Summary
This paper proposed the placement of multi unified power flow controllers (UPFCs) using the system critical modes and residue factor to increase damping of the electromechanical oscillations in power system. For this purpose, the critical modes are used to determine the number of UPFCs and their optimal locations are determined using residue factor. Also, the dynamic model of UPFC, which is consists of a voltage source and a current source is used for small signal stability analysis. To control the parameters of this model, supplementary controller is designed and applied. Detection of the input signal for this controller is based on the participation factor, which is a simple and effective method. Finally, the proposed method is investigated on IEEE 39‐bus system and the results are presented.