On Tue, 2010-06-08 at 17:23 -0400, Carl Denk wrote:
> I thought that way back in the early electricity days, that the issue 
> with DC was it couldn't be transported very far before the losses left 
> little power available, and the AC was necessary to get the power some 
> distance from the generating station. This goes back to Edison's days.

The "problem" with DC back in the day is you couldn't step it up/down
cheaply. 

Stepping it up was necessary due to I2R losses in the transmission
lines. AC got around the problem by using cheap transformers to step it
up, transmit it and then step it back down. For DC you'd have had to use
rotary converters, very expensive and a maintenance horror (imagine
every pole pig was a rotary converter!).

On the other side of things, AC has it's issues as well. For REALLY long
distances the skin effect starts to have a bearing, along with the
bigger issue of power loss (due to coupling) to the ground. DC doesn't
have these issues. 

As a result of advances in high power solid state electronics DC is now
a viable option for long runs, as evidenced by the line Olin described.

TTYL

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