基于小波包方法的配电网故障选线与仿真研究

Simulation Research and Fault Line Selection in Distribution Network Based on Wavelet Packet Method

配电网单相接地故障选线问题一直未能很好地解决。在分析配电网发生单相接地故障暂态特征基础上,对中性点经消弧线圈接地系统发生单相接地故障进行了仿真。介绍了一种利用小波包分解暂态零序电流的故障选线方法。该方法利用小波包对各条线路的暂态零序电流进行多层分解,按照能量最大的原则确定各线路暂态零序电流分布集中的特征频带,在征频带内进行幅值与极性综合比较选出故障线路。通过MATLAB仿真表明,该方法可以准确实现故障选线,具有较高的灵敏度,且不受过渡电阻、故障合闸角及电弧的影响。

The fault line selection of single-phase grounding fault has not been well solved in distribution network. On the basis of analysis transient characteristics of single-phase grounding fault in distribution network, the single phase grounding fault of power system with neutral grounding via arc suppression coil is simulated. A fault line selection method of decomposition transient zero-sequence current based on wavelet packet is proposed. The transient zero-sequence cur- rents of each line are decomposed to obtain the different frequency bands by using wavelet packets in this method. The characteristic frequency band is selected by the principle of maximum energy of transient zero-sequence current distribu- tion is concentrated of each line. The fault line is elected by comprehensive comparison transient zero-sequence current amplitude and polarity in this feature frequency band. The MATLAB simulation results show that the method can find out the fault line correctly. It has a high sensitivity and cannot be affected by faults resistance, faults current angle and arcing fault.