ABB Relion REQ650, Applications Manual

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Transformer
protection
Transformer
Line
Line
Setting of current input:
Set parameter
CTStarPoint 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
CTStarPoint with
Transformer as
reference object.
Correct setting is
"ToObject"
Setting of current input:
Set parameter
CTStarPoint with
Line as
reference object.
Correct setting is
"ToObject"
IEC11000020-2-en.vsd
I
s
I
s
I
p
I
p
I
p
IED
IED
IEC11000020 V2 EN
Figure 23: Example how to set CTStarPoint parameters in the IED
The figure 23 shows the most common case where the objects have their own CTs. For
the transformer protection, the protected object is the transformer. Therefore both
CTStarPoint directions should be set ToObject . For the line protection, the protected
object is the line. The line CT is earthed towards the busbar, therefore the CTStarPoint
should be set FromObject .
4.2.3.2 Example 2
Two IEDs used for protection of two objects and sharing a CT.
Section 4
1MRK 505 291-UEN A
Analog inputs
64
Application manual