Numerical modelling of MOV with Voronoi network and finite element method

Abstract

The electrical and thermal characteristics of metal oxide varistor (MOV) are essential for the study of MOV performance and degradation. This paper provides a modelling method of MOV to simulate its microstructure geometry with the Voronoi network and derive the electrical functions on the grain boundaries. A series of discrete data to describe the resistance-voltage (R–V) characteristics of MOV from experiments is applied to the proposed model. Through 8/20 μs surge current experiments, the electrical conductivity of MOV is determined to achieve the simulation of the clamping voltage. With this model, the current distribution and temperature distribution over a MOV sample are simulated and analysed by the finite element method (FEM). The simulation results show good agreement with the experimental measurement and inherent feature of MOV.