This project a study of the performance of distance protection relays when applied to protect shunt & series Flexible AC Transmission System (FACTS) compensated transmission lines. The objective of this study is to evaluate the performance of distance relays on transmission lines with FACTS devices applied for mid point control. Effect of two types of FACTS devices, Unified Power flow controller (UPFC) and Static Synchronous
Compensators (STATCOM) are studied. The project is conducted in three stages. First the situation is studied analytically, where the errors introduced in the impedance measurement due to the presence of FACTS devices on the line are analyzed. In the second stage, the situation is simulated using transient simulation matlab/EMTDC software. In this method, the response of FACTS devices for different fault conditions and system conditions is also modeled.This method brings out some unique problems that would be experienced by the distance relays due to some specific characteristics of the FACTS devices. Finally, the findings are confirmed by testing a commercial distance relay using a Real Time Digital Simulator (RTDS). The results obtained by testing the commercial
relay validate the analytical and simulation studies.