Arezi - Electric Power Research Center (EPRC)

This paper deals with the design of a 3 -zone quadrilateral distance relay. At first, it describes and compares different digital methods suitable for distance measurement, with particular attention to their accuracy and speed of calculation. Computer simulation is used for better comparison. Then a new method is presented for better harmonic effect reduction.A distance relay was constructed according to this method. A modern test set helped us to it. The relay was successfully tested for a number of different characteristics and the examine favorite results were obtained.