Analysis of the Lagging Time Characteristics of ZnO Varistor Under Application of Impulse Current

The process of the phenomenon of emerging lagging current under the application of impulse current is presented, which is based on the hole-induced tunnel breakdown theory and the dynamic V-A characteristics of ZnO varistor(MOV) under the impulse current. The main factors affecting the lagging time include the amplitude of the impulse current and the static characteristics of the ZnO varistor itself. By the experiments on the same type of MOV, the lagging time Δt becomes gradually shorter when the breakdown voltage becomes higher. The changes of Δt are small in the low current range. But in the high current range, the lagging time is longer when the amplitude of the impact current becomes higher