What is the reportable voltage deviation for an extended period of time in relation to nominal voltage?

The reportable voltage deviation for an extended period of time in relation to nominal voltage is typically defined as 10%. This threshold is established to ensure the reliability and stability of the electric transmission system. A deviation of this magnitude can indicate potential issues that may impact the system’s operational integrity, leading to adverse consequences like equipment damage, overloads, or even outages.

When voltage levels deviate significantly from nominal, monitoring and corrective actions may be necessary to maintain system reliability. A 10% threshold effectively balances the need for operational flexibility with the requirement for maintaining voltage levels within acceptable limits to support safe and reliable system operation. This allows reliability coordinators to respond appropriately when voltage levels stray too far from nominal, prompting necessary investigations and potential corrective measures to mitigate risks to the system.