ABB RET670 Applications Manual page 41

1MRK504116-UUS C
Figure 3: Example how to set CT_WyePoint parameters in the IED
Application manual
Transformer
I
p
Transformer
I
protection
s
Setting of current input:
Set parameter
CT_WyePoint with
Transformer as
reference object.
Correct setting is
"ToObject"
ANSI05000753 V1 EN
Figure 2: Example how to set CT_WyePoint parameters in the IED
The figure 2 shows the normal case where the objects have their own CTs. The settings
for CT direction shall be done according to the figure. To protect the line the direction
of the directional functions of the line protection shall be set to Forward. This means
that the protection is looking towards the line.
Example 2
Two IEDs used for protection of two objects and sharing a CT.
This example is similar to example 1, but here the transformer is feeding just one line
and the line protection uses the same CT as the transformer protection does. The CT
direction is set with different reference objects for the two IEDs though it is the same
current from the same CT that is feeding the two IEDs. With these settings the
directional functions of the line protection shall be set to Forward to look towards the
line.
Example 3
One IED used to protect two objects.
I
I
p
p
I
s
Setting of current input:
Set parameter
CT_WyePoint with
Transformer as
reference object.
Correct setting is
"ToObject"
Section 3
IED application
Line
Line
Reverse Forward
Definition of direction for
directional functions
Line protection
Setting of current input:
Set parameter
CT_WyePoint with
Line as
reference object.
Correct setting is
"FromObject"
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