Performance of Distance Relays in the Presence of Distributed Power Flow Controllers

Recent efforts to increase the power transmission capacity and increase the level of network stability have increased the use of Flexible AC Transmission Systems elements in the power system. The protective system, which is one of the most important parts of the power system's operation, is seriously affected by these devices, so their study is considered necessary. Among protection relays, the protection of the distances due to high speed, proper operation in different network conditions are used as the main protection of transmission lines. Consequently, it is inevitable that the lines compensated by flexible AC systems are protected by long-range relays. In this paper, the Distributed Power Flow Controller has been investigated and simulated, and then the effect of these devices on the measured impedance and the characteristic of the disturbance relay is shown. It is also shown in this paper that in addition to the effects of the relay seen on the relay due to changes in the power system, the type of control system and the adjustment of the parameters of these devices will have different effects on the impedance seen by the relay. To investigate the effect of controller distributed power distribution on the protection of the energy transmission distances, as well as the effect of the impedance seen on the relay due to the presence and type of control system that the distributed power controller works with, it uses the PSCAD / EMTDC software for the model These compensator have been used.