Microgrid Interconnection Decision Making Method Based on Economic Index Considering Supply Reliability

This paper discusses the mechanism of power trading based on the incremental reliability and incremental economy when a renewable energy-based standalone microgrid designed to have a certain level of supply reliability operates in coordination with other microgrids and the main grid. It examines the reliability and economy of the new power grid formed during coordination and demonstrates that the reliability and economy of micro-grids based on solar and wind power vary in load supply reliability due to the uncontrollability and intermittency/variability of output. Additionally, it shows that these factors can be altered by the introduction of energy storage systems and backup power supplies, allowing for reliability-economy trades that consider their differences during integrated operation of microgrids. Suggested method is applied and verified to PV and Wind microgrid interconnection and Jeju island, and showed the benfits and losses of interconnection. Also, the effects of source variability on LCOE at different demand style are discussed and suggested. © The Korean Institute of Electrical Engineers.