🚀 go-pugleaf

> Are there high-voltage DC lines? I didn't know this. What are they used for?

In power transmission, DC is increasingly used for *really* high voltage
transmission over distances (many hundreds of miles) that make impedance
effects a significant obstacle in AC transmission.  The main technological 
obstacle to DC used to be the feasibility of high-voltage, high-power 
conversion equipment.  There are also political obstacles (apparently with
acceptable technological fixes) having to do with telephone interference 
and pipeline corrosion. DC is also used for underground/underwater 
transmission lines.  

The silver anniversary edition of IEEE Spectrum, Volume 25, Number 11, 
has a good article on the subject in the context of the Pacific Intertie.  
The Intertie is an undeservedly obscure example of engineering on a 
grand scale -- obscure, perhaps, because unlike a dam or a skyscraper,
its scope has no visual cues and its technical audacity is not obvious
to the layman.  But I digress.  Spectrum, the general-interest science
magazine of the Institute of Electrical and Electronics Engineers, is
something you ought to monitor anyway if you're interested in the
alleged health effects of EMFs.

Happy reading,
--Joe
"Just another personal opinion from the People's Republic of Berkeley"