RE: New 8 second long 550 kV Power Arc

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

Air switches are made to open hot. but are vary rarely used.  Usually on 
remote rarely used equipment that does not justify the cost of oil filled 
power remote breakers.  They have long thin (1/4 inch x say 4 foot) steel 
rods that actually take the arc and are designed to be replaced after a few 
openings.  The rod usually has a snap action and directs the arc far away 
from the fixed line structure.  Operation of these breakers is never 
"dull".  They have a habit of being exciting.

These breakers can also be manually operated by some poor guy turning a 
crank as fast as possible.  It is an unpleasant job ;-))

In this case, this switch spins two rods to 90 degrees to suddenly provide 
a very long path to break the arc.  It would appear they were testing a new 
breaker since everything looks new and there is a camera and usual audience 
;-))  It is three phase and only one phase is live.  That is odd even for a 
test.  It does not allow for a few of the phases of the long arc to "hook 
up" and really cause a mess ;-))

500kV is a LOT for one of these breakers.  I guess this one is working as 
expected.  It did "finally" turn off ;-))  But rest assured that air 
breakers are regarded as pretty goofy and scary things buy the industry.

Cheers,

         Terry


At 08:34 PM 12/12/2003, you wrote:
>I think they are for isolation only. They are not meant to open hot.
>Tom L.
>
>Original poster: Chris Roberts <quezacotl_14000000000000-at-yahoo-dot-com>
>
>So what purpose do those air break switches serve? Do they usually open
>hot? What would cause that one switch to arc while normally it dosen't?
>(At
>least I would imagine this is a fairly rare occurence) Just trying to
>understand why this would happen, other than just a couple of bored
>utility
>workers wanting to see something really cool. =D
>By the way - AWESOME movie!
>
>Tesla list <tesla-at-pupman-dot-com> wrote:
>Original poster: Bert Hickman
>
>For all fans of Arcs and Sparks,
>
>A friend of mine at Fermilab just sent me a 1.5 MB MPEG of a 500 kV air
>break switch opening hot. One of the three phases has a problem
>disconnecting, resulting in one awesome power arc that's gotta' be at
>least
>50 feet long. It lends a new meaning to the term power arcing.
>
>And those utility guys have all the fun... listen to the guy whooping it
>up
>at the end of the MPEG. :^)
>
>See it at: http://205.243.100.155/frames/longarc.htm
>
>Merry Christmas,
>
>-- Bert --