A hybrid algorithm to tune power oscillation dampers for FACTS devices in power systems

Abstract The interaction between electrical and mechanical torques in the synchronous machines connected to bulk power transmission systems gives rise to electromechanical oscillations which, depending on the operating conditions and type of disturbance, may be poorly damped or even unstable. Recently, a combination of power system stabilizers (PSSs) and power electronic devices known as FACTS (flexible alternating current transmission systems) has been recognized as one of the most effective alternatives to deal with the problem. Tuning such a combination of controllers, however, is a challenging task even for a very skilled engineer, due to the large number of parameters to be adjusted under several operating conditions. This paper proposes a hybrid method, based on a combination of evolutionary computation (performing a global search) and optimization techniques (performing a local search) that is capable of adequately tuning these controllers, in a fast and reliable manner, with minimum intervention from the human designer. The results show that the proposed approach provides fast, reliable and robust tuning of PSSs and FACTS devices for a problem in which both local and inter-area modes are targeted.