System description
19
EDS460-490_D00085_01_M_XXEN/02.2016
Fault curve
Safe insulation fault location is only possible in the grey-shaded area.
A measuring channel where insulation fault location is not possible is marked
with "peak" in the "Alarm/meas. values" menu.
Example: A residual current of 2 A/20 Hz (marked with a point (•) in the dia-
gram) would be outside the permissible range.
Symmetrical insulation faults downstream of the
measuring current transformer are not recognised under
certain circumstances.
Low-frequency residual currents (caused by converters, for
example) may have the effect that insulation faults cannot
be found when their frequency is equal or nearly equal the
test cycle frequency of the IRDH575 respectively PGH… .
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