Damping inter-area oscillations by FACTS devices

Poorly damped inter-area electromechanical oscillations are a common phenomenon in modern electric power systems. These modes may be damped by retuning the existing PSSs or by installing FACTS devices in key points in the system. This paper deals with the latter solution and a unified decentralized approach is considered: in a first step the modal sensitivity analysis is used to determine the optimal location of FACTS and then the residue method is applied to select the proper input signal of the controller and to tune it. The use of global signals as inputs leave the local modes unaltered.