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RE: 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


-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Rick Fletcher
Sent: Thu, August 14, 2003 5:25 PM
To: William Leijenaar; amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] USA hams need GEOsat :-)


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