A single machine infinite bus power system damping control design with extended state observer

Abstract

As an alternative to power system stabilizer, this paper presents a robust controller known as extended state observer (ESO) for synchronous machine connected to an infinite bus (SMIB) power system. The ESO-based control scheme is implemented with an automatic voltage regulator in order to enhance the damping of low frequency power system oscillations so that the deviations in terminal voltage are compensated. The proposed ESO provides the estimates of system state as well as disturbance state together in order to improve the damping as well as compensate system efficiently in presence of parameter uncertainties and external disturbances. The closed-loop poles (CLPs) of the system have been assigned by the symmetrical root locus technique, with the desired level of system damping provided by the dominant CLPs. The performance of the system is analysed through simulating at different operating conditions. The control method is not only capable of providing zero estimation error in steady-state, but also shows robustness in tracking the reference command under parametric variations and external disturbances. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.