Technical Data
4.3 Inverse-Time Overcurrent Protection 51(N)
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
348
Dropout Time Characteristics with Disk Emulation acc. to IEC
Dropout Setting
Tolerances
Influencing Variables for Pickup and Dropout
Acc. to IEC 60255-3 or BS 142, Section 3.5.2 (see also Figures 4-1 and 4-2)
The dropout time curves apply to (I/Ip) ≤ 0.90
For zero sequence current, read 3I0p instead of I
p
and T
3I0p
instead of T
p
;
for ground fault, read I
Ep
instead of I
p
and T
IEp
instead of T
p
IEC without Disk Emulation approx. 1.05 · setting value I
p
for I
p
/I
N
≥ 0.3, this corresponds to approx.
0.95 · pickup value
IEC with Disk Emulation approx. 0.90 · I
p
setting value
Pickup/dropout thresholds I
p
, I
Ep
3 % of setting value or 15 mA for I
Nom
= 1 A, or 75 mA for I
Nom
= 5 A
Trip time for 2 ≤ I/I
p
≤ 20 5 % of reference (calculated) value +2 % current tolerance, or 30 ms
Dropout time for I/Ip ≤ 0.90 5 % of reference (calculated) value +2 % current tolerance, or 30 ms
Power supply direct voltage in range 0.8 ≤ V
PS
/V
PSNom
≤ 1.15 1 %
Temperature in range 23.00 °F (-5 °C) ≤ Θ
amb
≤ 131.00 °F (55 °C) 0.5 %/10 K
Frequency in range of 50 Hz to 70 Hz
Frequency in range 0.95 ≤ f/f
Nom
≤ 1.05 1 %
Frequency outside range 0.95 ≤ f/f
Nom
≤ 1.05 Increased
tolerances
Harmonics
- up to 10 % 3rd harmonic
- up to 10 % 5th harmonic
1%
1%
Transient overreaction during fundamental harmonic measuring procedure for τ > 100 ms
(with full displacement)
<5 %