Breakers

Front 1

To completely deenergize an electrical component and its associated control and indication circuits, the component breaker should be... A. open with the control switch in Pull-To-Lock. B. open with the control switch tagged in the open position. C. racked out and tagged in the racked-out position. D. racked out with control power fuses removed.

Back 1

D.

Front 2

Which one of the following describes the normal operation of a local breaker overcurrent trip flag indicator? A. Actuates when no lockout is present; satisfies an electrical interlock to remotely close a breaker. B. Actuates when a breaker overcurrent trip has occurred; can be manually reset when the overcurrent condition clears. C. Actuates when a breaker has failed to trip on an overcurrent condition; can be manually reset when the overcurrent condition clears. D. Actuates to cause a breaker trip when the overcurrent trip setpoint is reached; can be remotely reset when the overcurrent condition clears.

Back 2

B.

Front 3

Given the following indications for an open 4,160 VAC breaker: All phase overcurrent trip flags are reset. The control power fuses indicate blown. The line-side voltmeter indicates 4,160 VAC. The load-side voltmeter indicates 0 volts. Assuming no operator actions were taken since the breaker opened, which one of the following could have caused the breaker to open? A. A ground fault caused an automatic breaker trip. B. A loss of control power caused an automatic breaker trip. C. An operator tripped the breaker manually at the breaker cabinet. D. An operator tripped the breaker manually from a remote location.

Back 3

C.

Front 4

Which one of the following describes the local overcurrent trip flag indicators for a breaker? A. They actuate prior to breaker tripping to warn of imminent protective action. B. When actuated, they indicate that the breaker overcurrent trip relay has been reset. C. They indicate breaker overcurrent trip actuation during and after breaker trip actuation. D. When actuated, they indicate that the associated breaker has failed to trip open.

Back 4

C.

Front 5

Loss of breaker control power will cause... A. inability to operate the breaker locally and remotely. B. breaker line voltage to indicate zero regardless of actual breaker position. C. the remote breaker position to indicate open regardless of actual breaker position. D. failure of the closing spring to charge following local closing of the breaker.

Back 5

D.

Front 6

Which one of the following results from a loss of control power to a breaker supplying a motor? A. Motor ammeter indication will be zero regardless of actual breaker position. B. Breaker position will remotely indicate closed regardless of actual position. C. Breaker will trip open due to the actuation of its protective trip device. D. Charging motor will not recharge the closing spring after the breaker closes.

Back 6

D.

Front 7

Which one of the following would cause a loss of ability to remotely trip a circuit breaker and a loss of remote breaker position indication? A. Failure of the breaker control switch B. Racking the breaker to the "test" position C. Mechanical binding of the breaker tripping bar D. Loss of control power for the breaker

Back 7

D.

Front 8

Which one of the following will cause a loss of indication from the remote breaker position indicating lights associated with a typical 480 VAC load supply breaker? A. Loss of breaker line voltage B. Locally opening the breaker C. Burnout of the local breaker position indicating lights D. Removing the breaker control power fuses

Back 8

D.

Front 9

How is typical breaker operation affected when the associated breaker control power transfer switch is placed in the "Local" position? A. Control power will be available to provide protective trips, and the breaker can be electrically operated only from the control room. B. Control power will be removed from both the open and close circuits, and the breaker can be electrically operated only from the control room. C. Control power will be available to provide protective trips, and the breaker can be electrically operated only from the breaker cabinet. D. Control power will be removed from both the open and close circuits, and the breaker can be electrically operated only from the breaker cabinet.

Back 9

C.

Front 10

A typical 120 VAC manual circuit breaker has tripped due to overload. To close this circuit breaker the breaker handle must be moved from the... A. OFF position directly to the ON position; trip latch reset is not required. B. OFF position to the midposition to reset the trip latch, and then to the ON position. C. midposition directly to the ON position; trip latch reset is not required. D. midposition to the OFF position to reset the trip latch, and then to the ON position.

Back 10

D.

Front 11

Two identical 1,000 MW electrical generators are operating in parallel, supplying the same isolated electrical bus. The generator output breakers also provide identical protection for the generators. Generator A and B output indications are as follows: Generator A Generator B 22.5 KV 22.5 KV 60.2 Hertz 60.2 Hertz 750 MW 750 MW 25 MVAR (out) 50 MVAR (out) A malfunction causes the voltage regulator for generator B to slowly and continuously increase the terminal voltage for generator B. If no operator action is taken, which one of the following describes the electrical current indications for generator A? A. Current will decrease continuously until the output breaker for generator A trips on reverse power. B. Current will decrease continuously until the output breaker for generator B trips on reverse power. C. Current will initially decrease, and then increase until the output breaker for generator A trips on overcurrent. D. Current will initially decrease, and then increase until the output breaker for generator B trips on overcurrent.

Back 11

D.

Front 12

Two identical 1,000 MW ac electrical generators are operating in parallel, supplying all the loads on a common electrical bus. The generator output breakers provide identical protection for the generators. Generator A and B output indications are as follows: Generator A Generator B 28 KV 28 KV 60 Hertz 60 Hertz 150 MW 100 MW 25 MVAR (out) 50 MVAR (out) A malfunction causes the voltage regulator set point for generator B to slowly and continuously decrease. If no operator action is taken, the electrical current indication for generator B will... A. initially decrease, and then increase until the output breaker for generator A trips on overcurrent. B. initially decrease, and then increase until the output breaker for generator B trips on overcurrent. C. decrease continuously until the output breaker for generator A trips on overcurrent. D. decrease continuously until the output breaker for generator B trips on reverse power.

Back 12

A.

