Investigating the Impact of Interconnection Line Power Losses on Unit Commitment of Grid-Connected Microgrids

Microgrids are instrumental in the transition towards distributed energy systems, classified as independent or grid-connected based on the presence of interconnectivity with the main grid. In this paper, we focused on researching grid-connected microgrid systems capable of adjusting to fluctuations in power supply balance. During interconnection with the main grid, power flow occurs through interconnection lines, leading to inevitable power losses along these lines. Hence, we propose an optimal unit commitment methodology for grid-connected microgrids, designed based on mixed-integer linear programming, which considers the power losses in the interconnection lines. The power losses were modeled as a quadratic function and categorized into various cases using piecewise linear approximation. By simulating this proposed model in the IEEE 40-bus microgrid system incorporating distributed energy resources and energy storage systems, we validated the feasibility of considering the power losses in the interconnection lines as outlined in this research. © The Korean Institute of Electrical Engineers.