The Lake Shore Electric Corporation Generator Surge Protectors (GSP) provides surge protection for Medium Voltage rotating machines operating at voltages from 2400 VAC to 24,000VAC. They are typically installed directly at the generator output terminals.

Overvoltage conditions in electrical systems can reduce the useful life of insulation, which will appear as insulation failures, resulting in circuit faults. In rotating electrical machines such as generators, insulation space is limited. This creates a design balance and conflict between voltage stress and size which has an acute impact on useful life. To help reduce the electrical stress on a medium voltage generator caused by overvoltage, lightning, ground faults, switching surges, static, etc., Lake Shore Electric Corporation recommends that the use of Generator Surge Protection, as outlined in IEEE Standard 142, be considered.

The GSP integrates the combination of a station class arrester with a protective capacitor to limit voltage peaks which can commonly stress the generator beyond its impulse rating. The arrester helps protect the generator insulation by limiting the amplitude of applied impulse waves or reflections within the machine windings, shunting these high voltages to ground. The protective capacitors reduce the slope of the voltage peak by shunting the high rate of voltage change, (dv/dt), to ground.

It has been shown that the protection of rotating machinery from overvoltage conditions has resulted in increased reliability and decreased downtime.