Comparison of efficient procedures for hydropower unit commitment

Abstract

This paper explores three new competitive heuristic procedures, which are compared with the mixed integer linear programming (MILP), all used to commit units within a hydroplant to give the maximal electrical production during a study horizon, given the cascade operation has already determined the quarter-hourly releases from individual reservoirs. The problem incorporates constraints on the unit up/down hours and its shutdown times. The procedures are applied to seven hydroplants, with 2, 3, 4, 5, 6, 9 and 18 units installed respectively. The application suggests that the MILP performs the best in minimizing spillages and improving generating efficiency but volatile in computation time when the number of units is more than 4 in a hydroplant, while the heuristic procedures can obtain fairly good results and have a significant advantage in computation time when committing more than 6 units in a hydroplant. The heuristic procedures are valuable when incorporating unit commitment into a large-scale operational problem of cascaded hydropower reservoirs.

Keywords

• Large-scale hydropower reservoir system
• Hydropower unit commitment
• Mixed integer linear programming
• Heuristic procedures
• Computational burden
• Spillage reduction