Distance protection performance under single phase to Earth fault alone and simultaneously with open conductor failure

This paper presents performance of distance protection for overhead power line under a single phase earth fault alone and such fault simultaneously with an open conductor failure. The analysis is focused on steady state measurement of the fault-loop impedance and its placement in relation to distance protection first zone of MHO type. The considerations are based on using the fault data obtained from ATP-EMTP simulation of power line faults of different specifications. The sample results of the analysis are included and discussed.