EO1 B2 MAIN GEN Flashcards by Cody Rook

During a Turbine/Generator startup, which ONE of the following actions should be taken AFTER
increasing generator output voltage to 25 KV?

A. CLOSE the Exciter Field Breaker

B. CLOSE the Main Generator Field Breaker

C. Raise Main Generator loading to 50 MWE.

D. CLOSE the Main Generator Output Breakers (34560/34561)

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Per the Generator and Exciter Operating procedure, generator output breakers 34560 and 34561 should
be re-closed within one hour of being opened to

A. minimize pressure on seal components in the operating mechanism

B. minimize the potential for inadvertent main generator reenergization

C. avoid having to start an RCS cooldown within one hour

D. avoid reliance on disconnect switches for isolation

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If reverse power of 5.2 MW is detected on the Main Generator, it will trip

A. immediately

B. after 2-3 seconds

C. after 25-30 seconds

D. only if the turbine stop valves are closed

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The plant is at 100% power.

The following event occurs:

Annunciator 16-4-B, VOLTAGE REG TRBL, is in alarm
Generator Field Volts = O
Generator Field Bkr Control Switch green light is ON
Exciter Field Bkr control switch red light is ON

Assuming NO AUTOMATIC or OPERATOR actions occur, which ONE of the following conditions will result?

A. The Main Generator will fall out of synchronization with the Grid, resulting in slipping a pole.

B. An unbalanced loading between the three phase windings of the Main Generator.

C. An underfrequency condition, resulting in excessive temperatures being generated in the last
stages of the Low Pressure Turbines.

D. Oscillating current flows through the stator windings of the Main Generator resulting in
insulation breakdown.

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The following plant conditions exist:

The plant has commenced a power reduction.
Main Generator loading is 800 MWe.
Both isophase bus fans have tripped on overcurrent.
Zone II operator reports local isophase bus temperatures are 106 °C and rising.

Which one of the following is the maximum Main Generator stator amperage limit imposed?
A. 24600 amps

B. 18200 amps

C. 12400 amps

D. 6600 amps

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6 MC The Main Generator is being paralleled to the grid.

Generator voltage and grid voltage are matched.
Generator frequency is 60.1 Hz.
Grid frequency is 60.0 Hz.

Closing the generator output breaker will

A. cause the generator to immediately pick up load

B. cause generator voltage to rise

C. cause a reverse power trip

D. cause the turbine to overspeed

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Which ONE of the following is NOT a purpose of the Main Generator Exciter System?

A. To control Main Generator Terminal Voltage during Turbine Generator startup.

B. To control megawatt output of the main generator.

C. To control reactive loading on the Main Generator.

D. To supply DC current to the Main Generator Rotor.

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2 MC The purpose of the Main Generator is to

A. Ensure power to C1 and D1 during a loss of offsite power

B. Control reactor power during plant operations

C. Convert mechanical energy of the turbine to electrical energy

D. Prevent the Main Turbine from overspeeding during a partial loss of load

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4 MC The Main Generator converts the energy of the Main Turbine to energy for commercial sales.

A. thermal; rotational

B. mechanical; electrical

C. chemical; thermal

D. hydraulic; electrical

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4 MC The Main Generator converts the energy of the Main Turbine to energy for commercial sales.

A. thermal; rotational

B. mechanical; electrical

C. chemical; thermal

D. hydraulic; electrical

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Which ONE of the following will cause the Main Generator Voltage Regulator to transfer from
AUTO to MANUAL?

A. Stator Coolant flow LOWERS

B. Generator Field Breaker OPENS

C. Main Generator Hydrogen pressure LOWERS

D. Main Generator Output Breakers (34560 & 34561) OPEN.

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Which ONE of the following describes the effect of the URAL circuit on the voltage regulator if the voltage regulator is in MANUAL?

A. In MANUAL control the URAL has NO EFFECT

B. Main Generator MVAR loading cannot be changed (increased or decreased)

C. Attempts to increase incoming MVARs become less effective

D. The voltage regulator will automatically transfer to AUTO control.

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Which ONE of the following Main Generator components is the one into which terminal voltage is
induced?

A. Rotor windings

B. Stator Bars

C. Isolated phase bus

D. High voltage bushing

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9 MC Which ONE of the following could be utilized to determine the stator winding temperatures of
the Main Generator?

