Grid-connected microgrid participation in frequency-regulation markets via hierarchical coordination

The large integration of renewable energy into the power grid requires frequency regulation and ancillary services support. Grid-connected microgrids, which naturally include a portfolio of distributed energy resources and flexible loads, are a promising tool that can provide this utility by adapting their tie-line power to track frequency regulation signals. In this paper, we propose a framework by which grid-connected microgrids can participate in a frequency-regulation market and respond to a frequency-regulation request by leveraging their distributed energy resources and loads. The proposed framework is hierarchical, with a central and lower layers focusing on a microgrid. The central layer solves an energy dispatch problem that aims to match the tie-line power to the reference signal from the Regional Transmission Organization (RTO). The lower layer post-adjusts the optimum of the central layer through distributed optimization with consideration of the power flow constraints and uncertain loads in the microgrid. The framework combines recent progress on distributed algorithms, optimal power flow solvers, and regulation market in a novel way. Simulations demonstrate the effectiveness of the proposed framework.