Hydro unit commitment and loading problem for day-ahead operation planning problem

We describe a new model for the hydro unit commitment and loading (HUCL) problem that has been developed to be used as a support tool for day-ahead operation in the Brazilian system. The objective is to determine the optimal unit commitment and generation schedules for cascaded plants with multiple units and a head-dependent hydropower model. In this paper, we propose a new mathematical model for the hydropower function where the mechanical and electrical losses in the turbine-generator are included. We model the HUCL problem as a nonlinear mixed 0–1 programming problem and solve it with a strategy that includes a two-phase approach based on dual decomposition. The computational tool allows the model to effectively schedule hydro units for the problem in the Brazilian regulatory framework. Application of the approach is demonstrated by determining a 24-time step HUCL schedule for four cascaded plants with 4170 MW of installed capacity.

► A new hydropower function with mechanical and electrical losses explicitly included.
► An efficient solution strategy based on dual decompositions techniques.
► Solution Strategy Improvements based on alternative warm-start procedure.