Megger TTR310 - Notes to Table 5-5

SETUP AND CONNECTIONS
AVTMTTR310 Rev 8 May 2016
47
Notes to Table 5-5
Transformer terminal markings for power transformers marked in accordance
with requirements of International Standard CEI/IEC 76-1:2011.
Definition of Symbol Designations
1U, 1V, 1W External terminals on HV transformer winding
(alternate notation U, V, W).
2U, 2V, 2W External terminals on LV transformer winding
(alternate notation u, v, w).
1N External neutral terminal on HV transformer winding
(alternate notation N).
2N External neutral terminal on LV transformer winding
(alternate notation n).
* Inaccessible neutral point on HV or LV transformer winding.
U1 Nameplate voltage rating (line-to-line) of HV transformer
winding.
U2 Nameplate voltage rating (line-to-line) of LV transformer
winding.
U, V, W Phase tested.
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.