An Iterative Parameter-Free Fault Location Method on Three-Terminal Untransposed Transmission Lines

This paper proposes an iterative parameter-free fault location algorithm on three-terminal untransposed transmission lines. Three phase voltage and current synchrophasor measurements at three terminals of the line before and during the fault are typically required. The proposed method considers the lumped shunt capacitance and does not require any assumption on the tower structure. The method first builds the transmission line models before and during faults, which describe all the physical laws that the line should obey. Meanwhile, the parameters of transmission line as well as the location of the fault are introduced as unknown variables. Afterwards, the fault location is obtained using the NewtonRaphson iterative method. Numerical experiments in PSCAD/EMTDC validate the fault location accuracy of the proposed method, which is independent of fault locations, fault types and fault impedances.