Yd3 Transformer?

[AntonNel]

Hi.
Can anyone tell me what the advantages are on using a Yd3 vector group. These transformers are feeding a paper mill plant.
Can anyone suggest reading material or papers explaining the reasons for the different vector groups.
I understand how the phase shift occur. It is why that I am not clear on.
Thanks
Anton

 

[RalphChristie]

Anton

I've written a FAQ regarding vector groups:
FAQ238-1090

Yd3-transformers are very rare in practice. Actually you can change it to either a Yd1, Yd5, Yd7, Yd9 or Yd11 through external connections (unconventional connections) without opening the transformer. What are you feeding from the transformer? Are the transformer paralleled sometimes?
If it is feeding nothing special or not paralleled at any time, I can see no reason for chosing this transformer-connection, except that it could have been found cheaper for any reason at that stage.

Regards
Ralph