Front 13

Two identical 1,000 MW electrical generators are operating in parallel supplying the same isolated electrical bus. The generator output breakers also provide identical protection for the generators. Generator A and B output indications are as follows: Generator A Generator B 22 KV 22 KV 60.2 Hertz 60.2 Hertz 200 MW 200 MW 25 MVAR (out) 50 MVAR (out) A malfunction causes the voltage regulator setpoint for generator A to slowly increase continuously toward a maximum of 25 KV. If no operator action is taken, generator B output current will... A. initially decrease, and then increase until the output breaker for generator A trips on overcurrent. B. initially decrease, and then increase until the output breaker for generator B trips on overcurrent. C. increase continuously until the output breaker for generator A trips on overcurrent. D. increase continuously until the output breaker for generator B trips on overcurrent.

Back 13

A.

Front 14

Two identical 1,000 MW electrical generators are operating in parallel supplying the same isolated electrical bus. The generator output breakers also provide identical protection for the generators. Generator A and B output indications are as follows: Generator A Generator B 22 KV 22 KV 60.2 Hertz 60.2 Hertz 200 MW 200 MW 25 MVAR (out) 50 MVAR (out) A malfunction causes the voltage regulator setpoint for generator A to slowly and continuously decrease. If no operator action is taken, generator B output current will increase until... A. the output breaker for generator A trips on overcurrent. B. the output breaker for generator B trips on overcurrent. C. the output breaker for generator A trips on reverse power. D. the output breaker for generator B trips on reverse power.

Back 14

B.

Front 15

Two identical 1,000 MW electrical generators are operating in parallel supplying the same isolated electrical bus. The generator output breakers provide identical protection for the generators. Generator A and B output indications are as follows: Generator A Generator B 22 KV 22 KV 60.2 Hertz 60.2 Hertz 200 MW 200 MW 25 MVAR (out) 50 MVAR (out) A malfunction causes the voltage regulator setpoint for generator B to slowly increase continuously toward a maximum of 25 KV. If no operator action is taken, generator A output current will... A. increase continuously until the output breaker for generator A trips on overcurrent. B. decrease continuously until the output breaker for generator B trips on overcurrent. C. initially decrease, and then increase until the output breaker for generator A trips on overcurrent. D. initially decrease, and then increase until the output breaker for generator B trips on overcurrent.

Back 15

D.

Front 16

Refer to the drawing of a typical valve control circuit (see figure below). What is the purpose of depressing the S1 pushbutton? A. To deenergize the K3 relay after the initiating condition has cleared. B. To prevent energizing the K3 relay when the initiating condition occurs. C. To manually energize the K3 relay in the absence of the initiating condition. D. To maintain the K3 relay energized after the initiating condition has cleared.

Back 16

A.

Front 17

Refer to the drawing of a typical valve control circuit (see figure below). One purpose of the K3 relay is to... A. hold the valve open after one or both of the initiating conditions have cleared, even if the reset pushbutton (S1) is depressed. B. hold the valve open even if one or both of the initiating conditions have cleared. C. close the valve as soon as either initiating condition has cleared. D. close the valve as soon as both initiating conditions have cleared.

Back 17

B.

Front 18

Refer to the drawing of a typical valve control circuit for a 480 VAC motor-operated valve (see figure below). The valve is currently open with the contact configuration as shown. If the S1 pushbutton is depressed, the valve will ____________ and when the S1 pushbutton is subsequently released, the valve will ____________. A. remain open; remain open B. close; remain closed C. remain open; close D. close; open

Back 18

B.

Front 19

Refer to the drawing of a typical valve control circuit (see figure below). Which one of the following describes the function of the #3 contact? A. To keep the K-3 relay energized after the initiating condition clears B. To provide a method for manually energizing the K-3 relay C. To increase circuit reliability because any one of three contacts can energize the K-3 relay D. To ensure the K-3 relay can always be deenergized even with the initiating condition present

Back 19

A.

Front 20

Refer to the drawing of a typical valve control circuit (see figure below). The initiating condition occurs and closes the #1 and #2 contacts to energize the K-3 relay and open the valve. Which one of the following will close the valve? A. Loss of 125 VDC B. Both #1 and #2 contacts open C. Either #1 or #2 contact opens D. Depressing the S1 pushbutton with the initiating condition present

Back 20

A.

Front 21

Refer to the drawing of a valve control circuit (see figure below). Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. If the valve is presently closed, when will the alarm actuate? A. As soon as PB2 is pushed. B. Ten seconds after PB2 is pushed if the valve is still closed. C. Immediately upon pushing PB2 and for the next 10 seconds if the valve remains closed. D. Ten seconds after PB2 is pushed if the valve is still stroking open.

Back 21

B.

Front 22

Refer to the drawing of a valve control circuit for a valve that is initially fully closed (see figure below). Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following describes when the motor-operated valve will begin to stroke open? A. At the same time the alarm actuates B. 10 seconds after PB2 is depressed C. Immediately after PB2 is depressed D. Immediately after PB1 is depressed if contact #1 is closed

Back 22

C.

Front 23

Refer to the drawing of a valve control circuit (see figure below). Pushbutton PB2 was depressed to open the valve, and the current contact/pushbutton status is as shown with the following exceptions: LS1 is closed. LS3 is closed. #1 contact is closed. #2 contact is closed. Which one of the following describes the condition of the valve and its control circuit? A. The valve is closed and the valve motor circuit has just been energized to open the valve. B. The valve is closed and an open demand signal has existed for at least 10 seconds. C. The valve is partially open and the valve motor circuit is deenergized as PB2 was prematurely released. D. The valve is partially open and an open demand signal has existed for at least 10 seconds.

