Transmission Test Questions and
Answers Latest Version Top Rated
Question>> 1
When synchronizing sections of the transmission system that
have separated or islanded, frequency and voltage
magnitude on each side of the breaker and the power angle
across the breaker must be within proper limits. In order to
bring these values within proper limits, the system operator
should .
Adjust the tap changer on the nearest transformer.
Adjust the power angle on one side of the breaker to 90
degrees. Adjust generator MW and MVAR output in one of
the areas.
Open additional lines until the voltage is matched.
Answer>>
Adjust generator MW and MVAR output in one of the areas.
EPRI 2.5.7 Power flows from areas of more positive to less
positive voltage angles, and reactive power flows from areas
of higher voltage to areas of lower voltage. Therefore, to
minimize flows across the breaker as it is being closed, these
values must be within acceptable ranges on each side of the
breaker before closing is attempted. Power flow can be
manipulated by adjusting generation on one side of the
open breaker. Generation can be raised or lowered to adjust
the speed of one section of the system with respect to the
other. The power angle is the difference in voltage angles at
two points on the system. In this case, when we are
discussing the power angle across the breaker we are
Page 1 of 58
,referencing the difference in voltage angles of the two
busses which are connected by a transmission lines that we
are trying to synchronize. Most technical references, such at
the EPRI Interconnected Power System Dynamics Tutorial, on
which the NERC exams are partially based, stress the
importance of minimizing power angle across the breaker.
Question>> 2
In a power system, which type of power provides indication
of voltage problems, is critical for support of heavily loaded
transmission lines, and is necessary to have sufficient
dynamic reserves in preparation for a contingency?
Solar Power Reactive Power Real Power Apparent Power
Answer>>
Reactive Power.
VAR-001: Several of the Requirements in this standard
pertain to maintaining sufficient reactive resources.
Question>> 3
Which of the following is NOT a correct action a
Transmission Operator would consider when reactive
resources are limited?
When conditions get critical, consider reducing MEGAWATT
transfers to limit reactive power losses.
To prevent a loss of synchronism type of voltage collapse,
maintain system transfer limits to safe limits.
Ensure that sufficient dynamic and static Megavar sources
are available. Keep voltage schedules as low as the schedules
will allow.
Answer>>
Page 2 of 58
,Keep voltage schedules as low as the schedules will allow.
When reactive resources are limited, to prevent voltage
collapse, the System Operator should maintain system
transfer limits to safe limits to reduce the power angle
increase following a disturbance. Keep voltage schedules as
high as the schedules will allow. The higher the voltage the
lower the power angles necessary to transmit a given
amount of power. When conditions get critical, consider
reducing MW transfers to limit reactive power losses. Ensure
that sufficient dynamic and static MVAR sources are
available.
Question>> 4
The maximum and minimum voltage, current, frequency, real
and reactive power flows on individual equipment under
steady state, short-circuit and transient conditions, as
permitted by the equipment owner is .
Equipment Rating
The System Operating Limit The point of collapse Always
changing.
Answer>>
Equipment Rating.
NERC Glossary:
Equipment Rating - The maximum and minimum voltage,
current, frequency, real and reactive power flows on
individual equipment under steady state, short-circuit and
transient conditions, as permitted or assigned by the
equipment owner. This is not necessarily the System
Operating Limit. System Operating Limits are based upon
certain operating criteria. These include, but are not limited
to:
Page 3 of 58
, • Facility Ratings (Applicable pre- and post-Contingency
equipment or facility ratings)
• Transient Stability Ratings (Applicable pre- and post-
Contingency Stability Limits)
• Voltage Stability Ratings (Applicable pre- and post-
Contingency Voltage Stability)
• System Voltage Limits (Applicable pre- and post-
Contingency Voltage Limits)
Question>> 5
If a Transmission Operator or Balancing Authority is unable
to restore Real and/or Reactive Power Balance, they must
request emergency assistance from the Reliability
Coordinator. If operating reserves are not available,
corrective action need to include:
Implement manual load shedding.
Reduce voltage on the distribution system. Notify the RRO.
Reduce interchange between systems
Answer>>
Implement manual load shedding.
Implementing manual load shed is included as part of an
Operating Plan to mitigate operating emergencies, such as,
low voltage due to insufficient reactive resources, or
imbalance due to real power resources deficiency.
Question>> 6
During a system emergency, the System Operator can direct
other Transmission Operators and Balancing Authorities to
violate which limit?
