Nonlinear excitation and phase shifter controller for transient stability enhancement of power systems using adaptive control law

The highly nonlinear nature of the generator and system behaviour following a severe disturbance precludes the use of classical linear control techniques. In this paper, a nonlinear adaptive excitation and static phase shifter controller is proposed to enhance the transient stability of a power system. The phase shifter is located near the generator terminal in a power system. A third-order generator model is used, which is in the standard form of the nonlinear system representation. The phase shifter is represented by a first-order model. Nonlinear feedback control laws are found which linearize and decouple the power system. An adaptive control law is used to design the controller for the excitation and phase shifter. The design of the resulting controller is independent of the operating point. Our simulation results demonstrate that the proposed controller can ensure transient stability of the power system under a large sudden fault which may occur at the generator bus terminal. (C) 1996 Elsevier Science Ltd.