SOPD Emergency Response & System Restoration Procedures 5 — Questions and Answers
Question 1: When restoring service after a fault, before reclosing a breaker a system operator should confirm:
- The fault has been cleared and the protection system has reset (Correct answer)
- The energy management system has updated all topology models
- Neighboring control areas have reduced their exports by 10%
- The automatic generation control (AGC) has been disabled
Correct answer: The fault has been cleared and the protection system has reset
Before reclosing, operators must verify the fault has been physically cleared (e.g., by field crew confirmation) and that protective relays have reset to prevent re-tripping onto a live fault.
Question 2: An Emergency Action Level (EAL) framework in nuclear plant coordination requires system operators to:
- Automatically drop all load within 50 miles of the plant
- Notify the plant's control room when grid conditions could affect the plant's offsite power supply (Correct answer)
- Transfer plant generation to another Balancing Authority immediately
- Isolate the nuclear plant generator from the grid
Correct answer: Notify the plant's control room when grid conditions could affect the plant's offsite power supply
System operators maintain hotlines with nuclear plants and must notify them of grid emergencies that could degrade or interrupt the reliable offsite power supply required by NRC regulations.
Question 3: What is 'controlled islanding' as a defense against cascading outages?
- Shutting down all generation in a region to prevent overload propagation
- Intentionally splitting the grid into pre-planned self-sufficient islands to arrest cascade propagation (Correct answer)
- Automatically tripping all tie lines when frequency drops below 59.5 Hz
- Transferring all control authority to a single operator to coordinate response
Correct answer: Intentionally splitting the grid into pre-planned self-sufficient islands to arrest cascade propagation
Controlled islanding intentionally separates the system at pre-selected boundaries where generation and load are approximately balanced, containing the disturbance within one island rather than allowing it to topple the entire interconnection.
Question 4: A system operator must issue a 'Public Appeal for Conservation' under which condition?
- When spot market energy prices exceed $500/MWh
- When voluntary demand reduction is needed to maintain adequate reserves during a supply emergency (Correct answer)
- When a single large industrial customer is offline for maintenance
- When renewable generation exceeds 30% of total system load
Correct answer: When voluntary demand reduction is needed to maintain adequate reserves during a supply emergency
Public conservation appeals are issued when generation reserves are critically low and voluntary demand reduction can help avert forced load shedding.
Question 5: During system restoration, why must operators carefully monitor transformer inrush current?
- Inrush current activates demand response programs automatically
- High magnetizing inrush can falsely operate differential relays and trip the transformer off-line (Correct answer)
- Inrush current causes real power losses that slow restoration progress
- Transformer inrush lowers system frequency permanently
Correct answer: High magnetizing inrush can falsely operate differential relays and trip the transformer off-line
Transformer energization produces a large transient magnetizing current (inrush) that can look like an internal fault to differential protection, causing a false trip and interrupting the restoration sequence.
Question 6: The term 'reserve sharing group' refers to:
- A pool of spare transformers held by multiple utilities for mutual aid
- Balancing Authorities that have agreements to collectively meet contingency reserve requirements (Correct answer)
- A market mechanism for trading ancillary services on a real-time basis
- Generators that are held offline strictly for black start capability
Correct answer: Balancing Authorities that have agreements to collectively meet contingency reserve requirements
A reserve sharing group is a set of Balancing Authorities that pool their contingency reserves so individual members can rely on the group's combined reserves to meet NERC requirements after a contingency.
Question 7: After a major system disturbance is controlled, the operator's first post-emergency documentation requirement under NERC standards is:
- File an outage report with FERC within 24 hours for all events
- Notify the Reliability Coordinator and initiate a sequence-of-events report for any disturbance meeting reporting thresholds (Correct answer)
- Issue a press release to the public within one hour
- Archive all SCADA logs on removable media and send to NERC headquarters
Correct answer: Notify the Reliability Coordinator and initiate a sequence-of-events report for any disturbance meeting reporting thresholds
NERC standards (EOP-004) require entities to notify the Reliability Coordinator and submit a disturbance report for events meeting defined thresholds, preserving the sequence of events for post-event analysis.
SOPD Emergency Response & System Restoration Procedures 5
When restoring service after a fault, before reclosing a breaker a system operator should confirm: