基于触发角识别的脉动直流剩余电流有效值检测方法

Residual pulsating DC detection based on triggering angle identification

针对电力电子设备发生漏电故障时的脉动直流电流信号进行傅里叶分析,得到不同触发角下脉动直流电流各谐波分量幅值的变化趋势,并能通过谐波分量的幅值比对触发角进行识别;根据剩余电流互感器在不同触发角下脉动直流电流信号的传变误差对二次侧电流进行补偿计算,从而得到一次侧脉动直流电流有效值;对剩余电流互感器进行试验测试分析,在脉动直流剩余电流下,二次侧信号与一次侧信号存在较大传变误差,而采用补偿计算方法后最大误差不超过4.5%。因此所提的触发角识别方法和脉动直流剩余电流补偿计算方法有效,可以提高脉动直流剩余电流检测精度。

The pulsating DC during the leakage fault of electronic equipment is analyzed by Fourier transform and the variation curve of its spectrum vs. the triggering angle is obtained,based on which,the triggering angle can be identified according to the amplitude ratio of harmonic components. The RMS of the primary pulsating DC can be calculated by compensating the secondary current according to the pulsating DC transmission errors of residual current transformer under different triggering angles. The experimental analysis for residual current transformer shows that,the transmission error between the primary and secondary residual pulsating DCs is quite big and it is reduced to less than 4.5% after compensation,which proves that,the proposed compensation method improves the detection accuracy of residual pulsating DC effectively.