基于暂态零序电流频谱灰关联分析的谐振接地系统故障选线方法

Faulty feeder detection using grey relation analysis of transient zero-sequence current spectrum in resonant grounding system

为提高谐振接地系统单相接地故障选线的准确性和可靠性,提出一种充分利用故障暂态特征的故障选线方法。首先,通过对故障后暂态零序电流特征进行分析,利用快速傅里叶变换(FFT)对各线路暂态零序电流进行频率分解,保留特征频段内的成分,得到各线路暂态零序电流频率-幅值曲线图;然后,根据故障线路和非故障线路在特征频段内曲线的相似度较低,而非故障线路曲线相似度高,通过灰色关联分析求取各曲线间的绝对关联度,利用绝对关联度定义选线判定系数,通过比较各线路判定系数与设定阈值的大小进行选线。EMTP/ATP和MATLAB仿真结果表明:该方法不受故障线路类型、接地电阻、故障合闸角等因素的影响,同时能有效识别母线故障,具有很高的选线准确性和可靠性。

similarity between fault feeder and sound feeder and the strong similarity among sound feeders, the absolute relation degrees among all feeders were calculated by grey relation analysis, and the determination coefficient was defined by absolute rela-tion degree. The faulty feeder was detected by comparing determination coefficient and threshold. Finally, EMTP/ATP and MATLAB simulation results showed that this method had strong accuracy and reliability, it was not influenced by faulty feeder types, grounding resistance, fault initial phase angle and could identify the bus fault .