The impact of FACTS device on digital multifunctional protective relays

In this paper, the results of the application of multifunctional relays for the protection of compensated lines with FACTS devices is presented. The impact of different FACTS devices on the protective relays behavior is investigated. Since the distance relay is of great concern in transmission lines, the role of the applied protective algorithm in the presence of FACTS devices is presented. It is shown that different methods to perform the distance measurement in multifunctional relays could be effective in accurate discrimination. Some of them may be immune to the variations that would be caused by FACTS devices. The results indicate the importance of the protective relay specifications in the protection of the compensated lines.