A variable gain PI to improve the performances of a unified power flow controller system

The instability problems in the electrical supply networks have had a great impact on recent research studies on modern devices. The unified power flow controller (UPFC) is one of the various FACTS (Flexible Alternative Current Transmission Sys-tems) devices that allow the electrical supply networks to be stable with a strong effectiveness. In this paper, the performances of such a device using both a classical PI and a variable gains PI controllers are examined. For this instance, the compensator is first stabilized before trying to stabilize the network. A series of comparative simulation tests have been undertaken for both regulators and analyzed. From the obtained results it is clearly shown that when the system is equipped with the variable gain PI regulator, the performance are much better.