A Novel Modal Decomposition Control and Its Application to PSS Design for Damping Interarea Oscillations in Power Systems

The residue method has been widely used for tuning power system stabilizers (PSSs) in large power systems to improve the damping of interarea oscillations. However, an additional PSS installation may affect the performance of existing PSSs due to interactions among different modes. When contending with several interarea oscillations, compromise among different modes becomes necessary. In this paper, a novel method based on modal decomposition is proposed for tuning PSSs for damping of the concerned interarea mode, while minimizing its effect on other modes by weakening the interactions among different modes. Design considerations, PSS structure and tuning procedure are formulated. The performance of the proposed method has been validated based on a two-area four-machine system and an actual large power system, China Southern Grid.