Mixed integer programming based method for short-term scheduling of hydroelectric plants

The scheduling problem for short-term hydroelectric plants is studied. The nonlinear hydroelectric production functions, minimum-down/up time of hydro units, time delay between reservoirs and capacity limits of reservoirs and rivers are all considered in the model and a mixed integer programming is then formulated. Constraints on minimum-down/up time are added to prevent the units from being started-up/shut-down frequently. The nonlinear hydroelectric production functions are replaced by piecewise linear approximations and auxiliary integer variables are introduced such that the problem is re-formulated as a mixed integer linear programming. CPLEX package is adopted to solve the problem. Numerical testing results for a system with 3 reservoirs and 12 hydro units show that the model and the piecewise linear approximation techniques work well with the complex formulation of short-term hydroelectric plants scheduling.