ABB REC670 Applications Manual page 74

Section 4
Analog inputs
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
68
L2 L3
IL1
IL2
IL3
IN
Where:
1) 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.
2) 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 13.
• CTprim=600A
CTsec=5A
•
CTStarPoint=ToObject
•
Ratio of the first two parameters is only used inside the IED. 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.
Table continues on next page
IED
1
2
3
1MRK 511 401-UEN A
4
SMAI2
BLOCK AI3P
REVROT AI1
5
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AIN
IEC13000002-4-en.vsdx
Bay control REC670 2.2 IEC
Application manual