Research on measuring of DC breakdown voltage of MOV with series gap

Metal oxide varistor (MOV) with series gap is the key component for ensuring safety running of the electronic and communication system, DC breakdown voltage is one of its important parameters. In this paper, the experimental circuit was setup and the DC breakdown characteristics of MOV with series gap were researched. The influence laws between the breakdown current and DC breakdown voltage of MOV with series gap were obtained and the experimental results showed that the DC breakdown voltage of MOV with series gap increases with the increase of breakdown current when breakdown current is less than 1mA. When the breakdown current is controlled between 1mA and 5mA, the DC breakdown voltage of MOV with series gap is equal approximately to the sum of the DC reference voltage of varistorU_1mA and the breakdown voltage of series gap. And the turn on voltage is depended on the limited voltage of varistor and the arc voltage of the series gap, the uncertainty of the measuring instrument is less than 1% comparing with verified Tektronix oscilloscope TDS2012. Then the simulation circuit model of the MOV with series gap is established, the voltage and current characteristics are studied when DC high voltage is applied, and the experimental results are explained effectively.