Transformer Vector Group Connection 1

[Beo81]

What is the difference between a Yd11 tranformer and Dy11?

I have a distribution transformer (440V/230V) connected in Dy11. As I recommended. However, there are other people saying that it should be Yd11...

Please advise.

 

[ScottyUK]

The first character indicates the connection of the HV winding, the second the LV winding.

Do you need a neutral on the LV side?


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If we learn from our mistakes I'm getting a great education!

 

[Beo81]

Yes, what I suggested whas DYn11, and the other choice would be YDn11....

 

[Beo81]

sorry, the other choice would be YnD11, neutral on HV side.... So we do not necessary need neutral on LV side...

What are the impact of neutral on LV or HV side?

 

[slavag]

Hi.
Impact on the :
1. Insalation
2. Ground/Earth fault level

I think 400V is only solid grounding, except some special applications.

Best Regards.
Slava

 

[rbulsara]

What is the reasoning of "other people"? What was your reasoning for your recommendations?

What is the application? Primary voltage? Is this step up or step down application?

Too many unknowns.

 

[Beo81]

Step down, from 440 to 230V. It is a distribution transformer.

My recommendation was based on previous projects, "other people" I do not know, hence the question...

I strongly believe that this should be Dyn11. How would a YnD11 work in these conditions, could you at all have a transfomer of this type for distribution systems? Seems weird to me...

 

[rbulsara]

Dyn11 sounds like the right choice. Whether or not your load requires neutral, you still need a grounded system (secondary source). Wye secondary provides a balanced voltage system with neutral as a nice grounding point.

Many people erroneously believe that since the loads are only 3 phase, 3 wire, a delta secondary is needed. That is not true. Also Delta-Wye is most common and most popular choice, unless there is a great technical reason for other configuration.

 

[rbulsara]

I presume that you are not planning to parallel this unit with other transformer of a different vector group!

 

[Beo81]

Thank you.

No, it is paralleled with a similar transformer, divided by a bus tie...

 

[rbulsara]

ah, them there is no room for any other vector group, as long as fed from the same or identical primary.