Siemens SIPROTEC 7SJ62 Manual page 486

Technical Data
4.3 Inverse-Time Overcurrent Protection 51(N)
Dropout Time Characteristics with Disk Emulation acc. to ANSI/IEEE
Acc. to ANSI/IEEE (see also Figures 4-3 to 4-6)
The dropout time curves apply to (I/Ip) ≤ 0.90
For zero-sequence current read 3I0p instead of I
for ground fault read I
Dropout Setting
IEC without Disk Emulation
ANSI with Disk Emulation
486
p
instead of I and T instead of T
Ep p IEp
approx. 1.05 · setting value I
0.95 · pickup value
approx. 0.90 · set value I
and T instead of T ;
3I0p p
p
≥ 0.3; this corresponds to approx.
for I /I
p p N
p
C53000-G1140-C207-2, Release date 01.2008
SIPROTEC, 7SJ62/64, Manual