Megger TTR310 - Notes to Table 5-4

SETUP AND CONNECTIONS
AVTMTTR310 Rev 8 May 2016
35
Notes to Table 5-4
Transformer terminal markings for distribution and power transformers marked
in accordance with requirements of American National Standard Institute, Inc
(ANSI) standard C57.12.70 – 2011.
Definition of Symbol Designations
H
1
, H
2
, H
3
External terminals on HV transformer winding.
X
1
, X
2
, X
3
External terminals on LV transformer winding.
H
0
External neutral terminal on HV transformer winding.
X
0
External neutral terminal on LV transformer winding.
* Inaccessible neutral point on HV or LV transformer winding.
V
H
Nameplate voltage rating (line-to-line) of HV transformer winding.
V
X
Nameplate voltage rating (line-to-line) of LV transformer winding.
A, B, C Winding tested on HV side of transformer.
a, b, c Winding tested on LV side of transformer.
IEC Vector Group Coding
The letters indicate the three-phase winding connections; D, Y, and Z designate
the HV side winding; d, y, and z designate the LV side winding. D and d
represent a delta connection, Y and y represent a wye connection, and Z and z
represent a zigzag connection. N and n indicate that the neutral point of a star or
zigzag connected winding is accessible on the respective HV or LV side winding.
The number indicates the phase displacement (lag) of the LV winding with
respect to the HV winding in units of 30º.
For example, 0 = 0º lag, 1 = 30º lag, 2 = 60º lag, 6 = 180º lag, 11 = 330º lag.