Technical Data
4.17 Frequency Protection (ANSI 81)
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
491
4.17 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 66.00 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
Δf = | Pickup Value – Dropout Value | 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 direct voltage in range 0.8 ≤ U
Aux
/U
AuxN
≤ 1.15 1 %
Temperature in range 23.00 °F (–5 °C) ≤ Θ
amb
≤ 131.00 °F (55 °C) 0.5 %/10 K
Harmonics
- Up to 10 % 3rd harmonic
- Up to 10 % 5th harmonic
1 %
1 %