基于故障分量的孤岛微电网保护

摘要

微电网孤岛运行时的故障特性与并网情况有所区别,且与微电源的控制策略紧密联系,因而需要对孤岛微电网的保护进行具体的研究.根据U/f控制及PQ控制微电源在故障穿越下的故障模型,分析了不同故障类型时的输出电流特性,并对微电网中不同线路故障时各母线及馈线的相位特征进行分析,提出利用母线正序电压故障分量和各馈线正序电流故障分量的相位特征实现故障定位的孤岛微电网保护方案.最后,在PSCAD/EMTDC中建立了仿真模型,结果验证了该保护原理的正确性.%The fault characteristic of islanded microgrid is different from that of grid-connected microgrid,which is closely related to the control strategy of microsource,it is necessary to carry out specific research on the protection of islanded microgrid.According to the fault models of U/f controlled and PQ controlled microsources with fault ride-through (FRT) capacity,this paper analyzed their output current characteristics under different fault types and presented the phase characteristics in each bus and feeder when the fault occurs in different positions of microgrid.A protection principle is proposed to locate the fault point,which is based on phase characteristics between fault component of positive sequence bus voltages and those of feeder currents.Finally,a simulation model is established with PSCAD/EMTDC,and the results verify the validity of the proposed protection principle.