Fast accurate fault location on transmission system utilizing wide-area unsynchronized measurements

This article presents a closed-form solution for transmission line fault location without the need for GPS-synchronized sampling of wide-area measurements. Unsynchronized measurements recorded by sparse intelligent electronic devices (IEDs) across the grid are gathered and bus impedance matrix is utilized to relate the measurements to fault location by nonlinear complex functions. A linear reformulation of the problem allows for integrating unsynchronized voltage and current measurements, together with two auxiliary variables, into a linear least-squares problem. Schur-Banachiewicz inversion formula is next utilized to obtain a closed-form solution for fault location. The distributed parameter model of the line is considered and the method identifies the faulted line and locates the fault along it regardless of fault type and resistance. Furthermore, in contrast to previous methods, the proposed method on the one hand obviates the need for GPS-synchronized sampling, and on the other hand avoids iterative procedures. Extensive time-domain simulations for the WSCC 9-bus and a 22-bus subnetwork of the IEEE 118-bus test systems confirm the effectiveness of the method for different faults across the grid.