ABB Relion 670 Series Applications Manual page 532

Section 18
Monitoring
Table 84: LV side CTs input channels
Setting parameter
CTprim
CTsec
CTStarPoint
7. Enter the values for the general settings of the PTRSTHR function as shown in
Table 85: Through fault monitoring function general settings
Setting parameter
ConnTypeW1
ConnTypeW2
ClockNumberW2
ZSCurrCor
OLTCWinding
LowTapOLTC1
RatedTapOLTC1
HighTapOLTC1
StepSizeOLTC1
1) Zero-sequence current is removed by connecting main CTs in delta, so winding current with zero
Summary and conclusions
The IED can be used for through fault monitoring of transformers with main CTs are either star
or delta connected. However, the IED is designed with an assumption that all main CTs are star
connected. The IED can be used in applications where the main CTs are delta connected. For
such applications, consider the following:
• The ratio for delta connected CTs shall be set √3 = 1.732 times smaller than the actual
individual phase CT ratio.
• The power transformer vector group shall typically be set as Yy0 since the compensation
for power transformer the actual phase shift is provided by the external delta CT
connection.
• The zero sequence current is removed by the main CT delta connections. Therefore, when
star winding sides, the CTs are connected in delta the zero sequence current correction
shall be set to
Table below summarizes the most commonly used star-delta vector groups around the world
and provides information about the required type of main CT delta connection on the star side
of the transformer.
526
sequence current is not possible
Off in the IED.
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Selected value for solution 1 (star
connected CT)
500
5
ToObject
Select value for solution 1 (star
connected CT)
WYE (Y)
WYE (Y)
0 [0 deg]
Off
Winding 1 (W1)
1
12
23
1.5%
1MRK 511 401-UEN Rev. K
Selected value for solution 2
(delta connected CT)
500
=
289
3
EQUATION1892 V1 EN-US
(To compensate for delta
connected CTs)
5
ToObject
Table
Selected value for solution 2
(delta connected CT)
WYE (Y)
WYE (Y)
0 [0 deg]
1)
Off
Winding 1 (W1)
1
12
23
1.5%
GUID-CC53DA83-EBDA-407A-9FFB-153600B4B3D2 v1
Bay control REC670
Application manual
85.