Linear Quadratic Regulator Applied to the Load-Frequency Control Problem Considering Reheat Steam Turbine Generators

Frequency stability plays an important role in the electric power systems researches, and it is associated with the ability of the system to regulate and maintain constant the electric frequency of the network. Traditionally, classical control techniques are applied to perform frequency regulation, but although they present good results, it is probable that modern control techniques achieve better ones. In this sense, the aim of this paper is to design a modern controller to the frequency regulation problem, based on the the concepts of optimal control theory. It is considered that the generating units of the system are mainly constituted of reheat steam turbines, and some assumptions are made in their dynamics to simplify the system modeling. The proposed controller is tested via computational experiments in scenarios in which the turbine model adopted for the control design is mismatched with the turbine model used in the actual system. The results are compared to that obtained by the classical controller.