Effect of Grain Size Disorder on the Performance of ZnO Varistors Based on Voronoi Network and Finite Element Simulation

The construction of a reasonable numerical simulation model is of great significance for understanding and predicting the current distribution inside the ZnO varistor ceramics, which can provide the theoretical basis and guidance for improving the through-current performance of ZnO varistors. In addition to the electric field effect, the ZnO varistors involve the multi-physical field coupling problems of thermal field and force field when they are subjected to current impulses. This paper establishes a finite element multi-physical field model of ZnO varistor by combining Voronoi network and finite element method, and analyzes the effects of grain size disorder on the current distribution of ZnO varistor in different current regions and the temperatures and stresses under 2ms square wave current.