F1 And F2 - ABB REX 521 Technical Reference Manual, Standard Configurations

REX 521
7.1.11.
7.1.12.
88
Protection Relay
Technical Reference Manual, Standard Configurations
Uo>, Uo>> and Uo>>>
The residual overvoltage protection function blocks are designed for sensitive earth-
fault protection whenever the DT characteristic is appropriate. Suppression of
harmonics is possible.
Uo>
BS1
BS2
START
GROUP
TRIP
RESET
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Residual over voltage protection, low-set stage, Uo>, high-set stage, Uo>> and
instantaneous stage, Uo>>>
Start voltage
Operate time
Operation mode
Measuring mode
Operation accurcy
Start time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy in DT mode

f1 and f2

The frequency function blocks operate as either underfrequency or overfrequency
relays depending on whether the set operate value is above or below the rated
frequency of the relay. The operation is insensitive to harmonics and the DC
component.
Uo>>
BS1
BS2
GROUP
START
RESET TRIP
2.0...100.0 % Un
0.05...300.00 s
Not in use
Definite time
Peak-to-peak
Fundam.freq.
Note! The values below apply when f/fn = 0.95...1.05
±2.5% of set value or ±0.01 x Un
Injected voltages > 2.0 x start voltage:
internal time < 32 ms
total time < 40 ms
40...1000 ms
(Depends on the minimum pulse width set
for the trip output)
0.95
< 50 ms
±2% of set value or ±20 ms
1MRS 751802-MUM
Uo>>>
BS1
BS2
GROUP START
RESET TRIP