ABB Relion 670 series, Техническое руководство

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Different types of reset time can be selected as described in section "Inverse characteristics" .
There is a possibility to activate a preset change (
MultiPUx, x= 1, 2, 3 or 4) of the set operation
current via a binary input (enable multiplier). In some applications the operation value needs to be
changed, for example due to changed network switching state.
The function can be blocked from the binary input BLOCK. The pickup signals from the function
can be blocked from the binary input BLK.The trip signals from the function can be blocked from
the binary input BLKTR.
GUID-E3980B2D-EEDA-4BF1-A07D-E7B721130554 v6
A harmonic restrain of the directional phase overcurrent protection function OC4PTOC 51_67 can
be chosen. If the ratio of the 2nd harmonic component in relation to the fundamental frequency
component in a phase current exceeds the preset level defined by the parameter
2ndHarmStab
setting, any of the four overcurrent stages can be selectively blocked by the parameter
HarmBlockx setting. When the 2nd harmonic restraint feature is active, the OC4PTOC 51_67
function output signal ST2NDHRM will be set to the logical value
one.
a
b
a>b
BLOCK
AND
I
OP
Extract second
harmonic current
component
Extract
fundamental
current component
X
2ndHarmStab
a
b
a>b
a
b
a>b
0.07*IBase
IEC13000014-2-en.vsd
2ndH_BLOCK_Int
IEC13000014 V2 EN-US
Figure 251: Second harmonic blocking
When
DirModex is set to Forward/Reverse and Ix> is set at its minimum value, that
is, 5.0% of
IBase, the operation from the respective overcurrent step takes place at
20.0% of
IBase. This is done to avoid unintentional maloperations during
unbalanced loading conditions that might appear in power systems and the
unbalanced loading condition might lead to a neutral current in the range of 10.0%
to 15.0% of
IBase.
Section 8 1MRK 502 066-UUS B
Current protection
466
Technical manual