What does Dd0, Dyn11, YNd5 etc. mean? First symbol/symbols, capital letters: HV winding connection. Second symbol/symbols, small letters: LV winding connection. Third symbol, number: Phase displacement expressed as the clock hour number.

Winding connection designations High Voltage Always capital letters Delta -D Star -S Interconnected star - Z Neutral brought out - N Low voltage Always small letters Delta -d Star -s Interconnected star - z Neutral brought out - n

Phase displacement Phase rotation is always anti-clockwise. (international adopted convention) Use the hour indicator as the indicating phase displacement angle. Because there are 12 hours on a clock, and a circle consists out of 360, each hour represents 30. Thus 1 = 30, 2 = 60, 3 = 90, 6 = 180 and 12 = 0 or 360. The minute hand is set on 12 o'clock and replaces the line to neutral voltage (sometimes imaginary) of the HV winding. This position is always the reference point. Because rotation is anti-clockwise, 1 = 30 lagging (LV lags HV with 30)and 11 = 330 lagging or 30 leading (LV leads HV with 30)

To summarise: Dd0 Delta connected HV winding, delta connected LV winding, no phase shift between HV and LV. Dyn11 Delta connected HV winding, star connected LV winding with neutral brought out, LV is leading HV with 30 YNd5 Star connected HV winding with neutral brought out, delta connected LV winding, LV lags HV with 150 After some comments I've decided to include the following: The phase-bushings on a three phase transformer are marked either ABC, UVW or 123 (HV-side capital, LV-side small letters) Two winding, three phase transformers can be devided into four main categories (Clock hour number and phase displacement of those most frequently encountered in practice in brackets)

Group Group Group Group

I II III IV

- (0 o'clock, 0) - delta/delta, star/star - (6 o'clock, 180) - delta/delta, star/star - (1 o'clock, -30) - star/delta, delta/star - (11 o'clock, +30) - star/delta, delta/star

(Minus indicates LV lagging HV, plus indicates LV leading HV) Group I Example: Dd0 (no phase displacement between HV and LV) The conventional method is to connect the red phase on A/a, Yellow phase on B/b, and the Blue phase on C/c. Other phase displacements are possible with unconventional connections (for instance red on b, yellow on c and blue on a) By doing some unconventional connections externally on one side of the trsf, an internal connected Dd0 transformer can be changed either to a Dd4(-120) or Dd8(+120) connection. The same is true for internal connected Dd4 or Dd8 transformers. Group II Example: Dd6 (180 displacement between HV and LV) By doing some unconventional connections externally on one side of the trsf, an internal connected Dd6 transformer can be changed either to a Dd2(-60) or Dd10(+60) connection. Group III Example: Dyn1 (-30 displacement between HV and LV) By doing some unconventional connections externally on one side of the trsf, an internal connected Dyn1 transformer can be changed either to a Dyn5(-150) or Dyn9(+90) connection. Group IV Example: Dyn11 (+30 displacement between HV and LV) By doing some unconventional connections externally on one side of the trsf, an internal connected Dyn11 transformer can be changed either to a Dyn7(+150) or Dyn3(-90) connection. Additional Note By doing some unconventional connections externally on both sides of the trsf, an internal connected groupIII or groupIV transformer can be changed to any of these two groups. Thus, an internal connected Dyn1 transformer can be changed to either a: Dyn3, Dyn5, Dyn7, Dyn9 or Dyn11 transformer, by doing external changes on both sides of the trsf. This is just true for star/delta or delta/star connections. Changes for delta/delta or star/star transformers between groupI and groupII can just be done internally.

Ce inseamna Dd0, Dyn11, etc YNd5. nseamn? Prima simbol / simboluri, litere de capital: conexiune HV lichidare. n al doilea rnd simbol / simboluri, litere mici: LV conexiune de lichidare. Simbol al treilea rnd, numrul: deplasarea Faza Exprimat ca numr de or.

nfurrii Denumirile de conectare High Voltage ntotdeauna de capital scrisori Delta - D Star - Y Interconectate stele - Z Neutru-a scos - N Minima litere ntotdeauna mici de tensiune Delta - d Star - y Interconectate stele - z Neutru-a scos - n

