ABB RELION RET670 Applications Manual page 83

1MRK 504 163-UUS A
A
CT 600/5
Wye Connected
Protected Object
ANSI13000002 V3 EN-US
Figure 14: Wye connected three-phase CT set with wye point towards the protected object
Transformer protection RET670 2.2 ANSI
Application manual
B C
I_A
I_B
I_C
Where:
1) The drawing shows how to connect three individual phase currents from a wye 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 14.
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
Section 4
Analog inputs
4
SMAI_20
ANSI13000002-3-en.vsd
77