Thermal Unit Commitment Including Optimal AC Power Flow Constraints

We propose a new algorithm for unit commitment that employs a Lagrange relaxation technique with a new augmentation of the Lagrangian. The new augmentation involves a duplication of variables that allows relaxation of the coupling between generator timespanning constraints and system-wide instantaneous constraints. This framework allows the possibility of committing units that are required for the VArs that they can produce, as well as for their real power. Furthermore, although the algorithm is very CPUintensive, the separation structure of the Lagrangian allows its implementation in parallel computers. Our work builds upon that of Batut & Renaud, as well as that of Baldick.