A Novel Optimization Approach for Sub-Hourly Unit Commitment With Large Numbers of Units and Virtual Transactions

Unit Commitment (UC) is an important problem in power system operations. It traditionally planned for 24 hours with one-hour time intervals. To accommodate the increasing net-load variability, sub-hourly UC has been suggested improved flexibility. Such a larger and more complicated than hourly because of increased number periods reduced unit ramping capabilities per period. The computational burden further exacerbated systems large numbers virtual transactions leading to dense transmission constraint matrices. Consequently, state-of-the-art practice method, branch-and-cut (B&C), suffers from poor performance. In this paper, our recent Surrogate Absolute-Value Lagrangian Relaxation (SAVLR) enhanced by embedding ordinal-optimization concepts drastic reduction subproblem solving time. Rather formally subproblems using B&C, solutions satisfying SAVLR's convergence condition are obtained modifying previous iterations or crude subproblems. All included each reduce major changes across iterations. A parallel version also developed computation Testing on MISO's cases demonstrates that embedded approach obtains near-optimal efficiently, robust, provides new way other MILP problems.