Measured impedance by distance relay elements applied on a distribution feeder in a single phase to ground fault

Distance protection is not utilized in distribution networks, unlike the transmission systems, due to the inherent characteristic of the distribution networks and the additional required facilities of distance protection, compared with over-current protection, which is in use in the distribution systems. This paper discusses the measured impedance by six elements of distance relay first zone applied on a distribution feeder in the case of a single phase to ground (AG) fault. This is done by presenting the measured impedance at the source node the distance relay ideal tripping characteristic for each element. The variation of the ideal tripping characteristic due to the changes in the system parameters is investigated.