ABB RELION 650 Series Applications Manual page 46

Section 4
Analog inputs
L1
CT 600/5
Star Connected
Protected Object
IEC13000002 V4 EN-US
Figure 9: Star connected three-phase CT set with star point towards the protected object
Where:
1)
2)
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40
L2 L3
IL1
IL2
IL3
IN
The drawing shows how to connect three individual phase currents from a star connected three-
phase CT set to the three CT inputs of the IED.
The current inputs are located in the TRM. It shall be noted that for all these current inputs the
following setting values shall be entered for the example shown in Figure 9.
'
• CTprim=600A
• CTsec=5A
• CTStarPoint=ToObject
Inside the IED only the ratio of the first two parameters is used. The third parameter
(CTStarPoint=ToObject) as set in this example causes no change on the measured currents. In other
words, currents are already measured towards the protected object.
IED
1
2
3
1MRK 505 363-UEN A
4
SMAI2
BLOCK AI3P
REVROT AI1
5
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AIN
IEC13000002-4-en.vsdx
Application manual