VAMP 257 - Overfrequency and Underfrequency Protection (81 H;81 L)

VAMP 257 Feeder and motor manager
Technical description
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VM257.EN002
If a stage is configured as an underfrequency stage then it
functions as explained in paragraph 2.3.21.
When a stage is configured as an overfrequency stage, it starts
if the actual value of the frequency exceeds the setting value. If
the overfrequency situation continues after the start delay has
elapsed, the function trips.
Figure 2.3.20-1. Block diagram of the overfrequency stages f> and f>>
Setting parameters of overfrequency and underfrequency
stages:
f><, f>><< (81)
Parameter Value Unit Default Description
f><, f>><< 40.0…70.0 Hz 51.0 (f><)
52.0 (f>><<)
Frequency setting
t><, t>><< 0.10…300.0 s 0.20 (t><)
0.10 (t>>><)
Definite operation
time
S_On
Enabled;
Disabled
- Enabled Start on event
S_Off
Enabled;
Disabled
- Enabled Start off event
T_On
Enabled;
Disabled
- Enabled Trip on event
T_Off
Enabled;
Disabled
- Enabled Trip off event
Mode > or < . >
Frequency protection
mode
LVBlck 2…100 %Un 40
Configurable low
voltage blocking limit.
Common for f><, f<
and f><><, f<<