A Two-stage Optimization Method for Economic Operation of the Micro-grid

In this paper, a two-stage optimization method is presented to achieve the goal of economic operation of the Micro-grid. The first stage minimizes the user cost on the basis of load scheduling, taking user's satisfaction into consideration and the model is solved by Particle Swarm Optimization (PSO) algorithm. The second level is aimed at optimizing output of units including a wind turbine, a photovoltaic, a battery storage system and a micro-turbine in micro-grid. The economic operational cost is considered in micro-grid model, which is solved by mixed integer linear programming method. In the test case, operational costs in two scenarios including load characteristic and without load characteristic are separately analyzed, and the output of units are compared. The results show that based on the proposed two-stage optimization method, the operation cost of micro-grid will be reduced obviously.