Decentralized Servomechanism Control Design for Inter-Area Oscillations Damping in Power System

Inter-area oscillations are one of the main concerns in power system small signal stability. Since they involve a wide area in power systems, identifying the causes and damping the oscillations are considerably challenging. Undamped inter-area oscillations cause severe problems in power grids including large-scale blackouts. Designing a proper controller to damp inter-area oscillations in power systems is challenging due to the complexity of the system. Moreover, for a large-scale system it is difficult to collect all system information in one location as required for the design of a centralized controller. In this paper, we develop a new decentralized strategy to identify and damp oscillations in a large-scale power system. We consider a large-scale power system consisting of three areas in a loop shape configuration. After decomposing the system into three subsystems, each subsystem is modeled with a lower order system. Finally, a decentralized robust servomechanism controller is designed for each subsystem to maintain the large-scale system frequency at the desired level even in the presence of disturbances.