control,simultaneously and independently, the active power and the reactive power of the line. It can improve the transitory stability of the generators connected to the networks and guarantee a good reliability of operations of the generators of production. The objective of this article is the application of a regulator based on fuzzy logic for a robust drive of system UPFC. This regulator was to have a dynamic high efficiency while facing in an effective way to the problems of maladjustment of the operation of decoupling of the strategies of adjustments of flow of powers. In order to test the parametric robustness of the various control developed in this work, we carried out parametric variations of system UPFC and studied its performances on the performances of control.