Zig-Zag Transfomers 3

[jwilson3]

I'm familiar with the general purpose and use of these type transformers, but would be interested if anyone knows of any resource that provides a reasonably rigorous technical discussion of how the transformer reacts to various unbalanced conditions.

 

[dpc]

I would suggest starting with the old Westinghouse Transmission and Distribution book, now sold at an outrageous price by ABB.

Zig-zag transformers are rarely purchased any longer (in the US) so technical info will be hard to come by.

If you have access to Edith Clarke's books, those would be helpful as well. But these are long out of print.

Good luck...

 

[jwilson3]

DPC,
Thanks. I have both the Westinghouse and Clarke's books and have referred to them. They both briefly discuss the zig-zag transformer, but I was hoping for something more in depth.
Thanks again.

 

[cuky2000]

SUGGESTION: In addition to the Internet, search this forum for reference and ideas. Enclose are couple sample of discussion on application of zigzag transformers.
thread238-104607
thread238-94627

 

[RalphChristie]

The J&P Transformer Book, (12th edition - Martin J. Heathcote) also briefly discuss zigzag transformers. There are still a few manufacturers who build it in some countries. Alstom South Africa built two for us last year. Maybe you can contact them for some assistance:

http://tde.alstom.co.za/products_services/distribution_transformers.htm

Other zig-zag manufacturers (South Africa) are:

http://www.desta.co.za

(Products, Power & Distribution Transformers)

I think ABB South Africa also build zig-zag transformers.

Zig-zag transformers are also called earthing transformers, NECs or Neutral Earthing Compensators/Couplers

Regards
Ralph

 

[dpc]

I hope I didn't leave the impression that zig-zag tranformers were not available in the US. They can be made to order by some specialty transformer shops such as Uptegraff. We purchased one for a client about four years ago.

But they are becoming pretty rare.

 

[RRaghunath]

In Sultanate of Oman, the zig zag transformers are specified as a standard in the 33kV distribution system. The 132/33kV transformers are Yd type and 33kV system is earthed through zigzag transformer coupled with neutral grounding resistor to limit the earth fault current to ~1000A.