Example On How To Connect A Star Connected Three-Phase Ct Set To The Ied - ABB Relion REC670 Applications Manual

1MRK 511 358-UEN A
4.2.2.5 Example on how to connect a star connected three-phase CT set to the
IED
Figure 13
It gives also an overview of the actions which are needed to make this measurement available
to the built-in protection and control functions within the IED as well.
L1
CT 600/5
Star Connected
Protected Object
IEC13000002 V4 EN-US
Figure 13: Star connected three-phase CT set with star point towards the protected object
Where:
1)
2)
Table continues on next page
Application manual
gives an example about the wiring of a star connected three-phase CT set to the IED.
For correct terminal designations, see the connection diagrams valid for the
delivered IED.
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 Figure13.
'
• 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
Section 4
Analog inputs
SEMOD55055-352 v9
4
SMAI2
BLOCK AI3P
REVROT AI1
5
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AIN
IEC13000002-4-en.vsdx
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