SOPD Emergency Response & System Restoration Procedures 3 — Questions and Answers
Question 1: A 'hot line tag' differs from a 'clearance' in that a hot line tag:
- Requires the line to be de-energized and grounded
- Only cautions workers that a line is energized and in service — it does not de-energize it (Correct answer)
- Is issued by the transmission planning department
- Applies only to distribution voltage levels
Correct answer: Only cautions workers that a line is energized and in service — it does not de-energize it
A hot line tag advises workers that the equipment is energized; unlike a clearance, it does not guarantee a de-energized state and requires linemen to use live-line techniques.
Question 2: What is the purpose of a 'restoration priority list' maintained in an EOP?
- To rank transmission lines by their capital cost for replacement
- To pre-determine the order in which loads and elements are restored to minimize outage duration and protect critical facilities (Correct answer)
- To list generating units by fuel type for economic dispatch
- To document outage durations for regulatory reporting only
Correct answer: To pre-determine the order in which loads and elements are restored to minimize outage duration and protect critical facilities
Restoration priority lists pre-define the sequence for energizing critical loads and system elements, ensuring hospitals, water pumping stations, and backbone transmission are restored first.
Question 3: During a major disturbance, an operator receives conflicting SCADA readings on a breaker status. The safest assumption is:
- Assume the breaker is open and act accordingly
- Assume the breaker is closed and act accordingly
- Treat the breaker status as unknown and use field verification or secondary indicators before acting (Correct answer)
- Ignore the discrepancy and continue with planned switching
Correct answer: Treat the breaker status as unknown and use field verification or secondary indicators before acting
When telemetry is unreliable, operators must treat equipment status as unknown and verify via phone with field personnel or use secondary indicators such as current flow and voltage to determine true status.
Question 4: Which NERC standard specifically addresses the requirements for Transmission Operator Emergency Operations?
- FAC-001
- EOP-001 (Correct answer)
- TOP-001
- MOD-025
Correct answer: EOP-001
NERC EOP-001 establishes requirements for Transmission Operators to have documented emergency operations plans covering abnormal system conditions.
Question 5: A generator on black start duty fails to start. The system operator should:
- Wait 30 minutes and try again automatically
- Activate the alternate black start unit identified in the restoration plan (Correct answer)
- Declare a system emergency and notify FERC immediately
- Shed all remaining load to prevent further collapse
Correct answer: Activate the alternate black start unit identified in the restoration plan
Emergency restoration plans require at least one alternate black start resource so operators can pivot immediately if the primary unit fails to start.
Question 6: Over-excitation of a generator during restoration can result in:
- Reduced reactive output and a lagging power factor
- Generator step-up transformer saturation, high currents, and potential equipment damage (Correct answer)
- Increased real power output and improved frequency response
- Automatic activation of the governor droop control
Correct answer: Generator step-up transformer saturation, high currents, and potential equipment damage
Excessive field current causes the generator and transformer core to saturate, producing large harmonic currents and heating that can damage transformer insulation.
Question 7: When two subsystems are being synchronized before reconnection, which parameter mismatch poses the greatest immediate mechanical danger to generators?
- A 5% voltage magnitude difference
- A large phase angle difference at the moment of breaker closure (Correct answer)
- A 0.1 Hz frequency difference
- A reactive power flow imbalance of 50 MVAr
Correct answer: A large phase angle difference at the moment of breaker closure
A large phase angle difference at breaker closure creates a severe out-of-phase condition causing massive current surges and torque transients that can physically damage generator shafts and windings.
SOPD Emergency Response & System Restoration Procedures 3
A 'hot line tag' differs from a 'clearance' in that a hot line tag: