Time-domain fault location algorithm for double-circuit transmission lines connected to large scale wind farms

This article introduces a new time-domain fault location algorithm for two-terminal parallel transmission lines connected to large scale wind farms. The proposed algorithm employs only a half-cycle data window of synchronized current samples at both line terminals to avoid inaccurate estimation of current phasors due to the generated sub- and inter-harmonics currents by the wind farms. The proposed algorithm does not need any transformation method to decouple the double-circuit transmission line. Moreover, it takes into consideration the effect of the line asymmetry and the potential couplings between the six phases. The fault location equation is deduced by equalizing the differential components of the calculated instantaneous voltages at the fault point, and then the fault distance is estimated directly without any iterative algorithm. The two-terminal parallel transmission line is emulated by PSCAD/EMTDC platform utilizing the frequency-dependent phase model, and the required calculations for fault location are conducted by MATLAB software. The proposed algorithm is tested for several fault resistances and fault locations, and all fault types, including cross-circuit faults. In addition, the effect of measurement, synchronization, and line parameters errors on the fault location accuracy is investigated. The obtained results confirm acceptable accuracy of the proposed fault location algorithm.