An accurate fault location algorithm for transmission line based on R-L model parameter identification

An accurate time domain algorithm for fault location using one-terminal data is presented. The algorithm is based on the modal analysis and the R-L model of transmission lines, and utilizes the fault-superimposed components effectively. In the algorithm, the differential equations of fault condition networks and pure-fault networks are combined to determine the fault distance. The fault distance, fault resistance and source parameters at the remote end are solved as the unknown variables of a second-order system by finite difference method. This algorithm eliminates influence of the fault resistance and the opposite source parameters on the fault location accuracy, which have been the main source of error for conventional one-terminal approaches. In addition, the paper discusses manipulations of equations to solvable form and the minimum number of equations required. By the analysis to the correlation of measurement equations and the analytic solution of the fault current and voltage in time domain, the paper demonstrates that one-terminal algorithm has the same precision as two-terminal algorithm in theory. The EMTP simulation results show the validity and high accuracy of the new algorithm.