An Efficient MILP Approximation for the Hydro-Thermal Unit Commitment

In a hydro-thermal unit commitment (H-TUC) problem, accurate modeling of the hydro unit power generation, which is a nonlinear function of the net head and the total power release, is crucial but difficult due to its nonlinearity and non-concavity. This letter proposes an efficient mixed integer linear program (MILP) approximation method for the H-TUC problem based on the variable separation and piecewise linear (PWL) technique. Tests on different systems demonstrate the proposed method can provide high quality solutions more efficiently.