Table 26: Inverse time characteristics
Curve name
ANSI Extremely Inverse
ANSI Very Inverse
ANSI Normal Inverse
ANSI Moderately Inverse
ANSI/IEEE Definite time
ANSI Long Time Extremely Inverse
ANSI Long Time Very Inverse
ANSI Long Time Inverse
IEC Normal Inverse
IEC Very Inverse
IEC Inverse
IEC Extremely Inverse
IEC Short Time Inverse
IEC Long Time Inverse
IEC Definite Time
User Programmable
ASEA RI
RXIDG or RD (logarithmic)
The different characteristics are described in
Technical manual
.
Ix>
: Operate phase current level for step
x
given in % of
IB
.
Ix>Max
and
Ix>Min
should only be changed if remote setting of operation current level,
Ix>
, is
used. The limits are used for decreasing the used range of the
Ix>
setting. If
Ix>
is set outside
Ix>Max
and
Ix>Min
, the closest of the limits to
Ix>
is used by the function. If
Ix>Max
is smaller
than
Ix>Min
, the limits are swapped.
tx
: Definite time delay for step
x
. The definite time
tx
is added to the inverse time when inverse
time characteristic is selected. Note that the value set is the time between activation of the
start and the trip outputs.
kx
: Time multiplier for inverse time delay for step
x
.
IMinx
: Minimum operate current in % of
IB
for all inverse time characteristics, below which no
operation takes place.
IMinx
: Minimum operate current for step
x
in % of
IBase
. Set
IMinx
below
Ix>
for every step to
achieve ANSI reset characteristic according to standard. If
IMinx
is set above
Ix>
for any step
the ANSI reset works as if current is zero when current drops below
IMinx
.
txMin
: Minimum operate time for all inverse time characteristics. At high currents the inverse
time characteristic might give a very short operation time. By setting this parameter the
operation time of the step can never be shorter than the setting. Setting range: 0.000 -
60.000s in steps of 0.001s.
IxMult
: Multiplier for scaling of the current setting value. If a binary input signal ENMULTx
(enableMultiplier) is activated the current operation level is increased by this setting constant.
Setting range: 1.0-10.0
Section 7 1MRK 505 370-UEN D
Current protection
146 Busbar protection REB670
Application manual
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