Faza deplasare Faza de rotaie este ntotdeauna anti-sensul acelor de ceasornic. (Adoptat conveniilor internaionale) Utilizai indicatorul de or ca indicnd unghiul de deplasare de faz. Pentru c sunt 12 ore pe un ceas, i un cerc format din 360 , 30 reprezint fiecare or. Astfel, o = 30 , 2 = 60 , 3 = 90 , 6 = 12 = 0 i 180 sau 360 . Minutarul este ora 12 i nlocuiete setare de pe-the-line pentru tensiune neutru (uneori imaginare) de lichidare HV. Aceast poziie este ntotdeauna punctul de referin. Deoarece de rotaie este anti-sensul acelor de ceasornic, a = 30 rmas (LV GAL-uri cu HV 30 ) i 11 = 330 30 sau mai puin dezvoltate de conducere (LV Oportunitati HV cu 30 )

Pentru a rezuma: Dd0 Delta conectat lichidare HV, delta legate de lichidare LV, nu defazaj ntre IT i JT. Dyn11 Delta conectat lichidare HV, LV stele legate de lichidare, cu neutru-a scos, LV de IT este lider cu 30 YNd5 Steaua legate de lichidare HV cu neutru de lichidare a scos, delta conectat LV, LV lag-uri de IT cu 150 Dup unele comentarii am decis s includ urmtoarele:

Faza de trei cuzinet transformator faze suntei pe un marcate Fie ABC sau 123 UVW (HVpartea de capital, LV-side litere mici) Dou lichidare, trifazate transformatoare pot fi n patru categorii principale mprit (or numrul ceas i deplasarea faz de cele mai frecvent ntlnite n practic, n paranteze) Grupa I - (12, 0 ) - delta / triunghi, stea / stele Grupul II - (06, 180 ) - delta / triunghi, stea / stele Grupul III - (01, -30 ) - stea / triunghi, triunghi / stea Grupa IV - (11, 30 ) - stea / triunghi, triunghi / stea (Minus indic Lagging LV LV IT de conducere HV Indic plus) Grupul I Exemplu: Dd0 (nr deplasare de faz dintre IT i LV) Metoda convenional este de a conecta faza de rou pe A / a, faza de galben pe B / b, i faza de albastru pe C / C. Deplasari Alte Faza sunt posibile conexiuni cu neconvenionale (de exemplu rou pe b, c pe galben i albastru pe o) Prin a face unele conexiuni neconventionale exterior, pe o parte a trsf, un transformator de interne pot fi conectate Dd0, fie au schimbat ntr-o DD4 (- 120 ) sau DD8 (120 ) de conectare. Acelai lucru este valabil pentru intern sau conectate DD4 DD8 transformatoare. Grupul II Exemplu: Dd6 (180 deplasarea ntre IT i LV) Prin a face unele conexiuni neconventionale extern pe o parte a trsf, un transformator de interne pot fi conectate Dd6, fie au schimbat ntr-o DD2 (-60 C) sau DD10 (+60 ) de conectare. Grupul III Exemplu: DYN1 (-30 deplasare ntre IT i LV) Prin a face unele conexiuni neconventionale extern pe o parte a trsf, un transformator de interne pot fi conectate DYN1, fie au schimbat ntr-o Dyn5 (-150 C) sau Dyn9 (90 ) de conectare. Grupa IV Exemplu: Dyn11 (+30 deplasare ntre IT i LV) Prin a face unele conexiuni neconventionale extern pe o parte a trsf, un transformator de interne pot fi conectate Dyn11, fie au schimbat ntr-o Dyn7 (150 ) sau Dyn3 (-90 ) de conectare. Note suplimentare Prin a face unele conexiuni neconventionale extern pe ambele pri ale trsf, intern sau conectat groupIII groupIV transformator poate fi schimbat la oricare dintre aceste dou grupuri. Astfel, un transformator intern conectat poate fi modificat pentru a DYN1 Fie la: Dyn3, Dyn5, Dyn7, Dyn9 Dyn11 sau transformator, de a face modificri externe pe ambele pri ale trsf. Acest lucru este valabil doar pentru conexiuni stea / triunghi sau triunghi / stea. Modificri pentru delta / delta sau stea / stele transformatoare ntre grup i de grup pot fi la fel face pe plan intern.