基于暂态主频分量相关性分析的故障选线方法

提出了一种利用零序电流暂态主频分量相关性来进行小电流接地系统故障选线的新方法，以解决单纯利用零序电流选线效果不佳的问题。通过对故障零序电流特征的分析，提出了采用Prony算法来提取各线路暂态主频分量。利用故障后非故障线路暂态主频分量波形相似，而故障线路与非故障线路之间有着明显区别的特点，对其进行相关性分析，得出综合相关系数，实现正确选线。理论计算及仿真结果表明，该方法准确可靠，抗干扰能力强，无须整定，不受故障初相角、接地电阻、故障距离及接地方式的影响，进一步提高了保护的裕度。

A new correlation analysis approach to fault line selection based on transient main-frequency components

In order to solve the problem of the poor effect using simply zero-sequence current to select fault line, the paper introduces a new method to select fault line for neutral indirect grounding system by transient main frequency components of zero-sequence current. Based on the feature analysis of zero-sequence current, the paper utilizes Prony algorithm to extract the main frequency components of transient information of each line. Because its transient main frequency waveforms are similar between the non-fault lines when the fault occurred in system, and there is a clear distinction between the fault line and non-fault line, so the integrated correlation coefficients are obtained to achieve the fault line selection correctly by correlation analysis. Theoretical analysis and simulation results show the new method has validity, strong anti-interference, and without setting. It can select fault line successfully with different conditions, including different transition resistance, different initial fault angel, different fault position and grounding modes, and further improve the protection margin.