Siemens siprotec 7SD5

4.8 Earth Fault Protection in Earthed Systems (optional)
543
7SD5 Manual
C53000-G1176-C169-1
Zero Sequence Voltage Time Protection Stage (U0-inverse)
Zero Sequence Power Protection Stage
Inrush Restraint
Additional time delay T
3I0P add
0.00 s to 30.00 s
or ∞ (ineffective)
Increments 0.01 s
Characteristics See Figure 4-4
Tolerances
Times
inv. 5 % ± 15 ms for 2 ≤ I/3I
0P
≤ 20 and T
3I0P
/s ≥ 1
def. 1 % of setting value or 10 ms
Pickup value 3I
0P
for I
N
= 1 A 0.05 A to 25.00 A
or
0.003 A to 25.000 A
Increments 0.01 A
Increments 0.001 A
for I
N
= 5 A 0.25 A to 125.00 A
or
0.015 A to 125.000 A
Increments 0.01 A
Increments 0.001 A
Pickup value 3U
0
> 1.0 V to 10.0 V Increments 0.1 V
Voltage factor U
0 inv. minimal
0.1 V to 5.0 V Increments 0.1 V
Additional time delay T
directional
0.00 s to 32.00 s Increments 0.01 s
T
non-direction-
al
0.00 s to 32.00 s Increments 0.01 s
Characteristics See Figure 4-5
Tolerances times 1 % of setting value or 10 ms
Dropout Ratio Current Approx. 0.95 for I/I
N
≥ 0.5
Voltage Approx 0.95 for 3U
0
≥ 1V
The set times are pure delay times
Pickup value 3I
0P
for I
N
= 1 A 0.05 A to 25.00 A
0.003 A to 25.000 A
Increments 0.01 A
Increments 0.001 A
for I
N
= 5 A 0.25 A to 125.00 A
0.015 A to 125.000 A
Increments 0.01 A
Increments 0.001 A
Pickup value S FORWARD
for I
N
= 1 A
for I
N
= 5 A
0.1 VA to 10.0 VA Increments 0.1 VA
0.5 VA to 50.0 VA
Additional time delay T
3I0P add
0.00 s to 30.00 s; ∞ Increments 0.01 s
Characteristics See Figure 4-6
Tolerances pickup values 1 % of set value at sensitive earth current transformer
Tolerances times 5 % of set value or 15 ms at sensitive earth current transformer
6 % of set value or 15 ms at normal earth current transformer
/ without earth current transformer
Second harmonic content for inrush 10 % to 45 % Increments 1 %
Referred to fundamental wave
Inrush blocking is cancelled above for I
N
= 1 A 0.50 A to 25.00 A Increments 0.01 A
for I
N
= 5 A 2.50 A to 125.00 A
Inrush restraint may be switched effective or ineffective for each individual stage.
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