ABB Relion RES670, Applications Manual

Page: 55 / 382

With correct setting of the primary CT direction, CTStarPoint set to FromObject or
ToObject , a positive quantities always flowing towards the protected object and a
direction defined as Forward always is looking towards the protected object. The
following examples show the principle.
4.2.2.1 Example 1
SEMOD55055-23 v6
Two IEDs used for protection of two objects.
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
"FromObject"
IEC05000753=IEC05
000753=1=en=Origin
al[1].vsd
I
s
I
s
I
p
I
p
I
p
IED
IED
IEC05000753 V2 EN-US
Figure 6: Example how to set CTStarPoint parameters in the IED
Figure 6 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, direction
of the directional functions of the line protection shall be set to
Forward . This
means that the protection is looking towards the line.
4.2.2.2 Example 2
SEMOD55055-29 v7
Two IEDs used for protection of two objects and sharing a CT.
1MRK 511 407-UEN C
Section 4
Analog inputs
Phasor measurement unit RES670 2.2 IEC 49
Application manual