Known NERC Exam Questions

Question 1

A BA notices that Operating Reserves have steadily decline throughout the hour. What is most likely the cause?

Answer 1

An inaccurate load forecast

Question 2

Balancing Authority A notices that the Interconnection frequency is 59.94 Hz and their ACE is 0. Which of the following could be the cause of this reading?

Answer 2

A net under-generation in the Interconnection

Question 3

What is the penalty for a BA violating the Disturbance Control Standard?

Answer 3

Must carry additional Contingency Reserves

Question 4

Your ACE is a large negative value and system frequency is 59.80 Hz. Your AGC system is pulsing your units down. What should you do?

Answer 4

Suspend AGC and investigate.

Question 5

When two identical 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 (10%) governor droop will:

Answer 5

Respond less to frequency deviations.

Question 6

On a radial transmission system, a generator has a capacity of 600 MWs. The Droop characteristic is at 5% and the generator is currently loaded at 300 MWs. If frequency suddenly drops to 59.3 Hz, what would be the total generator output?

Answer 6

440 MW

Question 7

What is the main purpose of the Frequency Bias Setting in the ACE equation?

Answer 7

Assist with arresting frequency deviations

Question 8

A BA has a Frequency Bias setting of -200 MX/.1Hz. What is the BA’s Frequency Response for a frequency of 59.95 Hz?

Answer 8

100 MWs

Question 9

Inadvertent energy accumulation occurs due to a difference in Net Actual Interchange and Net Interchange Schedule over time. This energy accumulation can be paid back unilaterally by adjusting delivery of power:

Answer 9

During periods corresponding to those in which the inadvertent energy was accumulated.

Question 10

You are the Source Balancing Authority for an Arranged Interchange Transaction request. The request has a non-standard ramp rate specified. What action should you take?

Answer 10

Approve the request if able to accommodate.

Question 11

Who must approve an Interchange Transaction before it becomes Confirmed Interchange?

Answer 11

BA

Question 12

A BA is scheduled to receive 300 MWs from the north and 400 MW’s from the south for hour ending in 1300. The north schedule is curtailed starting at 1220 with a 10-minute ramp. What is the Net Interchange for the hour?

Answer 12

500 MWh

Question 13

When current flow increases in the power system, losses in the system will increase based on which of the following relationships?

Answer 13

I2R

Question 14

Which curve represents the results of a study on voltage response to power flow?

Answer 14

P-V Curve

Question 15

Two adjacent lines exist in a BA that are the same length and have the same ratings. One line is overhead and the other is underground. How do these two lines respond as load picks up through the day?

Answer 15

The underground line will carry more of the load increase.

Question 16

To be effective, reactive resources should be:

Answer 16

Located close to load areas.

Question 17

Voltage is high in an area due to off-peak demand. There are several lightly loaded high voltage transmission lines going to radial loads. All capacitor banks are out of service. Generators still have reactive reserves both leading and lagging. What should be done first to lower the voltage?

Answer 17

Use generators to absorb VARs

Question 18

A 50 MVA generator is currently producing 40 MWs and 10 MVARs. What are the dynamic reactive reserves currently on this generator?

Answer 18

20

Question 19

A System Operator is conducting switching operations. When he opens one end of a transmission line, there is an indication of load loss. What should the operator do?

Answer 19

Suspend the switching operation and verify indications.

Question 20

You have just placed a line in service and the receiving bus end of the line shows zero voltage, but there is indication of current flow. What is your primary concern?

Answer 20

Loss of primary protection

Question 21

You discovered that Bus A is de-energized. Each of the line breakers off of the bus are closed. However, the breakers at the other end of each line from the bus are open. What is the most likely cause for this arrangement?

Answer 21

Failure of a Differential Relay

Question 22

In a permissive protective relay scheme, the term “permissive” refers to:

Answer 22

The receipt of a telecommunications signal from the opposite line terminal.

Question 23

Which of the following is extremely important in determining system load when performing a next day study?

Answer 23

Forecasted weather

Question 24

Several SCADA alarms indicate a disturbance in Area B. There are 4 transmission lines connecting Area A to Area B which have become heavily loaded due to disturbance. One of the lines is above its SOL. Re-dispatching of generation has no effect on line flows. As the operator, which answer best applies to this situation?

Answer 24

There is a possible separation or islanding in Area B.

Question 25

Interconnection frequency is at 59.75 Hz. The System Operator has not experienced any disturbances. What does that indicate?

Answer 25

Interconnection system loads are higher than on-line generation.

Question 26

A trnamssion line in your area is overloaded by 50 MWs. An area generator has a .25 shift factor on the line. How much generation change is required to return the line to its limit?

Answer 26

200 MWs

Question 27

A study shows that a single contingency would result in an IROL violation and the corrective action would require opening a breaker with no SCADA control due to a failed RTU. What should the system operator do first?

Answer 27

Dispatch field personnel to the breaker’s substation.