What happens to ACE limits if replacement generation is not restored within the allowed time frame following a DCS event?

When replacement generation is not restored within the allowed time frame following a Disturbance Control Standard (DCS) event, reliability could be compromised. This situation arises because the Automatic Generation Control (AGC) system relies on sufficient and appropriate generation to maintain the balance between supply and demand in the electrical grid. If the replacement generation, which is necessary to replace lost capacity, does not come online quickly enough, it can lead to imbalances in the system.

Imbalances can cause issues like frequency deviations that may threaten the stability of the grid, potentially leading to larger-scale outages or disruptions. Therefore, maintaining proper generation levels is critical for the overall reliability of the electric grid, and failing to restore replacement generation in a timely manner directly impacts that reliability.