Optimal Dispatch of Microgrids in Islanded and Grid-Connected Modes: A Mixed-Integer Linear Programming Approach for Cost Minimization and Renewable Energy Integration

The depletion of traditional fossil fuel energy and the increasingly apparent environmental pollution issues have made the development of clean and environmentally friendly new energy sources the optimal solution to address these severe problems. The proposal and application of the microgrid concept provide a new option for integrating various renewable energy sources. Microgrids can not only improve the utilization rate of renewable energy but also enhance the reliability of renewable energy power supply, reduce the use of traditional fossil fuels, and lower pollutant emissions. However, highly uncertain categories such as wind and solar power constitute the main part of renewable energy generation, and the load side also has certain uncertainties. Therefore, optimizing the operational logic of microgrids to ensure their safe, stable, economical, and efficient operation has become a significant issue. This paper studies the optimal dispatch of microgrids under both islanded and grid-connected scenarios. The research approach is as follows: 1. Analyze the operational characteristics of photovoltaic units, energy storage modules, and loads in microgrids, and establish corresponding mathematical models. The interaction between the microgrid and the main grid for electricity sales and purchases is also introduced. 2. Establish the constraints for the microgrid. 3. Set the minimum cost as the optimization objective for microgrid operation and establish the objective function. 4. Solve the model using mixed-integer linear programming.