A review on Microgrid protection

Incorporation of Microgrid (MG) comprising of distributed generators (DGs), in the existing bulk power system has become an inevitable trend. The traditional distribution network designed to operate radially is protected by simple protective devices such as fuses, reclosers and over-current relays (OCRs). This changes the distribution system from single supply radial system to multi-source network which causes the multidirectional power flow and also having significant impact on protection coordination issues. The presence of DG and MG changes the Load-Flow of the overall network and also influences the fault current magnitude and direction. A lot of research work is carried out for improvement of the grid connected distributed generators for the safe and reliable operation of the overall system. This paper proposes a comprehensive review on the traditional protection scheme of the distribution system and the challenges associated with the MG protection system along with the discussion of some alternate protection strategies.