VAMP 265 - 2.6. Current Unbalance Protection I2>, I’2> (46)

2.6 Current unbalance protection
I2>, I’2> (46)
2 Protection functions
Technical description
60
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VM265.EN011
Recorded values of the overcurrent stages (8 latest faults)
I>, I>>, I>>> (50/51)
Parameter
Value
Unit
Description
yyyy-mm-dd
Time stamp of the recording, date
hh:mm:ss.ms
Time stamp, time of day
Type
1-N
2-N
3-N
1-2
2-3
3-1
1-2-3
Fault type
Ground fault
Ground fault
Ground fault
Two phase fault
Two phase fault
Two phase fault
Three phase fault
Flt
xIgn
Maximum fault current
Load
xIgn
1 s average phase currents before
the fault
EDly
%
Elapsed time of the operating time
setting. 100% = trip
SetGrp
1
2
Active setting group during fault
2.6. Current unbalance protection I
2
>, I’
2
>
(46)
The current unbalance stage protects against unbalanced
phase currents and single phasing. The protection is based on
the negative sequence current.
Both definite time and inverse time characteristics are
available. The inverse delay is based on Equation 2.6-1. Only
the base frequency components of the phase currents are used
to calculate the negative sequence value I
2
.
Inverse delay
The inverse delay is based on the following equation.
Equation 2.6-1
2
2
2
2
1
K
I
I
K
t
N










, where
t
=
Operation time
K
1
=
Delay multiplier
I
2
=
Measured and calculated negative sequence phase
current of fundamental frequency.
I
N
=
Rated current