Fault recorder data refinement for accurate fault location in a transmission system

This paper presents a data refinement process for fault data recorded by a group of associated digital fault recorders (DFR) for improving accuracy in line fault location in a transmission system. The refinement process employs weighted least square state estimation technique to compute calibration factors, using the measurements of pre-fault data of voltage and current from multiple correlated DFRs. The factors then are applied to correcting the corresponding during-fault data. To verify the effectiveness of the proposed refinement method, both simulated data from the IEEE 14 bus test system and field measured data from the Thailand´s transmission system have been tested using the standard two-terminal fault location algorithm. Test results strongly confirm that the improved accuracy in locating fault on a transmission line can be obtained when compares to the respective unrefined cases.