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Flashcards in EDG Deck (75):
1

What is EDG rated output?

  • Continuously rated for 2,500 KW at 80% power factor
  • 2,750 KW, 2-hour rating.
  • Output Breaker trips at 824 Amps. 752 ams is normal rating.

2

What Air Start System setpoints for operability and normal ranges? 

  • 100 rpm crank for 40 seconds with 90 psi to the starting air motor.
  • Starting air is normally provided to the air start motors at 150 psig and tank pressure is greater than 235 psig.
  • Tank pressure must be ≥215 psig per SOP-22 to be Operable
  • Starting air >=95 psig but <= 175 psig per SOP-22 to be Operable

3

For the Lube Oil System, describe its operational design basis and the normal operating range.

  • Provides lubrication for engine bearings, vibration damper, turbocharger, and internal crankcase components during engine operation.
  • Maintains the engine at approximately 120°F for fast starting when shutdown.
  • Normal operating temperature between 175°F and 190°F with max of 200°F.
  • The system normal operating pressure is between 80 psig and 90 psig.
  • System normal operating flow is approximately 320 gpm.
  • Must be >90F and < 205F

4

For the Fuel Oil System, describe its operational design basis and the normal operating range.

Provides storage of an adequate fuel supply,

  • 28,592 gallons is 6 day supply

The engine system normal operating pressure is between 40 psig and 60 psig.

5

For the Jacket Cooling Water System, describe its operational design basis and the normal operating range.

  • Removes heat from the engine cylinders, block, heads, turbocharger, and aftercooler during operation, and maintains the engine at an elevated "Standby" temperature of approximately 120°F for fast starting when shutdown.
  • Normal operating temperature is between 160°F and 185°F, maximum allowable is 195°F.
  • The system normal operating pressure is between 10 psig and 50 psig.
  • System normal operating flow is between 630 gpm and 700 gpm.
  • The jacket water surge tank provides for jacket water expansion, makeup, inhibitor addition, and pump suction head. The tank also provides sufficient static head to protect the turbocharger from low water and vents air entrapped in the system

6

For the Turbocharger, describe its operational design basis and the normal operating range.

Uses hot exhaust gases to drive a turbine that takes in fresh air, compresses it (15 to 24 psig), and forces the air into the cylinders on the intake stroke. Exhaust temperatures (loaded) reach approximately 1200°F. To prevent heat damage to the turbocharger and to ensure cool air is discharged into the intake manifold, jacket water and lube oil are piped to the turbocharger. At full rated load and speed, the maximum allowable turbocharger inlet exhaust gas temperature is 1350°F

7

For the NSD/DBA Sequencers, describe its operational design basis and the normal operating range.

  • There are two separate, independent load sequencing channels (left and right), each consisting of a load sequencer and its associated actuation logic located in in Control Room Panel C-13.
  • The sequencers and their input logic are powered from separate, independent Preferred AC panels (Y20 and Y30).
  • Each sequencer contains a processor, an AC input card, two AC output cards and three DC output cards.
  • 55 seconds cycle time

8

What is the 1-1 EDG Output Breaker?

152-107

9

What is the 1-2 EDG Output Breaker?

152-213

10

What are the features of the Emergency Diesel Generator Output Breaker Interlocks for manual operations?

  • The generator overcurrent/differential lockout relay is reset.
  • No bus overcurrent lockout relay present.
  • The breaker's manual synchro-switch is closed.
  • The synchro-check circuit senses generator output voltage and phase sufficiently close to that of the bus to provide the close permissive to the generator breaker

11

What are the features of the Emergency Diesel Generator Output Breaker Interlocks for automatic operations?

  • Both incoming bus supply breakers (i.e., from both the Safeguard Bus 152-105 and SUT 1‑2 152-106) are open.
  • The generator overcurrent/differential lockout relay is reset.
  • No bus overcurrent lockout relay present.
  • Adequate EDG output voltage (as determined by the "127D" voltage relays [3/3 logic]).
  • Confirmed 2400 V AC bus load shed (3 and 4 together = 106-D1 relay made up) The confirmed load shed is necessary to assure that the bus is sufficiently clear to preclude excessive blockloading of the generator upon breaker closure.

