ABSTRACT
The fault location algorithm is a key element in the digital relay for power transmission line protection. The core of the algorithm is the relaying function which relates the fault distance to the sampled waveforms. Various relaying functions are used, so fax, based mainly on the steady-state phasor approach, the differential equation approach and the traveling-wave approach, respectively. In this paper, the steady-state phasor approaches are reviewed. The effect of various algorithms on relay speed and accuracy is examined regarding the selection of the system model, the relaying function and the filtering technique.