机械式真空直流断路器弧后电流测量研究

Research on Measurement of Post-Arc Current of Mechanical Vacuum DC Circuit Breaker

机械式直流断路器弧后特性是表征其开断性能的重要参数。为获得直流开断过程中真空开关弧后电流峰值与时间、电流零点附近的di/dt、du/dt等影响规律,该文首先分析基于电流转移的机械式真空直流断路器弧后电流测量原理,设计机械式真空直流断路器弧后电流测量装置参数,搭建基于强迫过零方式的机械式直流开断实验平台,测量开断电流为1.5kA情况下机械式真空直流断路器弧后电流,讨论换向频率和恢复电压对弧后电流的影响。研究表明,基于电流转移的弧后电流测量装置可以有效测量弧后电流,弧后电流随着换向频率和恢复电压的增大而增大,恢复电压在相位上稍滞后弧后电流约100ns,且换向频率对弧后电流的影响大于恢复电压的影响,为断路器开断性能的优化研究提供了参考。

The post-arc characteristic of mechanical DC circuit breaker is an important parameter to characterize its breaking performance.In order to obtain the influence law of vacuum switch post-arc current,post-arc action time,di/dt and du/dt near current zero point during DC breaking process,this paper firstly analyzed the post-arc current of mechanical vacuum DC circuit breaker based on current transfer measurement principle.Then,the parameters of the mechanical DC circuit breaker arc current measurement device were designed,and a mechanical DC breaking experiment platform based on the forced zero crossing method was built.The mechanical vacuum DC circuit breaker arc was measured under the condition that the breaking current was 1.5kA,and the influence of the commutation frequency and the recovery voltage on post-arc current was discussed.The results show that the post-arc current measuring device based on current transfer can effectively measure the post-arc current.The increase of the commutation frequency and the recovery voltage will cause the post-arc current to increase.The recovery voltage slightly lags behind the post-arc current in phase by about 100 ns,and the change influence of the directional frequency on the post-arc current is greater than that of the recovery voltage,which provides a reference for the optimization research of the circuit breaker's breaking performance.