Partial preview of the text
Download Nerc exam questions with complete solutions and more Exams Engineering management in PDF only on Docsity!
NERC EXAM QUESTIONS with complete solutions 2025 A Balancing Authority notices that Operating Reserve has steadily declined throughout the hour. What is the most likely cause? a) Loss of a large generator in the area b) An inaccurate load forecast c) Loss of a major transmission line d) A malfunction of EMS - ANS v-b) An inaccurate load forecast Balancing Area 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? a) A net under-generation in Balancing Area A b) A net under-generation in the Interconnection c) A loss of load in Balancing Area A d) A loss of load in the Interconnection - ANS ¥ -b) A net under-generation in the Interconnection What is the penalty for a Balancing Authority violating the Disturbance Control Standard? a) Must carry additional Contingency Reserve b) Must develop a correction action plan c) Must re-evaluate and change its Frequency Bias Setting d) Must increase its Regulating Reserve - ANSV / -a) Must carry additional Contingency Reserve 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? a) Place AGC in flat frequency control b) Place AGC in flat tie line control c) Suspend AGC and investigate d) Do nothing as this is normal - ANS“ “-c) Suspend AGC and investigate When two identical generating units are operated in parallel on governor control, and on machine has a 5% droop and the other has a 10% droop, the unit with the greater (10%) governor droop will: a) Respond less to frequency deviations b) Respond more to frequency deviations c) Respond the same to frequency deviations d) Not adjust for frequency changes - ANSV Vv -a) Respond less to frequency deviations 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? a) 350 b) 400 c) 440 d) 600 - ANS /-c) 440 What is the main purpose of the Frequency Bias Setting in the ACE equation? a) Control frequency to 60 Hz for the entire Interconnection b) Assist with arresting frequency deviations c) Restore frequency to 60 Hz after a disturbance d) maintains frequency between 59.95 and 60.05 Hz - ANS /-b) Assist with arresting frequency deviations A Balancing Authority has a Frequency Bias Setting of -200 MW/.1Hz. What is the Balancing Authority's Frequency Response for a frequency of 59.95 Hz? a) 10 MWs b) 50 MWs c) 100 MWs d) 200 MWs - ANSv ¢-c) 100 MWs Scheduled Interchange is 250 MWs and Actual Interchange is 285 MWs. The Bias Setting is 35 MW/.1Hz and frequency is 60.00 Hz with no time error correction in effect. Frequency suddenly drops to 59.80 Hz. What does ACE indicate after the disturbance? a) 70 MW under-generating b) 70 MW over-generating c) 35 MW under-generating d) 35 MW over-generating - ANSV / -d) 35 MW over-generating 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: a) During off-peak periods b) During periods corresponding to those in which the inadvertent energy was accumutated a) 12R b) VI c) 12Z d) IR2 - ANSV /-a) I2R Which curve represents the results of a study on voltage response to power flow? a) D Curve b) P-V Curve c) Ferranti Curve d) VRS Curve - ANSY /-b) P-V Curve Two adjacent lines exist in a Balancing Area 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? a) The overhead line will carry more of the load increase b) The underground line will carry more of the load increase c) The load increase will be distributed evenly over the two lines d) The line with the higher impedance will carry more of the load - ANSv v -b) The underground line will carry more of the load increase To be effective, reactive resources should be: a) Centrally located in the system b) Located close to generation c) In areas subject to high voltages d) Located close to load areas - ANS /-d) Located close to load areas 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? a) De-energize the lightly loaded lines b) Use generators to absorb VARs c) Place capacitor banks in service as needed d) Increase voltage to increase load - ANS / -b) Use generators to absorb VARs A 50 MVA generator is currently producing 40 MWs and 10 MVARs. What are the dynamic reactive reserves currently on this generator? a) 50 b) 30 c) 0 a) 2U - ANod v -d) 2U In the diagram below, all three lines have the same impedance. What will be the flow on Line 2 if Line 1 is placed in service after an outage? a) 10 MWs b) 20 MWs c) 30 MWs d) 60 MWs - ANSv /-b) 20 MWs 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? a) Continue with the switching operation and investigate when complete b) Suspend the switching operation and verify indications c) Immediately close the breaker back in d) File a report to NERC for loss of firm load - ANS / -b) Suspend the switching operation and verify indications 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? a) The low voltage at the bus b) Loss of synchronizing capability c) Loss of primary protection d) A potential voltage collapse - ANSV /-c) Loss of primary protection 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? a) Failure of a Distance Relay b) Failure of a Differential Relay c) Breaker failure relay operation d) Inadvertent - ANS ¥ -b) Failure of a Differential Relay In a permissive protective relay scheme, the term “permissive” refers to: a) The receipt of a telecommunications signal from the opposite line terminal b) The process of automatic re-testing of a tripped line section c) The system operator granting permission for a line to trip d) The enabling of an automatic reclosing scheme - ANSV /-a) The receipt of a telecommunications signal from the opposite line terminal The NERC standards require the use of three-part communication when issuing and receiving Operating Instructions. Which of the following would fall into that category? d) Interruption of power to a large part of the BES - ANS / -d) Interruption of power to a large part of the BES Interconnection frequency is at 59.75 Hz. The System Operator has not experienced any disturbances. What does the indicate? a) Interconnection voltage and load are not balanced b) Interconnection system loads are higher than on-line generation c) Collective system generation is higher than system load d) A loss of load - ANS / -b) Interconnection system loads are higher than on- line generation A transmission 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? a) 50 MWs b) 100 MWs c) 200 MWs d) 250 MWs - ANSY /-c) 200 MWs 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? a ) Dispatch field personnel to the breakers substation b) Shed load near the IROL location c) Re-dispatch generation to reduce line loading d) Develop a new response plan for the contingency - ANSV / -a ) Dispatch field personnel to the breakers substation 
