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Re: USA hams need GEOsat :-)



As to what might have happened, from a purely technical perspective, you are
probably correct; however, every technical problem has a solution.
Following the blackouts of 1987, several investigations were made as to what
happened and how it could have been prevented.  Some of the recommendations
(grid maintenance/enhancement) were implemented but many others were not,
mostly for "financial" reasons.  Again, it eventually comes down to where
the money went versus where it should have gone.  This is where "hypotheses"
such as mine come in...

Anyway, enough on this - it didn't affect AO-40 so it probably doesn't
belong here.

Rick

----- Original Message ----- 
From: "Assi Friedman" <4x1kx@iarc.org>
To: "Rick Fletcher" <rfletcher@plumdragon.com>; "William Leijenaar"
<pe1rah@hotmail.com>; <amsat-bb@AMSAT.Org>
Sent: Thursday, August 14, 2003 6:34 PM
Subject: RE: [amsat-bb] USA hams need GEOsat :-)


> Interesting hypothesis, here is a more technical one:
> The power grid is very much like an RF transmission line. The vast amount
of
> power lines are huge inductors, and the lines running in parallel form
> capacitors. In addition to that, we don't have a simple source / load
> topology, but rather a huge distributed load, and several sources in
random
> locations along the line. Each source is of different type and capacity.
For
> instance, the gas turbine generators are very quick to react and could be
> brought online, and into phase quickly. On the other hand coal generators
> are very slow.
> Now, in order for a specific station to be on the grid, it needs to
control
> the amount of power it sinks into the grid. This is done by arc minute
> modifications to the phase of the generator. Therefore, all the sources on
> the grid are phase coherent with slight deltas between them to control the
> actual power output (I guess we can call that a "phased-array"). When a
> station is taken offline, its delta phase is take to zero deg, while
others
> increase their contribution to compensate for the need. This is a dynamic
> process and is done all the time to adapt for power trade (see Enron :-))
> and supply/demand control. In addition to this, power generators have
built
> in protection to protect the generator against erratic conditions.
> Based on this, I would estimate that what happened is that one of the
> stations abruptly went offline for whatever reason. If this was a
> significant station, all the sudden, the rest of the generators faced an
> unmatched load, and got overloaded themselves. Phase adjustments take
> minutes, not seconds and therefore, if a significant event happened on the
> network, the generators could not compensate in time, and their internal
> safety inhibits kicked into action. Off course, every station that wend
> offline meant a load increase for the remaining stations and then we have
a
> classic runaway problem...
> Assi 4x1kx/kk7kx


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