What is Digg?133 Comments
- kh6idf, on 10/12/2007, -2/+43This is probably normal for opening a switch with that much voltage across it. As the switch first swings open, the gap is very small and the voltage makes an arc as it breaks down the air (turning it from an insulator to a conductor.) Once this arc is established it grows in length as the switch is opened further since most of the air between the switch contacts has already been rendered conductive. Notice that the arc rises as time goes by because the arc heats the air and hot air goes up. The arc goes through the longer path because that hot air that is rising is still more conductive than the cold air down below which replaces it. Eventually the conductive air rises enough that the path through it has to also go through the colder non conductive air and this breaks the arc.
- whiterocker, on 10/12/2007, -0/+33This is an accident.
Shown in the video is a disconnect switch that is only supposed to open when the circuit is already dead. There are circuit breakers nearby (out of frame) that are designed open the line and constrain arcing with various strategies (air blast, SF6 gas, etc). They had a stuck/misoperating circuit breaker and used the disconnect in a non-standard way to isolate the circuit breaker for repair. They would have also had to repair/replace the switch after this operation because of (at least) charring and (at most) melting.
See http://www.arcfault.org/video.htm - hackman7, on 10/12/2007, -0/+12http://video.google.com/videoplay?docid=-3005249485929960832
345kV switch opening - TalenGTP, on 10/12/2007, -6/+12This is exactly 1/100000th the destructive force of a Chuck Norris Roundhouse Kick to the face.
- Nighthawke, on 10/12/2007, -1/+6The site that this vid came off of has a vid of a transformer at a substation frying and arc weldling everything in it's path when it's primary came loose. The climax was when the cooling oil boiled and started to vent, right into the arc! Yep, you guessed it, big assed *boom*! There's a rule in both the power and firefighting industry, "Linesmen don't fool around fighting fires, and the firemen don't screw around with power lines". So when something like this happens, they contact the upstream substation to cut the feeders, isolate the fire and let it burn itself out.
If you thought that raised the hair on your heads, these will make it stay there!
http://205.243.100.155/frames/longarc.htm - blakespot, on 10/12/2007, -1/+5"And now, young Skywalker, you _will_ die..."
- deut, on 10/12/2007, -1/+5@tigerx, nope this is definitely not a normal switching procedure. This kind of ACB will be for line isolation purposes only. The real switch will be a vacuum filed breaker or more commonly a sulfur hexafluoride filled one. Also it's very unusual to trip a line at the grid level (IE >400kv) most switching is actually done at the 11kv level to bring sub-circuits off load in a more gradual controlled manner.
Incidentally, in the UK, all our 400KV substations are contained in enclosed hangers and are usually on the same site as the power stations themselves. - sWeEtReVeNgE, on 10/12/2007, -1/+4Now can we disconnect 1,000 kV?
- Hackintosh, on 10/12/2007, -1/+3Wouldn't this oxidize the switch contacts, requiring the maintenance crew to scrub them every time they did this?
- mechtech, on 10/12/2007, -2/+4The same thing happens everytime I shut off my computer
- stewartallen, on 10/12/2007, -1/+3The video was taken at Eldorado Substation in Boulder City, NV. The feeder is called Lugo because this switch and shunt reactor are on the line that goes to Lugo. 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. 500 KV refers to the phase-to-phase voltage. Divide by 1.732 to get the phase-to-ground voltage (289 KV).
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. I have since learned that these shunt reactors are rated at 33.3 MVAR each to make up a 100 MVAR bank.
The switch being opened is called a "circuit switcher." It consists of two
series SF6 gas puffer interrupters (similar to 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 1.8 amps per-mile of line per phase. That's 1.8 amps per phase at 289KV, or about 1.56 Mega Vars (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. The arc is extinguished only when the circuit breaker energizing the line, circuit switcher, and reactor is opened by the operator. Because some trouble was expected on the switch, arrangements had been made ahead of time to trip open the circuit breaker if necessary. 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. Since I have seen many people speculate as to the amount of current in the arc, I will offer the actual calculations that are based on the assumption that the switch is only
interrupting the current into the shunt reactor and the second hand report I received that this is a 100 MVAR reactor bank. Let's look at only one phase:
33,300 KVAR divided by 289 K Volt = 115.2 amps. I was told by the person who
took the video that the current was "about 100 amps." - skytomorrownow, on 10/12/2007, -0/+2there is a detailed explanation on this page:
http://teslamania.delete.org/frames/longarc.htm - frakilk, on 10/12/2007, -1/+2Raiden, raiden!
- Werdock, on 10/12/2007, -1/+2Wouldn't lick that wire.
- Jams, on 10/12/2007, -1/+1That is very very old. Looks like a stream of plasma or somthing :P
- winkydo, on 10/12/2007, -1/+1this is a really old video. i remember when i first got the video from the guy who filmed it. rocks!
- adml_shake, on 10/12/2007, -4/+4"This is exactly 1/100000th the destructive force of a Chuck Norris Roundhouse Kick to the face."
