Phasor-based fault location algorithm for three-end multi-section nonhomogeneous parallel transmission lines

In order to estimate the fault location on three-terminal multi-section mixed nonhomogeneous transmission lines, all the previously published algorithms utilize the synchronized voltage and current measurements at all ends. In this article, a fault location algorithm for three-terminal multi-section mixed double-circuit untransposed transmission lines is presented utilizing only unsynchronized current measurements. Considering issues related to the shunt capacitance, un-transposition of the line, and mutual couplings between all phases, a threshold free identification algorithm is developed to differentiate the faulted line branch. In addition, analytical fault location equation is deduced independent of fault resistance and fault type. The three-terminal power system is modeled using MATLAB environment, and several fault cases are conducted, including all fault types, different fault resistances and locations, as well as different fault inception angles. The introduced work shows high accuracy under the effect of measurement and synchronization errors as well as line parameters errors.