Simulation on surge responses of ZnO varistors by Voronoi network with actual grain boundary model

A special simulation model for the surge responses of ZnO varistors is introduced in this paper. This model is based on the Voronoi network and contains the actual conduction mechanism of the grain boundaries, as well as the capacitances of the grain boundaries. The surge responses of the actual varistor samples were simulated and compared with the experimental results. The simulated waveforms agree with the measured ones very well, which indicates that the simulation model is quite reasonable.