AN ADAPTIVE BACKSTEPPING CONTROLLER FOR LOW FREQUENCY OSCILLATIONS DAMPING IMPROVEMENT OF A MULTI-MACHINE POWER SYSTEM INCLUDING UPFCS

Abstract

In this paper the low frequency oscillations damping of a multi machine power system including UPFCs is investigated by applying the Adaptive Backstepping Control (ABC) approach. Using the third order model of synchronous machine, the nonlinear state equations of the system are derived first. Then, based on ABC the supplementary excitation control inputs as well as the system parameters estimation law are designed based on the Lyapunov stability theory. Moreover considering the sixth order model of synchronous machine, simulation results are obtained for some faults. Although UPFCs effects are taken into account in dynamic simulations, but they are designed only to regulate active power of their lines and voltage magnitudes of their buses. These results show the validity and effectiveness of the proposed control approach