SOS NERC Prep - Reliability Exam
Questions and Answers
Question>> 1
What is the role of a Reliability Coordinator during system
restoration?
A) Direct Balancing to bring on generation
B) Coordination between the Transmission Operators
restoration plan
C) Ensure that all breakers are open prior to restoration start
D) Direct control over breaker operations
Answer>>
B) Coordination between the Transmission Operators
restoration plan
Question>> 2
If the frequency bias setting is less negative than the frequency
response of a Balancing Authority and a frequency decline is
caused by a sudden loss of generation in an external balancing
area, what will be the result?
A) The ACE will be a negative value and AGC will increase
generation.
B) This will not affect the ACE.
C) The ACE will be a positive value and AGC will lower
generation.
Page 1 of 89
,D) The ACE will be zero and will take no AGC action.
Answer>>
C) The ACE will be a positive value and AGC will lower generation.
Question>> 3
A Transmission Operator Area has an instantaneous automatic
Under-Frequency Load Shed Scheme segmented into a sequence
of 4 Steps:
Step 1 = 59.500Hz. removes 25MW; Step 2 = 59.300Hz. removes
20MW; Step 3 = 59.100Hz. removes 20MW;
Step 4 = 58.900Hz. removes an additional 15MW.
Step 3 & 4 will automatically reset and re-close restoring load
when the frequency returns to 60.00 Hz. A large event occurs
causing the system frequency to fall to 59.000Hz. and returns to
60.00Hz after 12 minutes. Assuming a constant load factor, what is
the total load the TOP must restore manually once the frequency
has recovered to 60.000Hz.?
A) 45 MW
B) 80 MW
C) 65 MW
D) 25 MW
Answer>>
A) 45 MW
Question>> 4
If generators are supplying reactive power to the system, the
generators are considered .
A) unity.
B) underexcited.
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,C) overexcited.
D) synchronous.
Answer>>
C) overexcited.
Question>> 5
Who must approve a Reliability Adjustment Arranged Interchange
before it becomes Confirmed Interchange?
A) Only the Source and Sink Balancing Authorities associated
with the Interchange
B) The Reliability Coordinator approves all Reliability
Adjustment Arranged Interchange
C) All Balancing Authorities involved in the Interchange
D) Each Balancing Authority and Transmission Service Provider
associated with the Interchange
Answer>>
A) Only the Source and Sink Balancing Authorities associated
with the Interchange
Question>> 6
Which of the following actions is used to prevent voltage collapse
when reactive resources are insufficient?
A) Lower transmission voltage regulator settings.
B) Reduce generator output.
C) Offset scheduled frequency.
D) Implement load reduction.
Answer>>
D) Implement load reduction.
Page 3 of 89
, Question>> 7
When two identical A/C generating units are operated in parallel
on governor control, and one machine has a 5% droop and the
other has a 10% droop, the unit with the greater governor droop
will...
A) No adjustment for frequency changes.
B) Share load equally with the other machine.
C) Tend to take the greater portion of load changes.
D) Tend to take the lesser portion of load changes.
Answer>>
D) Tend to take the lesser portion of load changes.
Question>> 8
Resources that a system operator should use to identify, and
correct emergency conditions include:
A) Field Personnel
B) Personal Experience
C) Operating Procedures
D) All the Above
Answer>>
D) All the Above
Question>> 9
Voltage of a 345 kV transmission line is at 90% of normal. If you
energize a capacitor rated at 100 MVar, what will be the actual
MVars gained?
A) 50 MVars
B) 81 MVars
Page 4 of 89
Questions and Answers
Question>> 1
What is the role of a Reliability Coordinator during system
restoration?
A) Direct Balancing to bring on generation
B) Coordination between the Transmission Operators
restoration plan
C) Ensure that all breakers are open prior to restoration start
D) Direct control over breaker operations
Answer>>
B) Coordination between the Transmission Operators
restoration plan
Question>> 2
If the frequency bias setting is less negative than the frequency
response of a Balancing Authority and a frequency decline is
caused by a sudden loss of generation in an external balancing
area, what will be the result?
A) The ACE will be a negative value and AGC will increase
generation.
B) This will not affect the ACE.
C) The ACE will be a positive value and AGC will lower
generation.
Page 1 of 89
,D) The ACE will be zero and will take no AGC action.
Answer>>
C) The ACE will be a positive value and AGC will lower generation.
Question>> 3
A Transmission Operator Area has an instantaneous automatic
Under-Frequency Load Shed Scheme segmented into a sequence
of 4 Steps:
Step 1 = 59.500Hz. removes 25MW; Step 2 = 59.300Hz. removes
20MW; Step 3 = 59.100Hz. removes 20MW;
Step 4 = 58.900Hz. removes an additional 15MW.
Step 3 & 4 will automatically reset and re-close restoring load
when the frequency returns to 60.00 Hz. A large event occurs
causing the system frequency to fall to 59.000Hz. and returns to
60.00Hz after 12 minutes. Assuming a constant load factor, what is
the total load the TOP must restore manually once the frequency
has recovered to 60.000Hz.?
A) 45 MW
B) 80 MW
C) 65 MW
D) 25 MW
Answer>>
A) 45 MW
Question>> 4
If generators are supplying reactive power to the system, the
generators are considered .
A) unity.
B) underexcited.
Page 2 of 89
,C) overexcited.
D) synchronous.
Answer>>
C) overexcited.
Question>> 5
Who must approve a Reliability Adjustment Arranged Interchange
before it becomes Confirmed Interchange?
A) Only the Source and Sink Balancing Authorities associated
with the Interchange
B) The Reliability Coordinator approves all Reliability
Adjustment Arranged Interchange
C) All Balancing Authorities involved in the Interchange
D) Each Balancing Authority and Transmission Service Provider
associated with the Interchange
Answer>>
A) Only the Source and Sink Balancing Authorities associated
with the Interchange
Question>> 6
Which of the following actions is used to prevent voltage collapse
when reactive resources are insufficient?
A) Lower transmission voltage regulator settings.
B) Reduce generator output.
C) Offset scheduled frequency.
D) Implement load reduction.
Answer>>
D) Implement load reduction.
Page 3 of 89
, Question>> 7
When two identical A/C generating units are operated in parallel
on governor control, and one machine has a 5% droop and the
other has a 10% droop, the unit with the greater governor droop
will...
A) No adjustment for frequency changes.
B) Share load equally with the other machine.
C) Tend to take the greater portion of load changes.
D) Tend to take the lesser portion of load changes.
Answer>>
D) Tend to take the lesser portion of load changes.
Question>> 8
Resources that a system operator should use to identify, and
correct emergency conditions include:
A) Field Personnel
B) Personal Experience
C) Operating Procedures
D) All the Above
Answer>>
D) All the Above
Question>> 9
Voltage of a 345 kV transmission line is at 90% of normal. If you
energize a capacitor rated at 100 MVar, what will be the actual
MVars gained?
A) 50 MVars
B) 81 MVars
Page 4 of 89
