8.4.3.5
Settings for each step (x = 1, 2, 3 and 4)
M15282-9 v12
Operation
: Sets the protection to
On
or
Off
.
DirModex
: The directional mode of step
x
. Possible settings are
Off
/
Non-
directional
/
Forward
/
Reverse
.
Characteristx
: Selection of time characteristic for step
x
. Definite time delay and
different types of inverse time characteristics are available.
Inverse time characteristic enables fast fault clearance of high current faults at the
same time as selectivity to other inverse time phase overcurrent protections can be
assured. This is mainly used in radial fed networks but can also be used in meshed
networks. In meshed networks, the settings must be based on network fault
calculations.
To assure selectivity between different protections, in the radial network, there has
to be a minimum time difference
D
t between the time delays of two protections. To
determine the shortest possible time difference, the operation time of protections,
breaker opening time and protection resetting time must be known. These time
delays can vary significantly between different protective equipment. The
following time delays can be estimated:
Protection operate time:
15-60 ms
Protection resetting time:
15-60 ms
Breaker opening time:
20-120 ms
The different characteristics are described in the technical reference manual.
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.
INx>
: Operate residual current level for step
x
given in % of
IB
.
INx>Max
and
INx>Min
should only be changed if remote setting of operation
current level,
INx>
, is used. The limits are used for decreasing the used range of
the
INx>
setting. If
INx>
is set outside
INx>Max
and
INx>Min
, the closest of the
limits to
INx>
is used by the function. If
INx>Max
is smaller than
INx>Min
, the
limits are swapped.
kx
: Time multiplier for the dependent (inverse) characteristic for step
x
.
IMinx
: Minimum operate current for step
x
in % of
IB
. Set
IMinx
below
INx>
for
every step to achieve ANSI reset characteristic according to standard. If
IMinx
is
set above
INx>
for any step, signal will reset at current equals to zero.
1MRK 505 393-UEN B
Section 8
Current protection
Line differential protection RED650 2.2 IEC
173
Application manual
Summary of Contents for RED650
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