Dynamic fault locator for three-terminal transmission lines for phasor measurement units

The study presents a fault locator for three-terminal transmission lines under dynamic conditions such as power oscillation based on synchronised phasor measurement units. This approach based on conventional static fault locator can express the dynamic characteristics of supplied signals and consider them as time-variant signals whose magnitude and frequency are changing against time. Therefore the authors can apply its ability of describing dynamic characteristics to three-terminal transmission lines and get the dynamic parameters of transmission lines under the dynamic conditions. By using Newton iteration, the proposed dynamic fault locator can acquire the three-terminal fault-location indices to identify a fault section and estimate the distance to fault. The performance of the proposed method is evaluated by Power Systems Computer Aided Design/Electromagnetic Transients including DC (PSCAD/EMTDC)-generated signals under various situations. An extensive set of simulation results show that the distinctive features of this method are that it performs with better accuracy than the conventional method for all types of faults at different fault locations and is practically immune to fault resistance.