Study on the Performance Degradation of a Plasma Jet Gun for Triggering High Pressure SF6 Gap

Plasma jet gun (PJG) has been proven to be an effective method to repetitively trigger the gas gap into conduction at a very low working coefficient. The performance degradation characteristics of the PJG are always the key parameters determining its lifetime. In this paper, the performance degradation of the PJG operated in high pressure
$\mathbf{SF}_{6}$
atmosphere was investigated in two different kinds of PJG structures, namely, laminated and integral structures. In each structure, the trigger pulse was applied to the PJG, and the time delay of breakdown, residual capacitor voltage, and peak voltage output of the pulse transformer were measured to characterize the performance variance versus shot time. The results showed that the time delay of both structures increased while the residual capacitor voltage decreased as the shot number increased. The peak voltage output of the pulse transformer gradually went up in the first 100 shots and then kept stable. Compared with the integral structure, the laminated structure had not only lower time delay and jitter of breakdown but also a longer lifetime. By analyzing the results of the two different structures, it was found that the performance of the laminated structure degraded more slowly. Based on the research, the performance monitoring method and life change rule of the PJG during the whole life cycle are mastered, which is of great significance for the application and life improvement of the PJG.