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NERC RANDOM Questions | Actual Questions and Answers Latest Updated
2025 /202 6 (Graded A+)
When current in an AC circuit is doubled, power losses in the circuit will respond in which way? a) half as much b) does not change c) doubles d) four times greater - ✔✔d) four times greater What determines the size of insulators used on power lines? a) Current flow on the line b) Voltage level of the line c) Reactance of the line d) Operating Limit of the line - ✔✔b) Voltage level of the line Reactive power is needed to support which type of load? a) Inductive b) Capacitive c) Impedance d) Resistive - ✔✔a) Inductive When isolating equipment in the electrical system, what device is most often used as a visual clearance point? a) Circuit switchers
b) Fuses c) Disconnect switches d) Circuit breakers - ✔✔c) Disconnect switches What is current? a) Electrons that flow on a conductor b) Electrical pressure applied to a conductor c) Sine wave d) Water flow rate - ✔✔a) Electrons that flow on a conductor How many phases are there in most high voltage power systems? a) 10 phases b) 1 phase c) 3 phases d) 2 phases - ✔✔c) 3 phases What does the term system fault mean? a) the physical problem in a device, component or element b) abnormal current flow on an unintended path c) a device or component not operating as designed d) the fault of the system for not operating as designed - ✔✔b) abnormal current flow on an unintended path What is the most common type of fault on the power system? a) Line to Ground
a) Real Power b) Apparent Power c) Reactive Power d) Hydro Power - ✔✔b) Apparent Power How are generators typically classified in the power system? a) Fuel source b) Cycling capability c) Capacity d) Generating voltage - ✔✔a) Fuel source When Interconnection frequency is below 60.00 Hertz, how do Balancing Authorities support Interconnection Frequency? a) Increasing excitation on field windings b) Decrease MW output c) Increasing MW output d) Remain at current MW output level - ✔✔c) Increasing MW output If load is balanced equally among each phase, how much current will flow on the neutral point? a) Neutral current will be zero when balanced b) Equal to the sum of the power flow c) Half the flow of each phase d) Equal to the flow on each phase - ✔✔a) Neutral current will be zero when balanced A generator is a machine that produces energy. Which of the following statements best describes this process?
a) A generator converts mechanical energy to electrical energy b) A generator produces imaginary power using real fuel c) A generator does not convert energy it makes it d) A generator converts electrical energy to mechanical energy - ✔✔a) A generator converts mechanical energy to electrical energy Which three variables are part of the OHM's law equation? a) Potential, Current, Transformers b) Current In, Current Out, Node c) MW, MVAR, MVA d) Voltage, Current, Impedance - ✔✔d) Voltage, Current, Impedance An electric power system that is experiencing low voltage is an indication of which of the following? a) A deficiency in reactive power b) Not enough reactors in service c) A surplus of reactive power d) Planned transmission line outages - ✔✔a) A deficiency in reactive power If the frequency on both sides of an open breaker is exactly matched, which of the following statements is true? a) The phase angle across the breaker is zero b) The power angle is 90 degrees c) The voltage angle is 180 degrees d) The phase angle across the breaker is constant - ✔✔d) The phase angle across the breaker is constant
What does the term Voltage mean in a power system? a) electromotive force that causes electrons to flow b) electromagnet induction c) a force that makes a generator rotate d) a force that prevents electrons to move - ✔✔a) electromotive force that causes electrons to flow In a three phase Alternating Current generator, each phase is physically how far apart? a) Offset by 90 degrees b) Offset by 360 degrees c) Offset by 120 degrees d) Offset by 180 degrees - ✔✔c) Offset by 120 degrees A Balancing Authority has an ACE reading of - 100MWs and frequency is 60.12 Hz. Is the BA exceeding the BAAL? a) It is impossible to determine from the given information. b) Yes c) Yes, but as long as the BA gets within its BAAL in 30 minutes, there is no violation. d) No - ✔✔d) No Feedback: When frequency is above schedule, as in this case, the BAAL LOW does not apply. Therefore, there is no negative ACE limit in effect. How is the Frequency Response Measure (FRM) of a Balancing Authority determined? a) It is the median of the BA's frequency response for the frequency deviation events identified by NERC for the previous year. b) It is the previous year's Control Performance Standard 1 (CPS1) score.
