低压配电网缺相与断零故障判据研究

Probe into Criterion for Open-phase and Open-neutral Fault in Low-voltage Distribution Network

"缺相"、"断零"故障对低压配电网的安全稳定运行具有重要影响。针对我国低压配电网为中性点直接接地的三相四线制系统的特点,通过对发生常见故障时的电气特征参数的分析,获得了基于正序电流突变量与相电流突变量的"缺相"故障判据和基于中性点偏移电压与中性线电流的"断零"故障判据。利用该判据可以有效辨识"缺相"、"断零"故障与其他类型的故障。仿真实验结果表明:该方法原理简单,信号便于提取。该方法对于"缺相"、"断零"故障的及时处理有重要意义。

The faults of open-phase and open-neutral have great influence on the stable operation of low voltage distribution network. Considering the characteristics of the low voltage distribution network which is three-phase four-wire system with neutral directly grounding, the paper discuses the electrical characteristics parameters when common faults occur, and proposes the fault criterion for the open-phase fault which is based on the variables of positive-sequence current and phase current as well the fault criterion for the open-neutral fault which is based on the deviation of neutral voltage and neural line current. These criterions help to diagnose the open-phase, open-neutral and other types of faults. The simulation results demonstrate that these criterions are proper and of great significance to the faults processing timely because of the simple principles of this method and ease to obtain signal.