TO LOAD (red):
→engine speed ≥ 425 rpm
→generator output voltage ≥ 6210 VAC.
What are the limitations for running EDGs unloaded?
Minimize running the EDG unloaded
→ ≤ 5 minutes recommended
→ if operated for >30 mins unloaded, then machine must be loaded to remove any unburned fuel in the exhaust system
→when loaded, should run at minimum of 3.5 MW for 60 mins
What are the Tech Spec Limits for EDG voltage and frequency?
Each EDG starts from standby and achieves:
→steady state voltage between 6480 V and 7150 V
→frequency between 58.8 Hz and 61.2 Hz
How will raising 1-01 EDG speed affect indication:
→if the EDG is parallelled?
→if the EDG is carrying the bus?
→if parallelled, MW will increase
→if carrying the bus, speed (frequency) will increase