Back 23

B.

Front 24

Refer to the drawing of a valve control circuit (see figure below). Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following describes the purpose of the alarm? A. Alert the operator when the valve motor circuit has been energized for 10 seconds after pushbutton PB2 is depressed B. Alert the operator when the valve has not moved off its closed seat within 10 seconds of depressing pushbutton PB2 C. Alert the operator that the valve is opening by sounding the alarm for 10 seconds after PB2 is depressed D. Alert the operator if the valve has not reached full open within 10 seconds of depressing pushbutton PB2

Back 24

B.

Front 25

Refer to the drawing of a valve control circuit (see figure below). Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. The valve is half open and moving to the open position. Which one of the following describes the current condition of the valve position indicating lights? A. Red light on, green light off B. Red light off, green light on C. Red light off, green light off D. Red light on, green light on

Back 25

D.

Front 26

Refer to the drawing of a valve control circuit (see figure below). Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Pushbutton PB2 has been momentarily depressed and then released, and the valve is currently at mid-stroke and moving to the open position. Under these conditions, which one of the following describes the position of contacts #1, #2, and #3? A. #1 closed; #2 open; #3 open B. #1 open; #2 closed; #3 closed C. #1 open; #2 open; #3 open D. #1 closed; #2 closed; #3 closed

Back 26

A.

Front 27

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully open and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following describes the valve response if the control switch is taken to the ÒCloseÓ position for two seconds and then released? A. The valve will not move. B. The valve will close fully. C. The valve will begin to close and then stop moving. D. The valve will begin to close and then open fully.

Back 27

C.

Front 28

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully closed and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following describes the valve response if the control switch is taken to the ÒOpenÓ position for two seconds and then released? A. The valve will not move. B. The valve will open fully. C. The valve will begin to open and then stop moving. D. The valve will begin to open and then close fully.

Back 28

B.

Front 29

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully open and has a 10-second stroke time. Limit switch LS2 has failed open. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following describes the valve response if the control switch is taken to the ÒCloseÓ position for 2 seconds and then released? A. The valve will not move. B. The valve will close fully. C. The valve will begin to close and then stop moving. D. The valve will begin to close and then open fully.

Back 29

A.

Front 30

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully closed and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. The operator takes the control switch to ÒOpenÓ momentarily and the valve begins to open. Five seconds later, the operator takes the switch to ÒCloseÓ momentarily and then releases the switch. Which one of the following describes the valve response after the switch is released? A. The valve will stop opening and remain partially open. B. The valve will stop opening and then go fully closed. C. The valve will open fully and remain fully open. D. The valve will open fully and then go fully closed.

Back 30

C.

Front 31

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully closed and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. An operator takes the control switch to ÒOpenÓ momentarily and the valve begins to open. Five seconds later, the operator places and holds the switch in the ÒCloseÓ position. Which one of the following describes the valve response with the switch held in the ÒCloseÓ position? A. The valve will stop opening and remain partially open. B. The valve will stop opening and then go fully closed. C. The valve will open fully and remain fully open. D. The valve will open fully and then go fully closed.

Back 31

D.

Front 32

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully closed and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. The operator takes the control switch to ÒOpenÓ. Two seconds later, after verifying the valve is opening, the operator releases the control switch. Which one of the following describes the valve motor control circuit alarm response after the switch is released? A. The alarm will continue to actuate for approximately 8 seconds. B. The alarm will continue to actuate until additional operator action is taken. C. The alarm will actuate after approximately 8 seconds. D. The alarm will not actuate until additional operator action is taken.

Back 32

A.

Front 33

Refer to the drawing of a motor controller circuit (see figure below). Note: Relay contacts are shown open/closed according to the standard convention for control circuit drawings. What is the purpose of the Time Delay Coil (TD) in the motor controller circuit? A. Ensures the motor cannot be started until the overload relays are reset. B. Ensures the motor cannot be started until the accelerating coil is energized. C. Allows the motor to come up to speed before bypassing the starting resistors. D. Allows the motor to come up to speed before placing the starting resistors in the circuit.

Back 33

C.

Front 34

Refer to the drawing of a motor controller circuit for a three-phase ac motor (see figure below). Note: Relay contacts are shown open/closed according to the standard convention for control circuit drawings. The motor receives overload protection from _________ overload (OL) relays, and _________ OL relay(s) must actuate to deenergize the motor. A. two; one B. two; two C. three; one D. three; two

Back 34

A.

Front 35

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully closed and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. The operator takes the control switch to ÒOpenÓ for 5 seconds and then releases the switch. After one minute the operator takes the control switch to ÒCloseÓ for 5 seconds and then releases the switch. Which one of the following describes the valve position immediately after the control switch is released the second time? A. Approximately fully open. B. Approximately fully closed. C. Approximately 50 percent open. D. Cannot be determined without additional information.

Back 35

B.

Front 36

Refer to the drawing of a motor and its control circuit (see figure below). Note: Relay contacts are shown open/closed according to the standard convention for control circuit drawings. How are the starting resistors employed before and after the motor is energized? A. Inserted before the motor is energized; simultaneously bypassed after the motor gains speed. B. Inserted before the motor is energized; sequentially bypassed as the motor gains speed. C. Bypassed before the motor is energized; simultaneously inserted after the motor gains speed. D. Bypassed before the motor is energized; sequentially inserted as the motor gains speed.

Back 36

A.

