Low frequency oscillations damping by STATCOM with a fuzzy supplementary controller

This paper presents a study of the application of a STATCOM to enhance the damping of an inter-area oscillation exhibited by a two-area four-machine interconnected power system. The adaptive fuzzy controller, of which the parameters are tuned by Orthogonal Least Squares (OLS) training algorithm, is incorporated into the supplementary control of STATCOM. Comparing to gradient descent algorithm, which may get trapped at a local minimum of the chosen optimization criterion during the learning procedure, the use of OLS algorithm give a faster and more robust parameter estimation. The inter-area oscillation damping is improved more by the STATCOM. The simulation results show that the designed fuzzy controller is efficient in damping power oscillations, and has better performance than the linear counterpart when operating condition changes.