Which of the following is considered a reportable event?

A reportable event in the context of Bulk Electric System (BES) emergencies is typically one that necessitates actions impacting the system's reliability or safety in a significant way. In this case, a BES Emergency requiring a public appeal for load reduction is particularly noteworthy because it indicates a situation severe enough that the system operators must reach out to the general public to manage demand. This response highlights the critical nature of the situation, as public cooperation is essential in mitigating the emergency effectively.

Engaging the public for load reduction is a proactive measure that reflects the seriousness of the emergency. It involves not just operational protocols within the control center but also community involvement, which can have a considerable impact on load management during a crisis.

The other options describe scenarios that, while serious, may not be characterized as reportable in the same manner. For instance, a system-wide voltage reduction or manual load shedding is typically managed within the operational framework without requiring external notification or actions from the public. Physical threats to a control center, while critical and needing immediate attention, are often categorized under security incidents rather than operational events, which alters their classification as reportable events in this context.

This distinction emphasizes the unique nature of public appeals, making it a vital reportable event that reflects