The Application of Dynamic Programming in the Stand-Alone Micro-Grid Optimal Operation

In a stand-alone micro-grid, due to the difference between peak and valley of the load curve and the intermittence of distributed generations´ outputs, there are large fluctuations of the active power difference in a day, which are not beneficial to stable and economic operation of the back-up powers. By installing energy storage (ES) devices appropriately and using effective charge and discharge strategies, it can make back-up power´s output stable, which can maintain the micro-grid frequency within the specified range. For this objective, this paper establishes a mathematical model to minimize the active power difference of the stand-alone micro-grid. In the model, it fully takes account of ES´s the state of charge (SOC), charge-discharge efficiency and loop control. The model is solved by dynamic programming algorithm and simulated by a case, which verifies the validity of the model and the applicability of dynamic programming algorithm.