[Beowulf] on powering off and its character

Lux, Jim (337C) james.p.lux at jpl.nasa.gov
Thu Aug 7 21:09:35 PDT 2014

Are you wondering about power turn on/off locally, or when the utility
shuts you down?

And are you interested in the voltage/current upstream or downstream of
the switch?

The power lines (of whatever length) are a transmission line with
distributed R, L, and C, and it¹s carrying an AC current, so when you
change something, there¹s a transient that propagates away from the

On the power lines from Northern California to Southern California, for
instance, a switching transient can take more than 8 hours to die out, as
it propagates around, bouncing back and forth.

James Lux, P.E.
Task Manager, FINDER ­ Finding Individuals for Disaster and Emergency
Co-Principal Investigator, SCaN Testbed (née CoNNeCT) Project
Jet Propulsion Laboratory
4800 Oak Grove Drive, MS 161-213
Pasadena CA 91109
+1(818)395-2714 (cell)

On 8/7/14, 11:19 AM, "H. Vidal, Jr." <hvidal at tesseract-tech.com> wrote:

> Just curious if anyone here among those well-informed about the nature
>of electrical power might know about documented or canonical analysis
>of AC power as it's being turned off......
> That is, is there existing and/or standard analysis or characterization
>typical AC power as power is removed? Does it ring, or spike, or otherwise
>modulate in understood or at least studied ways?
> Will google it as well, one of our engineers tried GIYF but came up
>H. Vidal, Jr.
>Tesseract Technology
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