Analysis of the failure mode of surge protector under multi-pulse lightning strikes and its mechanism

Abstract

This paper proposes a special disconnector for surge protector (SPD) with the ability to pass large pulse currents under multiple pulses, which has been verified to solve the problem of SPD fire and combustion under multiple pulses in engineering applications. The safety problem caused by the lightning strike failure of SPD has always been a difficult research point in low-voltage power distribution systems, especially the failure mechanism under multi-pulse lightning strike is still unclear. In this paper, the multi-pulse lightning generator is used to simulate the multi-pulse lightning current to carry out the SPD lightning impulse test. The results show that the SPD will have short-circuit breakdown and fire and combustion under multi-pulse lightning strikes, mainly because the continuous pulses will generate energy superposition, and the built-in disconnector and external disconnector fuses and circuit breakers cannot effectively cooperate with the SPD, and there is a protection blind spot. As a result, the SPD cannot be quickly detached at the moment of a short circuit. Based on the thermal effect of multi-pulse lightning strikes, a multi-pulse SPD special disconnector is designed, which can effectively solve the problem of lightning strike ignition of SPD under multi-pulse lightning strikes, and is of great significance to the lightning protection safety of low-voltage power distribution systems.