Distributed battery storage units for overload prevention in an islanded microgrid

In an islanded microgrid, the load demand must be met by the distrusted generators (DGs) connected to it. Usually this can satisfactorily. However load growth increases, especially the peak load. In such a case, more DGs are to be connected to cater to the load growth. Alternatively if the overloading conditions occur infrequently or remain for shorter periods, storage units can be employed. In this paper, distributed battery storage units (BSUs) are employed for the overloading prevention in an islanded microgrid. It has been assumed that the mi-crogrid only contains inertial DGs and ordinarily they share power in a frequency droop control. When an overloading is detected, the BSUs come on line and share power with the DGs using the same frequency droop control. The detection of overloading condition and when overload has been removed are crucial for this operation. An algorithm is proposed for this purpose. Through simulation studies, it has been demonstrated that the BSUs can be switched on and off seamlessly.