Front 37

Refer to the drawing of a motor and its control circuit (see figure below). Note: Relay contacts are shown open/closed according to the standard convention for control circuit drawings. The motor has been operating for several hours when it is decided to stop the motor. What is the status of the starting resistors before and after the motor STOP pushbutton is depressed? A. Initially inserted in the motor circuit; bypassed immediately after the STOP pushbutton is depressed. B. Initially inserted in the motor circuit; bypassed following a preset time delay after the STOP pushbutton is depressed. C. Initially bypassed; bypass is removed immediately after the STOP pushbutton is depressed. D. Initially bypassed; bypass is removed following a preset time delay after the STOP pushbutton is depressed.

Back 37

C.

Front 38

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully closed and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following describes the valve response if the control switch is taken to the ÒOpenÓ position for two seconds and then released? A. The valve will not move. B. The valve will open fully. C. The valve will begin to open and then close fully. D. The valve will begin to open and then stop moving.

Back 38

D.

Front 39

Refer to the drawing of a motor and its control circuit (see figure below). Note: Relay contacts are shown open/closed according to the standard convention for control circuit drawings. The motor has been idle for several days when it is decided to start the motor. What is the status of the starting resistors before and after the motor START pushbutton is depressed? A. Initially bypassed; bypass is removed immediately after the START pushbutton is depressed. B. Initially bypassed; bypass is removed following a preset time delay after the START pushbutton is depressed. C. Initially inserted in the motor circuit; bypassed immediately after the START pushbutton is depressed. D. Initially inserted in the motor circuit; bypassed following a preset time delay after the START pushbutton is depressed.

Back 39

D.

Front 40

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully open and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. The operator takes the control switch to ÒCloseÓ. Two seconds later, after verifying the valve is closing, the operator releases the control switch. Which one of the following describes the valve motor control circuit alarm response after the switch is released? A. The alarm will continue to actuate for approximately 8 seconds. B. The alarm will continue to actuate until additional operator action is taken. C. The alarm will actuate after approximately 8 seconds. D. The alarm will not actuate until additional operator action is taken.

Back 40

B.

Front 41

Refer to the drawing of a valve control circuit (see figure below). Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. Which one of the following will actuate the alarm? A. With the valve partially closed, the control switch is taken to the CLOSE position. B. With the valve partially closed, the control switch is taken to the OPEN position. C. With the valve fully open, the control switch is taken to the CLOSE position. D. With the valve fully open, the control switch is taken to the OPEN position.

Back 41

B.

Front 42

Refer to the drawing of a valve motor control circuit (see figure below) for a valve that is currently fully open and has a 10-second stroke time. Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings. The operator takes the control switch to ÒCloseÓ momentarily and the valve begins to close. Five seconds later, the operator takes the switch to ÒOpenÓ momentarily and then releases the switch. Which one of the following describes the valve response after the switch is released? A. The valve will stop closing and remain partially open. B. The valve will stop closing and then go fully open. C. The valve will close fully and remain fully closed. D. The valve will close fully and then go fully open.

Back 42

C.

Front 43

Which one of the following is an unsafe practice if performed when working on or near energized electrical equipment? A. Cover exposed energized circuits with insulating material to prevent inadvertent contact. B. Have a person standing by to deenergize the equipment in the event of an emergency. C. Use two hands for balance and to prevent dropping tools onto energized equipment. D. Stand on insulating rubber material to prevent yourself from being grounded.

Back 43

C.

Front 44

A 480 VAC motor is supplied power via an electrical disconnect in series with a circuit breaker. Which one of the following describes the proper operations to isolate power to the motor? A. Open the disconnect first, then the breaker. B. Open the breaker first, then the disconnect. C. Open the breaker and disconnect at the same time. D. Sequence is not important as long as the motor is operating.

Back 44

B.

Front 45

Which one of the following is an unsafe practice if performed when working on or near energized electrical equipment? A. Use insulated tools to prevent inadvertent contact with adjacent equipment. B. Cover exposed energized circuits with insulating material to prevent inadvertent contact. C. Attach a metal strap from your body to a nearby neutral ground to ensure that you are grounded. D. Have a person standing by with the ability to remove you from the equipment in the event of an emergency.

Back 45

C.

Front 46

The primary reason for isolating emergency electrical loads from their power supply bus prior to energizing the bus via the emergency diesel generator is to prevent an... A. overcurrent condition on the generator. B. overcurrent condition on the loads. C. underfrequency condition on the generator. D. underfrequency condition on the loads.

Back 46

A.

Front 47

A main generator is being connected to an infinite power grid that is operating at 60 Hz. Generator output voltage is equal to the grid voltage but generator frequency is at 57 Hz. Which one of the following generator conditions is most likely to occur if the generator output breaker is closed with voltages in phase (synchronized) but with the existing frequency difference? (Assume no generator breaker protective trip occurs.) A. Reverse power B. Underfrequency C. Undervoltage D. Overspeed

Back 47

A.

Front 48

Closing the output breaker of a three-phase generator onto a deenergized bus can result in... A. an overvoltage condition on the bus. B. an overcurrent condition on the generator if the bus was not first unloaded. C. a reverse power trip of the generator circuit breaker if generator frequency is low. D. a large reactive current in the generator.

Back 48

B.

Front 49

A main generator is being paralleled to an infinite power grid. Closing the output breaker of the generator with the frequency of the generator 0.1 Hz higher than grid frequency will result in the generator... A. supplying a portion of the grid reactive load (MVAR). B. supplying a portion of the grid real load (MW). C. behaving as a reactive load to the grid. D. behaving as a real load to the grid.

Back 49

B.

Front 50

Which one of the following generator conditions is most likely to cause generator damage because of high current? A. Tripping the output breaker under full-load conditions B. Tripping the generator prime mover under full-load conditions C. Closing the output breaker on a bus that has an open-circuit fault D. Closing the output circuit breaker on a bus that has a short-circuit fault

Back 50

D.

