What action should be taken when the interconnection frequency drops from 60Hz to 59.94Hz and the BA ACE is zero?

When the interconnection frequency drops from 60Hz to 59.94Hz and the Balancing Area Control Error (BA ACE) is zero, the correct response is to make known your ability to provide emergency assistance. This is crucial because a frequency drop indicates a potential imbalance between generation and load. Although the BA ACE is zero, meaning the balancing area is currently stable in terms of generation and load, a decline in frequency suggests that there may not be enough generation in the overall system to meet demand.

By announcing the ability to provide emergency assistance, a balancing authority can signal that it is ready to take action if the situation worsens, thus supporting the overall reliability of the electric grid. This readiness is essential in ensuring the interconnection can stabilize frequency and avoid potential blackouts.

Increasing generator output could be a response in some cases, but it may not be the immediate action to take if the BA ACE is already at zero, as this could risk oversupplying the system. Conducting a system audit and lowering demand response measures are less relevant in this situation since the goal is to promptly address the frequency drop proactively rather than reactively assessing or reducing demand.