A novel straightforward unit commitment method for large-scale power systems

In this paper, a novel fast straightforward method for thermal generating units scheduling is presented. The new method decomposes the solution of the unit commitment (UC) problem into three subproblems. In the first subproblem, the quadratic cost functions of units are linearized and hourly optimum solution of UC is obtained considering all constraints except the minimum up/down time constraints. In the second subproblem, the minimum up/down times are enforced through a novel optimization process by modifying the schedule obtained in the first step. Finally, in the third subproblem, the extra reserve is minimized using a new decommitment algorithm. For testing the proposed method, the conventional ten-unit test system and its multiples with 24-h scheduling horizon have been solved. Comparison of results with those of other methods justifies the effectiveness of the proposed method with regards to minimizing both the total operation cost and execution time. Also, the IEEE 118-bus system with 54 units and a practical large-scale system including 358 units have been analyzed to exhibit the superiority of the proposed approach.