Mal-operation of mho relay in transmission line due to presence of TCSC

Abstract

Distance protection is simple and it provides fast response to clear the fault. Distance protection is also providing primary and remote backup function depending upon distance of transmission line. Distance protection uses various relays like mho relay/admittance relay, impedance relay and reactance relay. In power transmission system, Flexible AC Transmission System (FACTS) controllers are used to increase power transfer capability and reactive power control, but distance relay get affected due to presence of FACTS devices. This may create the stability issues, security and it may affect on voltage profile. The changes in impedance level would affect the accuracy of distance protection. This paper represents the effect of TCSC on operation of mho relay in transmission line. The work presented here emphasis on the interaction of TCSC on distance protection and their performances under different condition i.e., load angle variation, variation of SCL, different fault location. Design and control performance of MHO relay during normal operation as well as during variation in different condition is verified by using PSCAD simulation software.