Comparative study on breakdown characteristics of trigger gap and overvoltage gap in a gas pressurized closing switch

Gas pressurized closing switches are one of the most important elements in FLTD-based
systems. Improving the trigger performance of gas switches is useful for optimizing the output
parameters and the reliability of the FLTD. In this paper, the breakdown characteristics of the
trigger gap and the overvoltage gap are studied experimentally. The reasons for the different
breakdown performance of the two gaps are also investigated. The results show that
the breakdown delay of the trigger gap is more influenced by the trigger voltage, while the
breakdown delay of the overvoltage gap is more influenced by the working coefficient and
always higher than that of the trigger gap. The jitter of the trigger gap is more influenced by the
trigger voltage and accounts more than 60% of the total switch jitter, while the jitter of the
overvoltage gap is hardly changed with the trigger voltage as well as the working coefficient and
maintains less than 1.4 ns. It is proved that the discharging product from the trigger gap can
effectively reduce the breakdown delay and jitter of the overvoltage gap. Based on that, the effect
and improvement of pre-ionization on the two gaps are also studied. It is concluded that the jitter
of the trigger gap reduces obviously when the pre-ionization is added, while the pre-ionization
almost has no effect on the jitter of the overvoltage gap. The jitter of the overvoltage gap is about
two times higher than the trigger gap in the pre-ionizing switch.