Detection of Transmission Line Faults in the Presence of Thyristor Switched Capacitor Using Stockwell Transform

The power system faults are frequently observed in transmission and distribution parts of the power system network. Behaviour of the power system faults changes in the presence of FACTS devices. Accurate detection of these faults is essentially required for providing effective power system protection and relaying system. This paper presents an approach for the transmission line faults in the presence of Thyristor switched capacitor (TSC). Investigated faults include line to ground (LG), double line (LL), double line to ground (LLG) and three phase fault involving ground (LLLG). The median based fault index is calculated from the S-matrix of the voltage and current for the investigated faults. The study has been carried out using a test system and results have been validated in MATLAB/Simulink environment.