Quadratic cost function design for linear optimal control systems

A systematic method for choosing a quadratic cost function for linear optimal control systems is presented. The method is based on the identification of the most controllable and observable modes of the system. The method is used for the design of an optimal proportional-plus-integral controller for a large-scale electric power system comprising 12 machines, transmission lines and load centers. It is shown that the controller obtained by the proposed method significantly improves the dynamic performance of the power system.<<ETX>>