A. Temperature meter in the Control Room.

B. Temperature readout located in “A” Switchgear Room.

C. Temperature readout located on Generator skirt.

D. Temperature readout located near Auxiliary Boiler.

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11 MC Which ONE of the following describes the function of the Main Generator Stator?

A. Supplies the magnetic field

B. Has the output voltage induced into it

C. Cools the Main Generator Core

D. Connects the Main Generator to the Auxiliary Transformer

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Which ONE of the following describes the FUNCTION of the Main Generator Rotor?

A. Supplies the magnetic field

B. Has the output voltage induced onto it

C. Contains stator cooling slots for cooling

D. Converts thermal energy to rotational motion

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Which ONE of the following indicates the normal speed at full power of the Main Generator Exciter?

A. 900 RPM

B. 1200 RPM

C. 1800 RPM

D. 3600 RPM

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Which ONE of the following is the function of the Main Generator Exciter Rectifiers?

A. Convert the Exciter DC to AC for the Main Generator Field.

B. Convert the Exciter AC to DC for the Main Generator Field.

C. Convert Main Generator field AC for use in the Exciter.

D. Couple Exciter AC and Main Generator Field to maintain 60 Hz.

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Which ONE of the following describes the location of the Alternator Exciter Field Breaker?

A. Exciter house, 623’ elev.

B. 13.8 KVA “A” bus, 585’ elev.

C. Control Room cabinet area, 623’ elev.

D. Voltage regulator cabinet, 603’ elev.

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Which ONE of the following describes the location of the Alternator Exciter Rectifier disconnects?

A. Exciter housing, 623’

B. 13.8 KVA “A” bus, 585’

C. Control Room cabinet area

D. Voltage regulator cabinet, 603’

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Which ONE of the following components applies the Direct Current directly to the Main Generator Field Windings?

A. brushes and collector rings

B. high voltage bushings

C. exciter field rectifiers

D. rotor retaining rings

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In accordance with OB-OP-06301, which of the following values is the maximum value that can
be applied to the Generator Field?

A. 500 VAC
B. 400 VAC
E. 250 VAC
D. 120 VAC

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4 MC Which ONE of the following combinations describes the field current of the Main Generator?
The current passes through the field breaker, then is supplied to the Main Generator
field windings via exciter brushes.

A. DC; generator

B. DC; exciter

C. AC; generator

D. AC; exciter

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ONE purpose of the lsophase Bus Cooling System is to cool the

A. Main Generator rotor

B. Main Generator stator

C. Power Rectifier cabinets

D. Main Generator High Voltage bushings

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Which ONE of the following sequences describes the flow path of air through the lsophase Bus
Cooling System?

A. fan, B phase duct, A and C phase ducts, cooling coil, fan

B. fan, cooling coil, B phase duct, A and C phase ducts, fan

C. fan, cooling coil, B phase duct, A and C phase ducts, outside air damper

D. fan, A phase duct, B phase duct, C phase duct, cooling coil, fan

Which ONE of the following combinations correctly arranges the Isolated Phase Bus Cooling System flowpath starting at the fan?

Cooling coils
De-ionizing
“B” phased
“A” and “C”

A. 1, 4, 3, 2

B. 2,3, 1, 4

C. 3, 2,4, 1

D. 4,3,2, 1

Which ONE of the following conditions is indicated if the Main Generator Core Monitor alarms?

A. Stator winding overheating

B. Power Rectifiers overheating

C. Exciter Rectifiers overheating

D. Rotor winding overheating

Which ONE of the following will cause Control Room annunciator 16-2-D, CORE MONITOR ALARM to
alarm?

A. Loss of power to monitor

B. Low Generator gas temperature

C. High TPCW cooling water flow

D. Hi / Low Generator gas pressure

Which ONE of the following describes the function of the Main Generator Core Monitor?

A. Provides indication of Main Generator pressure

B. Provides warning of Stator Coolant leaks into the Main Generator core

C. Provides warning of Main Generator core hydrogen flow imbalance

D. Provides indication of Main Generator overheating

3 MC Which ONE of the following annunciators normally comes into alarm following a Main
Turbine/Generator trip?
(Assume the T/G trip is due to a reactor trip).

A. VOLTAGE REG TRBL,

B. FIELD CURRENT HI,

C. VOLTS/HZ HI,

D. EXCITER RECT TEMP HI,

Which ONE of the following conditions would cause the “VOLTAGE REG TRBL” annunciator to come into alarm in the Control Room?

