Abstract：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.
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2017, Vol. 32 
