Optimal and Robust Power System Stabilizers in a Multi Machine System

One method for eliminating oscillations in power systems is using stabilizers. By applying an appropriate control signal in the excitation system of a generator, a power system stabilizer improves the dynamic stability of power systems. However, the issue that is of high importance is the correct design of these stabilizers. These stabilizers must be designed to have proper performance when operating conditions change. When designed incorrectly, not only they do not improve the stability margin, but also increase the oscillations. In this paper, the robust design of power system stabilizers on a four-machine power system has been performed. For this purpose, the differential evolution algorithm has been used. The studies have been repeated as three scenarios by producing different loading conditions for the generators. The performances of the conventional stabilizer and the optimized one have been compared. Simulation results indicate that the designed robust stabilizer outperforms other stabilizers in different conditions and has damped the interarea and intra-area oscillation modes in the shortest time with minimum amplitude.