基于高频分量相关度分析的故障选线方法

Fault Line Selection Method Based on Correlation Analysis of High-frequency Components

为解决单纯利用零序电流选线效果不佳的问题,提出了一种利用高频分量相关度分析的故障选线新方法。首先,利用各线路首端安装的录波装置采集各线路零序电流,经消噪处理后得到纯故障分量,然后借助EMD分解及瞬时频率分析剔除工频分量,提取出相应的高频分量。由于单相接地故障后非故障线路高频分量波形相似,而故障线路与非故障线路之间存在明显的区别,从而利用波形相关系数的大小来确定故障线路。仿真结果表明,该方法运算简单,无需整定,不受过渡电阻、故障距离等因素影响,能够有效克服系统噪音、不对称分量的干扰,进一步提高了保护的裕度。

To overcome the poor effect of fault line selection by simply using zero-sequence current, this paper introduces a new method of fault line selection based on correlation analysis of the high frequency components in zero-sequence current. First, the pure fault components are obtained by processing the zero-sequence current extracted from every line by recorders installed at the end of lines. Then, the corresponding high frequency components are obtained by empirical mode decomposition （EMD） and instantaneous freguency analysis. Because the wave forms of high-frequency components in non-fault lines are similar under single-phase grounding fault, while the wave forms between the fault line and non-fault lines are significantly different, the correlation coefficients between the wave forms can be utilized to select the fault line. Simulation results show that the proposed method is simple, and it has strong anti-interference ability without setting. Moreover, the fault line can be selected without being affected by transition resistance or fault distance, and the proposed method can overcome the interference due to system noise and nonsymmetrieal components, which further improves the margin of protection.