New fault location algorithm for four-circuit overhead lines using unsynchronized current measurements

Abstract

Few fault location techniques are introduced in literature for two-terminal four-circuit overhead lines. This article proposes a new fault location algorithm for two-terminal untransposed four-circuit overhead lines employing only current data at both line terminals. The potential couplings between the twelve phases and the line untransposition are considered in derivation. The algorithm is independent of fault impedance and knowing of faulty phases is not required. Analytical equation is derived for estimating the locations of faults based on the differential components of the estimated voltages at fault point from both line ends. The two-terminal overhead line is modeled by DIgSILENT Power Factory software and MATLAB is used to carry out the required calculations. The algorithm is tested for different fault locations and fault types including normal-shunt and inter-circuit faults. In addition, the impact of measurement errors, complex fault impedance as well as errors in overhead line parameters is checked. The simulation outputs confirm the high efficacy of the algorithm for all simulated fault cases.