>I don't know much about power systems,either,but I have heard that
some
>power companies are experimenting with using DC-DC converters instead
of
>transformers. In that case, they STILL use high voltage for
transmission
>(to minimize current and therefore also I^2R losses),but to step it
down
>for local distribution,they use a DC-DC converter (at least in some
>experiments,I don't know how widespread it is).


In Canada, there is at least one system running on a single wire
(saves on copper too) at 500,000VDC
It's been in operation quite a while.

>#3) Elimination of bulky transformers. Although, I'm not sure how
much less
>bulky or especially,less expensive, the HUGE DC-DC converters are.


I'd love to see how this is done. It's WAY out of my area, but it's
got to be very very special!