4.12 Frequency Protection (ANSI 81)
325
7UM61 Manual
C53000-G1176-C127-3
4.12 Frequency Protection (ANSI 81)
Setting Ranges / Increments
Times
Dropout Difference
Dropout Ratio
Tolerances
Influencing Variables
Number of Frequency Elements 4; can be set to f> or f<
Pickup Frequency f> or f< 40 Hz to 65.00 Hz Increments 0.01 Hz
Delay Times
T f1
T f2 to T f4
0.00 s to 600.00 s
0.00 s to 100.00 s
Increments 0.01 s
Increments 0.01 s
Undervoltage Blocking
(Positive Sequence Component U
1
)
10.0 V to 125.0 V and 0 V
(no blocking)
Increments 0.1V
The set times are pure delay times.
Pickup Times f>, f<
Dropout Times f>, f<
approx. 100 ms
approx. 100 ms
f = I Pickup Value – Dropout Value I approx. 20 mHz
Dropout Ratio for Undervoltage Blocking approx. 1.05
Frequencies f>, f<
Undervoltage Blocking
Time Delays T(f<, f<)
10 mHz (at U = U
N
, f = f
N
)
1 % of setting value or 0.5 V
1 % of setting value or 10 ms
Power Supply DC Voltage in Range
0.8 ≤ U
PS
/U
PSN
≤ 1.15
1 %
Temperature in Range
23°F or –5 °C ≤ Θ
amb
≤ 131°F or 55 °C
0.5 %/10 K
Harmonics
- Up to 10 % 3rd harmonic
- Up to 10 % 5th harmonic
1 %
1 %
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