Decision tree approach for fault detection in a TCSC compensated line during power swing

•Protection issues of TCSC compensated line during power swing.•A novel protection algorithm based on decision tree is proposed which uses three phase current signal to detect the fault during power swing in a modified WSCC nine bus three machine system.•This proposed method sensitivity is also tested in a New England IEEE 39 bus bigger system during power swing condition.•Use of the DT based technique for detecting fault in complex TCSC compensated transmission line during power swing is presented here for the first time.•This DT based algorithm is very sensitive for major fault cases like close in fault, CT saturation, high resistance far end fault during power swing. Also this algorithm does not respond any non fault event.