Siemens 7SK80 Manual page 366

Technical Data
4.3 Inverse-time Overcurrent Protection
Trip Time Curves acc. to ANSI
Acc. to ANSI/IEEE (see also Figures 4-3 to 4-6)
The tripping times for I/I
For zero sequence current read 3I0p instead of I
for ground fault read I
Pickup Threshold
366
≥ 20 are identical with those for I/I
p
instead of I and T instead of T
Ep p IEp
= 20.
p
and T instead of T ;
p 3I0p p
p
approx. 1.10 · I
p
E50417-G1140-C344-A5, Release date 11.2012
SIPROTEC, 7SK80, Manual