Fault location on one of two parallel lines is determined as a percentage of line length in the presence and absence of the mutual effect between lines. The methodology for fault location is based on the principle that at the fault E f1 +E f2 +E f0 = 0. This relation is utilized to determine the sequence voltages at the relay position, where the impedance to the fault location can be assessed. This makes it possible to devise new accurate algorithms for fault location, whatever the lines are fed from one end or both ends. The location of single line-to-ground (SLG) and double line-to-ground (DLG) faults at different points along the line is investigated. With the determination of the fault location, the impedance seen by the distance relay is defined for SLG and DLG faults. This impedance determines where the fault is within the reach of the relay.