c) It is the change in the BA's Net Interchange Actual for the largest frequency deviation during the previous year. d) It is the average of the BA's frequency response for all of the frequency deviations of the previous year. - ✔✔a) It is the median of the BA's frequency response for the frequency deviation events identified by NERC for the previous year. The Contingency Reserve Restoration period is. a) ninety minutes b) one minute c) fifteen minutes d) forty-five minutes - ✔✔a) ninety minutes Feedback: The Contingency Reserve Restoration Period begins at the end of the Disturbance Recovery Period. The default Contingency Reserve Restoration Period is 90 minutes. This period may be adjusted to better suit the reliability targets of the Interconnection based on analysis approved by the NERC Operating Committee. The Contingency Reserve Restoration period is ninety minutes beyond the (15-minute) Disturbance Recovery Period. This means that the Balancing Authority or Reserve Sharing Group must obtain enough reserves to respond to the next most severe single contingency not longer than 90 minutes later. Shedding load would be an option to acquire enough contingency reserves to meet the next reportable disturbance if the reserves cannot be obtained by more normal means. If a Reserve Sharing Group member has experienced a Reportable Disturbance condition but does not call for reserve activation from other members, the entire group shall still be considered to be in a disturbance condition. True or False - ✔✔False Feedback: Each Reserve Sharing Group shall comply with the DCS. A Reserve Sharing Group shall be considered in a Reportable Disturbance condition whenever a group member has experienced a Reportable Disturbance
a) positively b) economically c) precisely d) correctly - ✔✔b) economically Feedback: Automatic Generation Control automatically, with an economic component, adjusts a Balancing Authority's generation in response to change in its ACE. Which entities may determine if a deviation of a Dynamic Schedule constitutes a reliability concern? What entity must they notify of that determination? a) A Reliability coordinator to Transmission Operator makes the determination and must notify the Sink Balancing Authority b) A Reliability Coordinator or Transmission Operator makes the determination and must notify the Purchasing-Selling Entity c) Only the Transmission Operator may make the determination and must notify the Sink Balancing Authority d) Only the Reliability Coordinator may make the determination and must notify the Purchasing-Selling Agent - ✔✔b) A Reliability Coordinator or Transmission Operator makes the determination and must notify the Purchasing-Selling Entity Feedback: The Purchasing-Selling Entity responsible for the Dynamic Interchange Schedule shall ensure it is updated for the next available scheduling hours and future hours when a Reliability Coordinator or Transmission Operator determines the deviation, regardless of magnitude, to be a reliability concern and notifies the Purchasing-Selling Entity of that determination and the reasons for it. Actual System Frequency (FA) is 60.03 Hz, a Balancing Authority is under-generating slightly to prepare for an upcoming interchange transaction. What is the Balancing Authority doing?
a) The BA is hurting the Interconnection Frequency. b) The BA is in CPS1 violation. c) The BA is helping the Interconnection Frequency. d) The BA is in BAAL violation - ✔✔c) The BA is helping the Interconnection Frequency. Feedback: Since frequency is above schedule, the Interconnection as a whole is over-generating. The BA is under- generating, therefore doing its part to help return frequency to schedule. This will help the BAs CPS score at the end of the month Balancing Authorities should only implement or operate Pseudo-Ties that are included in what document? a) The NERC Reliability Standards b) The NAESB Electric Industry Registry c) The North American Electric Standards d) The FERC Standards of Conduct - ✔✔b) The NAESB Electric Industry Registry Feedback: NERC Standard INT- 004 Each Balancing Authority shall only implement or operate a Pseudo-Tie that is included in the NAESB Electric Industry Registry publication in order to support congestion management procedures. The Confirmed Interchange associated with a Dynamic Schedule is 370 MWs. Assuming the deviation is expected to persist, how much must the actual hourly integrated energy deviate from the Confirmed Interchange to require an update to be submitted for future hours? a) More than +/- 25 MWs b) More than +/- 15% c) +/- 10% d) More than +/- 37 MWs - ✔✔d) More than +/- 37 MWs
