Methodology for testing a parameter-free fault locator for transmission lines

This paper presents a comparison between two different approaches to fault location both with and without utilising transmission line parameters. Firstly, an impedance-based parameter-dependent algorithm, derived by using modal transformation theory and fast Fourier transform is presented. The methodology is able to locate the fault whether it is on an overhead line or on an underground power cable. The second algorithm is a parameter-free fault location method that uses time synchronised data. Here, the unknown fault location is determined from voltage and current phasors, synchronously measured at both line terminals. This approach to fault location avoids the requirement for prior knowledge of line parameters, which is advantageous as line parameters are not always known precisely. This paper presents the results of algorithm testing through the use of ATPDraw simulations and MATLAB. The results were validated through laboratory experiments. The results of the line parameter-free model are compared with those from the parameter-dependent model. Both algorithms were tested for single line to ground faults