Type a vector group (Dyn11, YNd1, YNyn0d5) or a line from a document. Below, a second transformer can be entered: the page compares the phase displacement of the windings.
A whole line can be pasted, such as "Vector group: Dyn11" or "Dyn11 and Dyn1": the page finds the symbol in it. A Russian line typed in Cyrillic letters is read too.
Equal phase displacement is one condition; the voltage ratio and the impedance must match too. The makers’ data and the class rules govern; IEC 60076-8 covers the parallel operation of transformers.
Enter the connection symbol from a nameplate or a document: Dyn11, Yyn0, YNd1, Dd0, Yzn5, YNyn0d5, YNa0d11, or the Russian writing of GOST 11677. The page splits the symbol into its parts: the HV winding and the other windings, the neutral brought out, the auto-connection and the clock number; it shows the phase displacement on a clock face and says what the symbol means in plain words. A second transformer can be checked against the first for its phase displacement, and the request line can be copied or added to the RFQ.
Only what two independent references give the same way is decoded. There are no transformer ratings here, no tables of compatible groups and nothing on which groups ships use: the nameplate, the maker’s data and the class rules give those.
The HV winding comes first in capitals, then the other windings in small letters, in descending order of voltage: D delta, Y star, Z zigzag. N or n after a star or zigzag letter means its neutral is brought out to a terminal. a marks a winding auto-connected with the HV winding. I and i are single-phase windings.
The HV vector stands at 12 o’clock, which is 0. The figure after a winding letter is the hour its vector points at, each hour 30° of lag. Dyn11: the LV lags the HV by 330°, that is, leads it by 30°. Two windings of the same connection give only even figures, a star with a delta only odd ones.
The Russian standard GOST 11677 divides the windings by / and puts the group after a hyphen, in Cyrillic letters: de for delta, u for star, en for the neutral, avto for an autotransformer. Delta to star with the neutral, group 11, is Dyn11. Some Russian texts mark the neutral with a 0 (Y0) and write group 0 as 12.
| Symbol | Meaning | Example |
|---|---|---|
| D, d | Delta winding (capital D for the HV winding, small d for the others) | Dd0 |
| Y, y | Star winding | Yyn0 |
| Z, z | Zigzag winding | Yzn5 |
| N, n | The neutral of a star or zigzag winding brought out to a terminal (N on the HV, n on the others) | Dyn11 |
| 0 to 11 | Clock number: how far the winding lags the HV winding, in steps of 30° | YNd1 |
| a | A winding auto-connected with the HV winding (autotransformer), followed by its clock number | YNa0d11 |
| I, i | Single-phase windings: in phase (0) or opposite (6) | Ii0 |
| Third letter | A further winding, with its own clock number against the HV winding | YNyn0d5 |
The page decodes every example in this table the same way. Open windings (III, iii) and a stabilising winding (+d) are not decoded here: the references give them differently or only one gives them.
The winding letters, the neutral, the auto-connection and the clock number as a lag in 30° steps: IEC 60076-1 as set out by a reference article on vector groups, the technical library of a transformer maker, a maker’s notes on Dyn11 and Yyn0 and an engineering reference site. The Russian writing: GOST 11677-85 (the tables of connection schemes and groups) and textbook pages on transformers, which also give the rule of even and odd groups (three independent sources) and the writing Y0 and group 12. Parallel operation: the same technical library, the reference article and lecture notes on transformers; that IEC 60076-8 covers parallel operation: standards catalogues. Single-phase windings (I, i): the IEC 60076-1 text and the documentation of a load-flow program. Where the references differ or only one gives a meaning (open windings III and iii, the stabilising +d, the parity of zigzag groups), the part is not decoded.
D: the HV winding is connected in delta. y: the LV winding is connected in star. n: the LV neutral is brought out to a terminal. 11: the clock number; the LV lags the HV by 11 x 30° = 330°, which is the same as leading it by 30°. The ratings of the transformer are not in the symbol: they are on the nameplate.
Put the HV vector at 12 o’clock, the 0 of the clock face. The vector of the other winding points at the hour of its clock number, and each hour is 30° of lag. 0 is in phase, 1 is 30° behind, 6 is 180° (opposite) and 11 is 330° behind, that is, 30° ahead. The figures run from 0 to 11.
Two windings of the same connection, star and star or delta and delta, give only even clock numbers (0, 2, 4, 6, 8, 10); a star and a delta give only odd ones (1, 3, 5, 7, 9, 11). Yy1, Dd11 or Dy0 on a document usually means a letter or a figure was copied wrongly: check the nameplate. Zigzag windings are not checked this way here.
The windings are listed in descending order of rated voltage, each after the HV with its own clock number. YNyn0d5: a star HV winding with the neutral brought out, a star intermediate winding with its neutral, in phase, and a delta LV winding lagging by 150°. In YNa0d11 the a marks a winding auto-connected with the HV winding (an autotransformer), in phase, and the delta winding lags by 330°.
Yes. The Russian standard GOST 11677 divides the windings by /, the HV first, and the group figure after a hyphen: delta and star with the neutral, group 11, is the same as Dyn11. Typed with Cyrillic letters (de, u, en) or with a Greek delta, the line is read the same way; the writing Y0 for the neutral and 12 for group 0 is read too.
Not as they are: the phase displacement is 330° for one and 30° for the other. Equal phase displacement is one condition for parallel operation; the voltage ratio and the impedance must match too. The makers’ data and the class rules govern, and IEC 60076-8 covers the parallel operation of transformers.
A decoded symbol is a cross-check, not a transformer selection. Attach a photograph of the nameplate and give the rating and the voltages, and Vessel Core checks the vector group before an offer goes back.
