Short-Term Hydrothermal Power System Unit Commitment: A Comparative Study

To supply the required load, most electric power systems contain a combination of hydro and thermal power plants. The aim of this work is to study the optimal short-term operation of this combination, where the objective function is to minimize the thermal fuel cost and at the same time satisfy the hydro and thermal constraints, such as power balance at every hour, available water resources, reservoir volumes, and generation outputs limits. Two different techniques are used to solve the problem, namely dynamic programming and coordination equations. The mathematical algorithms for the solution of the problem were developed and the results of some computer studies on selected sample systems were obtained. The results show that using coordination equations method leads to lower total cumulative cost than using the dynamic programming method; however, many of the realistic system constraints cannot be properly handled by the coordination equations method.