一种新的谐振接地系统单相接地故障选线方法

为解决谐振接地系统单相接地故障在小故障合闸角情况下选线准确率不高的问题，利用集合经验模态分解(EEMD)和希尔伯特变换在频带分析方面的优势，提出了一种新的谐振接地系统故障选线方法。通过分析单相接地故障时暂态零序电流的分布特征，比较系统暂态电容电流与衰减直流分量的能量大小，自适应将能量较大的信号用于故障选线。暂态电容电流能量大时通过比较暂态电容电流的极性确定故障线路；衰减直流分量能量大时通过比较消弧线圈与初选线路衰减直流分量的能量确定故障线路。分别对不同故障合闸角，不同过渡电阻的单相接地故障进行了仿真验证。仿真结果表明，该方法选线准确率高，在小故障合闸角情况下亦能准确选线，具有一定的应用价值。

A fault line selection method for resonant earthed system with high accuracy

To solve the problem of low accuracy of fault line selection in resonant earthed system when the fault switching angle is small, a novel fault line selection method is proposed by taking the advantage of Ensemble Empirical Mode Decomposition (EEMD) and Hilbert-transform in frequency band analysis. By analyzing the distribution characteristics of transient zero sequence current and comparing the energy of transient capacitance current with that of decaying DC component, the signal with higher energy is used for fault line selection adaptively. When the energy of transient capacitance current is higher, the fault line is identified by comparing the polarity of transient capacitance current. When the energy of decaying DC component is higher, the fault line is identified by comparing the decaying DC component energy of arc suppression coil with that of primary selection line. Simulations of single-phase earth fault under different switching angle and transition resistance conditions have been done, the results show that the proposed method has high accuracy and can select the fault line even in small fault switching angle occasions. The proposed method may take effect in its applications. This work is supported by National Natural Science Foundation of China (No. 51177108 and No. 51577128).