Technical description
2 Protection functions
2.14 Intermittent transient earth fault
protection I0T> (67NT)
VM50.EN004
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77
Setting groups
There are two settings groups available. Switching between
setting groups can be controlled by digital inputs, virtual
inputs (mimic display, communication, logic) and manually.
Figure 2.14-3. Block diagram of the directional intermittent transient earth
fault stage I
0T
>.
Parameters of the directional intermittent transient earth fault
stage I
0T
> (67NT)
Parameter Value
Unit Description
Note
Status -
Blocked
Start
Trip
Current status of the stage
F
F
SCntr
Cumulative
start
counter Clr
TCntr
Cumulative trip counter
Clr
SetGrp
1 or 2
Active setting group
Set
SGrpDI
-
DIx
VIx
LEDx
VOx
Digital signal to select the
active setting group
None
Digital input
Virtual input
LED indicator signal
Virtual output
Set
Force Off
On
Force flag for status forcing for
test purposes. This is a
common flag for all stages and
output relays, too.
Automatically reset after a five
minute timeout.
Set
Io1
Io2
pu
The detected I
0
value according
the parameter "Input" below.
Uo
%
The measured U
0
value.
U
0N
= 100 %
Uo>
%
U
0
pick up level. U
0N
= 100 %
Set