1 2 3 4 A - SIPROTEC

Functions
2.1 General
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The mode of connection CONNECTION S2 (address 324) and the vector group numeral VECTOR GRP S2
(address 325) must match the transformer data of the transformer windings at side 2. The vector group numeral
states the phase displacement of side 2 against the reference winding, side 1. It is defined according to IEC as
the multiple of 30°. If the higher voltage side is the reference (side 1), you may take the data directly from the
vector group designation. For instance, for a transformer Yd5 is CONNECTION S2 = D and VECTOR GRP S2
= 5. Every vector group from 0 to 11 can be set provided it is possible (for instance, Yy, Dd and Dz allow only
even, Yd, Yz and Dy allow only odd numerals). For the auto-connected winding of auto-transformers and for
single-phase transformers, only Y 0 is permissible.
If a reference winding other than the higher voltage one is used, it must be noted that this changes the vector
group numeral: e.g. a Yd5 transformer is regarded from the lower voltage side as Dy7.
Figure 2-11 Change of the transformer vector group if the lower voltage side is the reference side —
example
If the power transformer includes more than 2 windings or assigned sides, similar considerations apply for the
further windings (winding 4 and 5 only with 7UT635). If you have declared the starpoint connections of an autotransformer
bank as a separate side in order to establish a current comparison protection for each of the windings
(refer also to Figure 2-7 and the respective notes under „Auto-Transformer Banks“), no settings will be
presented for this side as they would have no meaning for this application. If in an auto-transformer side S3 or
S4 is a compensation winding, the mode of connection is always assumed to be „D“, and only odd-numbered
vector groups can be selected for these sides.
For the winding assigned to side 3, the following data are relevant:
• Address 331 UN-PRI SIDE 3 the primary rated voltage (consider regulating range),
• Address 332 SN SIDE 3 the primary rated apparent power,
• Address 333 STARPNT SIDE 3 the starpoint treatment,
• Address 334 CONNECTION S3 the winding connection mode,
• Address 335 VECTOR GRP S3 the vector group numeral.
For the winding assigned to side 4, the following data are relevant:
• Address 341 UN-PRI SIDE 4 the primary rated voltage (consider regulating range),
• Address 342 SN SIDE 4 the primary rated apparent power,
• Address 343 STARPNT SIDE 4 the starpoint conditioning,
• Address 344 CONNECTION S4 the winding connection mode,
• Address 345 VECTOR GRP S4 the vector group numeral.
SIPROTEC, 7UT6x, Manual
C53000-G1176-C230-2, Release date 06.2012