An Approach for Damping Low-Frequency Oscillations by

Abstract

Dynamic stability problems due to low frequency oscillations in power systems are a major concern for electrical engineers. These low frequency oscillations occur in the system because of the change in operating conditions due to the variation in load demand, generation level and line switching. Low-frequency oscillations are detrimental to the goals of maximum power transfer and optimal power system security. A contemporary solution to this problem is the addition of power system stabilizers (PSSs) to the automatic voltage regulators (AVRs) on the generators excitation system. The damping provided by this additional stabilizer provides the means to enhance the damping during low frequency oscillations. reduce the inhibiting effects of the oscillations. This paper presents a new technique utilizing fuzzy logic controller (FLC) power system stabilizer (PSS) for stability enhancement of a single machine real power system of Egypt. In order to accomplish the stability enhancement, speed deviation and acceleration of the rotor of synchronous generator were taken as the input to the fuzzy logic controller. These variables take significant effects on damping of the generator shaft mechanical oscillations. The stabilizing signals were computed using the fuzzy membership functions depending on these variables. The performance of the fuzzy PSS is compared with the conventional power system stabilizer (CPSS). The simulations were tested under different operating conditions. The simula