Unsynchronized fault location on untransposed transmission lines with fully distributed parameter model considering line parameter uncertainties

This paper proposes an unsynchronized two-terminal fault location method on three phase untransposed transmission lines considering line parameter uncertainties. The method utilizes three phase voltage and current phasor measurements before and during the fault, without requirement of synchronization between two terminals. The proposed method first formulates the fault location problem considering line parameter uncertainties in a standard syntax, where the distributed parameters as well as the asymmetry of untransposed transmission lines are carefully considered to ensure accurate representation of physical laws before and during the fault. The location of the fault and unknown parameters of the untransposed transmission line are introduced as states of the system. Afterwards, the states of the system, including the location of the fault, are systematically solved using the state estimation algorithm. Extensive numerical experiments validate that the proposed method has higher accuracy compared to the existing fault location methods considering line parameter uncertainties, regardless of fault types, locations and impedances.