The Influence of Electric Field Inhomogeneity on Repetitive Performance of a Corona-Stabilized Switch

The corona-stabilized switch has a great potential in pulsed power systems where high pulse repetition frequencies are required. Corona discharge in SF6 in highly inhomogeneous electric field is utilized to improve repetitive performance of this kind of switch. To clarify how the repetitive performance (insulation recovery and repetitive breakdown stability) of the switch depends on the field inhomogeneity, the insulation recovery and repetitive breakdown stability of a corona-stabilized switch are experimentally investigated and theoretically analyzed. An innovative double-pulse method combining breakdown voltage and discharge channel images is used to measure the insulation recovery of the switch. For different electrodes, their voltage jitters at pulse repetition frequencies of 1-2000 Hz are measured to illustrate the stability of repetitive breakdown. The experimental results are theoretically analyzed from the memory effect and behavior characteristics of the residual plasma, the critical volume and its dynamic characteristics. The results reveal the corona stabilization enhancement effect during the repetitive breakdown in SF6 in extremely inhomogeneous field. The influence of electrode profile on the propagation of discharge channel shock wave, the decay of residual plasma and the recovery of neutral gas density are clarified. Effect of the electrostatic conditions, including the critical volume and its dynamic characteristics, and the intensity of corona discharge, on the repetitive performance of the switch are also clarified.