Power fiow increase and environmental constraints in power Systems hâve led to FACTS (Flexible AC Transmission Systems) devices insertion in order to improve the power System exploitation. Thèse devices are able to cany out some funétions such as the voltage support, the power transfer control and the increase of power transfer capability. Moreover, due to their fast response time, they are an efficient tool for damping low frequency oscillations. This new FACTS devices application is important as power Systems are more and more interconnected and thereby more sensitive to inter-area eîectromechanical oscillations. However, the recourse to several FACTS devices in a power System requires the careful study of the possible controller interaction phenomena between FACTS devices and with others system éléments. This thesis deals with the analysis and resolution of dynamic phenomena due to interaction problems resulting from the insertion of one or several shunt FACTS devices. Sensitivity and influence indices are defined from the controllability and observability notions, respectively, in order to preview the interaction phenomena importance due to a FACTS device insertions and to identify the influence areas of a FACTS device. Thèse indices are applied to a two-area four-machine test system and to a simplified real 29-machine power system. Two coordination methods (" minimax " method and decentralized linear quadratic method) are used to coordinate the FACTS devices themselves and a FACTS device and PSS (Power System Stabilizer) in the two-area four-machine test system.
