Environmental short term hydrothermal coordination problem: a bundle stabilized approach

Abstract

Short Term Hydrothermal Coordination Problem resolution involves solving both the Unit Commitment and the Economic Dispatch problem for thermal and hydraulic units. Considering an AC detailed model of the transmission network, post-dispatch corrections avoidance is achieved. These facts lead to a very complex optimization problem which is quite time consuming and not suitable to solve using classical techniques. Also, the current concerns regarding environmental issues suggested the introduction of environmental constraints to the model. This is made in a way that does not affect the solvability of the problem for the proposed methodology. Generalized Benders Decomposition allows decomposing the problem into a quadratic mixed integer master problem and a non-linear subproblem. The former defines the state and the active power dispatched by each unit, whereas the latter determines the reactive power to meet the electrical constraints through a modified AC optimal power flow. The algorithm behavior is stabilized following Bundle techniques. The algorithm is applied to the IEEE 24-bus test case and to a 87-bus real system.