Front 51

A main generator is about to be connected to an infinite power grid. Closing the generator output breaker with the generator voltage slightly lower than grid voltage and with generator frequency slightly higher than grid frequency will initially result in: (Assume no generator breaker protective trip occurs.) A. the generator supplying reactive power to the grid. B. the generator attaining a leading power factor. C. the generator acting as a real load to the grid. D. motoring of the generator.

Back 51

B.

Front 52

A main generator is being paralleled to the power grid. Generator voltage has been properly adjusted and the synchroscope is rotating slowly in the clockwise direction. The generator breaker must be closed just as the synchroscope pointer reaches the 12 o'clock position to prevent... A. motoring of the generator due to unequal frequencies. B. excessive MW load transfer to the generator due to unequal frequencies. C. excessive MW load transfer to the generator due to out-of-phase voltages. D. excessive arcing within the generator output breaker due to out-of-phase voltages.

Back 52

D.

Front 53

During paralleling operations of the main generator to an infinite power grid, closing the generator output breaker with the frequency of the generator at 61 hertz and the grid frequency at 60 hertz will... A. cause the generator to immediately increase load. B. trip open the generator breaker on reverse power. C. cause the generator voltage to increase. D. cause the generator current to decrease.

Back 53

A.

Front 54

Which one of the following evolutions will draw the highest current from the main generator during operation of the output breaker? A. Opening the output breaker under full-load conditions B. Opening the output breaker under no-load conditions C. Closing the output breaker with voltages out of phase D. Closing the output breaker with voltages in phase

Back 54

C.

Front 55

Under which one of the following preexisting conditions will closing a circuit breaker between two electrical generators cause a sudden large and possibly damaging mechanical torque to be exerted on both of the generators? A. One generator is supplying a 3 percent higher voltage than the other. B. One generator is supplying a 3 percent higher frequency than the other. C. The voltage of one generator is out of phase with the other by 30E. D. The capacity of one generator is twice that of the other generator.

Back 55

C.

Front 56

A main generator is about to be connected to an infinite power grid with the following conditions: Generator frequency: 59.5 Hz Grid frequency: 59.8 Hz Generator voltage: 115.1 KV Grid voltage: 114.8 KV When the generator output breaker is closed the generator will... A. acquire real load and reactive load. B. acquire real load but become a reactive load to the grid. C. become a real load to the grid but acquire reactive load. D. become a real load and a reactive load to the grid.

Back 56

C.

Front 57

A main generator is about to be connected to an infinite power grid. Closing the generator output breaker with generator and grid voltages matched, but with generator frequency lower than grid frequency will initially result in the generator... A. picking up a portion of the grid real load. B. picking up a portion of the grid reactive load. C. experiencing reverse power conditions. D. experiencing overspeed conditions.

Back 57

C.

Front 58

A main generator is about to be connected to an infinite power grid. Closing the generator output breaker with the ____________ of the generator higher than that of the grid will initially result in generator real load ____________. A. frequency; decreasing B. frequency; increasing C. voltage; decreasing D. voltage; increasing

Back 58

B.

Front 59

A main generator is about to be connected to an infinite power grid. Closing the generator output breaker with generator and grid voltages matched, but with generator frequency 0.1 Hz higher than grid frequency will initially result in the generator... A. picking up a portion of the grid real load. B. picking up a portion of the grid reactive load. C. experiencing reverse power conditions. D. experiencing overspeed conditions.

Back 59

A.

Front 60

A main generator is about to be connected to an infinite power grid with the following conditions: Generator frequency = 59.8 Hz Grid frequency = 59.5 Hz Generator voltage = 114.8 KV Grid voltage = 115.1 KV When the generator output breaker is closed, the generator will initially... A. acquire real load and reactive load. B. acquire real load, but become a reactive load to the grid. C. become a real load to the grid, but acquire reactive load. D. become a real load and a reactive load to the grid.

Back 60

B.

Front 61

A main generator is being paralleled to an infinite power grid. Generator voltage has been properly adjusted and the synchroscope is rotating slowly in the counterclockwise direction. If the generator breaker is closed just prior to the synchroscope pointer reaching the 12 o'clock position, which one of the following will occur? A. The breaker will close and the generator will supply MW to the grid. B. The breaker will close and the generator will supply MW and MVAR to the grid. C. The breaker will close and then open due to overcurrent. D. The breaker will close and then open due to reverse power.

Back 61

D.

Front 62

A main generator is being connected to an infinite power grid. Which one of the following will occur if the generator output breaker is closed with generator frequency 0.1 Hz lower than power grid frequency? (Assume that no generator protection relay actuates.) A. The generator will motorize. B. The generator will accept too much load. C. The voltage of the generator will decrease to compensate for the lower frequency. D. The entire connected system will operate at the frequency of the lowest frequency (the oncoming) generator.

Back 62

A.

Front 63

A main generator is being prepared for paralleling with an infinite power grid. Which one of the following indicates that the main generator and the grid are in phase? A. The synchroscope pointer is at the 12 oÕclock position. B. The frequency of the generator is equal to the frequency of the grid. C. The synchroscope pointer is turning slowly in the clockwise direction. D. The synchroscope pointer is turning slowly in the counterclockwise direction.

Back 63

A.

Front 64

A main generator is being prepared for paralleling with an infinite power grid. Which one of the following conditions will cause the main generator to immediately supply reactive power (MVAR) to the grid when the generator output breaker is closed? A. Generator voltage is 1 percent higher than grid voltage. B. Generator voltage is 1 percent lower than grid voltage. C. The synchroscope is turning slowly in the clockwise direction. D. The synchroscope is turning slowly in the counterclockwise direction.

