距离保护在含分布式电源配电网中的应用研究

Application Research on Distance Protection in Distribution Network Containing Distributed Power Supply

由于传统电流保护在含分布式电源配电网中存在缺陷,考虑将距离保护应用到配电网中。通过仿真验证距离保护可以弥补电流保护的不足,但距离保护应用于中低压配电网时其耐受过渡电阻能力很差。为解决此问题,分析了分布式电源接入配电网后形成的双侧电源线路上发生短路故障时过渡电阻对距离保护的影响,利用序分量算法研究出一种不受过渡电阻影响,通过采集线路的电流、电压相量值来正确测量故障阻抗值的算法。建立含风电机组的配电网模型,利用MATLAB进行了仿真验证。仿真结果证明该算法可正确测量故障阻抗值,准确识别保护区内的故障,且其计算精度高,能很好地消除过渡电阻对距离保护的影响。

For that traditional current protection has defects in distribution network which contains distributed power supply, distance protection application in distribution network is suggested to be considered. It can make up shortages of current pro- tection by distance protection based on simulating verification, but its ability to tolerate transition resistance when being ap- plied in medium and low voltage distribution network is poor. For solving this problem, this paper analyzes influence on dis- tance protection by transition resistance when short circuit fault happening on double-side power lines in distribution network while connecting distributed power supply, studies out an algorithm by using sequence component algorithm for measuring fault resistance value by collecting current and voltage phase values of lines which may not be affected by transition resist- ance. Based on MATLAB simulating verification, it establishes a distribution network model containing wind power units. The simulating result proves that this algorithm can measure fault resistance value correctly and discriminate faults in protec- tion area. Meanwhile, it is of high precision in calculation to remove influence on distance protection by transition resistance well.