Abstract: Accurate fault locating on transmission lines is of great value to the power transmission operators. Most micro-processor based relays implement fault location using different impedance based methods. This paper describes an approach for the estimation of fault based on negative sequence voltage magnitude at both ends of the faulted circuit. A two-ended fault location method is used for estimating the fault distance measurement accuracy by using the data of two ends of the line to revoke the effect of fault resistance & mutual coupling between the negative sequence components of the two circuits since negative sequence circuit is considered. The two-ended method locates the unsymmetrical faults independent of fault classification & pre-fault conditions. Study of this work can be analysed using unsynchronized fault location for three terminal lines. Based on unsynchronized measurements, fault estimation is tested for different cases. Fault location will be modelled using lumped parameter & PI model & is implemented in MATLAB environment.

Keywords: Negative Sequence Voltage Magnitude, one end and two end methods, Impedance Measurements, Fault Location.