12

What lockout protection is provided to the Emergency Diesel Generator output breakers?

Lockout protection is provided to preclude auto-closure of the EDG breaker to a faulted bus. The bus lockout protection initiates when the normal supply (Station Power/Safeguards) breaker trips on overcurrent. The EDG will automatically start on an undervoltage signal but the overcurrent trip will block the EDG breaker automatic closure until the overcurrent lockout relay has been manually reset.

13

What is the Woodward Governor mechanical subsystem for speed/load control for the Emergency Diesel Generator?

  • It provides backup for the electrical governor during EDG operation.
  • The mechanical governor limits fuel to the engine to maintain the speed at setpoint.
  • The speed setpoint is maintained higher than the electronic governor setpoint.
  • Speed droop is applied to the speed setpoint to ensure proper operation (stability) when the EDG is paralleled to the grid.
  • A speed droop control knob located on the governor sets the speed droop input. If the EDG is operated in the isochronous (unit) mode, the speed droop must be set to zero to maintain frequency at 60Hz

14

What is the Woodward Governor electrical subsystem for speed/load control for the Emergency Diesel Generator?

  • The electronic governor control system normally assumes control of the engine fuel supply after intial startup.
  • It uses the electrical input section of the governor/actuator to control the generator output frequency in the unit mode or load in parallel mode.
  • The Woodward EGA Controller is located at Panel C-22 (C-26).
  • The electronic governor operates in the isochronous (unit) mode when the PARALLEL/UNIT selector switch is in the UNIT position and in the droop mode when in the PARALLEL position.

15

What is the Unit Control Mode of the Woodward Governor electrical subsystem for speed/load control for the Emergency Diesel Generator?

  • Established by the unit/parallel switch in the UNIT position
  • Used to control frequency during emergency operation when the generator operates independently from other 60Hz power sources.
  • In Unit mode, load shed breaker interlocks assure that the generator can only be connected to a dead bus.
  • Loading of the generator is "controlled" by the load shed system (which clears most loads from the bus automatically before generator connection), in conjunction with the DBA/NSD sequencer (which "controls" the maximum step loading and the total generator load automatically following connection to the bus).

16

What is the Parallel Control Mode of the Woodward Governor electrical subsystem for speed/load control for the Emergency Diesel Generator?

  • Established by the unit/parallel switch in the PARALLEL position
  • Used to control generator load during EDG load testing.
  • EDG runs in parallel and follows frequency with station or offsite power sources (grid), which appear as an infinite bus to the EDG.
  • When supplying power to the infinite bus (grid) during parallel operation, the emergency generator must be prevented from carrying too much real and reactive load due to fluctuations of grid frequency and voltage.

17

What is Speed Droop Control?

  • To prevent excessive real loading and add stability to the control system, the electronic governor operates with speed droop while in the Parallel Control Mode.
  • Speed droop is set internally in the EGA (electronic governor control).
  • Speed droop automatically adjusts the speed setting to a preset value based upon generator output (load).
  • To prevent excessive reactive loadings and add stability to the control system, the voltage regulator operates automatically with voltage droop while in the Parallel Control Mode.

    (a)    The voltage droop mode prevents the generator from carrying too much reactive load in the over-excited or under-excited mode with respect to the infinite bus (grid).

18

What are the EDG 187 Relays?

Three (187) differential relays (one per phase) are connected to current transformers, one set on the neutral side of the generator windings and the other set on the bus side of the 2400V EDG incoming circuit breaker.  

This arrangement protects the generator, generator incoming circuit breaker and the power cables against faults in this zone. 

The relays trip the 2400V EDG breaker via lockout relay (186) and shut down the diesel engine via the shutdown relay (SDR).

