A notice issued by the system operator when the contingency Reserve is less than the capacity of the largest Synchronized Generating unit or power import from a single interconnection whichever is higher.

A notice issued by the system operator when the contingency Reserve is less than the capacity of the largest Synchronized Generating unit or power import from a single interconnection whichever is higher.

• A. Blue alert
• B. Green alert
• C. Yellow alert
• D. Red alert

Answer: (C)

Contingency reserve is the extra capacity a system operator holds to cover the loss of the largest single generating unit or a major interconnection. When this reserve is less than the capacity of the largest synchronized generating unit or the largest interconnection, whichever is higher, the situation is a warning level for elevated risk. That threshold matters because losing the biggest unit or the biggest interconnection would require immediate, substantial rebalancing; if reserve is already below that level, the system could struggle to stay stable without rapid corrective actions. So a Yellow alert is issued to signal this elevated risk and to prompt preemptive measures such as re-dispatching generation, fast-ramping actions, or requesting demand reductions to restore adequate contingency margins. Red alerts indicate a more severe emergency with imminent instability and possible load shedding, while green implies normal operation with sufficient reserves.

Contingency reserve is the extra capacity a system operator holds to cover the loss of the largest single generating unit or a major interconnection. When this reserve is less than the capacity of the largest synchronized generating unit or the largest interconnection, whichever is higher, the situation is a warning level for elevated risk. That threshold matters because losing the biggest unit or the biggest interconnection would require immediate, substantial rebalancing; if reserve is already below that level, the system could struggle to stay stable without rapid corrective actions. So a Yellow alert is issued to signal this elevated risk and to prompt preemptive measures such as re-dispatching generation, fast-ramping actions, or requesting demand reductions to restore adequate contingency margins. Red alerts indicate a more severe emergency with imminent instability and possible load shedding, while green implies normal operation with sufficient reserves.