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Technical Data
4.4 Directional Time Overcurrent Protection 67, 67N
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
492
4.4
Directional Time Overcurrent Protection 67, 67N
Time Overcurrent Elements
Determination of Direction
For Phase Faults
For Ground Faults
Times
The same specifications and characteristics apply as for non-directional time overcurrent protection
(see previous Sections).
Moreover, the following data apply to direction determination:
Polarization
With cross-polarized voltages;
with voltage memory 2 s
Forward Range
V
ref,rot
±
86°
Rotation of the reference voltage V
ref,rot
–180° to +180°
Increments 1°
Dropout difference
2°
Directional sensitivity
Unlimited for single and two phase faults
For three phase faults, dynamically unlimited, steady-state
approx. 7V phase-to-phase.
Polarization
with zero sequence quantities 3V
0
, 3
I
0
Forward Range
V
ref,rot
±
86°
Rotation of the reference voltage V
ref,rot
–180°
to
+180°
Increments 1°
Dropout difference
2°
Directional Sensitivity
V
N
≈
2.5 V displacement voltage, measured
3V
0
≈
5 V displacement voltage, calculated
Polarization
with negative sequence quantities 3V
2
, 3
I
2
Forward Range
V
ref,rot
±
86°
Rotation of the reference voltage V
ref,rot
–180°
to
+180°
Increments 1°
Dropout difference
2°
Directional Sensitivity
3V
2
≈
5 V negative sequence voltage
3
I
2
≈
45 mA negative sequence current with
I
Nom
= 1 A
3
I
2
≈
225 mA negative sequence current with
I
Nom
= 5 A
Pickup times (without inrush restraint, with restraint add 10 ms)
50-1, 50-2, 50N-1, 50N-2
- for 2 x setting value
- for 10 x setting value
approx. 45 ms
approx. 40 ms
Dropout Times
50-1, 50-2, 50N-1, 50N-2
approx. 40 ms
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