[RFI] Power Lines

David Robbins K1TTT k1ttt at arrl.net
Sun Dec 23 15:05:30 EST 2007


Yep, that pretty well covers it.  And I have worked for EPRI (see
http://www.epri.com) for most of the last 10 years anyway even though that
is not my full time job right now.


David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
> Behalf Of Jim P
> Sent: Sunday, December 23, 2007 19:38
> To: Gary "Joe" Mayfield; 'Jim Miller'; rfi at contesting.com
> Subject: Re: [RFI] Power Lines
> 
> Just an observation - and somebody correct me
> if I'm wrong ..
> 
> >From what I have read and studied on power
> generation, power transmission and power
> distribution, the power companies extend out from
> the central (generating) station to the various sub-
> (step-down) stations all three phases of generated
> voltages from the generator (speaking of AC
> systems now! And I'm not addressing an inter-tied
> tructure as the present 'power grid' is built and
> operated either.).
> 
> This would seem to be done for several reasons,
> not the least of which is, three phase power generation
> provides for a more equal 'torque-loading' (on
> account of the sinusoidal function involved when
> a wire is rotated in a circle and made to 'cut' through
> magnetic lines of force) of the generator's armature
> than a single phase would, and this also translates
> out into the user segment of the system when higher
> amounts of power (e.g industrial users and greater
> amounts of torque as say provided by three-phase
> motors) is required.
> 
> It also seems that the power companies further
> extend three phase distribution lines out into the
> area to be served also for the purpose of being
> able to load-balance all three phases; single phase
> business and residential 'user' loads can easily
> be swung from a more heavily loaded phase,
> for instance, to a less loaded phase as an area
> develops or gets built-out. At some point, out
> towards the 'edge' of a service area single phase
> distribution lines begin to appear (we used to have
> an old REA line running along side one of our
> major secondary roads about 10 years back, but that
> 'line' has upgraded to all three phases now!)
> 
> So, it is this generation/transmission/distribution of
> all three phases would appear to the be basis for
> the "divisable by three" rule.
> 
> Caveat: All this is the result of observation and some
> self-paced study as I have never worked for, or worked
> in, the power generation or power transmission or
> power distribution industries.
> 
> Jim P // WB5WPA //
> 
> 
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