Noniterative Parameter-Free Fault Location on Untransposed Single-Circuit Transmission Lines

Extra high voltage transmission networks include many untransposed single-circuit overhead lines with horizontal configuration of phase conductors. This paper develops a setting-free fault-location method specific to these types of transmission lines. Utilizing synchronized measurements at line terminals, the proposed method accurately locates faults irrespective of fault type, fault resistance, external network parameters, and faulted-line parameters. As such, fault location is robust against ambient conditions as well as inherent inaccuracy of line parameters. The bisymmetry of the impedance matrix of the line is utilized to obtain a closed-form solution for fault location on short transmission lines. For long transmission lines, shunt capacitance of the line is taken into account to obtain an accurate closed-form estimation for fault location. Electromagnetic transient simulation in PSCAD/EMTDC environment validates the accuracy of the proposed fault-location method for a long untransposed 400-kV transmission line. The obtained results are also compared with an existing noniterative parameter-free fault-location method to demonstrate salient features of the proposed method.