Fault Location Using Wide-Area Measurements and Sparse Estimation

This paper describes a fault location method which uses sparsely located wide-area synchronized phasor measurements. The main contribution is the way fault location is reformulated as a sparse estimation problem. Faulted system is modeled by equivalent terminal bus injections which would cause the same changes in bus voltages with the fault current drawn at any point along the faulted line. Once these injections are estimated, the fact that the ratio between equivalent injections at the two terminal buses depends only on the ratio of serial impedances on each side of the fault point can be used to locate the fault. It is shown that this formulation applies to both two terminal lines as well as teed lines regardless of fault type or resistance. Assuming availability of an accurate three-phase network model and a sufficient number of phasor measurements over the entire network, an underdetermined set of linear equations can be formed and then solved for the sparse equivalent bus injections. This is accomplished by applying two L1norm regularization optimization methods namely Lasso and overlapping group Lasso. Effectiveness of these methods are verified by extensive simulations.