Fuzzy logic based power system stabilizer

Power system stabilizers must be capable of providing appropriate stabilization signals over a broad range of operating conditions and disturbances. Traditional PSS rely on robust linear design methods. In an attempt to cover a wide range of operating conditions, expert or rule based controllers have also been proposed. Recently, fuzzy logic as a novel robust control design method has shown promising results. In this thesis, a systematic approach to fuzzy logic control design is proposed. This paper presents a study of a fuzzy logic power system stabilizer for stability enhancement of a two-area four machine system. In order to accomplish the stability enhancement, speed deviation (Δω) and active power deviation (ΔP) of the rotor synchronous generator were taken as the inputs to the fuzzy logic controller. These variables have significant effects on damping the generator shaft mechanical oscillations. The stabilizing signals were computed using a fuzzy membership function depending on these variables. The performance of the system with fuzzy logic PSS is compared with the conventional PSS and the system without PSS.