Abstract
Renewable energies such as wind power or photovoltaic energy are environmentally focused but the fluctuation of output power of renewable energies may cause excess variation of voltage or frequency of the grid. Increase of the amount of renewable energies would violate the quality of the grid. The micro grid in which dispersed energies compensate the variation from the renewable energies can expand the installation limit of the renewable energies by maintaining the quality of the interconnected grid. In this paper how the distributed generation and secondary batteries absorb the power variation from the wind generation and the loads is discussed. In order to control the output power, gas turbines and gas engines must run at partial load operation, which results in lower efficiency. Considering the efficiency of the micro grid, installed capacity of wind power generation system, and frequency stability for islanded operation, performs the evaluation of the micro grid.
