Islanded and grid-connected are two working modes for microgrids, which they impose some challenges on overcurrent protection scheme. Microgrid Short Circuit (SC) level is different in both modes which causes mal-operation of relays. Therefore, a new idea, relay, or method is necessary to solve this problem. This paper proposes a curve optimization approach for the microgrid protection. Directional Over Current Relays (DOCRs) have different kinds, depended on their parameters like standard

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... se and extremely inverse. SC variation in two modes of microgrid can be compensated by appropriate relay curve selection. In this paper, DOCR curve optimization and selection are proposed for better protection coordination and microgrid protection. A hybrid Genetic Algorithm (GA) and linear programming method (LP) is also used for finding the optimal settings and the curve of relays. The proposed method is applied to Canadian distribution benchmark and modified IEEE 14 bus. The results indicate that the DOCR curve selection is an efficient tool for microgrid protection coordination and fast fault detection.