minimization of shaft oscillations by fuzzy controlled smes considering time delay

this paper analyzes the effect of fuzzy logic-controlled superconductive magnetic energy storage (smes) on minimizing shaft torsional oscillations of synchronous generators in a multi-machine power system. the proposed fuzzy logic controller has been designed in a very simple way considering only one input variable and one output variable. the time derivative of the total kinetic energy deviation (tked) of the synchronous generators is used as the global input to the fuzzy controller for smes switching. the influence of time delay associated with the global input calculation of the fuzzy controller on minimizing shaft torsional oscillations is investigated. global positioning system (gps) is proposed for the practical implementation of the calculation of the global input to the fuzzy controller. simulation results of a balanced fault at different points in a multi-machine power system show that the proposed smes can minimize the shaft torsional oscillations of synchronous generators well. moreover, the time delay has an influence on the performance of fuzzy controlled smes to minimize shaft torsional oscillations. however, even though the performance of fuzzy controlled smes is somewhat effected by the communication delay, it is clear from the simulation responses that the fuzzy logic-controlled smes considering typical communication delays can minimize the shaft torsional oscillations of synchronous generators well.