基于方向行波–小波熵的含DG配电网选线方法

Fault Line Selection Method for DG Distribution Network Based on Directional Traveling Wave—Wavelet Entropy

摘要: DG (distributed generation)的接入将影响小电流接地系统单相接地暂态电气量的分布，增加了单相接地选线的难度。理论分析可知，含DG配电网单相接地故障时，故障零模网络不受DG接入位置的影响，据此基于小波包变换理论和信息熵理论，提出一种利用方向零模电流行波的故障选线方法。对零模电流行波进行小波包分解，得到相应的小波包频带系数，选取特定频带的小波包系数来求解能量熵，根据每条线路的能量熵值来确定故障线路。仿真结果表明，此方法能准确选出故障线路，不受故障距离、过渡电阻以及噪音的影响。

Abstract: The DG access will affect the distribution of single-phase grounding transient electrical quantities in the small-current grounding system, increasing the difficulty of single-phase grounding routing. Theoretical analysis shows that the fault zero-mode network is not affected by the DG access loca-tion when single-phase grounding fault in DG-containing distribution network, based on wavelet transform theory and information entropy theory, a fault routing method using the directional ze-ro-mode current traveling wave is proposed. The wavelet decomposition of the zero-mode current traveling wave is performed to obtain the corresponding wavelet band coefficients, and the wavelet coefficients of specific frequency bands are selected to solve the energy entropy, and the fault line is selected according to the size of the entropy value under the fixed frequency band of each line. The simulation results show that this method can accurately select the fault line without the influence of fault distance, transition resistance and noise.