2.5 Overcurrent protection I> (50/51)
2 Protection functions
Technical description
50
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VM50.EN004
Inverse time limitation
The maximum measured secondary current is 50xI
n
. This
limits the scope of inverse curves with high pick-up settings.
See chapter 2.23 for more information.
Cold load and inrush current handling
See chapter 3.3.
Setting groups
There are two settings groups available for each stage.
Switching between setting groups can be controlled by digital
inputs, virtual inputs (communication, logic) and manually.
Figure 2.5-1 Block diagram of the three-phase overcurrent stage I>.
Figure 2.5-2 Block diagram of the three-phase overcurrent stage I>> and
I>>>.
Parameters of the overcurrent stage I> (50/51)
Parameter Value
Unit Description
Note
Status -
Blocked
Start
Trip
Current status of the stage
F
F
TripTime
s
Estimated time to trip
SCntr
Cumulative
start
counter Clr
TCntr
Cumulative trip counter
Clr
SetGrp
1 or 2
Active setting group
Set