Nonlinear back-stepping controller design for the enhancement of transient stability in power systems

In this paper, we propose a nonlinear back-stepping controller (NBC) to damp the generator oscillations and improve the transient stability in multi-machine power systems. An observer is designed to estimate the inaccessible states, which is different from previous back-stepping designs with complete states of the whole system. Moreover, in order to counteract the destabilizing effect of the observer errors, observation errors are treated as disturbances and accounted for using nonlinear damping term. Different from other back-stepping controller design in power system before, the proposed controller is designed on a reduced forth order nonlinear model of a synchronous generator with which the voltage error of steady state is decreased. The stability of the system is verified by Lyapunov methods. The 3-machine power system is applied to demonstrate the effectiveness of the proposed controller over tuned power system stabilizers.