Mis-Leading USA Article

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A USA Today article (10/27) quoted a Southern Company representative as follows: "...the power system is redundant. A faulty generator activates a backup, and electricity can be channeled though a nationwide power grid." Although probably meant to reassure people, the two statements are are mis-leading, if not borderline false!

Quenton

-- Anonymous, October 27, 1999

Answers

Quenton,

For those of us that are a bit "challenged" in understanding the details, could you be a bit more specific about why you feel this is misleading.

-- Anonymous, October 27, 1999


Gordon:

Perhaps an example would be best:

Let's say an 1100 MW generator, connected to the bulk power system and generating full load, trips off line. For the sake of discussion, let's call it the Green Nuclear unit in Southern California.

At the instant it trips...what it "activates" is the laws of physics. Power system frequency (normally 60 cycles everywhere) will spike to something much lower, all major transmission line power flows will changes intanteously and ALL connected generators will spike UPWARDS to some extent (this will occur throughout the western U.S.). The system operators responsible for that electrical area (normally called a Control Area) will see some automatic response from some generation and will initate manual load increases where available. NERC requirements give him 10 minutes to return power flows and freqency to normal.

The generator trip could have been caused by transmission lines opening on faults, complicating the problem further. But if the event was internal to the generator, it's still possible for external transmission lines to open on excessive power flows or other problems. Other generators can trip in electrical "sympathy". These further problems, that sometimes happen, only makes the event even more involved for resolution. (This was a very brief and general explanation of what happens when a generator trips).

In respect to "channeling" power on the national grid: LOAD "pulls" power from WHATEVER source...through the path of least resistance..no matter what...again, it's the laws of physics. Unless you drop major load, change generation dramatically...or OPEN transmission lines, you can only "channel" power flows, in general, and between regions. Some people think you can generate a megawatt in Idaho, for example, and color code it to appear at a megawatt of load in Arizona...can't do it! Again, this all a simplistic and general explanation.

Quenton

-- Anonymous, October 28, 1999


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