Siemens SIPROTEC 4 7UT6 Series Manual page 45

[beispiel-topologie-dreiwicklungstransformators-270503-st, 1, en_GB]
Figure 2-4
Sides:
S1 High voltage side of the main protected object (power transformer)
S2 Low voltage side of the main protected object (power transformer)
S3 Tertiary winding side of the main protected object (power transformer)
Measuring locations 3-phase, assigned:
M1 Measuring location, assigned to the main protected object, side 1
M2 Measuring location, assigned to the main protected object, side 2
M3 Measuring location, assigned to the main protected object, side 3
Special Considerations on Auto-Transformers
As mentioned above, the common windings on auto-transformers must always be defined as S1 and S2. A
third side may be present if the compensation winding is dimensioned as power winding (tertiary winding)
and accessible (Figure
metrization of the autotransformer, one must always start with the auto-winding.
[topologie-spartransformator-tertiaerwicklung-ausgleich-270503-st, 1, en_GB]
Figure 2-5
Sides:
S1 High voltage side of the main protected object (auto-transformer)
S2 Low voltage side of the main protected object (auto-transformer)
S3 Tertiary winding side (accessible compensation winding) of the main protected object
Measuring locations 3-phase, assigned:
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
Example of a topology on a three-winding transformer
2-5). In this example we have 3 sides and 4 assigned measuring locations. During para-
Topology of an auto-transformer with a compensation winding which is used as tertiary
winding
Functions
2.1 General
45