Description
2.8 Electronic trip unit ETU
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
Manual, 10/2018, L1V30499596002-01
77
Protection functions of the ETU
ETU650 LSI
ETU660 LSIG
Ground-fault return protection pre-alarm
—
50 to 90% x I
r
(in steps of
1%)
Default value: 90%
Switchover to alternative operating values with
ground-fault current during the switch-on phase
(inrush adaptation) for tripping characteristic t=k
(fixed) possible
—
●
Default value: OFF
Setting range of the switch-on phase (inrush
adaptation)
—
0.1 to 30 s (in steps of 0.01)
Default value: 0.1
Setting range I
g
= I
n
x … during the switch-on
phase (inrush adaptation)
—
0.1 to 1 (in steps of 0.01)
Default value: 1
DAS
DAS (Arc fault mitigation)
Protection function can be enabled/disabled
●
●
Setting range for operating value I
i_arc
= I
n
x …
1.5 to 15 (in steps of 0.1)
Default value: 1.5
1.5 to 15 (in steps of 0.1)
Default value: 1.5
I-NBA
Phase current unbalance I-NBA
Protection function can be enabled/disabled
●
●
Setting range I
nba
phase current unbalance
2 to 90% (in steps of 1%)
Default value: 50%
2 to 90% (in steps of 1%)
Default value: 50%
Setting range of the delay time t
nba
for phase
current unbalance
0.50 to 60 s (in steps of 0.5)
Default value: 10 s
0.50 to 60 s (in steps of 0.5)
Default value: 10 s
Enabling/disabling of tripping on phase current
unbalance
●
●
1)
ETU powered in at least 2 phases or self-powered with auxiliary voltage. In all other cases,
the following tolerances apply:
Current setting value
Tripping time
L
Tripping between 1.05 and 1.2 x I
r
± 20 %
S
± 10 %
± 20 %
I
± 15 %
≤ 60 ms
G
± 15 %
± 20 %
Other protection functions
± 15 %
± 20 %
Enhanced protection functions - only available with
MF Advanced metering function
ETU650 LSI
ETU660 LSIG
DST
Directed short-circuit protection DST
●
●
Protection function can be enabled/disabled
●
●
Enabling/disabling of tripping on directed (direc-
tional) short-circuit protection
●
●
Setting range I
dsd
= I
n
x … in forward direction
FW (top
→
bottom)
0.6 to 10 (in steps of 0.1)
Default value: 2
0.6 to 10 (in steps of 0.1)
Default value: 2
Setting range I
dsd
= I
n
x … in backward direction
BW (bottom
→
top)
0.6 to 10 (in steps of 0.1)
Default value: 2
0.6 to 10 (in steps of 0.1)
Default value: 2