基于改进双脉冲法的气体开关间隙绝缘恢复特性

Insulation Recovery Characteristics of Gas Switch Gap Based on Improved Double-Pulse Method

针对单级快速直线型变压器驱动源(fast linear transformer driver,FLTD)模块中气体开关在充电过程中发生的自击穿问题,分析了FLTD模块内其他未放电支路对自击穿气体开关绝缘恢复特性的影响,基于等价性研究建立了改进双脉冲法的气体开关绝缘恢复特性研究平台,获得了不同气压和续流参数条件下气体开关的绝缘恢复特性。研究表明,续流延长了气体开关绝缘恢复所需时间,在较长时间续流作用下,气体开关绝缘恢复过程分为2个阶段,气体开关绝缘恢复时间由截止电流出现时间和之后的耐压恢复时间决定。绝缘恢复时间随气体压力升高迅速减小,但截止电流有所减小,续流持续时间变长。这一特性有助于指导开关气体压力和间距等关键参数的选择。

The reliability of synchronous operation of fast pulse linear transformer driver is related to the insulation recovery characteristics of gas switch.When charging a single-stage fast linear transformer driver(FLTD)module,pre-fire is a kind of unexpected breakdown phenomenon of gas switch under the discharged voltage universally occurs in gas spark switch.The improved double-pulse method is designed to investigate the influence of other non-discharged branches in FLTD module on the insulation recovery of pre-fired gas switch,and the insulation recovery characteristics of the gas gap under different pressures and holding currents are obtained.It is suggested that the existence of holding current prolongs the time required for gas spark gap insulation recovery.Under the action of holding current,the process of gas switch insulation recovery is divided into two phases.The first phase is the existence of holding current,in which there is always a spark channel in the gas gap.And the second phase is the recovery of gas switch hold-off voltage.The insulation recovery time of gas switch decreases rapidly with the increase of gas pressure.In this case,the holding current time will be longer,and the current value when it is cut off will be smaller.The characteristics is helpful to select the key parameters such as switching gas pressure and gap spacing.