The properties of the Current Transformers, in particular the rated CT current In, must also
be specied in the settings, see ╚═▷ “11.1.3 Setting of the Rated CT current In”.
The input for earth (ground) current measuring – if available – can be connected to a
cable-type current transformer.
The test inputs are convenient for the secondary tests during commissioning: A test current
can be fed into the WIC1, without the need to disconnect the cables from the current
measuring inputs. See ╚═▷ “7.1.4.2 Wiring Checks”.
DANGER!
The WIC1 must be grounded/earthed at the correct terminal “PE”, see also ╚═▷ “3.3.1
Grounding”.
CAUTION!
The measuring winding (terminals S1and S2, and – if available – S3, S4) of the CTs must
not be earthed, otherwise the measurement results are distorted, ensuring in erratic
behavior of the WIC1.
DANGER!
The current measuring inputs may exclusively be connected to current measuring
transformers (with galvanic separation) of the type matching the ordered WIC1 variant.
DANGER!
The terminal block for connection to the current transformers is not a shorting block.
Therefore always short-circuit current transformers before loosening the terminals.
Ignoring this can result in dangerous voltages at the open contacts (up to dozens of
kilovolts depending on the CT type).
DANGER!
The WIC1-compatible current transformers are dimensioned for nominal voltages
< 1000 V. This means for an application in MV-switchboards (i. e. voltages < 36 kV)
that these current transformers may only be used with insulated primary conductors,
for example cables, with appropriate insulation resistance against earth. These current
transformers are not allowed to be used for non-insulated primary conductors > 1000 V
against ground (earth).
In addition, the medium voltage cables, whose phase currents shall be measured via the
CTs, must be furnished with a grounded/earthed shielding.
Ignoring this can result in dangerous voltages at the open contacts (up to dozens of
kilovolts depending on the CT type).
78 WIC1 WIC1-1.0-EN-MAN
3 Hardware
3.4 Phase and Ground Current Measuring Inputs
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