SOPD Power System Operations 2 — Questions and Answers
Question 1: What is the primary purpose of Automatic Generation Control (AGC) in an interconnected power system?
- To regulate voltage at transmission substations
- To balance generation and load while maintaining scheduled tie-line flows (Correct answer)
- To automatically trip generation when frequency drops
- To control reactive power injection at generator buses
Correct answer: To balance generation and load while maintaining scheduled tie-line flows
AGC continuously adjusts generator output to match load changes and maintain scheduled interchange with neighboring control areas.
Question 2: A power system operator observes that the Area Control Error (ACE) is persistently positive. What corrective action should be taken?
- Increase generation output within the control area
- Decrease generation output within the control area (Correct answer)
- Open tie lines to neighboring areas
- Shed load in the control area
Correct answer: Decrease generation output within the control area
Positive ACE indicates the area is generating more than scheduled, so generation must be reduced to restore balance.
Question 3: Which NERC reliability standard governs the Control Performance Standard (CPS) requirements for balancing authorities?
- FAC-001
- BAL-001 (Correct answer)
- TOP-001
- EOP-005
Correct answer: BAL-001
BAL-001 establishes the real power balancing requirements including CPS compliance for balancing authorities.
Question 4: During an N-1 contingency analysis, what does the 'N' represent?
- The number of transmission lines in the system
- The normal pre-contingency system state with all elements in service (Correct answer)
- The number of generators on-line
- The network bus count
Correct answer: The normal pre-contingency system state with all elements in service
N represents the intact system with all components in service, and N-1 means the loss of any single element.
Question 5: What is the function of a phase angle regulator (PAR) in transmission system operations?
- To regulate bus voltage magnitude by injecting reactive power
- To control real power flow on a transmission line by introducing a phase angle shift (Correct answer)
- To limit fault current during short circuits
- To compensate for reactive power losses in long transmission lines
Correct answer: To control real power flow on a transmission line by introducing a phase angle shift
A PAR inserts a controllable phase angle difference between its terminals to regulate active power flow on parallel paths.
Question 6: When a transmission line is de-energized for maintenance, what is the correct sequence for a safe outage?
- Open the breakers, apply grounds, issue clearance (Correct answer)
- Issue clearance, apply grounds, open the breakers
- Apply grounds, open the breakers, issue clearance
- Open the breakers, issue clearance, apply grounds
Correct answer: Open the breakers, apply grounds, issue clearance
The correct sequence is to open and lock the breakers first, then apply protective grounds, and then issue the clearance to the maintenance crew.
Question 7: What is 'reactive power scheduling' primarily intended to accomplish in a high-voltage transmission system?
- Maximize real power transfer capability on all lines
- Maintain acceptable voltage profiles across the transmission network (Correct answer)
- Reduce line resistance losses through power factor correction
- Increase the system short-circuit level at generator terminals
Correct answer: Maintain acceptable voltage profiles across the transmission network
Reactive power scheduling coordinates VAR sources and sinks to keep bus voltages within acceptable operating limits throughout the network.
SOPD Power System Operations 2
What is the primary purpose of Automatic Generation Control (AGC) in an interconnected power system?