A strategy for day-ahead prediction of residual capacity of energy storage unit of micro grid in islanded state

Research on energy management strategy is particularly important in the microgrid operation, especially in the isolated island operation state caused by external power grid fault or power quality unsatisfied with the requirements. Due to the uncertain of wind power and photovoltaic power output and deviation in load forecasting, it will make the energy storage unit of microgrid in islanded state frequently charge and discharge, which reduce power supply reliability of the microgrid and service life of energy storage unit, cause unnecessary energy loss and other problems. Through the analysis of two kinds of control mode of islanding operation of micro grid, this paper proposes a strategy for day-ahead forecasting of residual capacity of energy storage unit of microgrid in islanded state, using day-ahead prediction results of wind power and photovoltaic power. Then by calculating and analysis, we can obtain output instruction curve of the next day energy storage unit and optimize control scheme of energy management system of the storage energy unit, reduce the charge and discharge times and increases service life of the energy storage unit, so that to achieving the optimal configuration of a microgrid energy. Finally, this paper acquire the typical daily day-ahead forecasting of residual capacity curve of the microgrid in islanded operation by example analysis.