高压直流真空断路器安全开距的试验研究

高压直流断路器是保护直流输电系统的重要组成部分,机械式高压直流真空断路器是目前几种可行方案之一。断路器的安全开距是断路器重要的开断参数,临界开距是直流真空断路器确定换流时刻的依据,直接决定其开断性能。该文建立了基于换流的直流真空断路器安全开距试验系统,主开关和换流开关均选用电磁斥力机构,直流试验电流源由低频LC振荡电路近似。应用PSCAD对该系统的开断过程进行仿真,以验证参数设计的可行性。试验中系统开断模拟直流电流为4 kA,采用位移传感器对动触头轨迹进行检测,得到动触头的分闸速度约为2.4m/s。对比仿真与试验波形,分析了与熄弧时间对应的开距对开断能力的影响,通过试验得到最快熄弧时间和临界开距,其值分别为为0.9 ms和2.2 mm。试验结果对高压直流真空断路器确定换流时刻具有参考价值。

Experimental Research on the Safe Stroke of HVDC Vacuum Circuit Breaker

High voltage direct current(HVDC)circuit breaker is an important part of protection direct current(DC)transmission system.Mechanical HVDC vacuum circuit breaker(VCB)is one of several feasible schemes at present.Safe stroke is one of the basic breaking parameters of VCB.The critical safe stroke directly determines the commutation time and breaking property of the DC-VCB.In this paper,the DC-VCB safe stoke test system based on commutation is established.The main circuit breaker and the commutation switch are driven by electromagnetic repulsion actuator.The main current source for verification tests of this DC breaker system is provided by a LC oscillator circuit with lower frequency.The breaking process of the system is simulated by the PSCAD,and the feasibility of parameters design is verified.In the test,the simulated DC current of the system is 4 kA,and the moving electrode track is detected by a displacement sensor.The opening speed of the moving electrode is about 2.4 m/s.By comparing the simulation and experimental waveforms,the influence of the safe stroke corresponding to the arcing time on the breaking capacity is analyzed.The fastest arcing time and the critical safe stroke are obtained through the experiments,and their values are 0.9 ms and 2.2 mm.The result is valuable for the determination of commutation time for HVDC-VCB.