diesel Flashcards
Purpose of EDG
EDG system is a safety related system that is installed as an ES system to provide an alternate source of power to the ES buses in the event of a LOOP. Provides power for safe s/d and c/d of primary plant when offsite power is NOT available
SBO diesel purpose
Used to backup EG-Y-1A/B by supplying either 1D or 1E 4160V bus of the 1C 4160V bus if 1D/1E have power
EG-Y-1A/B specs
Description, speed, gen
Fairbanks-Morse 12 cyclinder (2 cycle engine, 900 RPM (fast start), 450 RPM (slow start)
3.0MW w/ 3.3MW overload rating, 8 pole 4kv 60hz 3 phase
EG-Y-1A/B auto starts
On ES (won’t load) or UV (will load) on 4kv buses (2 of 3 via UV relays)
EG-Y-1A/B exciter-regulator
(auto voltage reg)
Controls generator output by controlling field current
Auto voltage reg: compares generator output to setpoint
UNIT: ES standby mode with zero speed droop
Parallel: monthly testing when synched w/ grid, 70% speed droop
EG-Y-1A/B exciter-regulator
(Manual voltage reg)
Over-speed governor function
Stops engine if governor fails to hold the engine speed under max safe speed. Single weight and spring. On overspeed, weight moves outward overcoming spring pressure which forces lever and rod downward tripling latch
Speed adjustment
Changes engine speed when running ALONE (isochronous, UNIT) or change LOAD when paralleled to system
Speed droop control function
Adjusts the engines resistance to load change. A setting > 0 will cause decrease in engine speed when unit is running alone
Speed droops control (what happens when paralleled to grid at 0 speed droop, when diesel hz>grid hz, and when diesel hz< grid hz
0 speed droop = unstable
Diesel hz > grid hz = Diesel assumes entire load of grid and go to overload
Diesel Hz < Grid Hz = Diesel will reject load (Reverse Power)
EDG Trips
Parameter, type, on ES
Low Lube Oil Pressure
EDG Trips
Parameter, type, on ES
Start Failure
EDG Trips
Parameter, type, on ES
High Crankcase Pressure
EDG Trips
Parameter, type, on ES
STOP pushbuttons (engine and control room)
EDG Trips
Parameter, type, on ES
Low lube oil pressure
(running)
EDG Trips
Parameter, type, on ES
86G Diesel Generator Fault
EDG Trips
Parameter, type, on ES
Engine overspeed & emergency local trip
Emergency stop and reset lever
Function
Trips the overspeed governor. Engine CANNOT be restarted until the overspeed stop is reset with the Reset lever
Unit/Parallel Switch function
Selects voltage droop mode and selects which rheostat pot controls the field strength. Unit position shorts out voltage droop resistor. Voltage droop ensure EDG does NOT carry excessive VAR loading
Shutdown Solenoid function
DC current used to energize S/D solenoid taking governor to no fuel position. ALL S/D interlocks ultimately energize this solenoid
Ready to load light
Comes on when >59 hz and >4100V
86G generator fault relays
Lockout relay must be reset at 1D/1E 4160V breakers
AC EDG transfer pump
(DF-P-1A/C)
Auto start and trip setpoints
Auto starts: 20” level (from TOP of tank)
Trips: 15” from Top of Tank (high level), 13” HI-Hi with lockout
Auto starts: 24” level (from TOP) alarm comes in on pump start
DC EDG transfer pump (DF-P-1B/D)
Auto start, trips, control
AUTO Starts: 24” level (from TOP), Alarm comes in on pump start
Trips: 15” High Tank Level, 13” Hi-Hi with LOCKOUT
Control: Each pump has MANUAL-OFF-AUTO switches on EMMSB.
Duplex Filter
Indication
10# differential pressure indicates dirty filter element
Fuel injection system
function
Fuel injection pumps (2/cylinder) receive fuel oil at low
pressure from engine driven/motor driven fuel pumps, measures it, builds high
pressure, and delivers to fuel injection nozzle.
Fuel injection stick actions
IF fuel injector sticks, springs allow fuel injector rod to move even if 1 injector
sticks allowing others to go to no fuel position.
Scavenging air flow
Purpose
Removes exhaust gas during operation and acts as combustion
air for next cycle
Blower (Supercharger)
purpose
Provides scavenger air for starting and light load
operation.
Inlet Air check valve action
Startup (closed)
Normal operation (open)
STARTUP (CLOSED) -> Valve plate closed when starting diesel
NORMAL OPERATION (OPEN) -> Raising load creates suction, valve
gradually opens to direct flow directly to turbo with only some flow
to air blower.
