Directional Ground Overcurrent Protection 67N - Siemens SIPROTEC 7SK80 Manual
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Technical Data
4.4 Directional Ground Overcurrent Protection 67N
4.4
Directional Ground Overcurrent Protection 67N
Time Overcurrent Elements
The same specifications and characteristics apply as for non-directional time overcurrent protection
(see previous Sections).
Determination of Direction
Moreover, the following data apply to direction determination:
For Ground Faults
Polarization
Forward range
Rotation of the reference voltage V
Dropout difference
Directional sensitivity
Polarization
Forward range
Rotation of the reference voltage V
Dropout difference
Directional sensitivity
Times
Pickup times (without inrush restraint, with restraint + 1period)
67N-1, 67-2, 67N-2
- for 2 x setting value
- for 10 x setting value
Dropout times
67N-1, 67N-2
Tolerances
Phase-angle error for ground faults
Influencing variables
Frequency influence
358
with zero sequence quantities 3V
V
± 86°
ref,rot
-180° to +180°
ref,rot
Increments 1°
3°
V
≈ 2.5 V displacement voltage, measured
N
3V
≈ 5 V displacement voltage, calculated
0
with negative sequence quantities 3V
V
± 86°
ref,rot
-180° to +180°
ref,rot
Increments 1°
3°
3V
≈ 5 V negative sequence voltage
2
3I
≈ 45 mA negative sequence current with I
2
3I
≈ 225 mA negative sequence current with I
2
approx. 45 ms
approx. 40 ms
approx. 40 ms
±3° electrical
approx. 1° in the range of 0.95 < f/f
, 3I
0
0
2
< 1.05
N
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
, 3I
2
= 1 A
Nom
= 5 A
Nom
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