NERC Exam Study Guide 601 Questions With Correct Answers

What is the ACE equation? - Answer (NIa-NIs)-10B(Fa-Fs) What effect does an internal loss of load have on frequency and ACE? - Answer Frequency increases, ACE increases What effect does an external loss of load have on frequency and ACE? - Answer Frequency increases, No change in ACE What happens to your frequency, ACE value, and Tie-line flow when you experience a loss of generation external to your area? - Answer Frequency drops, No change in ACE, Tie-line flows increase out of your system What happens to your frequency, ACE value, and Tie-line flow when you experience a loss of generation inside your balancing area? - Answer Frequency drops, ACE drops, Tie-flows increase into your area How is Frequency Response Obligation (FRO) calculated? - Answer It is calculated based on the BA's annual percentage of generation and load in it's interconnection How is the FRO of a Frequency Response Sharing Group calculated? - Answer FRO determined by adding individual FROs of each member How is the Frequency Response Measure (FRM) calculated? - Answer It is the median of all frequency responses observed for frequency deviations events identifies by NERC for the previous year How should the Frequency Response Measure be set compared to the Frequency Response Obligation? - Answer Frequency Response Measure should be set equal to or more negative than Frequency Response Obligation Who determines your Frequency Bias Setting? - Answer It is determined by NERC based on previous years Frequency Response Measure What is CPS 1 (Control Performance Standard)? - Answer One minute clock average over a year and is based on ACE deviation in correlation to frequency deviation. CPS 1 has a 100% minimum compliance. Measures how well a BA balances load and generation to support the interconnection. What is BAAL (Balancing Authority ACE Limit)? - Answer ACE does not exceed its BAAL for more than 30 consecutive minutes When does BAAL high apply? When does BAAL low apply? - Answer BAAL high applies when frequency actual is greater than frequency scheduled BAAL low applies when frequency actual is lower than frequency scheduled What is DCS and what is the minimum compliance for DCS (Disturbance Control Standard)? - Answer 100% compliance, Measures BA's ability to carry adequate Operating Reserve What is the time limit for Disturbance Recovery Period? - Answer 15 minutes If ACE is positive or 0 at the time of a DCS event what does have to be returned to and in what time? - Answer ACE of 0 in 15 minutes If ACE is negative at the time of a DCS event what does ACE have to be returned to and in what time? - Answer ACE must be returned to the negative pre-contingency value in 15 minutes Your MSSC is 160 MW. You have an ACE Value of 0 when a DCS event causes ACE to drop 100 MW. 90 seconds later you have another event that causes ACE to drop an additional 50 MW. What value must ACE be returned to? - Answer -100 What is considered a DCS event? - Answer A loss of generation greater than or equal to 80% of your MSSC, multiple generator losses are considered a single event if occurring within 60 seconds of each other. When does the Contingency Reserve restoration period begin? How long do you have to restore contingency reserve equal to your MSSC? - Answer At the end of the Disturbance control recovery period, 90 minutes What makes up Operating reserves? - Answer Regulating reserves (must be spinning), Contingency reserves (both spinning and non-spinning) How much of your contingency reserve should be spinning reserves? - Answer 50% What is Regulating reserves used for? - Answer Used to meet load forecasting errors, system tie-line and frequency regulation needs What can be considered contingency reserve? - Answer Generation, controllable load, coordinated adjustments to interchange schedules For controllable load to be considered a contingency reserve what must it be? - Answer must be available within 15 minutes For generation to be considered spinning contingency reserve what must it be? - Answer must be synchronized to the system and available within the DCS period What is State Estimator? - Answer A real time model of the current conditions of the power system What is Contingency analysis? what does Contingency analysis rely on? How often should Contingency analysis be ran? - Answer evaluates potential outages and their impact on the remaining system, relies on State Estimator values, should be ran every 30 minutes what is the scan rate for ACE related data? - Answer 6 seconds What must a BA experience to declare an EEA? - Answer the BA is or expects to be unable to provide its customers load demands Who request an EEA? - Answer the load serving entity Who declares and EEA? - Answer The deficient areas Reliability coordinator Does an EEA have to be declared in order? - Answer No What is happening in an EEA1? - Answer the BA or load serving entity foresees or is experiencing conditions where all available resources are committed to meet firm load, firm transaction, and reserve commitments, and is concerned about sustaining its required Contingency reserves. Non firm wholesale energy sales have been curtailed. What is happening in an EEA2? - Answer the BA or load serving entity is no longer able to provide its customers expected energy requirements and is designated an Energy Deficient Entity. Procedures have been implemented. Maintaining contingency reserves. Public appeals to reduce demand, voltage reduction, Interruption of non-firm end use loads, Demand-side management, Utility load conservation measures What is happening in an EEA3? - Answer Firm load shed Where is voltage reduction implemented and why? - Answer On the distribution side. Used to lower load when the transmission system is heavily loaded. When would voltage reduction take place on transmission system? - Answer Only during restoration (+/- 10% nominal voltage) What are the AGC modes? - Answer Tie-Line Bias, Flat Frequency, Flat Tie-Line What mode should AGC always be in unless its use becomes detrimental to reliable system operations? - Answer Tie-Line Bias When would AGC be operated in Flat Frequency mode? - Answer When tie-line metering is unavailable (still have tie-lines. not islanded. flat frequency is not the same as isochronous) When would AGC be operated in Flat Tie-Line mode? - Answer When frequency metering is unavailable In an island situation what happens to AGC? - Answer It should be suspended What does a generator governor do? - Answer Arrests frequency but does not restore it What is Governor Droop? - Answer The amount of frequency change required for the generator to respond from no load to full load or vice versa (typically set to 5%) What is Isochronous mode? - Answer 0% Governor Droop, fully responsive to any change in frequency, used only in island conditions (1 unit per island) What is a Governor Deadband and what is its purpose? - Answer +/- 0.036 Hz, prevents governor from responding to slight variations in frequency