DAMPING POWER SYSTEMS OSCILLATIONS USING FACTS COMBINATIONS

摘要

The damping of electromechanical modes of oscillation in power systems, can be made by static VAR compensator, SVC, and / or Power system stabilizer, PSS. This paper presents a combinations of using static VAR compensator, SVC, controlled by a nonlinear dynamic controller based adaptive neural network with power system stabilizer, controlled by variable structure fuzzy logic control. The proposed system is used for both damping low frequency modes of oscillation of the power systems, and enhancing the system dynamic performance at post-fualt conditions. The proposed variable structure fuzzy logic controller implement the speed deviation, it's rate of change, internal machine angle deviation, and it's rate of change signals. The nonlinear dynamic controller based adaptive neural network implement the speed deviation signal. The proposed scheme is validated using sample single machine connected to infinite bus power system through a double transmission line circuit. The studied system is modeled and represented by a nonlinear differential equations,. The matlab softwar is used for solving the system equations. The time simulation indicates the superiority of using both SVC, and PSS over using any of them alone in the studied power system. The results shows that using the FACTS combinations provide very fast damping, with less overshoot, and reduce the amount of reactive compensation required for the static VAR compensator, and reduce the exciter gain.