According to DCS, ACE should return to what level within the recovery period for reportable disturbances?

The correct response indicates that during the recovery period for reportable disturbances, the Actual Controllable Error (ACE) should return to a level of 100%. This is significant because maintaining reliability in the power system is crucial, and ACE is a key metric used to gauge the balance between generation and load while accounting for system frequency.

When a disturbance occurs, it is essential for the system operator to effectively manage and restore system stability. A return to 100% ACE signifies that the system is back to optimal operation, with supply fully meeting demand and frequency being maintained within established limits. Achieving this level is critical for preventing further disturbances and ensuring the integrity of the bulk electric system.

In contrast, lower target levels such as 50% or 75% would suggest that the system has not completely recovered and that there may still be underlying issues affecting reliability. Therefore, aiming for a full 100% return of ACE is the standard practice in the industry following a disturbance. This ensures complete recovery and confidence in the stability of the electrical grid.