Fault location for parallel transmission lines with limited voltage and current measurements

This article presents a novel fault location algorithm for parallel transmission lines for scenarios where only limited synchronized voltage and current measurements are available. Existing methods usually request measurements at the faulted line to be available. However, this may not always be the case due to the limited number of recording devices placed in a power system. The proposed method makes the most of available measurements and does not require the measurements to be captured from the faulted line. The pre-fault and during-fault bus impedance matrices for the positive-sequence network are derived. Synchronized bus voltages and branch currents are then expressed as a function of fault location and line parameters. As a result, fault location can be estimated using the obtained measurements. The distributed parameter line model is adopted to fully consider the shunt capacitances of the line. To eliminate the influence of bad measurements, optimal estimation theory is adopted for enhanced accuracy of the fault location estimate. Simulation studies have been carried out based on a 27-bus power system, and encouraging results have been achieved.