Influences of the length of connecting leads on the coordination performance of cascaded SPD system

초록

Surge protective device (SPD) plays an important role to protect the valuable electrical and electronic equipment against transients originating from lightning. For the purpose of designing and applying the optimum surge protection, multistage coordinated surge protective device (SPD) system is suitable to successfully fulfill these tasks; first, to divert a large amount of transient energy; second, to clamp the overvoltage to the level below the withstand impulse voltage of the equipment to be protected. Class I tested SPDs are needed to divert large amount of surge energy due to direct lightning flashes. The length of SPD connecting leads should be as short as possible to achieve surge protection effectively in coordinated SPD systems. In this paper, the influences of the length of connecting leads on the current sharing in two-stage cascaded SPD systems were investigated experimentally by using a 10/350 μs current wave. It was confirmed that the protection voltage level and energy sharing in coordinated SPD systems are markedly influenced by the length of connecting leads.