Microstructure Simulation on Puncturing Phenomenon of ZnO Varistor under High Current

ZnO varistors are vulnerable to be destroyed under high current. The puncturing phenomenon of ZnO varistor under high current is simulated in a microstructure model. The Voronoi diagram can effectively simulate the actual microstructure of ZnO varistors, from which the electrical topology relation of the nonlinear resistor network of ZnO varistor microstructure can be derived. The steepest descent method and updated Newton iterative method are used to analyze the big scale nonlinear resistor circuit. The simulated results express that there is serious current concentration and temperature concentration in ZnO varistor, which can explain the puncturing breakdown of ZnO varistor under high current