Primary Current Settings; Ground-Current Calculation - Siemens SICAM Manual

NOTE
i
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If the CrossBlockTimer value is set as 0, then the fault indication is not blocked in case of an inrush-current
detection.

Primary Current Settings

4.1.26
Based on the selected current-transformer type, the rated primary current parameter can be set from 50 A to
1000 A via the user interface or Modbus registers.
After setting the parameters, connect the current inputs I
CTs) or conventional current transformers (CT). For interfacing via conventional CTs, use a 1 A CT adaptor
(MLFB 6MD2320-0AA10-1AA0) or a 5 A CT adaptor (MLFB 6MD2320-0AA20-1AA0).
The LoPo CTs convert the primary current to a proportional output voltage. The device has a rated primary
current setting of 300 A (@ 225 mV).

Ground-Current Calculation

4.1.27
For solidly-grounded systems, the ground currents are calculated from the vector sum of 3 phases. The ground
current is also calculated for isolated/resonant-grounded systems, when the phase-current sensor for phase L2
is connected to the I
If the ground-current sensor is connected to the I
isolated/resonant-grounded systems.
When the ground current is measured, the ground current can be configured from 25 A to 150 A.
For more information about the ground sensor, refer to
The calculation/measurement of the ground current is determined by setting the Ground-current acquisition
parameter.
NOTE
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When the cos φ/sin φ functionality is used in isolated or resonant-grounded systems, the deviation of the
ground current (I
NOTE
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For isolated systems, if the angle difference between V
lated ground current (I
NOTE
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For resonant-grounded systems, if the angle difference between V
the calculated ground current (I
NOTE
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When the ground-current calculation is used with the vector method, the deviation of the calculated
ground current is 3 %.
For more information about ground-current calculation, refer to
SICAM, Feeder Condition Monitor, Manual
E50417-H8940-C580-A4, Edition 03.2019
/I terminal.
2 N
) calculated is within 3 A.
dir
) can be more than 3 A.
dir
) can be more than 3 A.
dir
, I /I , I via low-power current transformers (LoPo
1 2 N 3
/I terminal, the ground current can be measured for
2 N
Ground Sensor, Page
and I is closer to 0°, the deviation of the calcu-
NG N
and I
NG N
Ground-Current Acquisition, Page 122
Device Functions
4.1 Description
123.
is closer to 90°, the deviation of
51