a big arc

Hows this for a good arc!!!

http://www.oldcrows.net/~oldcrow/LugoSWR.mpg

Ron
_________________
1973 Saab Sonett V4
1984 & 1986 200SX
1985 & 1986 300ZX

Holy god, is it supposed to do that?!??!?!?
_________________
DJ

Cars
86 CA20E: 1/4 17.723 @ 71.51mphgt
0-60: 11.463

87 CA20E(soon to be CA20ETi): 1/4 15mins @ 1 mph...me pushing

holy hell thats got to be for some kind of movie effect..
_________________
bart
'86 INTERCOOLED Turbo
1/4 mile: 14.964 @93.02mph
CEO of:
"Barts Parts Incorporated"
http://geocities.com/bartc_j
http://members.cardomain.com/bartc_2

I don't think its supposed to work that way. While utility stuff is way outside of my expertise, got feel suggests that some type of circuit breaker or load disconnect. I'm not sure if that was a test of some type that went wrong, or if it was an intentional failure.

I've got a friend in the utility business, I'll send it off to him and get his take on it. He told me about the time a riverboat casino captain forgot to drop his stacks, and hit a major transmission line. When it broke the 4" cable, the breakers blew, and then the nuclear reactor had to shut down by doing a major steam dump. It was at 2:00 in the morning, and the resulting steam dump probably woke everyone up for miles.

I think the video is from Rocky Flats, NW of Denver, CO. I did some subcontracting for there years ago. They used to make nuclear weapons there many years ago, and now its a real pita to clean it up. As such, Uncle Sam has pretty good security. If it was from Rocky Flats, how the mpeg got on the net is beyond me, as security was pretty tight.

You were guaranteed to get pulled over and searched weekly. Rumor was they'd even take your air cleaner off to make sure nothing was leaving the place that wasn't supposed to. I think there was a ratio of cops to citizens around 1:10, or it at least seemed that way. Once you got over the fact that the red lights were going to go on, it was no big deal, but the first few times, whoa...... and then they would search you, your breifcase, tool box, computer, car etc.

Ron
_________________
1973 Saab Sonett V4
1984 & 1986 200SX
1985 & 1986 300ZX

i think its real. if you look closely you can see shit moving in the backgorund with it. Fucked up though.
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Geoff Golda
1986 200sx Notchback, CA20E

That is really cool! I have never seen anything like it! ONly thing close would be when 4 teanformers blew at the same time up my street, man that was cool to! Huge Spark Plumes... icon_cool.gif
_________________
Mimmph'$$'

1986 200sx, Hatch, 5spd, CA20E w/mods
- http://www.cardomain.com/id/mimmphss

wicked
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Dan

I'm guessing it was intentional. It looked like the poles retracted, rather than anything breaking, plus there were guys standing around watching, and one of them whooped at the end like a frat boy after somebody does a keg stand.
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Here is one explantion I recieved this morning.

"In large circuit breakers or even large power contactors, they sometimes
employ a compressed air blast system to interrupt the arc which will
naturally occur when opening a circuit under high current and voltage
conditions.

In this video, the breaker opens slowly and there is little air movement to
"blow out" the arc so it makes a pretty impressive display before finally
quenching. The slow movement of the contacts encourages the formation of a
really excellent arc.

It's sort of the same as a "Jacob's ladder" where the contact spacing
effectively opens very slowly as the arc floats upward due to the buoyancy
of the lower density heated air surrounding the arc.

At the top of the "ladder", the rising heated air eventually stretches the
arc until the plasma (and the circuit) is finally broken. The voltage
across the contacts in this video is not high enough to re-establish the
arc at the large spacing that the contacts finally achieve (which is the
whole idea, I'm sure).

