A suboptimal control law to improve the transient stability of power systems

The application of optimal control theory to damp the electromechanical oscillations associated with the transient conditions in power systems has been given little attention. A suboptimal control law which minimizes the sum of the performance indices of the two linear systems given by a piece-wise linear model of a power system improves the transient stability better than the usual "optimal" control law obtained from a linearized model. Further, the suboptimal control law presented in this paper assures stability of the system for all disturbances resulting in rotor oscillations of magnitudes less than a preselected limit.