2.9 Undercurrent protection I< (37)
2 Protection functions
Technical description
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VM259.EN007
2.9.
Undercurrent protection I< (37)
The undercurrent unit measures the fundamental frequency
component of the phase currents.
The stage I< can be configured for definite time characteristic.
Parameters of the undercurrent stage I< (37):
Parameter
Value/unit
Description
Measured
value
ILmin
A
Min. value of phase currents
I
L1
…I
L3
in primary value
Setting
values
I<
xIn
Setting value as per times Imot
t<
S
Operation time [s]
Recorded
values
SCntr
Start counter (Start) reading
TCntr
Trip counter (Trip) reading
Type
1-N, 2-N
3-N
Fault type/single-phase fault
e.g.: 1-N = fault on phase
L1
1-2, 2-3
1-3
Fault type/two-phase fault
e.g.: 2-3 = fault between
L2
and
L3
1-2-3
Fault type/three-phase fault
Flt
%
Min. value of fault current as
per times Imot
Load
%
1s mean value of pre-fault
currents I
L1
—I
L3
EDly
%
Elapsed time as compared to
the set operate time, 100% =
tripping