Simplified modeling of the thermal regime of a metal oxide varistor in the leakage current region

The article presents a simulation of the electrical and thermal behavior of a metal oxide varistor (MOV) in the leakage current region. To simplify the thermal modeling, an approximate averaging of the thermal effect of MOV leakage currents over the period of the applied voltage was proposed. The proposed calculation method was verified by experimentally determining the “ E-σ” characteristics of the sample, calculating the thermal regime of the MOV based on the averaged characteristics, and comparing the calculation results with the experiment under similar thermal conditions. Temperature dependencies of conductivity for MOV were taken into account during calculations and experiments. The proposed technique allows for easy calculation of steady-state thermal regimes of surge arresters based on MOV, reducing calculation time and avoiding convergence issues with the model.