19

What are the EDG 151 Relays?

Three inverse time overcurrent relays (151) are connected on the generator side of the EDG 2400V breaker to protect the EDG circuit from overloads.

They function by tripping the EDG breaker via lockout relay (186) and shut down the diesel engine via the engine shutdown relay (SDR).

The relays provide an alarm at 100% of the generator nameplate loading and trip the generator at 110% of the nameplate rating, based on 3125 KVA at 80% power factor.

The overcurrent trip logic is a two out of three (2/3) coincidence.

Trip Setpoint is 824 amps.

20

What is Incomplete or Cranking Failure Start for the EDG?

  • Activated by Overcrank Timer 1 or OCT2 or Overcrank Relay (OCR).
  • Engine cranking for > 10 seconds with <= 10 psig Jacket Water Pressure and RPM < 120.

21

Describe the consequences of operating the Emergency Diesel Generators under improper temperature, pressure or flow parameters (water, air, oil)

If lube oil pressure <= 40 psig and EDG not tripped, then trip it.

If lube oil pressure DP > 20 psid, then EDG in operable. If conditions allow, shut down unit.

If lube oil temperature >= 200F with no service water, then trip it. Otherwise unload and secure if plant conditions permit. If less than 90F then EDG in operable.

If raw water pressure <= 25 psig and loss of service water, then trip the diesel. If operation required, maintain JW Temp <195F and Oil <205.

JW pressure less than 10 psig trips off crankcase exhausters and requries unit shut down if other power available.

If JW temperature >= 195 or <=95, then EDG in operable. If conditions permit, unload and stop.

If starting air pressure < 95 psig on two indicaters, EDG is inoperable.

22

Describe the consequences of operating the Emergency Diesel Generators in an under excited condition.

Excessive reactive load can result in generator high currents and over-heating. When the rotor field excitation is less than that required, leading reactive current flows in the generator stator windings.  These flows in the generator stator winding can cause the stator end-turns can overheat, this leads to insulation damage.  If left unchecked, the rotor field strength can weaken to the point that the generator could "slip a pole". This causes catastrophic failure of the coupling between the prime mover and the generator, and sometimes worse

23

Describe the consequences of operating the Emergency Diesel Generators in an over excited condition.

Over excitation of a generator causes saturation of the magnetic core of the generator, and stray flux may be induced in non-laminated components that are not designed to carry flux.  Excessive flux may also cause excessive eddy currents in the generator laminations that result in excessive voltages between laminations. This may cause severe overheating in the generator or transformer and eventual breakdown in insulation”

24

Describe the consequences of closing a breaker between buses with unmatched frequency or voltage.

Sync Check should not allow it. Generator/breaker damage is result.

25

Describe the consequences of operating the Emergency Diesel Generators with a Loss of Diesel Generator room cooling.

Generator/Exciter overheating. Both fans required if outside air temp 85F or greater.

26

Describe the consequences of operating the Emergency Diesel Generators with loss of bus control power, trip features.

EDG Damage, no start of EDG

27

Describe the consequences of operating the Emergency Diesel Generators with a loss of off-site power during full load testing of Diesel Generator in accordance with SOP-22, AOP-20/21, ARP-20. 

Output breaker trips, place in Unit mode after EOP-1.0 actions completed.

28

What is the power supply to P-18A?

480V MCC-8. MCC-8 is powered via LCC-12 via D-Bus

29

What is the power supply to P-18B?

480V MCC-1 via LCC-19 and C-Bus

30

What is the power supply to C-3A, 1-1 EDG Air Compressor?

Electrical: 52-116C, via 52-116 via MCC-1 via LCC-19 via C-Bus

Gasoline engine.

31

What is the power supply to C-3B, 1-2 EDG Air Compressor?

