Comparing Different Strategies of Decomposition to Solve the Short-Term Hydrothermal Scheduling Based on Lagrangian Relaxation

Fabrício Yutaka K. Takigawa; Erlon Cristian Finardi; Edson Luiz da Silva
The Short-Term Hydrothermal Scheduling – STHS problem is addressed in this paper. In this problem, hydro and thermal plants must be coordinated in order to supply the demand at a minimum cost and comply with a set of constraints, concerning the system and the plants themselves, in the short-term planning horizon (from one day to one week). Given the nonlinearities associated with the problem, the large number of decision variables and constraints coupled in time periods, the STHS problem results in a complex mathematical programming problem. The Lagrangian Relaxation – LR method is the most widespread procedure for solving this problem. This work presents two strategies to solve STHS, which are based on different decomposition schemes of the primal problem. These strategies make it possible to define, for large-scale problems, the most appropriate decomposition scheme, which is particularly important for power systems with high proportion of hydraulic generation. The studies were accomplished using a reduced system composed of five reservoirs, 22 hydro and two thermal units of the Brazilian Hydrothermal Power System.
Hydrothermal Systems; Short-Term Scheduling; Lagrangian Relaxation
Download | Back to Issue| Archive