Back 64

A.

Front 65

Two identical 1,000 MW electrical generators are being connected to the same electrical bus. Generator A is currently supplying the bus. Generator A and B output indications are as follows: Generator A Generator B 4,160 Volts 4,140 Volts 60.2 Hertz 60.8 Hertz 25 MW 0 MW 10 MVAR 0 MVAR When the output breaker for generator B is closed, which generator is more likely to trip on reverse power? A. Generator A due to the higher initial voltage B. Generator A due to the lower initial frequency C. Generator B due to the lower initial voltage D. Generator B due to the higher initial frequency

Back 65

B.

Front 66

A main generator is about to be connected to an infinite power grid. Generator voltage equals grid voltage and the synchroscope is rotating slowly in the clockwise direction. The generator breaker is closed just as the synchroscope pointer reaches the 12 o'clock position. Which one of the following will occur after the breaker is closed? A. The breaker will remain closed and the generator will supply only MW to the grid. B. The breaker will remain closed and the generator will supply both MW and MVAR to the grid. C. The breaker will trip open due to overcurrent. D. The breaker will trip open due to reverse power.

Back 66

A.

Front 67

A main generator is being prepared for paralleling with an infinite power grid. Which one of the following indicates that the generator and grid voltages are in phase? A. The voltage of the generator is equal to the voltage of the grid. B. The frequency of the generator is equal to the frequency of the grid. C. The synchroscope pointer is turning slowly in the clockwise direction. D. The synchroscope pointer is passing through the 12 oÕclock position.

Back 67

D.

Front 68

An isolated electrical bus is being supplied by generator A. Generator B is about to be connected to the same electrical bus. Generators A and B are both rated at 1,000 MW. Generator A and B output indications are as follows: Generator A Generator B 4,140 Volts 4,160 Volts 60.8 Hertz 60.2 Hertz 25 MW 0 MW 10 MVAR 0 MVAR When the output breaker for generator B is closed, which generator is more likely to trip on reverse power? A. Generator A due to the lower initial voltage B. Generator A due to the higher initial frequency C. Generator B due to the higher initial voltage D. Generator B due to the lower initial frequency

Back 68

D.

Front 69

A main generator is about to be connected to an infinite power grid. Generator voltage is slightly higher than grid voltage and the synchroscope is rotating slowly in the clockwise direction. The generator breaker is closed just as the synchroscope pointer reaches the 12 o'clock position. Which one of the following will occur after the breaker is closed? A. The breaker will remain closed and the generator will supply only MW to the grid. B. The breaker will remain closed and the generator will supply both MW and MVAR to the grid. C. The breaker will open due to overcurrent. D. The breaker will open due to reverse power.

Back 69

B.

Front 70

A main generator is being prepared for paralleling with an infinite power grid. If the synchroscope pointer is stopped, at which one of the following positions is the main generator output voltage the farthest out of phase with the grid voltage? A. 3 oÕclock B. 6 oÕclock C. 9 oÕclock D. 12 oÕclock

Back 70

B.

Front 71

A main generator is about to be connected to an infinite power grid. Generator voltage is equal to grid voltage and the synchroscope is rotating slowly in the counterclockwise direction. The generator breaker is closed just prior to the synchroscope pointer reaching the 12 o'clock position. Which one of the following will most likely occur after the breaker is closed? A. If the breaker remains closed, the generator will supply only MW to the grid. B. If the breaker remains closed, the generator will supply both MW and MVAR to the grid. C. The breaker will open due to overcurrent. D. The breaker will open due to reverse power.

Back 71

D.

Front 72

A main generator is about to be connected to an infinite power grid. Generator voltage is slightly higher than grid voltage and the synchroscope is rotating slowly in the clockwise direction. The generator breaker is closed just as the synchroscope pointer reaches the 3 o'clock position. Which one of the following will occur after the breaker is closed? A. The breaker will remain closed and the generator will supply only MW to the grid. B. The breaker will remain closed and the generator will supply both MW and MVAR to the grid. C. The breaker will open due to overcurrent. D. The breaker will open due to reverse power.

Back 72

C.

Front 73

A main generator is about to be connected to an infinite power grid with the following conditions: Generator frequency: 59.9 Hz Grid frequency: 60.1 Hz Generator voltage: 114.8 KV Grid voltage: 115.1 KV When the generator output breaker is closed, the generator will... A. acquire real load and reactive load. B. acquire real load, but become a reactive load to the grid. C. become a real load to the grid, but acquire reactive load. D. become a real load and a reactive load to the grid.

Back 73

D.

Front 74

A main generator is about to be connected to an infinite power grid with the following conditions: Generator frequency: 60.1 Hz Grid frequency: 59.9 Hz Generator voltage: 115.1 KV Grid voltage: 114.8 KV When the generator output breaker is closed, the generator will... A. acquire real load and reactive load. B. acquire real load, but become a reactive load to the grid. C. become a real load to the grid, but acquire reactive load. D. become a real load and a reactive load to the grid.

Back 74

A.

Front 75

A nuclear power plant is operating at 80 percent power in the middle of a fuel cycle. The main generator is connected to an infinite power grid with the following initial main generator output parameters: Frequency: 60 Hz Voltage: 25 KV Reactive Load: 300 MVAR (out) Real Load: 800 MW A hydraulic oil system malfunction causes the main turbine steam inlet valves to begin to slowly drift closed. Over the next 10 minutes, the main generator real load decreases to 600 MW. Assuming no operator actions were taken during the above 10 minutes, how have the following main generator output parameters been affected? Reactive Frequency Voltage Load A. Decreased Decreased No change B. Decreased No change Decreased C. No change No change No change D. No change Decreased Decreased

Back 75

C.