EG-P-7A/B Jacket Coolant Pump (Engine Driven)
function
Provides cooling to cylinder liner, turbocharger, and lube oil via
Engine Driven EG-P-7A/B pump.
EG-P-8A/B Aux Jacket Coolant Pump
Function
Used for standby heating when diesel
shutdown
Air Coolant system
Function
Designed to cool the scavenging air before it enters the engine.
Supplies cooling for the fan driven gear box via Engine Driven EG-P-2A/B.
Rejects its heat in the Air Cooler Coolant Radiator.
Standby Heater System
Purpose
Used when the diesel is NOT operating or <250rpm to maintain oil
temperature in engine sump warm while engine not running
Standby Heater system
interlock
**Heater is interlocked with pump so it can ONLY OPERATE when the pump is
running.
**
Diesel Lube oil system purpose
Removes friction by lubrication. A lubrication oil booster/accumulator is installed that supplies the upper main bearings with lubricating oil during the diesel start.
Low Lube Oil Pressure Switches (OPLS, OPL1, 2, 3)
Purpose/setpoint
OPL 1, 2, 3 protection during normal operation trips diesel at 16@
lowering (2 out of 3) with ES or NO ES.
Low lube oil pressure switch OPLS
Function/setpoint
OPLS for prolonged low speed, no load operation, activated 20 sec after
250 rpm. Set at 7# lowering OR <=16# after reaching 810 rpm. Trips
Diesel (defeated by ES).
Two air start Reservoirs (EG-T-1A/B-1/2)
Function, capacity
Function: Two per diesel generator to provide motive force for initial rotation of engine
on startup.
Capacity: 225
What reservoir pressure will diesel start at
> 100# reservoir pressure but won’t load in 10 second mission time
Air start Compressors (EG-P-1A/B)
Power supply and backup
1A ES MCC/1B ES MCC
Provided with separate 12v dc battery and charger
Emergency Diesel Air Start Solenoids (EG-V-16A/B/C/D)
Function
De-energized to inject air directly to start pistons moving (which drives the
engine driven fuel injection pumps) starting the engine.
Emergency Diesel Air Start Solenoids (EG-V-16A/B/C/D)
Fail position
OPEN on loss of power (1P DC, 1Q DC). This means the diesel generator
will START on loss of power.
EDG Testing
2 hour loaded run
@
Defeat AS1 (Air Start 1) or AS2 (AirStart 2):
On Defeat AS1, diesel starts on AS2. On defeat AS2, diesel starts on AS1
If an ES comes in while Group 1 or 2 are selected when actual ES or UV occurs, ES comes in other side to start diesel.
EDG Testing
2 hour loaded run
Third switch function
Third Switch allows bypass of air start
solenoid contacts to test individual solenoids
Every month you select different EF-V-16
to air start diesel
EDG Testing
Quarterly Test Switch
ES Test switch in Group 1
position (“A” start relay) causes diesel to start
ONLY on “A” relay during LOOP/ES. Drops out
connection to air start relay so you get light
indication but no EDG start.
EDG testing
Power Transfer Test
2R frequency, 1 EDG per outage
Diesel Room Ventilation
EDG Room supply fan (AH-E-29A/B)
function
provide heating and ventilation for the diesel generator control
rooms.** AH-E-29A/B suction lines are the path for diesel combustion air (fan discharges do NOT provide combustion air.)**
Diesel Room Ventilation
Heater trips
Fan Trips
Other considerations
Heater trips: 160F heater trips (auto reset)
190F heater trips (manual reset)
Loss of air flow de-energizes heating coils
Fan trips: 125F
IF AH-E-29A/B (EDG room supply fan) is NOT available, declare associated EDG INOPERABLE and enter appropriate 3.7.2 clock
SBO Diesel (EG-Y-4)
Purpose
Provides power to ES buses and “C” 4kv on station blackout
EG-Y-4 (SBO diesel)
Electric generator ratings
3000kw (3MW) w/ 3.3MW overload rating. 8 pole, 4160v, 60 hz, 3 phase generator
SBO diesel interlocks
High crankcake pressure (2 of 3) > 0.5” Water
Low Lube Oil Pressuer Idle <5#
Start Failure <250rpm or <20# lube oil pressure in 9 seconds
Low Lube Oil Pressure Running (2 of 3) <16# when >810rpms
86G Differential Overcurrent must be reset at 1F 4160V Bus
Overspeed Trip 960-1020
SBO Diesel
CAN’T cross connect multiple 4kv busses to 1F 4kv SBO bus
Explain interlock
Interlocks look at breaker 52 contacts (not an admin interlock). For example, if SBO
diesel sees 1C breaker 52 contacts CLOSED, it won’t close onto 1D 4kV. The normal feeder breaker must also be OPEN.
