配电线路单相断线故障保护方法

为了减小单相断线故障对供电质量造成的不良影响,针对配电线路单相断线故障,提出了一套系统的保护方法。利用电路原理和中性点电压偏移理论,对简单断线故障和伴随接地的复杂故障情况下线路首末两端电压和流经线路的电流特征进行了分析,总结了各电气量的变化规律,提出了一组由电流判据和电压判据组成的单相断线故障判断和保护方法。研究了基于电压判据的断线故障类型及故障区段的判断方法,进一步分析了不对称运行、互感器断线等异常情况对所提判据的影响和相应的改进方案。利用PSCAD/EMTDC仿真软件进行了算例仿真,结果验证了理论分析结果的正确性和断线故障保护方法的有效性。

Protection methods of single-phase broken-line fault for distribution line

In order to reduce the adverse effect caused by single-phase broken-line fault to the power supply quality, a systematic protection method is proposed for the single-phase broken-line fault of the distribution line. Using circuit principle and neutral point voltage shift theory, this paper analyses and summarizes the features of the voltages at both ends of the fault line and the current flowing through the fault line when single-phase broken-line fault with or without a grounding fault occurs. The judgement and protection method that consists of the current criterion and the voltage criterions for single-phase broken-line fault is proposed. The methods for judging the fault type and the fault location are studied based on the voltage criterions. The influences of abnormal operating status like asymmetry operation and transformer disconnection on the criterion and the corresponding protection methods are analyzed. Simulation is carried out in PSCAD/EMTDC, which ensures the correctness of the theoretical analysis and the effectiveness of the protection methods. This work is supported by National Natural Science Foundation of China (No. 51877126).