Fault Detection for Microgrid Feeders Using Features Based on Superimposed Positive-Sequence Power

With the integration of distributed generation (DG) into a microgrid, fault detection has become a major task to accomplish. A scheme for microgrid feeder protection based on a newly proposed feature, $\Delta \pmb{RP}$, defined as the ratio of the sum of positive-sequence real power (PSRP) at the two ends of the feeder to the larger of the PSRPs among the two ends, is proposed. If $\Delta \pmb{RP}$ is larger than a threshold, an internal fault is detected; otherwise, the fault is external or there is no fault. The proposed scheme is tested in various scenarios, including fault type, fault resistance, fault location, fault inception angle, varying DG penetration levels, and simultaneous, evolving, and composite faults. In addition to this, the proposed scheme offers a robust performance when subjected to noise, synchronization error, changes in sampling frequency, and changes in the topology of a microgrid. The dominancy of the proposed scheme is proven by a comprehensive comparative study with various available recent schemes. Test results on the IEEE 13-bus network indicate the viability of the proposed protection scheme for a microgrid. Finally, the proposed scheme has been validated on a real-time simulator.