基于正序阻抗的微电网线路故障定位策略的研究

Research on the line fault location of microgrid based on the positive sequence impedance

微电网线路结构的复杂性,造成了对线路的故障判断和定位困难。文章提出了一种基于等效正序阻抗的线路故障定位方法。通过对线路两端的电压、电流、有功功率以及无功功率进行3次测量,计算出每条线路两端的等效正序阻抗。通过对故障前后线路等效正序阻抗的对比分析,对出现故障的线路做出判断。在确定故障线路的前提下,比较短路点到线路端点的阻抗与故障前线路阻抗的大小,确定出线路短路点的具体位置。实验数据以及仿真波形与理论分析完全吻合,验证了所提出的故障定位方法是完全正确和有效的。

Because of complex circuit＇s structure, it is very difficult to judge circuit faults and their location in micro-grid system. A positioning method of transmission line fault is proposed in this paper and the proposed method obtains support from the positive sequence impedance. The positive sequence impedances are calculated by using voltages, currents, active power and reactive power at both line ends, where the electrical parameters are obtained from three measurements. The fault line can be found by comparing values of positive sequence impedance before and after fault. When fault line is confirmed, the specific location of the short circuit is judged, by compar- ing impedance from the short-circuit point to the end with whole value of the line before fault. The experimental data and the simulation waveform are in. perfect agreement with the theoretical analy- sis, which proves that the proposed fault location method is completely correct and effective.