This paper introduces the impact of installing FACTS devices on protection systems. STATCOM is used to indicate its impact on distance relay. To check the feasibility installing of STATCOM into power system for improving the distance relay performance, the zones are suggested (Z1, Z2 and Z3) and have been calculated in order to improve the performance of distance relay protection and to prevent circuit breaker disturbance tripping. The simulation results are carried out in MATLAB software. The results reveal that the apparent impedance doesn't change when the distance relay is tested without STATCOM device under different locations of faults. After installing STATCOM in transmission line, the apparent impedance doesn't change and it equals the actual impedance in spite of compensation modes of STATCOM