None. Equipment parameters should be maintained within
Page 4 of 58
Answers Latest Version Top Rated
Question>> 1
When synchronizing sections of the transmission system that
have separated or islanded, frequency and voltage
magnitude on each side of the breaker and the power angle
across the breaker must be within proper limits. In order to
bring these values within proper limits, the system operator
should .
Adjust the tap changer on the nearest transformer.
Adjust the power angle on one side of the breaker to 90
degrees. Adjust generator MW and MVAR output in one of
the areas.
Open additional lines until the voltage is matched.
Answer>>
Adjust generator MW and MVAR output in one of the areas.
EPRI 2.5.7 Power flows from areas of more positive to less
positive voltage angles, and reactive power flows from areas
of higher voltage to areas of lower voltage. Therefore, to
minimize flows across the breaker as it is being closed, these
values must be within acceptable ranges on each side of the
breaker before closing is attempted. Power flow can be
manipulated by adjusting generation on one side of the
open breaker. Generation can be raised or lowered to adjust
the speed of one section of the system with respect to the
other. The power angle is the difference in voltage angles at
two points on the system. In this case, when we are
discussing the power angle across the breaker we are
Page 1 of 58
,referencing the difference in voltage angles of the two
busses which are connected by a transmission lines that we
are trying to synchronize. Most technical references, such at
the EPRI Interconnected Power System Dynamics Tutorial, on
which the NERC exams are partially based, stress the
importance of minimizing power angle across the breaker.
Question>> 2
In a power system, which type of power provides indication
of voltage problems, is critical for support of heavily loaded
transmission lines, and is necessary to have sufficient
dynamic reserves in preparation for a contingency?
Solar Power Reactive Power Real Power Apparent Power
Answer>>
Reactive Power.
VAR-001: Several of the Requirements in this standard
pertain to maintaining sufficient reactive resources.
Question>> 3
Which of the following is NOT a correct action a
Transmission Operator would consider when reactive
resources are limited?
When conditions get critical, consider reducing MEGAWATT
transfers to limit reactive power losses.
To prevent a loss of synchronism type of voltage collapse,
maintain system transfer limits to safe limits.
Ensure that sufficient dynamic and static Megavar sources
are available. Keep voltage schedules as low as the schedules
will allow.
Answer>>
Page 2 of 58
,Keep voltage schedules as low as the schedules will allow.
When reactive resources are limited, to prevent voltage
collapse, the System Operator should maintain system
transfer limits to safe limits to reduce the power angle
increase following a disturbance. Keep voltage schedules as
high as the schedules will allow. The higher the voltage the
lower the power angles necessary to transmit a given
amount of power. When conditions get critical, consider
reducing MW transfers to limit reactive power losses. Ensure
that sufficient dynamic and static MVAR sources are
available.
Question>> 4
The maximum and minimum voltage, current, frequency, real
and reactive power flows on individual equipment under
steady state, short-circuit and transient conditions, as
permitted by the equipment owner is .
Equipment Rating
The System Operating Limit The point of collapse Always
changing.
Answer>>
Equipment Rating.
NERC Glossary:
Equipment Rating - The maximum and minimum voltage,
current, frequency, real and reactive power flows on
individual equipment under steady state, short-circuit and
transient conditions, as permitted or assigned by the
equipment owner. This is not necessarily the System
Operating Limit. System Operating Limits are based upon
certain operating criteria. These include, but are not limited
to:
Page 3 of 58
, • Facility Ratings (Applicable pre- and post-Contingency
equipment or facility ratings)
• Transient Stability Ratings (Applicable pre- and post-
Contingency Stability Limits)
• Voltage Stability Ratings (Applicable pre- and post-
Contingency Voltage Stability)
• System Voltage Limits (Applicable pre- and post-
Contingency Voltage Limits)
Question>> 5
If a Transmission Operator or Balancing Authority is unable
to restore Real and/or Reactive Power Balance, they must
request emergency assistance from the Reliability
Coordinator. If operating reserves are not available,
corrective action need to include:
Implement manual load shedding.
Reduce voltage on the distribution system. Notify the RRO.
Reduce interchange between systems
Answer>>
Implement manual load shedding.
Implementing manual load shed is included as part of an
Operating Plan to mitigate operating emergencies, such as,
low voltage due to insufficient reactive resources, or
imbalance due to real power resources deficiency.
Question>> 6
During a system emergency, the System Operator can direct
other Transmission Operators and Balancing Authorities to
violate which limit?
None. Equipment parameters should be maintained within
Page 4 of 58