That's a pretty great video! I wish it was a bit longer so I could hear
the rest of what the guy who starts yelling had to say about it icon_smile.gif

The fact that the video is so good, and the way the cameraman zooms out as
the arc develops so he can keep it all in frame makes me believe that the
technicians knew they were going to get a good arc like that when the
contacts opened and set up the camera beforehand. It's probably something
they've seen before and knew it would be worth taping. I'm glad they did!
That's really fun to watch and hear."

Ron
_________________
1973 Saab Sonett V4
1984 & 1986 200SX
1985 & 1986 300ZX

Here is another explanation in more depth from Larry Hendry.

"The file name Lugo suggests a large California substation that is populated with 500 KV
and 230 KV switching devices. This one is clearly a 500KV (I can tell by the size) three-
phase switch, probably rated at about 2000 amps of normal current carrying capability.

This type of switch typically is used at one end of a transmission line, in some cases in
conjunction with or instead of a circuit breaker for a variety of different configuration
reasons that vary greatly from one utility to the other. Or, it may be used to connect a
large transformer to the system.

In this case, the switch is being used to connect a special kind of transformer. The 3
single-phase transformers can be seen behind the truck. I say transformer, but as you
can see, they have leads going in, but not coming out. These are actually single winding
inductors connected from phase to ground and are commonly called "shunt reactors."
These inductors are installed to offset the capacitive effects of un-loaded transmission
lines, When a long 500 KV or 765 KV line is energized from one end, its inherent
capacitance causes an unacceptable voltage rise on the open end of the line. The
"shunt reactor" is installed to control that open-circuit voltage. Where current into the
capacitor component of the line impedance leads voltage by 90 degrees, current into
the shunt reactor lags voltage by 90 degrees.

The switch being opened is called a "circuit switcher." It consists of two series SF6
gas puffer interrupters (kind of like a circuit breaker) and an integrated center-break
disconnect. The interrupters are to the right of the switch blades. They just look like
gray porcelain insulators. At 345 and 500 KV these types of switches typically have
two interrupters per phase in series in order to withstand the open circuit voltage
encountered when de-energizing a line or transformer. They rely on synchronized
opening of the two interrupters and voltage even distributed across the two interrupters
by "grading" devices (typically lots of series capacitors or resistors).

The way they are supposed to work is the interrupters both trip, grading capacitors or
resistors cause the open circuit voltage to split evenly across the two interrupters, the
switch blades open with no current flow, and the interrupters close as the switch
reaches the full open position. I originally titled this very BIG capacitor because that
is what unloaded transmission line looks like. The parallel wires have a huge capacitive
effect between ground and each other. On a 500KV line like this the current (leading the
voltage by 90 degrees) required to energize this capacitor is approximately 2 amps per
mile of line per phase. That's 2 amps per phase at 500KV, or about 1.7 MegaVars
(million volt amps reactive) per mile. However, we are actually looking at the shunt
reactor current which is inductive and lags the voltage by 90 degrees. So, I should have
said "very big inductor."

The switch operation you see in this video in my opinion is a failed attempt to interrupt
that inductive current. The failure appears to be that the far right interrupter does not
open or the grading device has failed. The voltage across the remaining open
interrupter exceeds the rating and it flashes over (you can see the first arc develop
across one interrupter). Therefore, the switch blades are left to interrupt the current (not
designed to do that) as they open. As the interrupter closes you can see the arc across
it go out. However, the arc across the switch gets as tall as a 3 story building before the
arc resistance is sufficient for the ionized gas to quit conducting. Or, perhaps the
connected line has tripped out of service allowing the arc to extinguish. This is the only
failure I have ever seen where the arc lasted so long and grew so large without first
going phase-to-phase or phase-to-ground taking the circuit out of service. It just keeps
growing straight up where it contacts nothing."

Thanks
Ron
_________________
1973 Saab Sonett V4
1984 & 1986 200SX
1985 & 1986 300ZX

it makes me sad that I know what your talking about Ron. I really need to get out more. icon_biggrin.gif
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Jeff Hester
1986 200sx 2.0L
1967 El Camino 402ci