A Novel Impedance Fault Location Algorithm for UHV Transmission Lines

A novel impedance fault location algorithm is proposed for single-line-to-ground fault in UHV transmission line due to the limitation of direct application of traditional impedance algorithm caused by larger shunt capacitance. It is based on the precondition that the negative sequence current phase at meter location can precisely describe the phase information of negative current in fault path or fault voltage. The algorithm is immune to the influence of shunt capacitance with distributed parameters modelling for transmission line, and is not disturbed by fault resistance with fault location calculation at zero-crossing point of voltage at fault point. It is a type of fault point search algorithm, hence has no the puzzles of ´false root question´ in equation solution method and ´non convergence question´ in iteration methods. Theory analysis and simulation prove that the proposed method can guarantee the good fault location accuracy, and fulfil the requirements in field.