3.4 Insulation fault location
An additional function of the ISOMETER® in combination with the EDS is the selective in-
sulation fault location. Therefore, the ISOMETER® generates a periodic locating current af-
ter the values has fallen below the set response value R
an2
(LED ALARM 2). Thereby, the
system conductors are alternately connected to earth via a defined resistance. The result-
ing locating current depends on the size of the existing insulation fault and the system
voltage. It is limited by the ISOMETER® depending on the settings. The insulation fault is
selectively located by means of the EDS and the measuring current transformer connect-
ed to it. The locating current flows from the locating current injector via the live lines to
the insulation fault position taking the shortest way. From there, it flows through the in-
sulation fault and the conductor PE back to the ISOMETER®. This locating current pulse is
detected by the measuring current transformer on the insulation fault path and signalled
by the connected EDS.
For the duration of the insulation fault location, the function of the insulation monitoring
device is deactivated. If during the insulation fault location the locating current falls be-
low the value measurable by the EDS, the insulation fault location is ended by the
ISOMETER®.
3.5 Interfaces
• Communication protocol Modbus TCP
• BCOM for Bender device communication via Ethernet
• BS bus for communication of Bender devices (RS-485)
• BB bus for communication of Bender devices (Bender-internal device bus)
• Integrated web server for reading out measured values and for parameter setting
Risk of malfunctions due to excessive locating current on sensitive
system parts!
The locating current flowing between the IT system and earth can cause
controller faults in sensitive parts of the system, such as the PLC or relay.
Ensure that the level of the locating current is compatible with the system
to be monitored.
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