Experimental investigation of surface flashover characteristics in vacuum

This paper devotes itself to the experimental study on surface flashover characteristics of insulating material, which is closely connected to the compact pulsed power system operating in vacuum. The rated voltage of the pulsed power source is several kV and the peak current is several kA. To simulate the actual operating condition and possible failure mode of pulsed power system, a series of experiments are performed to validate the adaptability of high pulsed power device in vacuum. This paper concentrates on the mechanism of surface flashover in vacuum and corresponding influence factors. Different metal electrode materials, different creepage distances and the interference effect of hot plasma have been studied. Research indicates that external plasma plays a key role in the formation of surface flashover. In medium vacuum (1×10⁻³ Pa), the surface flashover voltage of 3mm surface creeping distance on organic glass is above 17 kV; But if there is external plasma source, the flashover voltage would reduce significantly with the increase of plasma density; flashover voltage would rush to 1 kV or lower. Based on the experiment study, some measures are taken on the several kilovolts pulsed power source (PPS) produced in prior work. The device can operate stably in the vacuum of 10⁻³ Pa.