Commitment of Combined Cycle Plants Using a Dual Optimization–Dynamic Programming Approach

Due to the existence and building of an important number of combined cycle plants throughout electric power systems around the world, there exists the growing need to have a more accurate and practical model to represent these type of power plants when solving the unit commitment problem. A commonly used optimization technique implemented to solve the unit commitment problem is dual programming. This work focuses on solving the subproblem of scheduling a combined cycle plant using dynamic programming under a dual optimization framework. The model used to represent the combined cycle plants is component based; this new way of modeling combined cycle plants takes into account such constraints as the feasible transitions between configurations, and the minimum and maximum time that a combined cycle plant must remain on a certain configuration. The advantage of the model presented in this paper is that it accurately models all the physical constraints of combined cycle plants. Also, this paper presents the modeling of hybrid combined cycle plants; these are the ones that use an auxiliary boiler in order to increase the production of steam used by the steam turbine.