基于移动FFT的PD在线检测中正弦干扰抑制方法  

Moving FFT Based Approach for Rejecting Sine Interference in On-line PD Measurements

作　　者：白建社[1] 陈丹[2] 王成多[3] 徐政[1] 关长毅 

机构地区：[1]浙江大学电气工程学院,杭州310027 [2]西安理工大学自动化与信息工程学院,西安710048 [3]杭申控股集团有限公司博士后工作站,杭州311234

出　　处：《电力系统及其自动化学报》2007年第6期118-123,共6页Proceedings of the CSU-EPSA

摘　　要：为剔除局部放电在线检测中干扰信号,尤其是连续正弦干扰(continuous sine interference,CSI),应用移动(fast Fourier transform,FFT)算法,以递推的方式求取信号的离散傅里叶变换(discrete Fouriertransform,DFT),提高信号处理的实时性。通过对频域信号进行阈值处理,来抑制局部放电测量中的CSI干扰,并通过离散傅里叶反变换(inverse discrete Fourier transform,IDFT)获得处理结果。另外,每次提取处理结果的中间数据(大小等于步长)作为本步的处理结果,避免了DFT的边沿效应和窗函数的影响。实验结果表明,所提出的方法能够很好地滤除局部放电中的连续正弦干扰,且使局部放电脉冲衰减很小,实时性好。将该方法应用于地铁牵引变电站馈线电缆绝缘性能的在线检测中,取得良好的效果。In order to eliminate the interfering signal in online detection of partial charge （PD）,especially continuous sine interference（CSI） ,discrete Fourier transform（DFT）of signal is recursively evaluated by using moving fast Fourier transform （FFT）,which can improve the real time of signal processing. CSI in the PD measurement is restrained by the threshold processing of frequency domain signal and processing results are obtained through inverse discrete Fourier transform（IDFT）. The middle data （its size is equal to the step length）of processed results are acquired as the PD results every time,which avoid the influence of DFT edge effects and window function. Experimental results show that the proposed method can filter the CSI in PD well,which makes the PD pules attenuate less and has good real time. Meantime,the proposed one is applied to online detect the insulation of feeder line cable in metro substations and has already obtained good results.

关 键 词：移动快速傅里叶变换 连续正弦干扰 局部放电 自适应滤波 

分 类 号：TM711[电气工程—电力系统及自动化]