Development of a parallel PSS for inter-area mode power oscillation damping

This paper describes a PSS that can damp inter-area modes of a wide band more effectively than the available PSS such as (/spl Delta/P+/spl Delta//spl omega/)-PSS and which has been developed as part of an improvement of the thyristor excitation control system with relatively low cost. The feature of this PSS is that it includes the element operating in parallel with (/spl Delta/P+/spl Delta//spl omega/)-PSS with the ability to damp inter-area modes. This PSS is referred to as a parallel PSS. Large-scale simulation of the actual power system with 130 generators was performed. The parallel PSS was demonstrated to have about 2.5 times the inter-area mode damping capability of (/spl Delta/P+/spl Delta//spl omega/)-PSS and an almost equal local plant mode damping capability.