Dynamic Optimal Unit Commitment and Loading in Hydropower Systems

Abstract

The hydropower unit commitment and loading problem represents a complex decision-making process involving the integrated hourly scheduling of generators in a multiproject hydropower system. Optimal scheduling maximizes basinwide operating efficiency while satisfying power load demands, water demands, reliability constraints, operational restrictions, and security requirements. Often considered as a sequentially static optimization over each operational period, the problem actually embodies a highly dynamic structure when considering realistic operational restrictions on unit commitment and loading. A dynamic programming (DP) optimization model maximizes basinwide operating efficiency subject to (1) plant constraints on total generation requirements, generation shape requirements, and spinning reserve; and (2) operational restrictions on rough zone avoidance, minimum up and down time requirements, and unit outage modes. Application of the DP model to the hydropower system of the Lower Colorado River Basin demonstrates its capabilities for real-time optimal unit scheduling in satisfying complex operational constraints while improving basinwide generation efficiency.