Study on Triggering Failure Test Criterion and the Law of ‘Touch-Through’ Characteristics of Gas Switch Plasma Jet

The jet plasma triggered gas gap switch has the advantages of fast response and simple structure. It may meet the requirements for fast fault removal and isolation of the converter branch of hybrid high-voltage dc circuit breakers used in multiterminal flexible dc power grids. However, there is still insufficient research on the influence of trigger circuit parameters on the gas switch touch characteristics under high injection energy. The research on methods for improving triggering life and triggering failure criteria that consider multiple factors is not yet clear. A research platform for the triggering life of gas gap switches has been established for this purpose. The results indicate that the degradation of triggering cavity performance is the main reason for the failure of gas gap switch triggering. Increasing the charging voltage and capacitance value of the pulse capacitor can shorten the conduction time interval of the secondary cavity. Simultaneously increasing the capacitance of the energy storage capacitor can improve the plasma injection capability. There are two triggering failure states for gas gap switches. One is that the gas switch enters a weak triggering state, and the plasma jet from the primary cavity cannot “ignite” the secondary cavity to establish the main discharge circuit. The second reason is that the secondary cavity jet plasma cannot induce the high-voltage electrode discharge of the gas gap switch. Increasing the voltage value of the energy storage capacitor in the triggering circuit can effectively reduce the discharge delay jitter, but the impact on the lifespan improvement can be ignored. By increasing the charging voltage of the pulse capacitor in a stepped manner, the triggering life and touch stability can be significantly improved. The research results can provide theoretical reference and engineering application guidance for the triggering failure judgment and life improvement methods of gas gap switches.