Study on self-breakdown voltage dispersion characteristics in corona-stabilized spark gap switch

The breakdown stability of spark gap switch critically governs the output characteristics of pulsed power systems. In this paper, a corona-stabilized spark gap switch with a corona needle structure is designed to reduce the dispersion of breakdown voltage. The volt-ampere characteristics of corona discharge in the switch gap and the self-breakdown voltage characteristics of the switch are investigated numerically and experimentally. Experimental results demonstrate that the corona needle amplifies the local electric field within the switch, generating macroscopically measurable corona currents. This process supplies seed electrons for the breakdown initiation, while the stabilized corona formation effectively homogenizes the electric field distribution across the main electrodes, thereby reducing the stochasticity of breakdown events and diminishing the dispersion of breakdown voltages. In particular, within a certain range, as the corona needle tip approaches the opposing main electrode (increasing l), the corona current amplitude before switch breakdown increases, and the breakdown voltage dispersion decreases. Notably, at a charging voltage of 40 kV and a repetition frequency of 20 Hz, the corona-stabilized spark gap switch achieves an average breakdown voltage dispersion of 0.54% (tested 5 sets × 200 trials) at l = 1 mm, demonstrating excellent breakdown stability to meet potential application requirements in pulsed power systems.