To verify and validate the performance of the two methods, previously developed within the CINELDI centre, for locating earth faults in closed-ring distribution networks using a real-world/field network.
Work performed
Field tests in a ring-operated 22 kV resonant grounded network.
Analysis of the field test measurements.
Focus on identifying potential sources of error that were not observed in the simulation tests.
Significant results
The observed accuracy in field tests has not aligned with simulation results, the analysis identified and demonstrated potential sources of errors with further simulations:
Inaccurate line impedance data can reduce precision.
Phase angle drift due to off-nominal frequency affects high fault resistances but has limited impact.
Measurement accuracy, has also impact particularly for negative sequence current based method.
Impact for distribution system innovation
To obtain high precision in practical implementation the issues identified must be given attention.
