Centralized Generation Control of Real Power for Thermal Units by a Parametric Linear Programming Procedure

Abstract The problem of the centralized control of the active power is here considered as being subdivided into three levels with a hierarchy versus time: the scheduled hourly dispatching running the day before, the advance dispatching (AD), operating on the basis of the short-term load forecasting, the instantaneous economic dispatching (ED) integrated with the load frequency control (L.F.C.). This paper emphasizes AD and in particular the algorithm for its solution. AD modifies the trajectories of the thermal units scheduled the day before, taking into account the on-line load predictions and the constraints on the maximum allowable rate of the output changes of thermal generating units as well as the security of the network. Furthermore, the procedure is able to supply the trajectories which restore the security, should the system go into a non-secure or vulnerable status. Outputs of AD are also suitable participation factors to be used by ED. The linearization of both the objective function and the constraints allows the utilization of a parametric linear programming algorithm for determining at each instant the optimal operating point for the system. The system is supposed to evolve into an infinite number of steady state conditions. The procedure proposed for the AD results in a very fast solution of the problem and is, therefore, able to operate in a real time environment in large systems as well.