Improvements to fault location analysis based on voltage sag data - Verifying the improvements to the fault location accuracy of the prototype tool -

This paper proposes improvements in the fault location accuracy and data handling efficiency of a fault location tool previously developed by the authors. The tool determines the fault location by comparing the measured voltage sags with a set of postulated voltage sags yielded by calculations. The tool still suffers some problems in the accuracy of fault location for a trunk power system network and in the method for sorting observation data. As to the accuracy of the fault location scheme for a trunk power system network, this paper shows that the accuracy is improved by placing more weight on measurements. As to the observation data sorting method, by employing a new sorting method that relies only on data which become available immediately after a fault, it is not necessary to accumulate information on measured errors recorded in the past. For a practical assessment, the proposed improvements are applied to the fault location tool and the tool is tested on the actual power system network model of a power company using voltage sag measurements from real faults. The results demonstrate the usefulness of the proposed methods for improvement.