Electrical: 52-216C via 52-216 via MCC-2 via LCC-20 via D-Bus

Gasoline Engine

32

Given a loss of or malfunction of the Emergency Diesel Generator System describe the effects on the NSD/DBA load sequencer and Safety Related Systems in accordance with ARP-3, ARP-7, AOP-20/21.

OOS

33

For automatic actions associated with the Emergency Diesel Generator System,
a. state the parameter and value (setpoint) at which each automatic action occurs
b. explain the purpose of each automatic actuation

EDG Trips:

  • Overspeed: 1060 - 1105 rpm
  • Low Lube Oil Pressure: Less than 40 psi (2/2) & Engine Running > 20 sec
  • Low JW Pressure: <10 psi for >45 sec (2/2)
  • Cranking W/O Start: ESR with JWP <10 psi for >10 sec
  • Electrical: Overcurrent or Differential

Load Shed: Under/Degraded Voltage
Sequencer: NSD or DBA

 

34

What and where is the control room EDG Control Switch?

Located on C-04:  
Allows starting and stopping EDG: Two position – start/stop

  • Green EDG Ready Light: light goes out on EDG trouble alarm
  • White EDG Cranking Light: On when EDG is cranking with start switch from control room. Off when overcrank relays CR1 and CR2 are satisfied via Jacket Water Pressure >10 psig and tach >120 rpm.
  • Red EDG running light on when EDG speed > 820 RPM and RLTS switch in "REMOTE" position.

35

What and where is the control room EDG Governor Setpoint Switch?

Location: C04

  • Used to raise or lower engine speed
  • Two position switch – Raise turn counterclockwise, Lower turn clockwise
  • Blue governor limit lights lighted when at the highest or lowest speeds you can obtain with raise/lower switch

36

What and where is the control room EDG Field Rheostat  Switch?

Location: C-04

  • To raise or lower EDG voltage
  • Two position – raise/lower
  • Blue auto limit lights
  • Applies when voltage control is in auto
  • Lights when voltage is at "Raised Limit" (RL) or "Lower Limit"(LL)

37

What and where is the control room EDG Unit Parallel Switch?

Location: C-04

Selects mode of governor operation
Two position switch – PARL/UNIT

a)      Green light indicates in parallel

b)      Red light indicates in unit

38

What and where is the control room voltage regulator switch?

Location: C-04

  • Allows either manual or automatic control of voltage
  • Two position switch – Man/Auto
  • Blue manual limit lights
    Applies when voltage control is in manual
    Lights when voltage is at "Raised Limit" (RL) or "Lower Limit" (LL)

39

What and where is the control room Voltmeter Selector switch?

Location: C-04

AC voltmeter Selector switch

Phase selector switch
Four positions: OFF / 1-2 / 2-3 / 3-1

40

What and where is the control room EDG Sync switch?

EDG synch switch

  • For paralleling to energized bus using EDG output breaker
  • Two position switch – Off/On

41

What and where is the control room EDG Output Breaker switch?

Location: C-04

EDG Output Breaker Control Switch

Four position switch

  • Trip
  • Close
  • Normal After Trip
  • Normal After Close

Green Open Light
White Springs Charged Light
Red Closed Light

42

What and where is the control room EDG Synchroscope and Synchronizing Voltage Indicators?

Location: C-04

1)      Common indicators for all bus synchroscoping

43

What and where is the control room EDG AC ammeters for X, Y, Z EDG output current?

Location: C-04

  • Current depends on load
  • All three should read approximately the same
  • +/- 10% differential between indicators
  • Local meters are provided in the EDG room.

44

What and where is the control room EDG AC voltmeter?

Locaton: C-04

  • Selected by phase selector switch
  • Should read same as bus voltage (2400 volts)
  • A local meter is provided in the EDG room.

45

What and where is the control room EDG Watt Meter?

Location: C-04

  • Depends on load
  • Digital indication. 
  • Powered up by the EDG output voltage. 
  • Meters will be normally blank and are illuminated when voltage on the generator is greater than ~1800 volts.

