Electro-thermal Modeling and Verification of MOV in SPD Based on Various Experiments

Metal oxide varistor (MOV) is an important component for suppressing overvoltage and diverting surge current in modern power systems. Its excellent nonlinear resistance characteristics has been widely used in the manufacture of metal oxide arresters (MOAs), surge protective devices (SPDs) and other overvoltage protection products. Although the temperature increase of MOV in SPD will lead a significant decrease in performance or even a failure, there are very few studies describing its electro-thermal modeling. In this paper, three electro-thermal experiments including 10mA DC thermal stability experiment, temporary overvoltage (TOV) experiment and 8/20μs impulse experiment are carried out on MOV sample firstly, which temperatures are measured with the help of thermocouples and infrared camera. Then the temperature obtained from the experiments are compared with the electro-thermal model to verify its accuracy. It is shown that the experimental measurements are in well agreement with the simulation results, which verifies the validity of the proposed model.