基于零相位误差滤波的局部放电故障识别

Recognition of Partial Discharge Faults Using Zero Phase Error Filtering

开关柜局部放电放电信号中混有较大的噪声信号,传统的有限冲激响应(finite impulse response,FIR)滤波方法会造成滤波后信号相位的偏移,从而影响以功率谱为特征量的故障识别的正确率。针对这种情况,提出了基于零相位误差滤波方法的局部放电故障识别方法。首先,通过高速电流互感器采集局部放电信号。然后,采用零相位误差滤波(zero phase error filtering,ZPEF)滤除放电信号中的噪声。其次,通过FFT变换分析放电信号的功率谱,取1.0~1.5 MHz和2.5~3.0 MHz 2个频段的功率谱构造故特征向量。最后,采用最小二乘支持向量机对局部放电信号进行故障识别。实验结果表明,采用ZPEF可以提高局部放电故障的识别率。由此也得出一个推论:在确保相同的故障识别率的情况下,采用ZPEF可以提高故障的识别速度。

There is a large noise signal in the partial discharge （PD）signal of the switch cabinet. The traditional FIR filter willcause the phase shift of the filtered signal. Thus,the correct rate of fault identification using power spectrum is considered. Tosolve the problem,a PD fault identification method using zero phase error filtering （ZPEF）method is proposed. Firstly,PDsignals are collected by high speed current transformer. Then,ZPEF is used to filter the noise in the discharge signal.Secondly,the power spectrum of the discharge signal is analyzed by FFT transform. Two bands power spectra of 1 0～1 5 MHzand 2 5～3 0 MHz are used to construct the eigenvectors. Finally,least squares support vector machine （LSSVM）is used toidentify PD faults. Experimental results show that the recognition rate of PD fault can be improved by using ZPEF. A corollaryis also drawn：ZPEF can improve the speed of fault identification by ensuring the same fault recognition rate.