基于小波包的小电流接地故障选线仿真研究

Research of Simulating the Small-Current Neutral Grounding Systems’ Fault Line Selection Based on Wavelet Packets

在配电网故障特征的基础上,利用小波包分析技术提出了一种基于能量最大原则确定零序暂态电流最集中的特征频带,再比较各线路特征频带的模极大值和系统零序电压首半波的极性以确定故障线路,并利用MATLAB/SIMU-LINK建立小电流接地系统单相接地故障仿真模型。仿真结果表明,该方法准确可行,而且不受中性点接地方式、故障接地时刻等因素的影响,具有良好的通用性。

According to the distributed power system fault characteristics, a new criterion based on the principle of maximum energy is built, which selects the special frequency band that has the major characteristics of zero sequence current. Comparing the polarity of the special frequency band of each line with the polarity of the zero sequence voltage＇ s first half wave, a method is put forward to distinguish the fault lines in this paper. The single phase-to-earth fault model of smallcurrent grounding systems is built with MATLAB/SIMULINK. The simulation suggests that the new criteria can distinguish correctly the fault lines, whose performance is independent on the grounding model of the centric dot and the fault occurring time, and the new criteria has an excellent adaptability to various fault conditions.