Why No Toroidal Distribution Transformers?

[samgillis]

NYU did a study and made a couple prototype toroidal core pole mount transformers and they tested better in every way compared to traditional EI transformers. They were more efficient, safer (dry, so no oil), cooler, lower load/no load losses, lower EMI, and more.

Are they not used just because of cost? Even though the study estimated they should cost about the same as a traditional xformer? I would think with the lower losses and probably lower maintenance that they would be cheaper in the long run. Performance wise they just seem the best.


Study link:

https://research.engineering.nyu.edu/power/sites/engineering.nyu.edu.power/files/uploads/Development%20of%20Toroidal%20Core%20Distribution%20Transformer.pdf

 

[LarryFine]

Torroid cores are used in electronics. I have two power amps in my home theater system with them.

I believe manufacturing costs, especially winding the windings, makes them uneconomical for POCOs.

 

[Jraef]

Most likely the “cost about the same” was not done at a utility scale basis. Toroidals absolutely cost a lot more to manufacture and even if you get “close”, to the utility industry it could represent billions…

They also have comparatively high inrush current when switched on. In electronics, where they are used in power supplies, they can use pre-charge circuits to limit that. But that’s not something you want to put into every pole pig because it just becomes another thing to fail.

I’m sure that if there was even a slight advantage to the utilities, they would use them. A lot of people thought, back in the 1980s when PCBs were outlawed and had to be removed from transformers, that toroidals for pole pigs were the answer because they didn’t need an oil bath. But even that didn’t pencil out.