True or False - ✔✔False Feedback: A Balancing Authority that is a member of a REGULATION Reserve Sharing Group is the Responsible Entity only in periods during which the Balancing Authority is not in active status under the applicable agreement or the governing rules for the REGULATION Reserve Sharing. Which of the following would be a use of the IME portion of the ACE equation? a) Account for the governor response of a Jointly Owned Unit. b) Represent a generator meter which is off by 20 MW. c) Represent flow of a tie line with an out of service meter. d) Comply with a DCS event. - ✔✔c) Represent flow of a tie line with an out of service meter. Who must approve a Reliability Adjustment Arranged Interchange before it is confirmed? a) Only the Source and Sink Balancing Authorities associated with the Interchange. b) The Reliability Coordinator approves all Reliability Adjustment Arranged Interchange c) Each Balancing Authority and Transmission Service Provider associated with the Interchange. d) All Balancing Authorities involved in the Interchange. - ✔✔a) Only the Source and Sink Balancing Authorities associated with the Interchange. Feedback: The Source Balancing Authority and the Sink Balancing Authority Receiving a Reliability Adjustment Arranged Interchange shall approve or deny it prior to the expiration of the time period defined in Attachment 1. Two Balancing Authorities have arranged for an Interchange Transaction. However, a High-Voltage Direct Current (HVDC) tie is on the scheduling path. What must the Balancing Authorities in the area where the HVDC tie is controlled do to complete the Interchange Agreement?
a) Send the HVDC Transmission operator a copy of the Interchange Agreement after the Schedule has started ramping b) Nothing has to be done with the HVDC Transmission Operator because they will rectify any amount of megawatt flow as long as it does not exceed their operating limits c) Coordinate the Interchange Schedule with the Transmission operator of the HVDC tie prior to implementation d) Request the RC to complete the transaction - ✔✔c) Coordinate the Interchange Schedule with the Transmission operator of the HVDC tie prior to implementation Feedback: Each Balancing Authority in whose area the high-voltage direct current tie is controlled shall coordinate the Confirmed Interchange prior to its implementation with the Transmission Operator of the high- voltage direct current tie. is a term used to describe the loss of a generating unit or plant after a close-in fault, or short circuit that is not cleared quickly enough. a) Voltage Collapse b) Cascading Outages c) Dynamic Instability d) Transient Instability - ✔✔d) Transient Instability Feedback: Transient Instability is a term used to describe the loss of a generating unit or plant after a close-in fault, or short circuit that is not cleared quickly enough. Transient instability is not likely to occur as part of cascading events leading to a blackout, but it could be an initial event that gets the ball rolling if the system is particularly heavily stressed. Since such instability causes generation to lose synchronism in a second or less, operators would only see the result. What process according to NERC Standard EOP- 005 Attachment 1 directs operating personnel to evaluate how well the Restoration Plan works?
Dynamic Instability can develop between one generator, or a group of generating plants, and the interconnection. It can happen when the transmission network connections between a generating unit, or a geographic grouping of units and the rest of the interconnection have become weakened such as can occur when cascading events are happening. If, following a disturbance in the system, the synchronizing power oscillations become smaller in magnitude over several seconds, this is normal stable behavior. If, however, these oscillations grow larger over time, then dynamic instability is happening, and it will probably lead to the affected generation losing synchronism with the rest of the system and tripping off line with the loss of generation to the network. Please note that normally this phenomenon happens in seconds, too fast for operators to see it or to react. Cranking power or energizing power (station service) should be restored to power plants how soon? a) Within 1 hour b) Within 30 minutes c) Within 3 - 4 hours depending on which units were on line prior to the disturbance d) Within 24 hours - ✔✔b) Within 30 minutes Feedback: Cranking power or station service should be restored to the generating sites as soon as possible (within 30 minutes) to improve their availability. Relatively short delays in restoring auxiliary power can result in delays of several hours (or even days) in restoring the effected units due to the nature of boilers cooling down and steam condensing in the system. Station emergency generators and backup batteries may provide power for only the most essential safety systems but cannot be counted on as a source for a unit start-up. The syncroscope should be used to synchronize two systems together when at least one if not both systems are in an islanded condition. How is synchronization performed? a) The frequency and voltage must be equal. The incoming system should be a bit slower than the running system and the phase angle lights must be out (dark) when the breaker is closed. b) The frequency and voltage must be within 1%. The incoming system should be a bit faster than the running system and the phase angle lights must be out (dark) when the breaker is closed.
