NERC Reliability Test Bank | WITH COMPLETE SOLUTION 2023/24

NERC Reliability Test Bank | WITH COMPLETE SOLUTION 2023/24 A Balancing Authority has a sudden loss of a large block of load in its area. This loss will be seen instantaneously in the change of which of the following values? 1. Actual Net Interchange 2. Scheduled Frequency 3. Scheduled Net Interchange 4. Area Control Error 1 & 4 3 & 4 1 & 3 4 only - 1 & 4. Due to the loss of load in the area, the BA will have excess generation and the excess will be exported into the Interconnection through the tie lines. This will cause the NIa to increase. Scheduled Frequency and Interchange only change when changed by an operator. A Balancing Authority has twenty units on governor control. The units have different capacities that range from 200 MW to 1000 MW and droop settings from 2% to 5%. The biggest adjustments in megawatt output in response to a frequency disturbance will be provided by units that have _______________. small capacity and small droop setting large capacity and small droop setting large capacity and large droop setting small capacity and large droop setting - large capacity and small droop setting When a generator synchronizes to the Interconnection, it couples itself to hundreds of other machines rotating at the same electrical speed. All generators should have a droop feature added to their governor. This will allow the generators to respond to the frequency deviation in proportion to their size whenever there is a disturbance or load-resource mismatch. What controls a generator's response is the governor "droop setting." The smaller the droop the closer a generator gets to being an isochronous generator. A 4 % droop gives more generator response to frequency variations than a 5% droop. - NERC training document "Understand and Calculate Frequency Response", Section; Droop. Page 5 In your Interconnection, a generator tripped that was large enough to reduce the frequency from 60.00 Hz to 59.94 Hz. Your Balancing Authority's Frequency Bias is -200 MW/0.1 Hz. How many MW would your system initially contribute to frequency support? 200 MW 120 MW 100 MW 80 MW - 120 MW. BAL-003, Each Balancing Authority shall achieve an annual Frequency Response Measure (FRM) (Attachment A) that is equal to or more negative than its Frequency Response Obligation (FRO) to ensure that sufficient Frequency Response is provided by each BA or Frequency Response Sharing Group (FRSG). For Example: Frequency Bias (which is always a negative number) is measured in MW per tenth Hz (MW/0.1Hz) means if scheduled frequency is 60.00 Hz and actual frequency drops to 59.90 Hz, a Balancing Authority with a 200 MW/0.1 Hz Frequency Bias would contribute 200 MW to help arrest the frequency decline. The frequency portion of the ACE equation is -[10*B*(Fa - Fs)]. If Frequency drops to 59.94 Hz then - (10 * -200 MW/0.1 Hz) * (59.94 Hz - 60.00 Hz) = -(- 2000 MW/Hz * -0.060 Hz) = -120 MW. To return ACE to zero, your Balancing Authority would have to over generate by 120 MW. This should happen with the response of your generator governors and loads due to the declining frequency. Governor droop is used to: Restore Frequency to normal Represent energy lost due to inefficiencies in generation Arrest Frequency Variations Maintain Voltage - Arrest Frequency Variations. Governor response is a component of Balancing Authority Frequency Response Characteristic. Generator governor systems determine generator response to frequency deviations based on the droop characteristic of the governor control system. Governor droop controls the generator's response in arresting frequency deviations. A generator's response to frequency deviations will be in proportion to its MW rating allowing many generators on governor control to respond in parallel. EPRI Chapter 4: Frequency Control What is the most common cause of frequency fluctuations? System generation and load imbalance Market activity Power losses Load shed - System generation and load imbalance Frequency of the Interconnection is determined by the total Interconnection load and total Inte