If frequency, voltage, and phase angle are all too high for breaker closing, what should a system operator consider first?

When frequency, voltage, and phase angle are all elevated for breaker closing, the first consideration for a system operator should be re-dispatching generation. This action is crucial because high frequency and voltage levels can indicate an over-supply condition in the power system. Re-dispatching generation involves altering the output levels of generation resources, potentially reducing the output of certain units or increasing the output of others to balance the system.

By re-dispatching, the system operator can mitigate the high levels of frequency and voltage. Additionally, controlling generation helps to stabilize the power system before attempting to close any breakers, which could otherwise exacerbate instability or damage equipment due to excessive electrical stress.

The other options, while potentially relevant to system operation, may not address the immediate need to rectify elevated frequency and voltage levels before closing circuit breakers. Increasing load may further stress the system. Opening connecting lines can isolate issues, potentially worsening the overall system conditions. Reducing generation selectively should only be considered after assessing other actions, like re-dispatching, that can first bring the system back into an acceptable operating condition.