FACT systems have been used for four decades and present very good dynamic and transitory performances in the electrical networks. In this work, the behavior of a new generation of static compensator, I-STATCOM, installed in the middle of a long 400 kV line is investigated. The project is located in the eastern area of the electricity production and transmission in Algeria. I-STATCOM with its properties of reactive power compensator and voltage regulator is an intelligent system operator which has access to the generator references, assists the synchro check in the network coupling operations and has the capacity of changing the state of the breakers to maintain service continuity even in the most severe operation modes. Analysis of exploitation incidents and experience feedbacks led us to this choice, which could be generalized in the future on more complex inter-connected networks assisted by AVR–PSS Matlab/Simulink controllers of the same type.