VAMP 257 - Reverse Power and Underpower Protection

VAMP 257 Feeder and motor manager
Technical description
VAMP Ltd
62
VAMP 24h support phone : +358 (0)20 753 3264
VM257.EN002
Setting parameters of undervoltage stages:
U<, U<<, U<<< (27)
Parameter Value Unit Default Description
U<, U<<,
U<<<
20 … 120 %Un 80 (U<)
70 (U<<, U<<<)
Undervoltage
setting
t<, t<<,
t<<<
0.08 … 300.00
0.06 … 300.00
s 20.00 (U<)
2.00 (U<<, U<<<)
Definite
operation time
NoCmp 0…80 %Un 10
Self-blocking
value
ReleaseDly 0.06…300.0 s -
Release delay
(only U<)
Hysteresis 0.1…20.0 % -
Deadband
(only U<)
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 undervoltage stages:
U<, U<<, U<<< (27)
Parameter Value Unit Description
Measured
value
Umin V
Minimum value of line
voltages
SCntr -
Start counter (Start)
reading
TCntr -
Trip counter (Trip)
reading
Flt %Un The min. fault value
Recorded
values
EDly %
Elapsed time as
compared to the set
operating time, 100%
= tripping
2.3.19. Reverse power and underpower protection
(32)
Reverse power function can be used for generators against
motoring to protect the prime mover or to disconnect a motor in
case the supply voltage is lost and thus prevent power
generation by the motor. Underpower function can also be used
to detect loss of load of a motor.
Reverse power and underpower function is sensitive to active
power. For reverse power function the pick-up value is
negative. For underpower function a positive pick-up value is
used. Whenever the active power goes under the pick-up value,
the stage picks up and issues a start signal. If the fault