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Re: power-grid physics



Probably, because a DC setup requires a generating station on every city
block, making a county-wide distribution grid very unlikely if not
impossible. With DC, transmission line power losses are too high for long
distances. I'll have to recheck my 1908 engineering book for exact numbers,
but I think 300-500 feet from the generator was about the maximum, and they
didn't have nearly the power loads we have...just a few electric arc lights,
incandescent lamps, the occasional motor, not much in the way of appliances
and no refrigeration or air conditioning. BTW, Edison was the DC guy, and
his company actually did put generating stations on nearly every city block.
Tesla pioneered AC at Niagara Falls, but was financially ruined by Edison.
(Lots of facinating history omitted) However, you can't argue with
physics...DC was quickly abandoned in favor of AC.

Vickie Frohne

-----Original Message-----
From: Robert Cohen [mailto:Robert.Cohen@PO-BOX.ESU.EDU]
Sent: Friday, August 22, 2003 2:01 PM
To: PHYS-L@lists.nau.edu
Subject: Re: power-grid physics


This discussion has got me thinking about whether Nikola Tesla's DC
setup would have any advantages over Thomas Edison's AC setup. Would
such a blackout as what happened last week be less likely with a DC
setup?

____________________________________________________
Robert Cohen; 570-422-3428; www.esu.edu/~bbq
East Stroudsburg University; E. Stroudsburg, PA 18301

On Thursday, August 21, 2003 1:18 PM, James R. Frysinger wrote:

In a DC circuit that is what is done and that is=20
intuitively obvious. In an AC circuit, it's a whole lot more=20
complicated and I cannot think of a simple, emailable,=20
written explanation that would explain that.

On Thursday, August 21, 2003 6:11 PM, John S. Denker wrote:

If we had a DC system, it's clear how this would
be handled: The increased load would cause the
voltage to drop. An op-amp would notice this,
and would inform the generators to increase their
output. This is easy to arrange, by increasing
the excitation in the field coils.
=20
You might imagine that the AC system works the
same way, but it doesn't.