Megger AVTMTTR100 - Page 38

M
AVTMTTR100-ENG Rev 6 Nov 2015
30
Table 5-2. ANSI Transformer Winding Phase Relationship
Copyright 2009 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 Remarks
20 Yyn0
A+C
B+A
C+B
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
1
- X
3
X
2
- X
1
X
3
- X
2
No
accessible
neutral on
high-voltage
winding
21 Yy0
A
B
C
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
1
- X
3
X
2
- X
1
X
3
- X
2
No
accessible
neutral both
wye windings
22 YNy6
A
B
C
H
2
- H
0
H
3
- H
0
H
1
- H
0
H
1
-(H
2
-H
0
)
H
2
-(H
3
-H
0
)
H
3
-(H
1
-H
0
)
X
2
- X
1
X
3
- X
2
X
1
- X
3
No
accessible
neutral on
low-voltage
winding
23 Yyn6
A+C
B+A
C+B
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
3
- X
1
X
1
- X
2
X
2
- X
3
No
accessible
neutral on
high-voltage
winding
24 Yy6
A+C
B+A
C+B
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
3
- X
1
X
1
- X
2
X
2
- X
3
No
accessible
neutral on
both wye
windings
25 Yzn1
A
B
C
H
1
- H
3
H
2
- H
1
H
3
- H
2
X
1
- X
0
X
2
- X
0
X
3
- X
0
No
accessible
neutral on
wye winding
V
V
H
X
V
V
H
X
V
V
H
X
V
V
H
X
V
V
H
X
V
V
H
X
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