分布式电源的微网故障分析及保护方案研究

Fault Analysis and Protection Program of Distributed Generation Grid Through the Line

分布式电源大多是通过母线并入配电网,但是分布式电源直接接于配电网线路上与通过母线接入情况不同,分布式电源接于线路上,线路中间增加多余的支路,对线路两侧的电流大小方向造成影响,传统的方向保护无法正确动作。通过分析含有分布式电源的配电网线路两侧的故障电流特性,提出了采用基于正序故障分量的方向元件来判断故障的方法,用PSCAD软件建立了分布式电源直接接于线路上的配电网模型。仿真结果表明,基于正序故障分量的方向保护元件能有效的解决DG在线路并网的配电网问题,其有效性不随分布式电源容量的变化而变化,不随故障类型的变化,且耐过渡电阻能力强。

Distributed generations grid trough the distribution network by bus mostly, but it is different that when distributed generation grid trough the net from the line. Because of the different grid, it will add excess branch between the lines and impact the magnitude and the direction of the fault current at both ends of the line, and the tradition direction protection can not work. By analyzing the characteristics of the fault currents at both sides of the line, this paper used the direction elements based on the fault components to determine the fault, and then simulated it with PSCAD. The result proves that the direction element based on the fault component can solve the problem, and the validity will not change with the capacity of the distributed generation, the type of the fault and the resistance at the fault point.