Robust Power system stabilizer design for single machine infinite bus system with different membership functions for fuzzy logic controller

This paper presents an evaluation of membership functions on a single machine infinite bus (SMIB) system with Power system stabilizers (PSSs). The PSS is added to excitation system to enhance the damping during low frequency oscillations. In this paper the system is analyzed for conventional PSS, fuzzy PSS and without PSS. This paper presents a study of fuzzy logic power system stabilizer (FPSS) for stability enhancement of a single machine infinite bus system. The speed deviation (Δω) and acceleration (Δϖ) of the rotor of synchronous generator are taken as the input to the fuzzy logic controller to improve small signal stability by improving damping. The effect of these variables on damping at the generator shaft mechanical oscillations is very significant. The stabilizing signals were computed using the different fuzzy membership functions. The general membership functions under consideration are triangular, trapezoidal, Gaussian, bell, sigmoidal and polynomial types. The performance of the fuzzy logic PSS with different membership functions is compared with the system Response without PSS and with Conventional PSS (CPSS). The simulation results obtained from the different plants over a wide range of operating conditions indicate the improved performance of FPSS over the CPSS by considering the triangular and Gaussian type of membership functions in the design of fuzzy logic controller.