A. The Control Room Operator transferring the Voltage Regulator from Auto to Manual.

B. A high temperature condition for any bank of Power Rectifiers.

C. The Generator Field Breaker tripping open.

D. The Voltage Regulator reaching the URAL (Underexcited Reactive Ampere Limiter) limit.

Which ONE of the following conditions is indicated by annunciator 16-4-B, VOLTAGE REG TRBL?

A. The generator field breaker has TRIPPED

B. The voltage regulator is transferred from MANUAL to AUTO

C. A ground has been detected on the exciter field

D. Main generator stator voltage is LOW

Which ONE of the following Main Generator relays is NORMALLY actuated following a Main Turbine trip?

A. Unit Differential Current (87x11)
B. Generator Ground (64G)
C. Generator Reverse Power (32)
D. Loss of Field (40)

Turbine speed has decreased to 1500 RPM. Which ONE of the following Control Room alarms
would be expected?

A. GEN UNDER FREQUENCY TRIP (16-1-D)
B. ESOP ON (16-1-H)
C. FIELD VOLTAGE HI (16-3-B)
D. VOLTS/HZ HI (16-5-B)

The plant is at 79% RTP with a power increase in progress. A Main Generator lockout occurs due to the activation of the 51V relay (overcurrent).

Which ONE of the following lists the breakers which will automatically trip open as a result of
this condition?

ACB 34560 and ACB 34561 (Main Generator Output Breakers)
ABS 34620 (Main Generator Disconnect)
Main Generator Field Breaker
HX01A, HX02B (SU XFMR 01/02 Output)
HX11A, HX11B (X11 XFMR Output)

A. 1, 2, 3

B. 1, 2, 5

C. 1, 3, 4

D. 1, 3, 5

Which ONE of the following conditions will allow the Control Room operator to manually open the Exciter Field Breaker?

A. The Main Generator Field Breaker OPEN

B. Both Main Generator Output Breakers (ACB 34560, ACB 34561) OPEN

C. The Main Generator Voltage Regulator in MANUAL (DC) control

D. The Main Generator Ground Switch (34645) being OPEN.

The plant is at 100% power.
Which ONE of the following actions will NOT occur as a result of an overcurrent (51 V Relay) condition being sensed by the Main Generator Protective Relays?

A. Main Turbine speed will INCREASE to ~105%.
B. The Generator Field Breaker will OPEN.
C. The Main Generator output breakers (34560 & 34561) will OPEN.
D. A and B bus will be energized via the Startup Transformers.

Which ONE of the following will occur if the EXCITER FIELD GROUND DETECTOR senses a ground?

A. The Exciter Field Breaker OPENS, and a CTRM annunciator alarms.

B. The Main Generator Field Breaker OPENS, and a CTRM annunciator alarm.

C. The Main Generator Output Breakers (34560/34561) OPEN, and a CTRM annunciator alarms.

D. A CTRM annunciator ALARMS only.

Which ONE of the following occurs if the Generator Field Ground Detector senses a ground?

A. A CTRM annunciator ALARMS.

B. The Main Generator Field Breaker OPENS.

C. A Main Generator Exciter Field Breaker OPENS.

D. The Main Generator Lockout occurs.

Which ONE of the following conditions is indicated if the Main Generator Core Monitor alarms?

A. Stator winding overheating

B. Power Rectifiers overheating

C. Exciter Rectifiers overheating

D. Rotor winding overheating

Which ONE of the following Main Generator Component’s temperature is monitored by resistance
temperature detectors AND thermocouples?

A. Stator

B. Rotor

C. lsophase Bus

D. Power Rectifier

Which ONE of the following could be utilized to determine the stator winding temperatures of
the Main Generator?

A. Temperature meter in the Control Room.

B. Temperature readout located in “A” Switchgear Room.

C. Temperature readout located on Generator skirt.

D. Temperature readout located near Auxiliary Boiler.

Which ONE of the following is the purpose of the Shaft Grounding Device on the Main Turbine/Generator?

A. To detect ground faults in the Main Generator stator windings.

B. To detect failure of the Main Turbine shaft grounding straps.

C. To detect a flashover of the Main Generator field brushes and collector ring assemblies.

D. To prevent the removal of more than three sets of field brushes when the Generator field breaker
is closed.

Which ONE of the following Main Generator indications CAN NOT be read in the Control Room?

A. Wattmeter

B. Temperature

C. Frequency

D. Megavar

Which ONE of the following describes the function of the Main Generator Core Monitor?

