4 Technical Data
464
7SA522 Manual
C53000-G1176-C155-3
4.11 Time Overcurrent Protection
Operating Modes
Characteristics
Definite Time High Set Current Stage
As Emergency Overcurrent Protection or Back-up Overcurrent Protection:
Emergency overcurrent protection Operates on failure of the measured voltage,
• On trip of a voltage transformer mcb (via binary input)
• For pickup of the “Fuse Failure Monitor”
Back-up overcurrent protection Operates independent of any events
Definite dime stages (definite) I
Ph
>>,3I
0
>>, I
Ph
>, 3I
0
>
Inverse time stages (IDMT) I
P
, 3I
0p PICKUP
; one of the characteristics according to
Figure 4-1 to 4-3 (see Section 4.5)
can be selected
Pickup value I
Ph
>> (phases) For I
N
= 1 A 0.10 A to 25.00 A
or ∞ (ineffective)
Increments 0.01 A
For I
N
= 5 A 0.50 A to 125.00 A
or ∞ (ineffective)
Pickup value 3I
0
>> (earth) For I
N
= 1 A 0.05 A to 25.00 A
Or ∞ (ineffective)
Increments 0.01 A
For I
N
= 5 A 0.25 A to 125.00 A
Or ∞ (ineffective)
Delay T
Ph
>> (phases) 0.00 s to 30.00 s
Or ∞ (ineffective)
Increments 0.01 s
Delay T
3I0
>> (earth) 0.00 s to 30.00 s
Or ∞ (ineffective)
Increments 0.01 s
Dropout Ratio Approx. 0.95 for I/I
N
≥ 0.5
Pickup times Approx. 25 ms
Drop-off times Approx. 30 ms
Tolerances Currents 3 % of setting value or 1 % nominal current
Times 1 % of setting value or 10 ms
The set times are pure delay times
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