Unit-commitment via logarithmic aggregated convex combination in multi-unit hydro plants

• Published in: Electric power systems research Vol. 189; p. 106784
• Main Authors: Brito, Brunno H., Finardi, Erlon C., Takigawa, Fabrício Y.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2020; Elsevier Science Ltd
• Subjects: Convex analysis; Electric power plants; Hydro production function; Hydro unit commitment; Hydroelectric plants; Integer programming; Linear programming; Logarithmic aggregated convex combination; Mixed integer; Mixed-Integer Linear Programming; Two-step strategy; Unit commitment; Logarithmic aggregated convex combination; Two-step strategy; Hydro production function; Mixed-Integer Linear Programming; Hydro unit commitment
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2020.106784

•A strategy is developed for the unit commitment problem in multi-unit hydro plants.•The strategy based on mixed integer linear programming is divided into two steps.•The production function is linearized via logarithmic aggregated convex combination. We present a new strategy to solve the hydro unit commitment (HUC) in plants with many generating units (GUs), where the nonlinear Hydro Production Function (HPF) is linearized via Logarithmic Aggregated Convex Combination (LACC). Although the LACC is an efficient technique, the solution procedure via Mixed-Integer Linear Programming (MILP) solver in plants with several GUs is still a challenging task. Thus, this paper proposes a solution strategy that is divided into two steps. In the first step, the identical GUs are aggregated into an equivalent one, and the resulting MILP is resolved for obtaining the starting values of the gross head (GH). In the second step, the GH is used to determine the optimal dispatch considering the individualized HPF for each UG. The performance of the proposed strategy is analyzed in a Brazilian hydro plant composed of 50 GUs of two different types.