At 07:59 AM 3/6/2004 +0100, George Brock-Nannestad wrote:

>Italian electric railroads used 14 Hz, because the motors used switches that
>could function at that "high" frequency.

Interesting...I never knew that!

>As to length of AC power lines: the grid going from the north of Sweden to
>the South of Denmark once got into wild oscillations - a huge standing wave.
>We, too, and the Russians, use AC-DC conversion at convenient points.

Yes, I didn't mean to imply it was a U.S. invention. In fact, the
undisputed world leader in this is a Swedish corporation (although it is
now Swedish Swiss since 1988). Asea Brown Bovari.

Here is an interesting link to their DC business:!opendatabase&db=/global/abbzh/abbzh262.nsf&v=23762&e=us&m=9f2&c=b85b46aa2b155615c1256cca005e7fa8

I didn't do a lot of research, but the new Three Gorges project in China is
using ABB DC transmission.

We have two DC lines coming into LA, one from the Columbia River and the
other from the Hoover Dam on the Colorado River.

Vancouver Island gets its power over a DC link to the mainland.

There is a DC tie between the North and South islands of NZ...

Fascinating stuff. If you're interested in this, be prepared to spend a
couple of hours on the ABB site. I did a couple of years ago and am
resisting going back right now.



>Best regards, and looking forward to seeing lots of you in Cleveland,