Characteristics of long-gap AC streamer discharges under low pressure conditions

Abstract

The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of long-gap discharge in a high-altitude area. This paper describes laboratory investigations of streamer discharge under alternating current (AC) voltage in a low pressure test platform for a 60 cm rod–plane gap at 30 kPa, and analyzes the characteristics of streamer generation and propagation. The results show that the partial streamer and breakdown streamer all occur in the positive half-cycle of AC voltage near the peak voltage at 30 kPa. The partial streamer could cause the distortion of current and voltage waveform, and it appears as the branching characteristic at the initial stage. With the extension of the streamer, the branching and tortuosity phenomena become gradually obvious, but the branching is suppressed when the streamer crosses the gap. The low-pressure condition has little influence on the tortuosity length and the tortuosity number of the streamer, but affect the diameter of streamer obviously.