Siemens 7SR51 - Logic of the Function; Application and Setting Notes

Logic of the Function
[lo_7SR5_50BFlogicdiagram, 1, en_US]
Figure 6-1
Logic Diagram: 50BF Circuit-Breaker Failure Protection – 3 Pole
Application and Setting Notes
Parameter: Setting
•
Default setting: 0.2 x I
n
(0.2 ⋅ I
rated
)
When any phase current is measured above this setting the CB is determined as being in the closed posi-
tion i.e. current is still flowing.
The phase current setting must be set below the minimum phase protection setting current.
Parameter: Ig Setting
•
Default setting: 0.05 x I
n
(0.05 ⋅ I
rated
)
When earth current is measured above this setting the CB is determined as being in the closed position
i.e. current is still flowing.
The earth fault current setting must be set below the minimum earth fault protection setting current.
Parameter: Delay 1
•
Default setting: 60 ms
See Settings Example, Page 370.
6.1.3
6.1.4
Supervision Functions
6.1 50BF Circuit-Breaker Failure Protection – 3 Pole
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 369
C53000-G7040-C014-1, Edition 11.2019