c) The frequency and voltage must be equal. The incoming system should be a bit faster than the running system and the phase angle lights must be out (dark) when the breaker is closed. d) The frequency and voltage must be equal. The incoming system should be a bit faster than the running system and the phase angle lights must be on (bright) when the breaker is closed. - ✔✔c) The frequency and voltage must be equal. The incoming system should be a bit faster than the running system and the phase angle lights must be out (dark) when the breaker is closed. Feedback: The process for synchronizing is as follows: voltages on the "incoming" and "running" sides of the breaker must be equal (or within 2 kV); the speed of the incoming system should be slightly faster (clockwise) than the running system; phase angle across the breaker must be the same; when the sweep hand rotates clockwise to 5 minutes before 12 - CLOSE the breaker. If there is a voltage phase angle difference the amber lights will glow. The amber lights will be dark when NO PHASE ANGLE DIFFERENCE exists. Close the breaker only when the lights are dark. Operating entities may choose what type of safety strategy during the restoration activities to minimize the likelihood that a circuit will automatically reclose when a substation or line is energized? a) System Operators may be directed to perform a supervisory OPEN control on all "open" breakers prior to being energized b) System Operators Should perform a thorough system assessment and dispatch personnel to substations to retrieve relay targets c) System Operators may be directed to open all closed breakers on the system d) System Operators may choose to retrieve relay targets by interrogating the substation relays via specialized communications interface software - ✔✔a) System Operators may be directed to perform a supervisory OPEN control on all "open" breakers prior to being energized Feedback: Operating Entities may choose to implement a safe operating technique that addresses automatic reclosing on circuit breakers. Operators may be directed to perform a "Supervisory OPEN" control on an already open breaker to disable any reclosing feature. Performing an "OPEN" by supervisory control will usually disarm, disable, or inhibit most auto-reclosing relays from operating when the substation bus or connected line is energized. This feature of course is based on the design and implementation of the specific relay in use.
d) 60 calendar months - ✔✔a) 13 calendar months Each Reliability Coordinator shall conduct System Restoration drill(s), exercise(s), or simulation(s) per calendar year; a) two b) twelve c) one d) four - ✔✔a) two How often must a Reliability Coordinator review and update their backup functionality Operating Plan? a) Only when changes are made b) Semi-annually c) Annually d) Every quarter - ✔✔c) Annually When a transmission line trips, the power flow on that line will be reflected in other transmission lines and equipment. In order to ensure that the redistribution of power flowing on the remaining elements will not result in further uncontrolled outages and possibly cascading outages, System Operators should plan on mitigating the consequences of contingencies. What method is used to determine the reliability of the power system after a contingency? a) Real-time Monitoring b) Interconnection Agreements c) Operational Planning Analysis d) Seasonal studies - ✔✔c) Operational Planning Analysis Feedback: Operational Planning Analysis is an evaluation of projected system conditions to assess anticipated (pre- Contingency) and potential (post-Contingency) conditions for next-day operations. The evaluation shall
reflect applicable inputs including, but not limited to, load forecasts, generation output levels, Interchange, known Protection System and Special Protection System status or degradation, transmission outages, generator outages, Facility Ratings, and identified phase angle and equipment limitations. Which type(s) of power transformers are affected by GMDs? a) Generator step-up transformers b) Direct current (DC) transformers c) Delta connected transformers d) Wye connected transformers - ✔✔d) Wye connected transformers Feedback: GICs enter a transformer through its ground connection, producing an off-setting DC excitation current. Delta connected transformers do not have a ground connection and therefore are not susceptible to GICs. What is a contingency? a) A change in electrical loading due to a generators output. b) An assessment of scheduled outages. c) Unexpected failure of a system component. d) A condition where resources are exhausted. - ✔✔c) Unexpected failure of a system component. What tool relies on the State Estimator? a) Energy Management System b) SCADA c) Contingency Analysis d) ACE - ✔✔c) Contingency Analysis