SBO Diesel
1Y 480 V disconnect switch has NO kirk key interlock
Explain
It will be Opened under load only by procedurally opening 480V feeder to minimize arc damage
What provides DC control and DC motor power for the SBO diesel
A 1R DC distribution panel in the SBO diesel switchgear room is normally supplied by the battery charger
SBO Diesel
Emergency Operations
Automatic ES load sequencing is NOT permitted while
the SBO diesel is supplying power to 1D or 1E bus. Large ES motors should remain
in PTL unless operation is required. When operation is required, large ES motors
should be started one at a time
Diesel Generator Operations
Unit switch position function
Shorts out voltage droop resistor
Diesel Generator Operations
Parallel switch position function
Allows voltage droop circuit to work, this ensures EDG doesn’t carry excessive VAR loading if grid voltage drops
Speed droop purpose
Prevents EDG from trying to control grid frequency when connected to grid.
ES Standby conditions
Diesel set to AUTO start on ES with Speed droop at 0% and unit/parallel switch in Unit
Control switch on EMIP at Normal
SDR (auto electronic trips) and 5A (gen fault and manual electronic trip) are TRIP RELAYS, should be de-energized in relay cabinet, they prevent EDG restart for 60 secs
Low speed/load ops
Pre cautions
Running diesel at low speed or low load can lead to
build-up of oil in exhaust (fire hazard). You must load the diesel to 50% (1.5
MWe) for 30 minutes and load to 100% for 1 hour prior to shutdown.
What are the conditions and sequence of events for the Emergency Diesel Generator (EDG) to automatically start and connect to the bus?
The EDG will AUTO Start on an ES signal (4# RB, 1600#, or 500# RCS) OR on a
loss of voltage 3760 for 10 sec or 2400V for 1.5sec. Diesel Gen breaker CLOSES
when diesel is up to speed and voltage, both normal bus feeder breakers
OPEN, and bus was de-energized for >3 seconds. Time delay allows fields to
collapse before closing breaker and block loading.
Emergency Diesel Operations
How to stop a runaway diesel?
Only way to stop a runaway diesel is to CLOSE air intake EG-V-15A/B and inject CO2 into air intake or diesel itself.
What happens on loss of 1A/1B DC power?
While operating in PARALLEL, excitation is lost but no power
to OPEN 4kV breaker. Requires immediate tripping of gen breaker using
manual plunger (inside 4kV breaker) to stop motoring and limit damage.
What happens on loss of 1P/1Q DC power?
Excitation lost but output breaker will OPEN. Diesel can only
trip on overspeed (loss of interlocks)
What happens to the Emergency Diesel Generator (EDG) if it is in standby mode and an automatic start is initiated?
IF in STANDBY, diesel will AUTO Start (air start valves fail OPEN), exciter
INOPERABLE, Diesel cannot be stopped by ANY electrical pushbuttons
(MCR, 1E Bus, EMIP)
What to do if EDG is in standby and Ready to Load Light is NOT Illuminated following start?
Must adjust ES voltage rheostat (local) to >4.1kV since Console
exciter in AUTO or place CR exciter in MANUAL and use console rheostat
Precautions & limitations
If DC is lost to the D/G and its 4160V ES bus while operating in parallel with the grid what do you do?
then the generator breaker must be tripped immediately using the manual plunger at
the breaker. This will stop motoring of the D/G and limit damage to the generator.
How many gallons required in DT-T-1 to support EDG operations?
25,000 gallons, DF-LI-152 must indicate 98 inches
(dipstick would have to be >99 – 9/16” )
What low receiver air pressure setpoint would declare EG-Y-1A/B inoperable?
<175# and EG-Y-1A/B is not running
Which dampers, if NOT available would consider the diesel inoperable?
AH-E-29A/B
What position of voltage control position in requires CRO and AO to perform voltage adjustments at panel rheostat?
Voltage control in: Auto
Administrative time clock must be entered for how many days if what happens?
14 days, if SBO diesel is removed from service for extended periods.
OP-TM-864-901
What is not permitted if SBO diesel is supplying power to 1D or 1E 4kv bus?
Auto ES load sequencing
What position should Large ES motors be in, how should they be started if needed?
Pull to lock, started one at a time if needed
