overvoltage

frame|Voltage spike.

In electrical engineering, overvoltage is the raising of voltage beyond the design limit of a circuit or circuit element. The conditions may be hazardous. Depending on its duration, the overvoltage event can be transient—a short (milliseconds) voltage spike—or sustained (also known as power frequency overvoltage) with a stable value on multiple terminals. In an electrical grid, voltage control and reactive power management are inseparable facets of a single activity.