Multi-time scale coordinated optimal dispatch of microgrid based on model predictive control

Multi-time scale optimal dispatch of microgrid is an effective way to integrate intermittent distributed energy into the bulk system. In light of the problems that the conventional multi-time scale optimization scheme based on power flow is easy to appear not timely unit response, large tracking errors and so on, a multi-time scale coordinated dispatch method based on model predictive control (MPC) is proposed. During the day-ahead scheduling, an optimal economic dispatch model with the aim of minimum operation cost is developed, which takes into account peak-valley difference of electricity price, energy storage life, and the randomness of renewable energy sources (RESs). During the intra-day scheduling, an MPC-based rolling optimization correction strategy is proposed to depress power fluctuations caused by RES forecast errors at tie-line and ensure the daily energy balance of the energy storage. By using the rolling optimization scheduling of limited time window instead of the conventional single section optimization scheduling, the future changes of the renewable energy output and the tie-line plan can be perceived ahead of time so as to adjust the unit generation in advance. At the same time, by combining receding horizon and feedback correction of the real-time state of the system, the influence of uncertainty factors in the microgrid can be eliminate greatly to ensure the rationality of the day-ahead plan and the stability of the system. Finally, a microgrid demonstration project is taken as case study and simulation results verify the effectiveness of the model and algorithm proposed. © 2016 Automation of Electric Power Systems Press.