Function
Locating pulse pattern
The length of the pulse and pause intervals depends on the system conditions (R
F
, C
e
).
For further information, refer to Bender Main Catalogue, chapter “Equipment for insulation fault location” at
https://www.bender.de/en/service-support/download-area/.
Measured value depending on the system leakage capacitance
The influence of system leakage capacitances may cause false indication of the locating current.
The locating current of the locating current injector is limited. Due to this limitation, the resistance of the
insulation fault may be lower than the value signalled by the indicated locating current.
Project planning
During project planning care must be taken that there are no system parts where the locating current can
cause harmful reactions even in unfavourable cases.
Symmetrical insulation faults
Under certain conditions, symmetrical insulation faults located downstream of the measuring current
transformer are not detected. Lowfrequency residual currents (e.g. caused by converters) may prevent
insulation faults from being detected if their frequency is identical or almost identical to the test pulse
frequency of the locating current injector.
Influence by other components
Components, loads or EMC influences within an IT system may interfere with the locating of insulation
faults. Thus, reliable localisation may not be possible under all circumstances or false tripping may occur.
14 EDS44x_D00201_10_M_XXEN/11.2023
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