Functions
2.9 Ground Fault Protection 50N(s), 51N(s)
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
148
2.9.2
Logic
The following figure illustrates a state logic of the sensitive ground fault protection. The ground fault detection
can be turned
ON
or (address
3101
). When ground fault protection is
ON
, tripping is possible. The entire func-
tion may be blocked via binary input. Switching off or blocking means the measurement logic shown in Figure
2-50 is deactivated. Therefore, time delays and pickup messages are reset.
All elements can be blocked individually via binary inputs. In this case, pickups are still reported but tripping is
prevented because the time stages are blocked.
Figure 2-49
Activation of the sensitive ground current protection