If the function block Filter is configured and if you have enabled the filter, the gained RMS value is automati-
cally used.
NOTE
When the function block Filter is applied, only one 3-phase current measuring point is allowed to be
connected to the 3-phase current interface of the function group.
I0 Elimination (Advanced Stage)
In order to increase the sensitivity for the 2-phase short circuit on the transformer low-voltage side, use the
I0 elimination of the phase currents for the overcurrent-protection application on one transformer.
In order to determine the I0 elimination of the phase currents, the transformer neutral point current I
Y
must be
measured.
[dwsgaocp-230414-01, 1, en_US]
Figure 7-64 I0 Elimination Principle
In case of an I0 elimination, the following calculations result:
I
A-elim.
= I
A
- 1/3 I
Y
I
B-elim.
= I
B
- 1/3 I
Y
I
C-elim.
= I
C
- 1/3 I
Y
The phase current I
phx-elim.
is necessary for the following protection process.
If the Method of measurement parameter is set to fundamental comp., the I0 elimination is applied.
The currents I
phx-elim.
are available as functional values.
Pickup delay (Advanced Stage)
If the current exceeds the threshold value, the pickup delay is generated. If the threshold remains exceeded
during the pickup delay time, the pickup signal is generated.
Dropout Delay (Advanced Stage)
If the value falls below the dropout threshold, the dropout can be delayed. The pickup is maintained for the
specified time. The tripping delay continues to run. If the time delay expires while the pickup is still main-
tained, the stage operates.
Blocking of the Stage (Basic and Advanced Stage)
The following blockings reset the picked up stage completely:
•
Via the binary input signal >Block stage from an external or internal source
•
Via the functionality of the dynamic settings (only available in the Advanced function type, see
subtitle Influence of other functions via dynamic settings and chapter 7.4.8.1 Description ).
Protection and Automation Functions
7.4 Overcurrent Protection, Phases
SIPROTEC 5, High-Voltage Bay Controller, Manual 605
C53000-G5040-C015-9, Edition 11.2017
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