The statistic analysis on principal electric parameters of MOV for surge arrester

The statistic analysis of 1 mA DC voltage and impulse residual voltage of a typical MOV are discussed in this research. The relative standard deviations of 1 mA DC voltages for low-voltage and high-voltage MOV are 1.98% and 4.10% respectively. The respective relative standard deviations of impulse residual voltages are 2.24% and 3.14%. The minimum Gobble distribution was used to describe the distribution of 1 mA DC voltage and impulse residual voltage, low- and high-voltage MOV were verified conforming to the minimum Gobble distribution by the Kolmogorov-Smirnov test. The impulse residual voltage and 1 mA DC voltage has a close relative degree by t-test and another test method, and the impulse residual voltage can be estimated by voltage ratio and 1 mA DC voltage. The current overload of MOV with reduced residual voltage is not serious in the tested deviation range according to the simulation analysis, and there is no problem for these varistors operating in parallel.