Transient stability enhancement of multimachine power systems using nonlinear observer-based excitation controller

This paper presents an approach to design a nonlinear observer-based excitation controller for multi machine power systems to enhance the transient stability. The controller is designed based on the partial
feedback linearization of a nonlinear power system model which transforms the model into a reduced order linear one with an autonomous dynamical part. Then a linear state feedback stabilizing controller is designed for the reduced-order linear power system model using optimal control theory which enhances the stability of the entire system. The states of the feedback stabilizing controller are obtained
from the nonlinear observer and the performance of this observer-based controller is independent of the operating points of power systems. The performance of the proposed observer-based controller is compared
to that of an exact feedback linearizing observer-based controller and a partial feedback linearizing controller without observer under different operating conditions.