Raytech TR-1 - Three Phase Transformer Testing Guide; Understanding Transformer Vector Groups; HV and LV Winding Connection Charts

Raytech USA, Inc. All rights reserved Ver. 1.13 11
THREE PHASE TRANSFORMER TESTING: 10 – 0
Ratio tests on three phase transformers are carried out on a single phase basis.
Understanding the configuration, phase relationship, and vector diagrams is required.
A detailed explanation and description of terminal markings, phase relationship, and vector diagrams is contained
in specification: C57.12.70 American National Standard Terminal Markings and Connections for Distribution and
Power Transformers.
The tables on the following pages are guidelines for connecting and testing three phase transformers.
Table Key:
VECTOR GROUP:
The vector group column is the IEC vector group coding. The number indicates the phase displacement in
increments of 30 of the low side winding to the high side winding. For example a D-Y transformer with a Vector
group number of 3 would have a phase displacement of 3 x 30 or 90. The low side winding has a lagging
displacement with respect to the high side winding.
PHASE:
The transformer phase that is being tested.
HV WINDING & LV WINDING:
The transformer connections that are selected for testing.
For example: D – Y, phase “A” would require H1 & H3 to be tested against X1 & X2-X3
Note: (X2-X3 are jumpered together).
See charts on following pages:
PAGE 10
YN-yn 0
YN-yn 2
YN-yn 4
YN-yn 6
YN-yn 8
YN-yn 10
PAGE 10
YN-y 0
YN-y 2
YN-y 4
YN-y 6
YN-y 8
YN-y 10
PAGE 11
YN-zn 1
YN-zn 3
YN-zn 5
YN-zn 7
YN-zn 9
YN-zn 11
PAGE 11
YN-d 1
YN-d 3
YN-d 5
YN-d 7
YN-d 9
YN-d 11
PAGE 12
D-d 0
D-d 2
D-d 4
D-d 6
D-d 8
D-d 10
PAGE 12
D-yn 1
D-yn 3
D-yn 5
D-yn 7
D-yn 9
D-yn 11
PAGE 13
D-y 1
D-y 3
D-y 5
D-y 7
D-y 9
D-y 11
PAGE 13
D-zn 0
D-zn 2
D-zn 4
D-zn 6
D-zn 8
D-zn 10
PAGE 14
Y-yn 0
Y-yn 2
Y-yn 4
Y-yn 6
Y-yn 8
Y-yn 10
PAGE 14
Y-y 0
Y-y 2
Y-y 4
Y-y 6
Y-y 8
Y-y 10
PAGE 15
Y-zn 1
Y-zn 3
Y-zn 5
Y-zn 7
Y-zn 9
Y-zn 11
PAGE 15
Y-d 1
Y-d 3
Y-d 5
Y-d 7
Y-d 9
Y-d 11