Transformer Vector Group 2

[alanElec]

We usually use Dyn11 transformers in distribution side.For one of new projects i got an offer from a company and in their technical specification the vector group was Dyn5.I understand that Dyn5 means a phase difference of 180 dgree.Is it possible to connect such a transformer to the existing grid..?

 

[odlanor]

see

http://www.estv.ipv.pt/PaginasPessoais/vasco/Doc NET/TRtri_indicehora.pdf

page 12

 

[stevenal]

Similar question discussed at faq238-1154.

 

[alanElec]

Thanks Steven i went through the post,still it is not clear for me whether i can use Dyn5 transformers in a grid using Dyn11 transformers.?

 

[davidbeach]

By careful selection of which phase is connected to which terminal, you can wire it so that it functions as a Dyn11. Any Dy transformer can produce any of the Dy vector groups.

 

[alanElec]

thanks ddavid..can u tel me how to rewire Dyn5 to obtain Dyn11 configuration..i mean 30 degree phase diff

 

[stevenal]

You do realize this is only an issue if transformers are paralleled, right?

 

[davidbeach]

If the Dyn5 is connected X1-A, X2-B, and X3-C, then you can get to Dyn1 by connecting X1-B, X2-C, and X3-A. The you can use the referenced FAQ to get from Dyn1 to Dyn11.

 

[alanElec]

Steven,connecting a transformer to supply implies paralleling it with other transformers ryt??Forgive me if its wrong,I'm a newbie.

 

[davidbeach]

It is paralleled only if it is connected on both the high- and low-sides to other sources. If only the high side is connected to other sources but the low side is only connected to radial load with no other source of supply it is not in parallel.

 

[alanElec]

Hv side is connected to 11Kv ring via Ring main unit and the LV side is connected to load..Im talking about a dedicated transformer used only for serving a particular district cooling plant equipments..

 

[davidbeach]

Then no, it's not paralleled and the vector group is irrelevant.

 

[alanElec]

so i can use a dyn5 transformer without any changes in the external connections..