Influence of Damp Status on Leakage Current of ZnO Lightning Arrester

ZnO lightning arresters are widely used for overvoltage protection in power systems. To ensure the reliable operation of lightning arresters, it is necessary to evaluate their health status. Leakage current has been proposed to show the damp status of lightning arresters. To determine a reasonable diagnostic criterion, it is necessary to know the variation pattern of leakage current before and after the valve plate is moisturized. This study reports the experimental results done on a ZnO lightning arrester under different moisturized conditions. It is found that both the amplitude and growth rate of leakage current can characterize the damp state of the lightning arrester. A new method was proposed for determining the damp state of lightning arrester valve plates through leakage current, which is helpful for the condition based maintenance of lightning arresters.