Contents I. Introduction
Microgrid is local distributed power system using local sustainable power sources. As it does not use wider utility grid, it provides energy security for local community. Microgrid technology represents three principles to the society such as reliability, sustainability and economics. Microgrid also generates, distributes and transmits power like conventional grid. But it differs in the distance between generation points and consumption points, because it is installed nearer to the consumption points. Microgrid also combines with distributed generations like combined heat and power (CHP), renewable energy facilities powered by solar energy, wind power, geothermal, biomass and hydro power generation units. Though the power rating for Microgrid is limited to minimum, it is relative to its application area and type of grid employed. In macrogrid, only one third of fossil fuel is converted in to electricity and remaining two third is distributed as heat energy. Microgrid on the other hand distributes power suitable to demands exactly and no resources are wasted. [1] Micro grid consists of many electrical powers generating resources and loads that can operate as a single unit either by isolating from main grid or coupled with main grid and operating with proper coordination. When it is isolated from main grid, it is considered as local resources which are capable of meeting the local demands [2]. The different generating resources used in micro grid applications are called Distributed Generations (DG). The development of DG has many advantages like meeting the power quality requirements, avoiding investments in transmission lines, ohmic losses minimization and environmental protection [3]. These distribution units are limited in size and connected directly to the distribution network on customer site. Table: I provides the typical technologies used in DG [4].
