DEVICE AND METHOD FOR LOCATING EARTH FAULTS IN ELECTRICAL DISTRIBUTION GRIDS
FIG12: Schematic representation of results of an embodiment of repetition of the similarity calculation for the EF between BB 6 and 7 as in FIG8, but now for a time interval of only 1ms after the fault 
FIG12 shows that the choice sim2 for the similarity metric, as the squared difference between the two curves, keeps the minimum at BB6 and even shows a clearer result on the faulty-phase for the second lowest value at BB7. Hence this choice of the similarity metric clearly shows the fault-location between BB6 and BB7. Again, the disclosed approach is rather robust, even if a similarity metric, as the squared difference between the two curves, provides improved results.
schematic
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at Busbar fault at Bus-Bar
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- left graph zooms into Steps Step Example
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at Busbar Bus-Bar
6
between BB
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Busbar
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impedances there are
['1. Device for locating earth faults in a compensated electrical distribution grid comprising an electronic data processor configured for: waiting until an earth fault detection signal that an earth fault has occurred; obtaining a time-domain captured voltage or current signal wherein said time-domain comprises a time period ensuing said earth fault; calculating the correlation of said time-domain captured signal with a database comprising a plurality of time-domain, voltage or current respectively, signature signals, wherein each signature signal is a time-domain signal corresponding to an earth fault location from a plurality of predetermined locations in said electrical distribution grid; outputting the earth fault location corresponding the signature signal from said plurality of signature signals which has the highest correlation with the captured signal; characterized in that  the time-domain captured voltage or current signal is obtained at only one operational location of the electrical distribution grid;  and in that  the operational location of the electrical distribution grid is a substation of said electrical distribution grid, the substation being where the time-domain captured voltage or current signal is captured.']