Vector Group Changing 1

[cunin]

Gentelmen
Could you please explain using unconventional connections externally on both sides of the transformer. How a Dyn1 transforemer can be changed to either a Dyn3,Dyn5, Dyn7, Dyn9, or Dyn11 transformer.
I thank you in advance for your replies.

 

[veritas]

Hi cunin

I did this exercise a couple of years ago. I do not know where my vector diagrams are now but what I can tell you is you can make a Dyn1 trfr behave like a Dyn11, Dyn3 or Dyn7 by phase swapping on both the lv and hv sides. For example swapping A and B phase on both sides will give you one of the vector groups. Swapping A and B on hv side and B and C on lv side will give you another vector group and so on.

It is critical that the phase swopping be done BOTH sides of the trfr. If there is diff protection then the phase swopping must either be done both in the diff zone or both outside the diff zone.

I am not aware that one can get a Dyn5 or Dyn9 from a Dyn1. Will be interested to know if that's possible and how to do it. What I do know is that you can get these from a Dyn11 by the same phase swopping as mentioned above.


Hope this helps.

 

[davidbeach]

You can get any odd multiple of 30 degrees. There is a paper on the Basler web site that gives all the gory details.

 

[ProtectionEngineer]

Here is the Basler paper on transformer Vector.