Front 76

Which one of the following will cause the most damage to the contact surfaces of a main generator output breaker? A. An operator attempts to close the main generator breaker with the generator and power grid frequencies matched but with voltages 180 degrees out of phase. B. An operator attempts to close the main generator breaker with the generator and power grid voltages in phase but with generator frequency 0.5 percent higher than power grid frequency. C. The main generator breaker automatically trips open on a loss of offsite power while the main generator is operating at its minimum rated load. D. The main generator breaker automatically trips open on a loss of offsite power while the main generator is operating at its maximum rated load.

Back 76

A.

Front 77

A main generator is about to be connected to an infinite power grid. The main generator has the following initial conditions: Generator frequency: 59.9 Hz Generator voltage: 115.1 KV Grid frequency: 60.1 Hz Grid voltage: 114.8 KV When the generator output breaker is closed, the generator will... A. acquire real load and reactive load. B. acquire real load, but become a reactive load to the grid. C. become a real load and a reactive load to the grid. D. become a real load to the grid, but acquire reactive load.

Back 77

D.

Front 78

During a routine inspection of a main generator output breaker, a technician discovers severely damaged main contact surfaces. Which one of the following is the most likely cause of the damaged contact surfaces? A. The main generator breaker automatically tripped open after it was closed with the generator and power grid voltages 60 degrees out of phase. B. The main generator breaker automatically tripped open due to a faulty trip relay actuation while the main generator was operating unloaded. C. The main generator breaker automatically tripped open on a loss of offsite power while the main generator was operating at its maximum rated load. D. The main generator breaker automatically tripped open after it was closed with the generator and power grid voltages in phase but with generator frequency 0.2 Hz lower than power grid frequency.

Back 78

A.

Front 79

A main generator is about to be connected to an infinite power grid. Generator output frequency is slightly higher than grid frequency and generator output voltage is equal to grid voltage. Which one of the following situations will exist when the main generator electrical conditions stabilize immediately after the generator output breaker is closed? (Assume no additional operator actions are taken.) A. Generator output current will be 0. B. Generator power factor will be 0. C. Generator output MVAR will be 0. D. Generator output MW will be 0.

Back 79

C.

Front 80

A main generator is being connected to an infinite power grid. The following frequencies exist just prior to closing the generator output breaker: Generator frequency: 59.9 Hz Grid frequency: 60.1 Hz When conditions stabilize just after the generator output breaker is closed, the generator frequency will be _________ and the grid frequency will be _________. A. 59.9 Hz; 59.9 Hz B. 59.9 Hz; 60.1 Hz C. 60.0 Hz; 60.0 Hz D. 60.1 Hz; 60.1 Hz

Back 80

D.

Front 81

When a typical 4,160 VAC breaker is racked to the "test" position, control power is __________ the breaker and the breaker is __________ the load. A. available to; connected to B. available to; isolated from C. removed from; connected to D. removed from; isolated from

Back 81

B.

Front 82

Which one of the following functions or capabilities would remain following a loss of control power to a typical 480 VAC bus feeder breaker? A. Remote breaker control capability B. Breaker closing spring automatic recharging capability C. Remote bus voltage indication D. Remote breaker position indication

Back 82

C.

Front 83

Which one of the following statements describes the use of high-voltage disconnects? A. Disconnects should be limited to normal load current interruption. B. Disconnects may be used to isolate transformers in an unloaded network. C. Disconnects trip open like circuit breakers, but must be manually closed. D. Disconnects must be closed with caution when under load because of possible arcing.

Back 83

B.

Front 84

The function of high voltage electrical disconnects is to provide__________ electrical isolation of equipment during __________ conditions. A. manual; no-load B. manual; overload C. automatic; no-load D. automatic; overload

Back 84

A.

Front 85

High voltage electrical disconnects are used to... A. adjust the output voltage range from a main power transformer. B. protect bus feeder breakers by opening upon bus short-circuit faults. C. provide equipment isolation under no-load conditions. D. bypass and isolate an electrical bus while maintaining the downstream buses energized.

Back 85

C.

Front 86

What is an advantage of using high voltage electrical disconnects instead of breakers to isolate main power transformers? A. Disconnects can be operated either locally or remotely. B. Disconnects provide direct visual indication that the circuit is broken. C. Disconnects are cheaper and provide the same automatic protection as a breaker. D. Disconnects are capable of interrupting a higher current flow with less heating than a breaker.

Back 86

B.

Front 87

Which one of the following describes a characteristic of high voltage electrical disconnects? A. They close automatically requiring no operator action. B. They should not be used to interrupt a circuit under load. C. They require a remote means of indication to determine actual position. D. They should be connected so that they ground the supply bus prior to opening a circuit.

Back 87

B.

Front 88

Typical high voltage electrical disconnects are designed to... A. protect circuits during overcurrent conditions. B. automatically trip open to protect breakers. C. isolate equipment electrically during no-load conditions. D. interrupt circuits under load.

Back 88

C.

Front 89

Typical main transformer high voltage electrical disconnects are designed to... A. automatically protect the transformer from overcurrent conditions. B. automatically trip open prior to transformer output breaker trip. C. manually isolate the transformer during no-load conditions. D. manually interrupt the transformer output circuit under load when grounds are detected.

Back 89

C.

