VAMP 257
Feeder and motor manager
Technical description
VAMP Ltd
46
VAMP 24h support phone : +358 (0)20 753 3264
VM257.EN002
Inverse time multiplier (only for
I
0
>
)
0.05 ... 20.00
(IEC)
(IEEE)
(IEEE2)
Pa
ra
m
.
k>
Ra
nge
0.5 … 20.00
(RI)
Default
1.0
Event enabling
Range:
Enabled/disabled
S_On
Start on event
Enabled
S_Off
Start off event
Enabled
T_On
Trip on event
Enabled
Pa
ra
m
.
T_Off
Trip off event
Default
Enabled
Measured and recorded values of earth fault protection:
I
0
>, I
0
>>, I
02
>, I
02
>> (50N/51N)
Parameter Value Unit Description
Measured
value
Io>, Io>>,
Io2>, Io2>>
A
Primary earth fault current Io
Display
Io>, Io>>,
Io2>, Io2>>
A
Setting value Io
SCntr
-
Cumulative start counter
TCntr
-
Cumulative trip counter
Flt
pu
The max. fault value
Recorded
values
EDly
%
Elapsed time as compared to the
set operating time; 100% =
tripping
2.3.13.
Capacitor bank unbalance protection
The manager enables versatile capacitor, filter and reactor
bank protection, with its five current measurement inputs. The
fifth input is typically useful for unbalance current
measurement of a double-wye connected unearthed bank.
Furthermore, the unbalance protection is highly sensitive to
internal faults of a bank because of the sophisticated natural
unbalance compensation. However, the location method gives
the protection a new dimension and enables easy maintenance
monitoring for a bank.
This protection scheme is specially used in double wye
connected capacitor banks. The unbalance current is measured
with a dedicated current transformer (could be like 5 A/5 A)
between two starpoints of the bank. The unbalance current is
not affected by system unbalance. However, due to
manufacturing tolerances, some amount of natural unbalance
current exists between the starpoints. This natural unbalance
current affects the settings, thus, the setting has to be
increased.
