Small signal stability improvement of large interconnected power systems using power system stabilizer

Abstract

Small signal stability analysis is an effective tool for analyzing system stability and performance. Disturbances of small magnitudes are very common and low frequency oscillation is a major problem in large scale interconnected systems. Power System Stabilizers are used to generate auxiliary control signals to the generator excitation input and have a great impact in damping out low-frequency oscillations of an interconnected power system network. In this paper, symbiotic organism search algorithm, a meta-heuristic approach based on the interactive behavior of the organisms, has been applied for the optimal design of Power System Stabilizers (PSS), to be incorporated into both single machine infinite bus system and multi-machine power system. PSSs parameters are tuned based on the objective function, involving eigenvalues and damping ratios of the lightly damped electromechanical modes for a wide range of operating conditions. The results of the proposed method have been compared with those obtained by genetic algorithm and particle swarm optimization methods, establishing the robustness of PSS under different operating conditions.