基于“电压零休”的机械式直流断路器介质恢复特性研究

Study on Dielectric Recovery Characteristic of Mechanical HVDC Circuit Breaker Based on"Zero-voltage"Principle

机械式直流断路器是高压直流开断的主要方向之一,为提升以真空开关为主开关的机械式高压直流断路器的开断性能,文中提出了一种基于"电压零休"原理的新型机械式直流断路器拓扑结构,分析了其工作原理,初步得到了续流支路可以为主开关创造"电压零休"时间。搭建了基于真空开关的新型机械式直流断路器的仿真模型,分析了"电压零休"受反向电流支路等参数影响规律。通过真空开关固有介质恢复特性测试得到真空开关介质恢复强度随时间变化的规律。仿真与试验结果表明:续流支路可以为主开关创造0~359μs的"电压零休"时间,而固有介质恢复特性数据表明在"电压零休"时间为20~30μs以上时,真空间隙的介质恢复强度得以完全恢复。通过传统与新型机械式高压直流断路器的试验对比,验证了电压零休原理的可行性和有效性,为新型机械式高压直流断路器的研制提供了参考依据。

Mechanical HVDC circuit breaker(CB)is one of the main directions of HVDC interruption. For improving the breaking performance of the mechanical HVDC CB using vacuum circuit breakers as main switch,the topology of a novel type of mechanical HVDC CB based on“zero-voltage”principle is proposed in this paper. Its operating principle is analyzed and the“zero-voltage”time,created by the high voltage continuous diode for the main switch,is preliminarily obtained. The simulation model of the novel HVDC CB based on vacuum switch is set up. The influence law of such parameters as reverse current branch on“zero-voltage”time is analyzed. The variation law of the dielectric recovery strength of the vacuum switch with the time is obtained by the intrinsic dielectric recovery characteristics of vacuum. The simulation and test results show that“zero-voltage”time ranging from 0 to 359 μs can be created through the continuous diode. While,the intrinsic dielectric recovery characteristic data shows that the dielectric recovery strength of vacuum switch can be completely recovered when the“zero-voltage”time is above 20~30 μs. By comparing the test results of the traditional HVDC CB with that of the novel mechanical CB,the feasibility and effectiveness of the“zero-voltage”principle are preliminarily verified,which provide a reference for the development of a novel mechanical HVDC CB.