Front 90

Refer to the simplified drawing of an electrical distribution system (see figure below). The high voltage side of each step-down transformer has a remote-operated disconnect to allow transformer maintenance while keeping the other transformers in service. The control circuit for each disconnect is position-interlocked with the associated MCC feeder breaker. Which one of the following describes the purpose served by the interlock? A. Prevent damage to the disconnect. B. Prevent damage to the transformer. C. Prevent damage to the feeder breaker. D. Prevent damage to the 480V MCC.

Back 90

A.

Front 91

A 480 VAC motor control center supplies a load through a breaker and a manual disconnect. If both isolation devices are operated to isolate the load, which one of the following sequences will provide the greatest level of personnel safety when deenergizing the load for maintenance and when reenergizing the load after the maintenance? DEENERGIZING REENERGIZING A. Open breaker first Shut breaker first B. Open breaker first Shut disconnect first C. Open disconnect first Shut breaker first D. Open disconnect first Shut disconnect first

Back 91

B.

Front 92

Refer to the simplified drawing of an electrical distribution system showing 7.2 KV switchgear, step-down transformers, and 480 V motor control centers (MCCs) (see figure below). The high voltage side of each step-down transformer has a remote-operated disconnect. The control circuit for each disconnect is position-interlocked with the associated MCC feeder breaker. Which one of the following describes the interlock operating scheme that will provide the greatest protection for the disconnect? A. Permits opening the feeder breaker only if the disconnect is closed. B. Permits opening the feeder breaker only if the disconnect is open. C. Permits opening the disconnect only if the feeder breaker is closed. D. Permits opening the disconnect only if the feeder breaker is open.

Back 92

D.

Front 93

The following remote indications are observed for a 480 VAC load center supply breaker. (The breaker is normally open.) Red indicating light is on. Green indicating light is off. Load center voltage indicates 0 volts. Breaker incoming voltage indicates 480 volts. What is the condition of the breaker? A. Open and racked in B. Closed and racked in C. Open and racked to "test" position D. Closed and racked to "test" position

Back 93

D.

Front 94

The following indications are observed for a motor breaker in the control room: Red position indicating light is off. Green position indicating light is off. Load amps indicate normal load current. Assuming one of the indicating lights is burned out, what is the condition of the breaker? A. Closed and racked in B. Open and racked in C. Closed and racked to "test" position D. Open and racked to "test" position

Back 94

A.

Front 95

The following indications are observed in the control room for a normally-open motor control center (MCC) breaker that directly starts/stops a 480 VAC motor: Red position indicating light is on. Green position indicating light is off. Motor load current indicates 0 amps. MCC voltage indicates 480 volts. What is the condition of the breaker? A. Open and racked in B. Closed and racked in C. Open and racked to "test" position D. Closed and racked to "test" position

Back 95

D.

Front 96

The following indications are observed in the control room for a normally-open breaker that directly starts/stops a 480 VAC motor: Red position indicating light is on. Green position indicating light is off. Load current indicates 50 amps. Supply voltage indicates 480 volts. What is the condition of the breaker? A. Open and racked to "test" position B. Closed and racked to "test" position C. Open and racked in D. Closed and racked in

Back 96

D.

Front 97

While remotely investigating the condition of a normally-open breaker that feeds a motor control center (MCC), an operator observes the following indications: Green breaker position indicating light is out. Red breaker position indicating light is lit. MCC voltmeter indicates normal voltage. MCC ammeter indicates zero amperes. Based on these indications, the operator should report that the breaker is __________ and racked __________. A. open; in B. closed; in C. open; out D. closed; out

Back 97

B.

Front 98

While remotely investigating the condition of a typical normally-open motor control center (MCC) feeder breaker, an operator observes the following indications: Green breaker position indicating light is lit. Red breaker position indicating light is out. MCC voltmeter indicates zero volts. MCC ammeter indicates zero amperes. Based on these indications, the operator can accurately report that the breaker is open and racked to __________ position. A. the OUT B. the IN C. the TEST D. an unknown

Back 98

D.

Front 99

While remotely investigating the condition of a normally-open 480 VAC motor control center (MCC) feeder breaker, an operator observes the following indications: Green breaker position indicating light is out. Red breaker position indicating light is lit. MCC voltmeter indicates 480 VAC. MCC ammeter indicates zero amperes. Based on these indications, the operator should report that the feeder breaker is __________ and racked __________. A. open; in B. closed; in C. open; to the test position D. closed; to the test position

Back 99

B.

Front 100

While remotely investigating the condition of a normally open feeder breaker to a 480 VAC motor control center (MCC), a control room operator observes the following indications: Green breaker position indicating light is out. Red breaker position indicating light is lit. MCC voltmeter indicates 0 VAC. MCC ammeter indicates zero amperes. Based on these indications, the operator should report that the feeder breaker is __________ and racked __________. A. open; in B. closed; out C. open; to the test position D. closed; to the test position

Back 100

D.

Front 101

Breaker local overcurrent trip flag indicators, when actuated, indicate that... A. a breaker trip will occur unless current is reduced. B. a breaker overcurrent condition is responsible for a breaker trip. C. an overcurrent condition has cleared and the breaker can be closed. D. the associated breaker has failed to trip open during an overcurrent condition.

Back 101

B.

Front 102

Given the following indications for an open 4,160 VAC breaker: ¥ The local OPEN/CLOSED mechanical flag indicates open. ¥ A breaker overcurrent trip flag is actuated on one phase. ¥ The line-side voltmeter indicates 4,160 VAC. ¥ The load-side voltmeter indicates 0 volts. Assuming no operator actions were taken since the breaker opened, which one of the following could have caused the breaker to open? A. A ground fault caused an automatic breaker trip. B. A loss of control power caused an automatic breaker trip. C. An operator opened the breaker locally. D. An operator opened the breaker from a remote location.

Back 102

A.