配电网弧光接地故障相辨识方法研究

Phase Identification Method of Arc Grounding Fault in Distribution Network

目前,我国城市中低压配电网电容电流骤增且消弧线圈补偿能力不足问题突出,为解决由此带来的单相接地故障电弧难以自熄问题,故障相接地消弧技术在配电网逐渐开展试用,故障相准确辨识是该技术可靠熄弧的基础。本研究分析故障后三相电压暂态信号,得到故障相暂态电压波形与非故障相极性相反的特征,提出利用故障相和非故障相暂态电压波形相似度判断故障相的方法;采用Matlab&Simulink建立10kV典型配电网模型和电弧故障模型,并在不同中性点接地方式下改变过渡电阻、故障点距离、故障相角、间歇性接地等弧光接地故障条件,对故障相辨识方法进行验证。仿真结果表明,所提故障相辨识方法均能正确地对不同过渡电阻,故障距离及间歇性电弧故障条件下的单相接地故障进行选相。

The problem of capacitor current increasing sharply and insufficient compensation capacity of arc suppression coil in urban low and medium voltage distribution network in China is prominent.In order to solve the problem that the ground fault arc is difficult to self-extinguish,the fault phase grounding arc suppression technology is gradually being tested in the distribution network.The accurate identification of the fault phase is the basic of this technology for reliable arc extinguishing.The author analyzes the three-phase voltage signal in the transient process after the fault,and obtains the characteristics of the fault phase transient characteristic voltage waveform and the non-fault phase opposite in polarity,and proposes the use of the similarity between the fault phase and the non-fault phase transient characteristic voltage waveform to judge the fault phase.The author establishes a 10kV typical distribution network model and arc grounding model in Matlab&Simulink,and verifies the fault phase identification method under different neutral point grounding methods for different transition resistance,fault point distance,fault phase angle,intermittent grounding and other arc ground fault conditions.Simulation results show that the proposed fault phase identification method can accurately select phases in transition resistance,fault distance and intermittent arc ground fault.