Effects of glow discharge pre-treatment on flashover voltage of polyimide insulator in vacuum

The effects of glow discharge frequency, current magnitude and treatment time are studied by using glow discharge to treat the insulator in order to improve the flashover voltage of insulator in vacuum. Experiment results show that the flashover voltage of insulator could be greatly improved through glow discharge pre-treatment. The flashover voltage of unconditioned insulator is 55 kV. After treating for 40 min by high frequency glow discharge, the saturated flashover voltage becomes 100 kV. After treating for 40 min by AC glow discharge, the flashover voltage reaches to 125 kV, which is 25 kV higher than that of high frequency glow discharge. Meanwhile，the larger the current is, the higher the saturated flashover voltage will be. However, as the current gets larger, the growth of flashover voltage saturates gradually.