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4.4
Directional overcurrent protection ground
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 inrush restraint + 1 cycle)
67N-1, 67N-2, 67N-3
- for 2 x setting value
- for 10 x setting value
Dropout times
67N-1, 67N-2, 67N-3
Tolerances
Phase-angle error for ground faults
Influencing variables
Frequency influence
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
with zero sequence quantities 3V
± 86°
V
ref,rot
-180° to +180°
ref,rot
Increments 1°
3°
≈ 2.5 V displacement voltage, measured
V
N
≈ 5 V displacement voltage, calculated
3V
0
with negative sequence quantities 3V
± 86°
V
ref,rot
-180° to +180°
ref,rot
Increments 1°
3°
≈ 5 V negative sequence voltage
3V
2
≈ 45 mA negative sequence current with I
3I
2
≈ 225 mA negative sequence current with I
3I
2
approx. 45 ms
approx. 40 ms
approx. 40 ms
±3° electrical
approx. 1° in the range of 0.95 < f/f
4.4 Directional overcurrent protection ground
, 3I
0
0
, 3I
2
< 1.05
N
Technical Data
2
= 1 A
Nom
= 5 A
Nom
373
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