VAMP 135 - Overfrequency and Underfrequency Protection (81 H;81 L)

VAMP Ltd
Over-, under-, residual voltage and
frequency relay
Technical description
VAMP 135
VM135.EN008 VAMP 24h support phone : +358 (0)20 753 3264
13
2.3.4. Overfrequency and underfrequency
protection (81H/81L)
The overfrequency and underfrequency protection consist of
two separately adjustable frequency stages (stage f>< or
abbreviated form fX and f>><< or abbreviated form fXX). The
protection stages operate with definite time characteristics.
The stages can be separately configured as either
overfrequency or underfrequency stages. The frequency
function measures the frequency based on the measured
voltages depending on the configurations of the relay.
If a stage is configured as an underfrequency stage then it
functions as explained in paragraph 2.3.5.
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 2.3.4-1. Block diagram of the overfrequency stages f> and f>>
Setting parameters of overfrequency and underfrequency
stages:
f><, f>><< (81)
f><, f>><< (81)f><, f>><< (81)
f><, f>><< (81)
Parameter
ParameterParameter
Parameter Value
ValueValue
Value Unit
UnitUnit
Unit Defau
DefauDefau
Default
ltlt
lt Description
DescriptionDescription
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