Robust Damping Controller for Synchronous Generators under Operational Uncertainties

Abstract

Power system stabilizers have been widely used to create sufficient damping against low-frequency oscillations in power systems. Due to appearing uncertainties in operational conditions of power systems, robust design of power system stabilizers is a crucial requirement for small signal stability. In this paper, a robust local damping controller is developed considering the possible uncertainties in operational conditions. The developed damping controller is optimized based on the H-infinity method in presence of uncertainties in electrical variables of the synchronous machine. In the proposed robust damping controller, only the practically available control signals such as the deviation of the rotor speed of the synchronous generators are used. To fulfill the robust and internal stabilities of the damping controller under a given horizon of operational uncertainties, a novel design based on the combination of the developed robust damping controller and the conventional power system stabilizer is introduced. Simultaneous damping of local oscillatory modes and the internal stability of the proposed robust controller is achieved via a multi-objective function. The efficacy of the proposed local dampingcontroller is compared with the conventional power system stabilizer and a damping controller that is designed using the pole placement approach.