A. Provides indication of Main Generator pressure

B. Provides warning of Stator Coolant leaks into the Main Generator core

C. Provides warning of Main Generator core hydrogen flow imbalance

D. Provides indication of Main Generator overheating

The voltage regulator holds the Main Generator Field voltage constant

and the voltage regulator holds the Main Generator Terminal Voltage constant .

A. Droop, auto

B. Manual; auto

C. Auto; manual

D. Manual; droop

Which one of the following will NOT cause the amber neon lamps on the main generator rectifier cabinet to illuminate?

A. Low voltage

B. Shorted diode

C. High SCR temperature

D. Blown fuse

During your Zone 2 tour, you notice that the red indicating light on one of the power rectifier
cabinets is on.
Which ONE of the following explains why the light is on?

A. Low voltage
B. Shorted diode
C. Blown fuse
D. High SCR temperature

The plant is operating at 100%.
During rounds the Zone 2 operator notices that the yellow neon lights associated with the #1 bank
of power rectifier assemblies on the exciter housing are ON.
Which ONE of the following would be the reason for this indication?

A. This is their NORMAL condition.

B. A fuse has BLOWN on the rectifier.

C. A rectifier diode has FAILED.

D. The generator field breaker has TRIPPED.

MC Plant conditions are as follows:

The plant is at 100% reactor power
Generator gross MWe = 921
Generator terminal voltage = 24 KV
#1 and #2 Turbine Plant Cooling Water pumps are in service

While taking readings the Zone 2 operator reports that the RED light located on the #2 power rectifier bank door is lit.

Which ONE of the following could be a reason for this condition?

A. Stator cooling flow has been LOST to the #2 rectifier bank.

B. The disconnect for the #2 Rectifier Bank is NOT in the fully engaged position.

C. A diode circuit has FAILED in the #2 Rectifier Bank.

D. The Rectifier Bank is in service. This is a NORMAL indication.

6 MC The frequency of the Main Generator is related to which of the following?

A. Turbine speed

B. Exciter field strength

C. Reactive Load

D. Combined intercept valve position

Excessive AC generator currents CAN NOT be caused by operating the generator in an
condition.

A. overvoltage

B. undervoltage

C. overload

D. underload

Which ONE of the following combinations represent the NORMAL values for the Main Generator output
frequency and output voltage at full power?

A 60 Hz., 25 KVAC
B 30 Hz., 25 KVAC
C 60 Hz., 345 KVAC
D 30 Hz., 345 KVAC

Which ONE of the following components is NOT required to be in operation for the Main Generator to
produce electrical power?

A. Generator Field Breaker

B. Exciter Field Breaker

C. Main Transformer

D. High Voltage Bushing

Voltage (volts) can be defined in terms of

A. an electrical potential difference

B. the rate of doing electrical work

C. coulombs of charge

D. cycles per second

Current can be defined in terms of

A. electrical work

B. cycles per second

C. coulombs per second

D. an electrical potential difference

Frequency can be defined in terms of

A. electrical work

B. coulombs of charge

C. cycles per second

D. an electrical potential difference

Reactive power is the portion of the apparent power that is

A. effectively returned to the source and is measured in KVARs

B. effectively returned to the source and is measured in KVAs

C. actually dissipated in the load and is measured in watts

D. obtained by multiplying applied voltage and line current and is measured in watts reactive

True power is that portion of apparent power that is

A. effectively returned to the source and is measured in KVAs

B. actually dissipated in the load and is measured in watts

C. effectively returned to the source and is measured in KVARs

D. obtained by multiplying applied voltage and line current and is measured in watts reactive

The Main Generator is being paralled to the grid. The following conditions exist:
* Main Generator frequency 59.9 Hz

Grid frequency 60 Hz

Which one of the following will occur when the first generator breaker is closed?

(Assume that NO generator protection relay actuates)

A. The generator will motorize.

B. The generator will accept to much load.

C. The voltage of the generator will lower to compensate for the frequency.

D. The entire connected system will operate at the frequency of the lowest frequency generator.

Reactor power is 100%.

The following conditions occur:

The Generator Condition Monitor (GCM) has a verified alarm indicating 50%.
What action is required?

A. Remove the Generator from service

B. Have l&C check the GCM calibration

C. Lower Generator load to raise the GCM reading to 80%

D. Maintain current Generator load until engineering evaluations are completed

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EO1 B2 MAIN GEN Flashcards

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