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Low-Voltage Measurement
The device can be configured for low-voltage measurement. In the low-voltage system, 230 V is directly
connected to the V
1
, V
2
, and V
3
terminals. The current terminals I
1
, I
2
, and I
3
are also connected in the low-
voltage system with appropriate current-transformer sensors.
This function can be selected by configuring the Secondary voltage parameter to 230 V.
In this mode, the settings for primary voltage do not have any relevance.
The following figure shows how the device is connected to the low-voltage system.
[dw_sfcm-lowvolmsrmt, 2, en_US]
Figure 4-20 Low-Voltage Measurement
Determination of Medium Voltage via Low-Voltage Measurements
The voltages in the medium-voltage (MV) system can be determined by measuring the voltages from the low-
voltage (LV) system. In this variant, the voltage inputs (V
1
, V
2
, and V
3
) of the device are connected to the
secondary side of the transformer in the LV system and the current inputs (I
1
, I
2
, and I
3
) of the device are
connected to the LoPo current sensors in the medium-voltage system.
The figure illustrates the transformer type (Dy-11) used in the medium-voltage/low-voltage measurement. For
more information about transformer types, refer to
Transformer Type, Page 114 .
[dw_sfcm_mv_lv_measurement, 2, en_US]
Figure 4-21 Medium-Voltage/Low-Voltage Measurement
This function can be selected by configuring the
Secondary voltage
parameter to 400/√3. By using this
application, no additional VTs are necessary. The fault determinations are made with the help of LV-side
voltage references.
The device is able to detect the direction of phase faults and ground faults in solidly grounded MV networks.
The primary voltages affected by transformer losses can be corrected by providing an offset in the
Primary
voltage correction
parameter.
4.1.30
4.1.31
Device Functions
4.1 Description
SICAM, Feeder Condition Monitor, Manual 53
E50417-H8940-C580-A4, Edition 03.2019