NERC PRACTICE SET 3

Question 1

Your system is experiencing heavy loading and low voltage. What is the first response for a System Operator?

a) Take lines out of service
b) Put capacitors in service
c) Put reactors in service
d) Lower loads

Answer 1

b) Put capacitors in service

Question 2

Which of the following action is appropriate for mitigating heavy power transfer on a transmission line?

a) Put parallel line in service
b) Put a capacitor in service
c) Put a reactor in service
d) Increase generation

Answer 2

a) Put parallel line in service

Question 3

Line A is a 100 mile 500 kV transmission line. Line B is a 10 mile 500 kV transmission line. Both
lines are lightly loaded. Line B is contributing 3.2 MVAR to the bus. How much MVAR will line A
contribute to the bus?

a) 10 times 3.2 MVAR
b) Less than 3.2 MVAR
c) Equal to 3.2 MVAR
d) More than 3.2 MVAR

Answer 3

d) More than 3.2 MVAR

Question 4

What are the effects of transmission line loading above its surge impedance loading?

a) The line acts like a capacitor
b) The line acts like a reactor
c) The line ceases to function
d) The line’s losses decrease

Answer 4

b) The line acts like a reactor

Question 5

After a forced outage, a contingency analysis study shows that one more outage will cause an
IROL violation. There is a parallel line out for maintenance that can be returned within a 4 hours
window if requested. What must be done first to mitigate this condition?

a) Put the parallel line in service with protection
b) Put the parallel line in service without protection
c) Take the protective tripping off the line
d) Call the RC and formulate an Operating Plan

Answer 5

d) Call the RC and formulate an Operating Plan

Question 6

A transformer rated at 100 MVA has 80 MW flowing through it. How many MVARS could flow
through it without exceeding its rating?

a) 80 MVAR
b) 60 MVAR
c) 50 MVAR
d) 20 MVAR

Answer 6

b) 60 MVAR

Question 7

A system operator notices that frequency has dropped to 59.95 Hz and his Balancing Area’s ACE
is near zero. The Balancing Authority has plenty of generation to help restore the Interconnection Frequency. Which statement best describes the appropriate action?

a) Increase generation to improve his CPS score.
b) Notify the deficient BA to sell them power.
c) Take units off of AGC.
d) Ensure that generators are providing governor response.

Answer 7

d) Ensure that generators are providing governor response.

Question 8

A transmission path is rated at 550 MVA and has 500 MW and 55 MVAR of power flowing on the
line. What action is required of the system operator?

a) The line has exceeded its rating is beyond its rating and power flow must be reduce.
b) The line will trip if not removed from service.
c) No action beyond continued monitoring is required
d) Reconfiguration is needed to lower the reactive power flow

Answer 8

c) No action beyond continued monitoring is required

Question 9

If two heavily loaded transmission lines into a Balancing Authority area trip resulting in that area
being islanded, what is the likely impact to Interconnection frequency?

a) Interconnection frequency will remain the same
b) Interconnection frequency will likely increase
c) Interconnection frequency will likely decrease
d) The island will have its own frequency

Answer 9

b) Interconnection frequency will likely increase

Question 10

Which transmission line type will likely produce more reactive power?

a) Underground cable
b) Lightly loaded short overhead line
c) Loaded tie-line
d) Radial Lines with capacitor banks in service

Answer 10

a) Underground cable

Question 11

Power is flowing from source BA 1 to sink BA 2 and loading the tie-lines. Which action would
reduce the power flow on the tie-lines?

a) Reliability Coordinator declaring an EEA
b) Increasing generation in the sink BA
c) Increasing generation in the source BA
d) Buy more power from source BA

Answer 11

b) Increasing generation in the sink BA

Question 12

An Emergency outage request would result in exceeding an SOL? Which actions need to be
considered prior to taking the outage?

a) Will it exceed SOL study
b) Redispatch generation or reconfigure transmission
c) Shed Load to allow outage
d) Open the line that will exceed SOL

Answer 12

b) Redispatch generation or reconfigure transmission

Question 13

A local transmission line trips after making contact with a tree. At one terminal SCADA shows
every breaker on the bus standing open. What likely caused this result?

a) Differential relay
b) Ground relay
c) SPS/RAS
d) Breaker Failure relay

Answer 13

d) Breaker Failure relay

Question 14

A line has 200 ohms of capacitive reactance and 600 ohms of inductive reactance, what is the
total reactance of the line?

a) 200 ohms
b) 400 ohms
c) 600 ohms
d) 800 ohms

Answer 14

b) 400 ohms

Question 15

When you need to increase MVARS due to inductive reactive power demands, which equipment
would you primarily use?

a) Generators kV setpoint
b) Capacitor Banks
c) Shunt Reactor
d) Transformer Tap Changer

Answer 15

b) Capacitor Banks

Question 16

Which line would a GMD most likely impact?

a) 0% series compensation over Igneous Rock
b) 25% series compensation over Igneous Rock
c) 50% series compensation of farmland
d) 75% series compensation over farmland

Answer 16

a) 0% series compensation over Igneous Rock

Question 17

A transformer is loaded to 150% of its capacity, and the only other transformer capable of
relieving the loading is at 90%. How should the overload be alleviated?

a) Adjust the tap changer on the 90% transformer
b) Raise Transmission voltage
c) Shed load
d) Remove 150% transformer from service

Answer 17

c) Shed load

Question 18

If the ICCP is down and will take an unknown amount of time to repair, what is the appropriate
response?

a) Establish functionality at the backup center
b) Power cycle ICCP Server
c) Call the neighbors to monitor until repaired
d) Gather data manually

Answer 18

a) Establish functionality at the backup center

Question 19

If a Transmission Operator loses the ability to run a Contingency Analysis and reports it to its RC,
what should the RC do?

a) The RC should run RTCA for the TOP area
b) Inform TOP it is in violation of NERC Standard
c) Continue to perform Contingency Analysis for the entire RC area and report to the TOP
issues in its area
d) Issue an Operating Instruction to fix Contingency Analysis

Answer 19

c) Continue to perform Contingency Analysis for the entire RC area and report to the TOP
issues in its area

Question 20

Which type of power cannot travel far and should be deployed close to inductive loads.

a) Real power
b) Reactive power
c) Total power
d) Horsepower

Answer 20

b) Reactive power

Question 21

What are the two measured parameters of a transmission line that will caused a distance relay
to operate?

a) Power and Voltage
b) Voltage and Current
c) Resistance and Losses
d) Current In and Current Out

Answer 21

b) Voltage and Current

Question 22

Real-time contingency analysis shows that a transmission line will overload for the loss of Line X.
The loss of Line X will also result in the overloaded line being radial. What is the best course of
action for the Transmission Operator?

a) Open the line
b) Redispatch generation
c) Shed load immediately
d) Be prepared to shed load if Line X trips

Answer 22

d) Be prepared to shed load if Line X trips

Question 23

How much contingency reserve does a BA have to carry if its total generation is 4500MW
comprised of three 500 MW unit and three 1000 MW units.

a) 450 MW
b) 500 MW
c) 750 MW
d) 1000 MW

Answer 23

d) 1000 MW