Microgrids: A brief review of architectures and Operation

This paper presents A brief review of architectures and Operation in microgrids. A microgrid is a decentralizedgroup of electricity sources and loads that normally operates connected to and synchronous with the traditional wide areasynchronous grid (macrogrid), but is able to disconnect from the interconnected grid and to function autonomously in"island mode" as technical or economic conditions dictate. In this way, microgrids improve the security of supply within themicrogrid cell, and can supply emergency power, changing between island and connected modes. Another use case is theoff-grid application, it is called an autonomous, stand-alone or isolated microgrid. These microgrids are best served by localenergy sources where power transmission and distribution from a major centralized energy source is too far and costly toexecute. They offer an option for rural electrification in remote areas and on smaller geographical islands. As a controllableentity, a microgrid can effectively integrate various sources of distributed generation (DG), especially renewable energysources (RES). Control and protection are difficulties to microgrids, as all ancillary services for system stabilization must begenerated within the microgrid and low short-circuit levels can be challenging for selective operation of the protectionsystems.

Keywords:

microgrids , renewable energy , distributed generation , island and connected modes