永磁真空断路器预击穿特性实验研究

Experimental Study on Pre-breakdown Character of Permanent Magnetic Actuator Vacuum Breaker

为了实现永磁真空断路器的同步关合,必须先分析断路器关合时的最佳相位。永磁真空断路器在关合时,动静触头间会发生预击穿,要使断路器在预定的相位角关合,需分析预击穿对同步关合的影响。采用27.5kV用永磁真空断路器,分别在直流和工频交流电压下进行了实验研究。采用高速高精度的采集系统,运用Matlab软件的非线性拟合功能对采样数据进行拟合,得到预击穿间隙和电压之间的关系,分析了在零相位附近实现同步关合时对合闸速度的要求。分析得出,在触头间隙非常小的情况下发生预击穿时可忽略预击穿对同步关合的影响。通过对实验数据进行分析,说明要实现同步关合就必须对机械分散所带来的误差进行补偿。

In order to implement synchronous switching of permanent magnetic actuator（PMA）,the optimal switching phase should be analyzed.During the switching of vacuum breaker,vacuum gap will pre-breakdown,and the influence of pre-breakdown on PMA should be included to ensure closing in the proposed phase.We experimentally studied 27.5 kV PMA vacuum breaker in DC and AC voltage.Using the nonlinear fitting function of matlab,we processed the experimental data obtained from high speed and high accurate instruments,and obtained relations between voltage and the pre-breakdown gap,respectively.Moreover,we analyzed the closing speed to synchronous switching when the closing angle is nearby zero angle of system voltage.It is found that the influence of pre-breakdown on synchronous switching can be ignored if the distance of pre-breakdown is very small.Finally,we analyzed the effect of mechanical dispersion on dynamic pre-breakdown characteristics of synchronous switch phase.