Bender ISOSCAN W Series - Commissioning; Requirements for Reliable Insulation Fault Location; Before Switching on

Commissioning
6 Commissioning
WARNING
Make sure that the basic settings meet the requirements of the IT system.
CAUTION
Make sure that the operating voltage is correct!
Prior to insulation and voltage tests, the EDS44… must be disconnected from the IT system for the
duration of the test. In order to check the correct connection of the device, a function test has to be
carried out before starting the system.
CAUTION
Device damage due to overcurrent
Devices connected to the analogue output must have a suitable protective circuit against
overcurrent to protect the device in the event of a defective analogue output.
Start the cyclic test of the EDS44… at regular intervals (e.g. once a year) to ensure that the relays work and
switch correctly.
6.1 Requirements for reliable insulation fault location
The EDS has the task of locating the insulation fault downstream of the measuring current transformer R
Fd
. To
do this, it must reliably detect the locating current caused by the insulation fault. This is only possible under
the following conditions:
•
One current transformer must be connected to each activated channel.
•
The locating current I
L
is within the specified range. See chapter Kapitel “Technical data ISOSCAN® EDS440
and EDS441”, page 73.
•
The upstream capacitances C
Lu
must be at least as high as the downstream capacitances C
Ld
.
•
The system leakage capacitance must not be too high. See “Diagrams”, page 57.
•
The residual current can be within the following range:
– EDS440: 0.1…10 A
– EDS441: 0.1…1 A
•
Along with the amplitude, the frequency of the residual current influences the reliable detection of the
locating current. Observe the “Fault curve EDS440 and EDS441”, page 72.
6.2 Before switching on
CAUTION
Malfunctions due to excessive locating current
An excessive locating current flowing between the IT system and earth may cause control faults in sensitive
system parts, such as PLC or relays.
•
Ensure that the level of the locating current is compatible with the system to be monitored.
Ensure the following:
•
The connected supply voltage U
S
matches the information on the nameplates of the devices.
•
The maximum permissible nominal insulation voltage of the measuring current transformers and the
ISOMETER® with integrated locating current injector is not exceeded.
•
The protective earth conductor is not routed through the measuring current transformer.
38 EDS44x_D00201_10_M_XXEN/11.2023