Closed-Loop Hierarchical Operation for Optimal Unit Commitment and Dispatch in Microgrids: A Hybrid System Approach

TL;DR

This paper introduces a hybrid system approach with a closed-loop hierarchical algorithm for optimal unit commitment and dispatch in microgrids, considering demand response and carbon trading, validated through simulations.

Contribution

It reformulates the UCD problem as a hybrid system switching problem and develops a CLHO algorithm for optimal scheduling in microgrids.

Findings

The CLHO algorithm produces optimal schedules effectively.

Demand response and carbon trading influence emission reductions.

Simulation confirms the algorithm's efficiency and environmental benefits.

Abstract

To contribute to a smart grid, the unit commitment and dispatch (UCD) is a very important problem to be revisited in the future microgrid environment. In this paper, the UCD problem is studied by taking account of both traditional thermal units and distributed generation units (DGs) while considering demand response (DR) and carbon emissions trading (CET). Then, the UCD problem is reformulated as the optimal switching problem of a hybrid system. The reformulation allows convenient handling of time-dependent start-up cost for dynamic programming (DP). Afterwards, a closed-loop hierarchical operation (CLHO) algorithm is developed which is capable of producing the optimal schedule in the closed-loop behavior. Theoretical analysis is also presented to show the equivalence of the reformulation and the effectiveness of the CLHO algorithm. Finally, the closed-loop behavior and the effectiveness of the algorithm are further verified by simulation studies. It is also shown that low emission quotas and high emission trading price help reduce the total carbon emissions.