ABB RELION 650 SERIES, Applications Manual

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With correct setting of the primary CT direction,
CT_WyePoint set to FromObject or ToObject, a
positive quantity always flows towards the protected object and a direction defined as Forward is
always looking towards the protected object. The following examples show the principle.
4.2.3.1 Example 1
SEMOD55055-23 v5
Two IEDs used for protection of two objects.
Transformer
protection
Transformer
Line
Line
Setting of current input:
Set parameter
CT_WyePoint with
Transformer as
reference object.
Correct setting is
"ToObject"
Forward Reverse
Definition of direction for
directional functions
Line protection
Setting of current input:
Set parameter
CT_WyePoint with
Transformer as
reference object.
Correct setting is
"ToObject"
Setting of current input:
Set parameter
CT_WyePoint with
Line as
reference object.
Correct setting is
"ToObject"
ANSI11000020-2-en.vsd
I
s
I
s
I
p
I
p
I
p
IED
IED
ANSI11000020 V2 EN-US
Figure 9: Example how to set CT_WyePoint parameters in the IED
The figure 9 shows the most common case where the objects have their own CTs. For the
transformer protection, the protected object is the transformer. Therefore both
CT_WyePoint
directions should be set
ToObject. For the line protection, the protected object is the line. The line
CT is grounded towards the busbar, therefore the
CT_WyePoint should be set FromObject.
4.2.3.2 Example 2
SEMOD55055-29 v5
Two IEDs used for protection of two objects and sharing a CT.
1MRK 505 287-UUS B Section 4
Analog inputs
Busbar protection REB650 39
Application manual
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