During what condition should a transmission operator primarily focus on preventing voltage collapse?

A transmission operator should primarily focus on preventing voltage collapse during conditions of low reactive power availability. In power systems, reactive power is essential for maintaining voltage levels. When there is insufficient reactive power, voltage stability can be threatened, leading to potential voltage collapse. This situation often occurs when the demand for reactive power exceeds the supply, which can be exacerbated by factors such as high load conditions or constraints in the availability of reactive power support devices.

While peak load conditions, severe weather events, and normal operating conditions are relevant to overall system management and reliability, low reactive power availability holds a critical role in directly influencing voltage stability. In situations where reactive power is lacking, the risks of voltages dropping to dangerously low levels increase, which can lead to cascading failures and widespread outages. Therefore, it is crucial for transmission operators to monitor and manage reactive power resources actively, especially during these particular conditions.