采用形态学峰谷检测的谐振接地系统故障选线方法

摘要

Transient electrical quantity information is very abundant when single-phase grounding fault occurs in resonant earthed system.The short window data of 1/4 period of zero sequence current fault of each line are transformed by wavelet transform.The frequency band of power frequency is eliminated and the feature frequency band is selected according to the principle of maximum energy sum.The reconstructed wavelet coefficients under the feature frequency band are checked by morphological peak-valley detection.The peak-valley characteristic of the fault feeder is opposite to that of the total feeders, which is used as the fault line selection criterion.The simulation analysis and practical verification demonstrate the feasibility and effectivity of this method.%谐振接地系统发生单相接地故障时暂态量十分丰富.文中对各线路发生故障后1/4周期零序电流的短窗数据进行小波变换, 剔除工频所在频带, 按能量和最大的原则选取特征频带, 并对特征频带下重构的小波系数进行形态学峰谷检测.故障线路零序电流首波头峰谷形态与各线路零序电流首波头整体的峰谷形态相反, 据此构成故障选线判据.仿真分析和实录数据验证均表明所提方法选线准确、可靠性高.