Design of High voltage Dry type transformers 11KV

Have standard designs for high voltage secondary.
For 12 kV corona free, 25 kV hipot would use
Major 0.031 inch insulation, 5/8 inch duct, 0.082 inch insulation.
Copper to end steel would be 2.5 inches each end.
Of course duct thickness and insulation thickness would increase with large transformer.

The book Reference Data for Radio Engineers 5th edition has a formula for corona start. Note that the formula is for best case conditions and many times corona will start at a lower voltage than predicted by the formula. Corona rarely or never starts at a higher voltage.

If you will contact me:

Carl Pugh
5642 Ravenwood Ave.
Newark, CA 94560 USA

Will provide you with information that I have.

Good Luck
Carl Pugh

Hi Carl,

thanks a lot for your response. those parameters you gave will definitely help me. By the way, i've been involved previously with oil-filled distribution designs and i just switched to dry type. though the basic principles are similar, still much can be said from experience which i don't have with dry types. So whatever available info that i could get would be very much appreciated.

thanks again and best regards,
James Martinez