46

What and where is the control room Frequency meter?

Location: C-04

  • 61.4 Hz blue line on dial represents the correct meter at rest position.
  • A local meter is provided in the EDG room.

47

How does Service Water relate to the EDG?

Critical Service Water provides required coolant to the lube oil and jacket water heat exchangers of each diesel engine.

48

What Critical Service Water Headers feed the EDGs?

EDG-1 is off 'B' Header
​EDG-2 is off 'A' Header

49

How does the Primary System Makeup Water System interact with the EDGs?

The Primary System Makeup Water System provides required makeup water to the Jacket Water System via the system surge tank. Low Level Alarm at 4" from bottom of tank.

50

How does T-926 interface with the EDGs?

The Fuel Oil Storage Tank (T-926) provides backup fuel supply to T-10A from an on-site source.

51

How does the 125 DC system interface with the EDGs?

The 125V DC System supplies EDG field flashing and control power.

52

How does the 120V AC Preferred Power interface with the EDGs?

The 120V AC Preferred Power supplies power to the sequencer schemes.

53

How does the 480v AC system interact with the EDGs?

The 480V AC System supplies EDG system pumps and the starting air compressor.

54

Describe the recommended loading rates and the reasons for those rates

  • 2500 KW for continuous operation
  • 2750 KW (10%) overload rating for two hours. 

 

55

Explain why a cylinder leak test is to be performed prior to engine start

Purpose of the leak check is used to identify any fluid in the engine cylinders that could cause a hydraulic lock and engine damage.

56

Describe the required actions for a failed Cylinder Leak Test

IF moisture accumulation is greater than a fine mist, THEN:
1. RECORD cylinder number(s). __________
2. RECORD approximate amount and type of fluid.
3. INITIATE a Condition Report.
4. ENSURE engine is NOT rotated until the condition has been
evaluated.

57

Predict how operation of the Emergency Diesel Generator System impacts fuel consumption rate with load.

Fuel consumption increases linearly as load increases. Approximately double fuel for double load.

58

Predict how operation of the Emergency Diesel Generator System Cylinder differential temperature with load.

Recommended maximum difference between cylinder exhaust temperatures is 150 F. If differential temperature between cylinders exceeds 150 this may indicate degrading performance of fuel system. Vendor manual maximum acceptable difference is 400 F.

59

Given plant conditions involving an EDG surveillance test, explain the consequences of not restoring the EDG voltage regulator to the proper setpoint upon completion of testing in accordance with SOP-22.

EDG output may not be at required 2400v (2390v - 2410v)

60

Explain why the generator load is only reduced to 50 Kw prior to opening the generator output breaker in accordance with SOP-22.

Prevents possible motoring

61

Describe what is expected to occur if/when Relay 127-7 (Relay 127-8) is reset when the diesel generator, (D/G 1-1/D/G 1-2) is manually started from the Control Room in accordance with SOP-22.

WHEN Relay 127-7 (127-8) is reset, THEN D/G 1-1 (D/G 1-2) output breaker will
automatically close and appropriate sequencer should start.

62

Identify redundant Control Room indications that can be used to validate EK-0549, "DIESEL GEN BKR 152-207 TRIP"

  • Bkr status lights for 152-107
  • 186-107 Bkr Lockout Relay White status light (Bkr 152-107)
     

63

Identify redundant Control Room indications that can be used to validate EK-0550, "DIESEL GEN NO 1-1 FAIL TO START"

  • No indication on D/G voltmeter (EC-04)
  • Local indications

64

Identify redundant Control Room indications that can be used to validate EK-0553, "DIESEL GEN NO 1-1 & 1-2 OVERLOAD"

  • D/G amps (EC-04)

65

Identify redundant Control Room indications that can be used to validate EK-0554, "DIESEL GEN DAY TANK T-25A HI-LO LEVEL"
 

