周期性脉冲电压作用下绝缘局部放电的测量与分析

Measurement and Analysis of Partial Discharge Under High Voltage Continuous Impulses for Inverter-fed Insulation

局部放电是导致变频电机绝缘失效的主要原因之一。逆变器输出的脉冲方波上升沿陡、频带宽,使局部放电测量更加困难。文中采用脉冲电流传感器有效地测量出脉冲方波下的局部放电,利用小波包方法提取局部放电信号,并根据其统计结果,探讨了脉冲方波幅值和频率对放电次数、最大放电量、平均放电量的影响,为研究绝缘材料在脉冲方波下的老化机理创造了条件。

Partial discharge （PD） is one of the key factors in insulation failure of inverter-fed traction motor. Due to the high steepness of impulse with broad frequency range, PD under continuous impulses is not easy to be detected by a conventional PD detection system. In this paper, impulse current sensor （ICS） has been applied to develop a new PD detection system and the wavelet packet method is used to extract the PD signals. Moreover, the coil of traction＇motor is used as the test sample. The statistics of test results of PD signals show that PD signals can be successfully identified by the new PD detection system. Finally, issues about the influence of voltage and frequency of square wave pulses on discharge number, maximum discharge and mean amplitude of PD signals are discussed.