AN OVERVIEW OF THE DIGITAL FAULT LOCATION ALGORITHMS FOR THE POWER TRANSMISSION-LINE PROTECTION BASED ON THE STEADY-STATE PHASOR APPROACHES

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 wave forms. Various relaying functions are used, so far, based mainly on th e 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 th e system model, the relaying function and the filtering technique.