Design of SSMFs fuzzy logic based power system stabiliser using genetic algorithms

This paper presents an efficient and simple fuzzy logic power system stabiliser for damping electromechanical modes of oscillations and enhancing power system synchronous stability. The essential feature of the proposed fuzzy controller is that the shrinking span membership functions (SSSMFs) is used for membership functions. The SSMFs is a new means of designating membership functions of a fuzzy logic controller (FLC). A genetic algorithm is used to select optimum values for SSMFs FLC parameters namely shrinking, overlapping and gain factors. A single machine connected to an infinite bus system through a transmission line is considered to demonstrate the suggested technique. The parameters of a SSMFs FLC, which simultaneously stabilises the set of plant operating conditions is determined off-line using a genetic algorithm and an objective function based on integral absolute and steady state errors in Δw. The results validate the effectiveness of the proposed SSMFs fuzzy logic based power system stabiliser in terms of less overshoot/undershoot and enhancing the power system stability over a wide range variation of generator loading conditions and a variety of exciter gain