If a frequency bias setting is higher than the frequency response and frequency declines due to a loss of generation, what is likely to happen to the ACE?

When a frequency bias setting is higher than the frequency response and there is a frequency decline due to a loss of generation, the system's response, specifically the Area Control Error (ACE), will typically reflect the imbalance caused by the generation loss. In this scenario, the frequency is decreasing, which indicates that there is not enough generation to meet the load.

When generation decreases and frequency drops, the ACE is calculated based on the difference between actual frequency and scheduled frequency, as well as the net interchange between areas. Since the actual frequency is lower than the expected level, the ACE will register as a negative value. This negative ACE indicates that the system is under-generating compared to the demand, and corrective actions will be necessary to restore system balance.

The implication of having a frequency bias setting that exceeds the frequency response means that the system is not responding adequately to the loss of generation, allowing the ACE to remain negative, thus reinforcing the need for increased generation or a reduction in load to stabilize the frequency and correct the ACE.