Siemens SIPROTEC 4 7SJ61 Manual page 322

Technical Data
4.13 Ground Fault Detection (Sensitive/Insensitive)
Logarithmic inverse trip time characteristic
[kennlinie-amz-log-invers-050803, 1, en_US]
Figure 4-11
Logarithmic
inverse
Note:
322
Trip time characteristics of inverse time ground fault protection with logarithmic inverse time
characteristic
t =51Ns Tmax – 51Ns TIME DIAL · 51Ns(Ι/51Ns PICKUP)
For Ι/51Ns PICKUP > 35 the time applies for Ι/51Ns PICKUP = 35; for t < 51Ns Tmin
the time 51Ns Tminapplies.
SIPROTEC 4, 7SJ61, Manual
C53000-G1140-C210-6, Edition 05.2016