Investigation on the characteristics of self-breakdown in FLTD gas spark switches

Self-discharge is one of the key limiting factors to FLTD gas spark switches and it in most cases is determined by characteristics of the self-breakdown voltage. In this paper, mode of particle-induced breakdown voltage is elaborated for FLTD gas spark switches, the self-breakdown voltage is calculated, and the characteristics of self-breakdown are investigated by both calculation and experiment. We have simulated and calculated the electric field distribution and the breakdown voltage functioned by gas pressure and gap distance of the plate-plate gas spark switch to find the pattern and sensitivity of it to the two factors. Tested switches are plate-plate and multi-gap switches operated at ±90kV and under 10+ kA nanosecond current pulse, whose breakdown voltage data obey 3-parameter-Weibull distribution. Results show that increasing the gap distance and reducing the pressure within a certain range can reduce the amplitude of breakdown voltage, dispersion of self-breakdown voltage and reduce the self-discharge probability of switch. The pattern of multi-gap switches perform the same as plate-plate switches and the particle-induced breakdown mode. Both of the results and deduction are instructive for solutions of self-discharge problems.