A Tight Unit Aggregation for Unit Commitment to Eliminate Symmetry

Unit commitment (UC) is typically formulated as a mixed-integer linear programming problem, which is addressed by the classic branch-and-bound and branch-and-cut algorithms. However, the symmetry in UC problems brings many invalid searches, leading to significant computational burdens. To eliminate the symmetry, this paper proposes a unit aggregation model with tight constraints on the maximum aggregated power output trajectory, effectively reducing computational time while preserving optimality. Numerical experiments are conducted to demonstrate the computational efficiency and validate the effectiveness of the proposed method.