  • Local level indication on T-25A, Diesel Generator Day Tank

66

Identify redundant Control Room indications that can be used to validate EK-0555, "DIESEL GEN BKR 152-213 TRIP"

  • Bkr status light for 152-213
  • 186-213 Lockout Relay white status light (Bkr 152-213)

67

Identify redundant Control Room indications that can be used to validate EK-0556, "DIESEL GEN NO 1-2 FAIL TO START"

  • No indication on D/G voltmeter (EC-04)
  • Local Indications

68

Identify redundant Control Room indications that can be used to validate EK-0559, "DIESEL OIL STORAGE TANK T-10A LOW LEVEL"

  • T-10A dipstick

69

Identify redundant Control Room indications that can be used to validate EK-0560, "DIESEL GEN DAY TANK T-25B HI-LO LEVEL"
 

  • Local tank level

70

Identify redundant Control Room indications that can be used to validate EK-1121, "SEQUENCER CONTROL ENERGIZED"

None

71

What is LCO 3.3.5, its Applicability and 1 hour or less action statements?

  • Three channels of Loss of Voltage Function and three channels of Degraded Voltage Function auto-initiation instrumentation and associated logic channels for each DG shall be OPERABLE.
  • APPLICABILITY: When associated DG is required to be OPERABLE.
  • Immediately enter applicable conditions and required actions for INOPERABLE EDG

 

72

What is LCO 3.8.1, its Applicability and 1 hour or less action statements?

The following AC electrical sources shall be OPERABLE:

  • Two qualified circuits between the offsite transmission network and the onsite Class 1E AC Electrical Power Distribution System;
  • Two Diesel Generators (DGs) each capable of supplying one train of the onsite Class 1E AC Electrical Power Distribution System.

APPLICABILITY: MODES 1, 2, 3, and 4.

1 Hour Actions

  • Perform SR 3.8.1.1 (offsite source check) for OPERABLE offsite circuit.

73

What is LCO 3.8.2, its Applicability and 1 hour or less action statements?

Shutdown AC Sources: The following AC electrical power sources shall be OPERABLE:

  • One qualified circuit between the offsite transmission network and the onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.10, "Distribution Systems - Shutdown"; 
  • One Diesel Generator (DG) capable of supplying one train of the onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.10.

APPLICABILITY: MODES 5 and 6, During movement of irradiated fuel assemblies.

1 Hour or Less Actions Statements

All actions are immediate and identical for EDG or qualified circuit

  • Enter applicable Conditions and Required Actions of LCO 3.8.10,
  • Declare affected required feature(s) with no offsite power available inoperable.

OR

  • Suspend CORE ALTERATIONS.

AND
Suspend movement of irradiated fuel assemblies.
AND
Initiate action to suspend operations involving positive reactivity additions.
AND
Initiate action to restore required offsite power circuit to OPERABLE status

74

What is LCO 3.8.3, its Applicability and 1 hour or less action statements?

For each Diesel Generator (DG):

  • The stored diesel fuel oil, lube oil, and starting air subsystem shall be within limits
  • Both diesel fuel oil transfer systems shall be OPERABLE.

APPLICABILITY: When associated DG is required to be OPERABLE.

1 Hour or Less ACTIONS

Immediately declare associated EDG inoperable if stored diesel fuel oil, lube
oil, or starting air subsystem not within limits for reasons other than:

  • Fuel oil or lube oil inventory less than a 7 day supply and greater than a 6 day supply.
  • Fuel oil properties other than viscosity, and water and sediment, not within limits.

75

Describe the basis for the diesel generator being INOPERABLE when running in parallel with its respective safeguards bus in accordance with Technical Specification Bases, MO-7A-1, MO-7A-2.

EDG is considered inoperable due to the Droop Selector Switch or the
Regulator Auto/Manual Switch in "Parallel" or "Manual" respectively. Under these
conditions the EDG, while synchronized to the grid, will not respond, as designed, if
grid voltage dips sufficiently to trip the EDG output breaker.