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. Therefore, in this paper, the electro-thermal experiment including 10mA DC thermal stability experiment, temporary overvoltage (TOV) experiment and 8/20μs impulse experiment are performed on the MOV sample firstly. Then the temperatures of different parts of the MOV samples are measured with the help of thermocouples and infrared camera. Moreover, by establishing 3D MOV thermal model, the temperatures of the MOV in experiment are compared with these in the simulation. The results show that the experimental measurements are in well agreement with the simulation results, which verifies the validity of the proposed model.
 

Metal oxide varistor (MOV), surge protective device (SPD), electro-thermal experiment, electro-thermal model.