Investigation of an adaptive distance scheme for protecting teed feeders

This paper describes a new adaptive digital distance relaying scheme which compensates the effects due to the fault current from the remote end. The proposed distance relay could give an accurate measurement at the reach point and a proper discrimination between in-zone and out-of-zone faults. The relay performance equation is derived and its response is investigated under various conditions. The relay operating time for different fault resistance, fault positions and source impedance is also included. An evaluation of the performance of the adaptive scheme in a typical 400 kV system of teed type configuration is also presented. Fault data was obtained from EMTP