A Practical Methodology for Fault Location in Transmission Lines Without Line Parameter Settings and Data Synchronization

Abstract

Reliable fault location for power transmission networks requires line parameters and time synchronized voltage and current measurements from all terminals which may not always be available. In this work, a setting-free fault location methodology using unsynchronized data from the line terminals is proposed. This requires computation of data synchronization error which manifests as a phase angle error between the two terminal phasor measurements. The data synchronization angle is computed using unsynchronized phasors and a design factor related to the line. The design factor can be estimated from a set of synchronized measurements and stored. Upon detecting failure of the data synchronization mechanism, the same can be used to calculate the data synchronization angle between the unsynchronized measurements. The line parameters and subsequently fault location is computed using unsynchronized data and the estimated data synchronization angle. The proposed solution is verified using laboratory experimental and field data and it is found to be accurate.