快脉冲直线变压器驱动源 (FLTD)是目前经济、高效构建大型脉冲功率源的重要技术途径，但其多 “子块”串并联的电路拓扑对开关提出极严苛的技术要求。针对多开关同步时系统自放电概率骤增的难题，开展 FLTD气体火花开关自放电特性研究。选取三电极场畸变和多间隙两种典型开关结构，在 ±100 kV条件下研究放电电流和开关结构参数对自放电概率的影响规律。研究结果表明， 29 kA脉冲电流多次作用下，三电极场畸变开关和六间隙开关自放电电压均服从 Weibull分布，三电极开关放电分散性约 4%，而六间隙开关放电分散性超过 15%，两类开关均出现较明显的提前放电现象。分析认为开关放电分散性大与中间电极悬浮导致间隙电压分布不均有关，采用电阻强制均压的方式，三电极场畸变和六间隙多通道开关放电分散性明显减小，分别减小至 2%和 5%。

Fast Linear Transformer Driver(FLTD) is an economic and effective technical routine for constructing high-current high-voltage pulsed power drivers, but its circuit topologies, multi “bricks” in series and parallel, put forward strict technical requirements on gas spark switches. Aimed at the problem of pre-fire, which seriously restricts the reliability and stability of FLTD facilities, researches of this paper are carried out on the focus of pre-fire in FLTD gas spark switches. Three-electrode field distortion gas switch and multi-stage multi-channel gas switch are employed, and the influence of discharge current and switch parameters on pre-fire characteristics is studied at ±100 kV. The results show that the self-breakdown voltage of both switches fits well with Weibull distribution. Increasing the switch pressure and shortening the gap length can help decrease switch trigger delay, but directly increase pre-fire probability. Under 29 kA current amplitude and 75% working ratio, the discharge dispersivity of the three-electrode field distortion gas switch is about 4%, while the dispersivity of the discharge of the six-stage multi-channel gas switch is more than 15%. Both types of switches have obvious early discharge phenomena. The uneven distribution of potential of each gap in six-stage switch is thought to be responsible for the increase of pre-fire rate. By resistors parallel-connected with each gap to mandatorily realize voltage sharing, the pre-fire rates of the three-electrode field distortion and the six-stage gas switch decrease to 2% and 5%.