New Method for Earth Fault Localization using the Hilbert Transform

In this paper the architecture of a software prototype of earth fault localization is explained and the results of a sensitivity analysis of the elements of digital models of medium voltage grids are shown and how these results affect earth fault localization. Eight grid elements were studied in the sensitivity analysis: primary transformer, secondary transformers, cables, loads, synchronous machine generators, infeeders, leakage capacitances and a private grid with lack of information of cables. The cases of including leakage capacitances and synchronous machine generators are interesting for the field of electromagnetic transients in power systems. Tables with the summary of the results with the minimum, average and variance of the correlation between the generated fault signatures with the models of the cases of the sensitivity analysis and with the reference models are presented. Based on the average correlation results, ranges associated to a low, medium and high impact level were defined. One case of every impact level was used to evaluate the preprocessing step of the Hilbert transform for earth fault localization with correlation, which is a new and effective method and therefore an important contribution to the field of earth fault localization in medium voltage grids.