Abstract

Temporary overvoltage is a common, but often overlooked stress condition on modern electric distribution systems. Although it receives less attention than lightning and fast transients, it can damage equipment, overheat surge arresters, and distort voltage waveforms long enough to trip protective devices or trigger customer complaints. A sound grasp of temporary overvoltage mechanisms supports better design decisions, protection coordination, power quality monitoring, and claims evaluation.

This paper concentrates on power-frequency overvoltages that last from a few cycles to several hours. The emphasis is on distribution-level phenomena that occur between the substation low-voltage bus and the customer service entrance. Grounding practices, switching procedures, and equipment configuration largely determine the severity of each event. Intended readers are utility power quality, protection, and reliability engineers who need practical guidance that connects field signatures with root causes and credible magnitude–duration ranges.