During restoration, how much should the Bulk Electric System (BES) be operated above or below nominal voltage profile?

The Bulk Electric System (BES) is typically operated within strict parameters to ensure stability and reliability during restoration periods. During restoration, it's crucial to manage voltage levels effectively, as deviations from the nominal voltage profile can lead to instability, equipment damage, and potential cascading failures. Operating the BES within a tolerance of 10% above or below the nominal voltage profile is a recognized standard that helps maintain system integrity and reliability.

This 10% margin provides enough flexibility for adjusting system operations while minimizing risks associated with operating outside of established voltage limits. By adhering to this guideline, operators can better manage system loads, generation resources, and reactive power while facilitating a smooth and coordinated restoration process following disturbances or outages.

In contrast, options representing larger percentage tolerances may be less desirable, as they could introduce higher risks of voltage instability and compromise the overall reliability of the system during crucial restoration phases.