An Energy Trading Framework for Interconnected AC-DC Hybrid Smart Microgrids

Abstract

This paper proposes a three-stage energy trading framework (ETF) for interconnected AC-DC hybrid microgrids (IHMGs) in the presence of renewable distributed generators (DGs) and battery energy storage systems (BESSs). The proposed ETF aims at minimizing the operating cost of each microgrid (MG), and it includes three stages: a pre-trading stage, a trading stage, and a post-trading stage. The ETF determines the optimal hourly trading prices and powers while preserving the privacy of information for each MG. The proposed framework allows each MG to schedule its operation economically and reliably through optimizing its local resources (i.e., DGs and BESSs) as well as exchanging power with neighboring MGs and the main grid. The proposed ETF takes into account the internal topology and power flow constraints for different types of MGs (i.e., AC, DC, and AC-DC hybrid MGs). The proposed three-stage ETF is tested using a case study that includes different types of MGs with different types of loads and DGs. The effectiveness of the proposed ETF is verified through a comparison with the base-case system for both grid-connected and isolated modes of operation.