Security-constrained unit commitment considering voltage stability: A parallel solution

Security-constrained unit commitment (SCUC) is being executed every day to find the optimal hourly schedule over the next horizon of the time. In order to have a reliable and secure operation condition, it is desirable to include the AC networks constraints and the system's stability indices into the day-ahead generating scheduling problem of power systems. However, including such a non-convex set of constraints in the problem formulation, the complexity and size of the SCUC problem would increase; thus, the convexity of the mathematics model and the computational burden of the SCUC problem increases significantly. To avoid this issue, in this paper, we present a decentralized solution methodology where the voltage stability constrained SCUC (VSC-SCUC) problem is divided into multiple smaller subproblems; then, using the auxiliary problem principle (APP), the operating points of the subproblems are coordinated with each other iteratively in a parallel manner. In order to justify the effectiveness of the proposed method, several case studies are presented and discussed.