We extract a mathematical model to simulate the steady-state charging and discharging behaviors of an electrochemical storage over a 24-hour time interval. Moreover, we develop a model for optimizing the daily operational planning of an interconnected micro grid considering electrochemical storage. The optimization model is formulated to maximize the total benefit of the micro grid via selling power to its end consumers and also exchanging power with the wholesale energy market so that the constraints of distributed energy resources (DERs) and low-voltage grid are met. The optimization problem is solved by a genetic algorithm, and applied on two micro grids operating under different scenarios containing the absence or presence of electrochemical storages. Comparison of the results of the optimization model for this micro grid, with and without electrochemical storage, shows that the electrochemical storage can improve the economical efficiency of the interconnected micro grids by up to 10.16%.

关键词： Electrochemical storage,  Micro grid,  Operational planning,  Distributed energy resources