Protection of AC and DC microgrids: Challenges, solutions and future trends

In future, distributed energy resources (RESs) will be utilized at consumption points. As a consequence, power flow and fault current would be bidirectional and topology-dependent; and hence the conventional protection strategies would be inefficient. This paper categorizes the main challenges in AC and DC microgrids, and then investigates the existing and promising solutions for the corresponding challenges. To the authors' knowledge, three parts of smart grids are required to be developed to facilitate implementation of protection scheme in microgrids. The main requirements and open issues of these three parts are discussed at the end of this paper.