Breakdown mechanism and repair method induced by edge porosity defect of ZnO varistor

The ZnO varistor is a key component of lightning arresters. It inherently develops more porosity around the edge area during the sintering process, leading to varistor failure through phenomena such as puncture and explosion. This paper investigates the mechanism of pore induced failure by establishing a simulation model to calculate the electric field intensity and energy density distribution within the ZnO varistor. Through the analysis of edge treatment during the varistor manufacturing process, we highlight the existing defects in the edge area of the varistor. In response to these defects, we propose a rectification strategy that remedies the shortcomings of the current methods, thereby enhancing the performance of the varistor.