VAMP 265 - 3.3. Current Transformer Supervision

Technical description
3 Supporting functions
3.3 Current transformer supervision
VM265.EN011
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103
3.3. Current transformer supervision
The relay supervise the external wiring between the relay
terminals and current transformers (CT) and the CT them
selves. Furthermore, this is a safety function as well, since an
open secondary of a CT, causes dangerous voltages.
The CT supervisor function measures phase currents. If one of
the three phase currents drops below I
min
< setting, while
another phase current is exceeding the I
max
> setting, the
function will issue an alarm after the operation delay has
elapsed.
Setting parameters of CT, CT’ supervisor CTSV ( ):
Parameter
Value
Unit
Default
Description
Imax>
0.0 … 10.0
xIn
2.0
Upper setting for CT
supervisor
Imin<
0.0 … 10.0
xIn
0.2
Lower setting for CT
supervisor
t>
0.02 … 600.0
s
0.10
Operation delay
CT on
On; Off
-
On
CT supervisor on event
CT off
On; Off
-
On
CT supervisor off event
Measured and recorded values of CT, CT’ supervisor CTSV ( ):
Parameter
Value
Unit
Description
Measured
value
ILmax
A
Maximum of phase
currents
ILmin
A
Minimum of phase
currents
Display
Imax>,
Imin<
A
Setting values as primary
values
Recorded
values
Date
-
Date of CT supervision
alarm
Time
-
Time of CT supervision
alarm
Imax
A
Maximum phase current
Imin
A
Minimum phase current