If your frequency bias is -50 MW/0.1 Hz and a large generator in another BA trips, how should your ACE ideally read?

In the context of balancing authority operations, the Attributed Control Error (ACE) is a key indicator used to manage the balance between generation and load. When a large generator in another Balancing Authority (BA) trips, it results in a decrease in generation, which can affect the overall frequency in the interconnected power system.

The frequency bias value of -50 MW/0.1 Hz means that for each 0.1 Hz drop in frequency, the balancing authority would need to increase generation by 50 MW in order to maintain frequency stability. Therefore, the negative bias indicates a tendency to increase generation when the frequency drops.

When a large generator trips, the expected outcome is a drop in frequency. If the frequency drops and your bias of -50 MW/0.1 Hz comes into play, the ACE should ideally read zero (0 MW) to indicate that your BA is effectively balancing the change by adding equivalent generation to counter the loss from the tripped generator. In this scenario, maintaining an ACE of zero would imply that your generation adjustments have compensated for the loss in generation due to the generator tripping.

Thus, aiming for an ACE value of zero means that the balancing authority has successfully managed its generation in response to the disturbance, fulfilling its