M
AVTMTTR25 Rev C April 2008
48
Table C-2
ANSI Transformer Winding Phase Relationship
Copyright 1999
©
Megger
Winding Connection
Winding Tested
Diag
No.
IEC
Vector
Group
High-Voltage
Winding (H)
Low-Voltage
Winding (X)
Phase
Tested
Winding
Shorted
By TTR
High-
Voltage
Winding
Low-
Voltage
Winding
Measured
Turn Ratio
26
Yz1
A
B
C
H
3
- H
2
H
1
- H
3
H
2
- H
1
H
1
-(H
3
+H
2
)
H
2
-(H
1
+H
3
)
H
3
-(H
2
+H
1
)
X
1
- X
2
X
2
- X
3
X
3
- X
1
V
V
H
X
•
3
2
27
Yzn5
A
B
C
⎯
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
3
- X
0
X
1
- X
0
X
2
- X
0
V
V
H
X
•
3
28
Yz5
A
B
C
H
3
- H
2
H
1
- H
3
H
2
- H
1
H
1
-(H
3
+H
2
)
H
2
-(H
1
+H
3
)
H
3
-(H
2
+H
1
)
X
3
- X
1
X
1
- X
2
X
2
- X
3
V
V
H
X
•
3
2
29
Yzn7
A
B
C
⎯
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
0
- X
1
X
0
- X
2
X
0
- X
3
V
V
H
X
•
3
30
Yz7
A
B
C
H
3
- H
2
H
1
- H
3
H
2
- H
1
H
1
-(H
3
+H
2
)
H
2
-(H
1
+H
3
)
H
3
-(H
2
+H
1
)
X
2
- X
1
X
3
- X
2
X
1
- X
3
V
V
H
X
•
3
2