As defined by the U.S department of energy, a microgrid is a group of interconnected loads and distributed energy resources (DERs) with the... Show moreAs defined by the U.S department of energy, a microgrid is a group of interconnected loads and distributed energy resources (DERs) with the ability of self-supply and islanding. The significant advantages of microgrids have resulted in extensive research and development efforts and rapidly growing implementation in electric power systems. There are, however, still many challenges to be addressed in order to efficiently design, control, and operate microgrids when connected to the grid, and also when in islanded mode. Based on the type of voltages and currents in the network, different microgrid types can be considered, including AC microgrids, DC microgrids, and Hybrid AC/DC microgrids. This thesis presents a review of AC, DC and Hybrid microgrids with a focus on control, operation, and planning issues. A thorough comparison between these microgrid types is further provided based on the system layout and the type of DERs that are commonly utilized. Communication issues are also investigated to demonstrate and compare the existing deployment practices. The thesis is concluded by providing a list of potential areas of research associated with AC, DC, and hybrid microgrids. M.S. in Electrical Engineering, July 2016 Show less