Siemens 7SJ82 - Current-Flow Criterion

[lopro3pt-171012-01.tif, 2, en_US]
Figure 5-90 Logic Diagram of the Overall Function Process Monitor
Current-Flow Criterion
[loproikr-011112-01.tif, 2, en_US]
Figure 5-91 Logic Diagram of the Current-Flow Criterion Function Block
The phase currents are provided via the interface to the protection function group.
The I open signal of one phase is generated if one of the following conditions is met:
•
A phase current falls below the set threshold of the Current thresh. CB open parameter. The
hysteresis stabilizes the signal.
•
The corresponding phase current, for example, I A, falls below 10 % of the phase current when the trip
command arrives. If the current does not drop until after a delay due to current transformer influences,
an open pole can therefore be detected quickly even after a high-current fault on the line.
5.8.3
Function-Group Types
5.8 Process Monitor
SIPROTEC 5, Overcurrent Protection, Manual 295
C53000-G5040-C017-8, Edition 07.2017