VAMP Ltd
Feeder and motor manager
Technical description
VAMP 257
VM257.EN002
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63
situation stays on longer than the delay setting, a trip signal is
issued.
The pick-up setting range is from –200 % to +200 % of the
nominal apparent power S
n
. The nominal apparent power is
determined by the configured voltage and current transformer
values.
Equation 2.3.19-1
3
Pr
Pr
⋅
⋅
=
imary
Rated
imary
Rated
n
CT
VT
S
There are two identical stages available with independent
setting parameters.
Setting parameters of P< and P<< stages:
Parameter Value
Unit Default
Description
P<, P<<
-200.0...200.0
%Sn -4.0 (P<),
-20.0(P<<)
P<,P<< pick-up setting
t< 0.3…300.0
s
1.0
P<, P<< operational
delay
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
Measured and recorded values of P< and P<< stages:
Parameter Value Unit Description
Measured
value
P
kW
Active
power
SCntr
-
Start counter (Start) reading
TCntr
-
Trip counter (Trip) reading
Recorded
values
Flt
%Sn Max value of fault
Recorded
values
EDly
%
Elapsed time as compared to
the set operating time, 100%
= tripping
2.3.20.
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.