The FACTS devices control the interrelated parameters that rulethe operation of the transmission systems, including the serialimpedance, the derivation impedance, the current, the tension,the phase angle and the muffling of oscillations to differentfrequencies under the nominal frequency. The FACTStechnology has a collection of controllers, that can be usedindividually or co-ordinated with other controls installed in thenetwork, thus permitting to profit better of the network’scharacteristics of control. The configurations of compensators based on switchedinverters, called static compensators of reactive power, aretoday the most used in the electric current transmissionsystems. The apparition of high-powered electronic converters,makes possible the generation or absorption of reactive powerwithout using banks of condensers or inductors. The STATCOM is a device connected in derivation that canoperate in networks of transport as well as of distribution. Thefunctions will depend on the type of network in which it will beinstalled, it could fulfill functions of reactive power control andtension regulation, or other functions as power factor regulator,shock absorber of system oscillations or filtering of harmonics,depending on the systems applications and the tension level wewish to install.