复合开关自然换流型混合式直流断路器的研究及测试

Natural Commutation Hybrid DCCB Based on Vacuum and Gas Mechanical Switch

混合式直流断路器(hybrid DC circuit breaker,HDCCB)是解决直流开断最有前景的方案之一。但基于电力电子的负载换流开关(load commutation switch,LCS)在主通流支路上的导通损耗和成本较高,阻碍了HDCCB的应用。该文提出一种基于真空开关与气体开关串联的复合开关自然换流型混合式直流断路器,其利用气体开关的高弧压特性驱动自然换流,利用真空开关的快介质恢复特性承担暂态恢复电压,具有损耗低、换流可靠、体积紧凑、成本低等特点。该文分析气体机械开关的电弧电压特性,详细研究分闸速度、燃弧电流、气体类型和磁场、气体压强等不同因素对气体机械开关弧压的影响规律,并提出气体机械开关的设计方法。在此基础上,研制10kV复合开关自然换流型直流断路器原理样机,并进行开断测试,开断电流可达15kA,有效验证了该自然换流方法的可行性。

Hybrid DC circuit breaker is one of the most promising solutions to the problem of DC circuit breakers.In this paper,a natural commutation hybrid DC circuit breaker based on vaccum switch and gas switch in series is proposed.In principle,the natural commutation is driven by the high arc voltage of gas arc,and the transient recovery voltage caused by the turn-off of power electronics devices is withstood by the vacuum gap due to its fast dielectric recovery.The proposed breaker is characterized by the qualities of low loss,reliable breaking,small size and low cost.The characteristics of the arc voltage of gas mechanical switch are analyzed,and the laws of effects of different factors such as opening speed,magnetic field,gas type,arc current,and gas pressure on the arc voltage of gas mechanical switch are researched.The design method of gas and vaccum mechanical switch is presented.Based on this,a 10 kV natural commutation DCCB prototype is developed and tested,and the breaking current reaches 15kA,which effectively verifies the feasibility of the proposed hybrid switches scheme.