NERC NERC Interconnection and Balancing Operations 1 — Questions and Answers
Question 1: Which NERC standard requires Balancing Authorities to maintain frequency within defined limits?
- BAL-001 (Correct answer)
- BAL-003
- BAL-005
- IRO-010
Correct answer: BAL-001
BAL-001 requires Balancing Authorities to maintain real power balance to keep Interconnection frequency within established limits.
Question 2: What is the nominal frequency of the Eastern, Western, and Texas (ERCOT) Interconnections in North America?
- 50 Hz
- 60 Hz (Correct answer)
- 55 Hz
- 65 Hz
Correct answer: 60 Hz
All three major North American interconnections operate at a nominal frequency of 60 Hz.
Question 3: Under NERC BAL-003, what is the purpose of the Frequency Response Obligation (FRO)?
- To require generators to ramp up output within 10 minutes of a dispatch signal
- To ensure each Balancing Authority contributes sufficient primary frequency response to arrest frequency decline after a generation loss (Correct answer)
- To mandate that BAs purchase frequency regulation products in organized markets
- To set the maximum permissible frequency deviation before load shedding is triggered
Correct answer: To ensure each Balancing Authority contributes sufficient primary frequency response to arrest frequency decline after a generation loss
BAL-003 establishes each BA's Frequency Response Obligation — the minimum primary frequency response each BA must provide to stabilize interconnection frequency after disturbances.
Question 4: What does 'Automatic Generation Control' (AGC) do in a Balancing Authority's control area?
- Automatically installs new generation resources when demand exceeds supply
- Continuously adjusts generator output to maintain scheduled tie-line flows and area control error at zero (Correct answer)
- Controls the automatic tap changers on substation transformers
- Automatically issues emergency alerts when frequency drops below 59.5 Hz
Correct answer: Continuously adjusts generator output to maintain scheduled tie-line flows and area control error at zero
AGC adjusts generator MW output to regulate Area Control Error (ACE), keeping scheduled interchange and frequency on target.
Question 5: The 'Area Control Error' (ACE) in a Balancing Authority represents:
- The difference between actual and scheduled interchange plus the BA's share of frequency deviation (Correct answer)
- The maximum allowable current on a transmission line before a trip
- The error rate in SCADA telemetry data for the BA's footprint
- The difference between bid-in capacity and actual generator output
Correct answer: The difference between actual and scheduled interchange plus the BA's share of frequency deviation
ACE is the instantaneous difference between a BA's actual net interchange and scheduled interchange, adjusted for the BA's frequency bias contribution.
Question 6: Under NERC IRO-006, Reliability Coordinators are required to have which type of agreements in place?
- Power purchase agreements with neighboring generators
- Reliability Coordinator Information Exchange Agreements with adjacent RCs (Correct answer)
- Interconnection agreements with large industrial customers
- Memoranda of understanding with FERC and state regulators
Correct answer: Reliability Coordinator Information Exchange Agreements with adjacent RCs
IRO-006 requires Reliability Coordinators to have Information Exchange Agreements with neighboring RCs to facilitate real-time operational coordination.
NERC NERC Interconnection and Balancing Operations 1
Which NERC standard requires Balancing Authorities to maintain frequency within defined limits?