An online fault-locating scheme for EHV/UHV transmission lines

The authors describe the principle of an online fault-locating scheme using the voltage and current synchronously sampled from both ends of a long EHV/UHV transmission line. This is based on a distributed parameter model of the line. Steady-state transmission line equations are used to construct a fault-locating function, with the effect of distributed capacitive current taken into account. Application is extended to practical situations where in-line shunt reactors are present for compensation. The fault-locating scheme is insensitive to fault path resistance, fault inception angle, load current and source impedance. Test results verify the high accuracy and speed of the scheme for different types of faults.