Under what condition can low voltage occur without an initiating event?

Low voltage can occur without an initiating event when there is a deficiency in reactive resources. Reactive power plays a critical role in voltage regulation within the electric power system. When there is an inadequate supply of reactive power, it can lead to voltage drops across the system, resulting in low voltage conditions. This situation can happen due to factors such as insufficient capacitor banks, a lack of synchronous generators, or inadequate Voltage Support resources.

In contrast, the other conditions listed typically involve a specific initiating event. Overloads in generation create a scenario where generation capacity is exceeded, potentially leading to low voltage as a consequence rather than an event with no prior trigger. Sudden load shedding directly results from an operational decision or response to system conditions and is an active event that influences voltage levels. Maintenance outages refer to scheduled or unscheduled work on the system that can affect voltage stability, again related to an event rather than occurring spontaneously without cause.