基于LCD能量相对熵的小电流接地故障选线方法

针对小波变换不具有自适应性、易受小波基种类影响的问题，及经验模态分解EMD（empirical modal deco-mposition）存在的模态混叠现象，提出了一种基于局部特征尺度分解LCD（local characteristic-scale decomposi-tion）和能量相对熵的故障选线新方法。首先利用具有自适应性、抗混叠性的LCD对各线路暂态零序电流进行分解，计算各频带暂态能量；再结合能量相对熵对信号间的细微差异进行识别放大，根据各条线路综合能量相对熵的大小进行选线。通过在Matlab仿真平台上搭建具有5回出线的10 kV线缆混合配电网发生单相接地故障的模型，验证了所提方法不受故障合闸角、故障距离和过渡电阻的影响，可实现正确选线。

Fault Line Selection Method for Small Current Grounding System Based on LCD Energy Relative Entropy

Considering that wavelet transform is not adaptive and susceptible to the types of wavelet bases, and the phenomenon of modal-aliasing exists in empirical modal decomposition(EMD), a novel fault line selection method is pr-esented based on local characteristic-scale decomposition(LCD) and energy relative entropy. First, the transient zero-se-quence current of each line is decomposed by LCD, which has characteristics of self- adaptability and anti-aliasing. Then, the transient energy of each frequency band is calculated. In addition, the small differences in signals are distinguished and magnified with the combination of energy relative entropy, and the fault line is selected according to the com-prehensive energy relative entropy of various lines. A model of 10 kV cable hybrid distribution network with 5 back lines under single-phase grounding fault is established on the Matlab simulation platform. Results verify that the proposed method is not affected by the fault switching angle, fault distance or transition resistance, and it can be used to realize the fault line selection correctly.