Restricted Earth Fault Protection - Siemens SIPROTEC 7UT613 series Manual

4.3

Restricted earth fault protection

Setting Ranges
Operating Time
Frequency Influence
7UT613/63x Manual
C53000-G1176-C160-2
Differential current
Limit angle
Trip characteristic
Pickup tolerance
(with preset characteristic parameters and one
3-phase measuring location)
Time delay
Time tolerance
The set times are pure delay times
Pickup time at frequency
at 1.5 · set value I > approx. high-speed relays
REF
> approx. high-speed relays
at 2.5 · set value I
REF
Dropout time, approx.
Dropout ratio
Frequency influence
Figure 4-6 Tripping characteristic of the restricted earth fault protection depending on the
earth current ratio 3I
I > = setting; I
REF
4.3 Restricted earth fault protection
I
>/I 0.05 to 2.00
REF NObj
ϕ
110° (fixed)
REF
see Figure 4-6
5 % at I < 5 · I
T 0.00 s to 60.00 s
REF
or ∞ (no trip)
1 % of set value or 10 ms
high-speed relays
high-speed relays
within the frequency tagging range
"/3I ' (both currents in phase + or counter-phase —);
0 0
= tripping current
Trip
Steps 0.01
N
Steps 0.01 s
50 Hz 60 Hz 16.7 Hz
35 ms 30 ms 110 ms
30 ms 25 ms 105 ms
33 ms 29 ms 87 ms
28 ms 24 ms 82 ms
26 ms 23 ms 51 ms
approx. 0.7
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