How DARE you insult the feet of Chuck Norris by thinking that this in any way shape or form could compare to the pure destructive power of his feet! Only Chuck Norris can compare other things to the destructive power of Chuck Norris. - luma, on 10/12/2007, -1/+1Can anybody explain what's going on here? Is this sort of thing normal when they throw a switch, or is this somewhat unexepcted? Cool video though! +digg
- whiterocker, on 10/12/2007, -1/+1"Not even close to an accident"
Accident might be a little stong, but these disconnect switches are not meant to operate under load. Period. - Bert, on 10/12/2007, -1/+1To etruscan:
The reason why the arc rises is that it's very hot. Since hot air rises, the conductive arc rises, becoming longer. Eventually, the arc may become long enough that it can no longer be sustained and it may self-extinguish. However in this video, power was cut upstream before the arc could do any further damage to the equipment. - B0jangles, on 10/12/2007, -1/+1Is that supposed to be happening?
- UtubeWatcher, on 10/12/2007, -0/+0Sexy Utube Videos: http://sexy.utube-videos.info/very-sexy-utube-videos.html sexy utube videos.
- inactive, on 10/12/2007, -1/+0!!!!!!!!!!!!!!!!
- clickwir, on 10/12/2007, -1/+0@dhuges
Actually there is a perfectly good explination for each point you make. I'll sum them up for you. You simply don't know what you are talking about. Really, just because you don't know doens't mean the video is fake.
It's real, I've seen the same thing happen in person. Things are not supposed to happen like that. Like was posted by others, there are circuit breakers (which you cannot see in this video) that are supposed to do the disconnect. The arc just simply disappeared because electricity stopped flowing. It was cut at some other point which cannot be seen here. - Lacero, on 10/12/2007, -1/+0I watched it 15 times, each time simply more in awe. :O
- dcipjr, on 10/12/2007, -1/+0This is old.
The line was opened under load, by the way. Not usually a good way to disconnect. - Vladk1000, on 10/12/2007, -2/+1I wonder what would happen if it was raining.
_________________________
http://ultra-tech.blogspot.com/ - jlbraun, on 10/12/2007, -1/+0From another site:
"As impressive as this huge arc may be, the air break switch was really NOT disconnecting a real load. This arc was "only" carrying the relatively low (about 100 amps) magnetizing current associated with the line reactor. The transmission line associated with the above circuit normally carries over 1,000 megawatts (MW) of power between Boulder City, Nevada (from the generators at Hoover Dam) to the Lugo substation near Los Angeles, California. A break under load conditions (~2,000 amps) would have created a MUCH hotter and extremely destructive arc. Imagine a fat, blindingly blue-white, 100 foot long welding arc that vaporizes the contacts on the air break switch and then works its way back along the feeders, vaporizing them along the way. Still, you've got to admit that this "little" 33 MVAR arc is certainly an awesome sight! " - SolidGun1, on 10/12/2007, -1/+0I wonder what it feels like to be near (not next to) that much energy.
- pixelwerx, on 10/12/2007, -1/+0One more reason I never wanted to be an electrical engineer.
- sipsipi, on 10/12/2007, -1/+0DIGG
It's ALIVE!! - spling, on 10/12/2007, -1/+0How the hell did a story with 2500+ diggs get buried?
- splatnik, on 10/12/2007, -1/+0I can't digg this story either, I get strange javascript errors too.
- pixelwerx, on 10/12/2007, -1/+0For some reason, I cannot Digg this story, and I really really want to. I keep getting javascript errors in both Firefox and IE. Anyone else having this problem?
- salmonfish, on 10/12/2007, -1/+0Check out the guy's other awesome video, a documentary explaining the new world order. Very informative.
- xelloss, on 10/12/2007, -1/+0Did you guys knock it off front page? I don't see it anymore
- DeathonWheels, on 10/12/2007, -1/+0Professor showed us that video in my Power Engineering class.
- dave830, on 10/12/2007, -1/+0This rocks.
But man, I thought I'd get through all the comments without some doofus saying "this is old." I just don't get why people do that. You mean to say electricity has been discovered before this, dcipjr? Wow! We shouldn't put cool stuff up because you've seen sparks before? No one cares. Plenty of us never saw it before. When 80 +digg comments say it's amazing, you come up with a preschool "I know more than you know" comment. Restrain your pride, dude.
+digg
lol- Chuck Norris, erection help, young Skywalker.... - tempusrob, on 10/12/2007, -1/+0Eerie timing ... I dug this out of my archives to show to the guys at work just the other day.
- thekurst, on 10/12/2007, -1/+0Wow.....
- Malik112099, on 10/12/2007, -1/+0wooo...that's old...saw it sometime last year (maybe longer than that) still pretty cool though
- LowGan, on 10/12/2007, -1/+0i eat 500kV for breakfast....i'm a real man
- niqhil, on 10/12/2007, -1/+0Really cool . .Digg++ . .1000kV ?
- dhughes, on 10/12/2007, -1/+0 I think digg is getting to me.
To me the 345kV video (hackman5 submitted) looks real but the 500kV one doesn't. The sound seems like it should echo being so far away and also the electric arc just disappears, it doesn't fade smoothly. The electric arc in the air in the 345kV video goes away quickly but it has a slight fade to it.
I need post traumatic digg paranoia therapy. - KB3JUV, on 10/12/2007, -1/+0That was an awesome video!
- Pandaman, on 10/12/2007, -1/+0Because I like pretty lights :)
- tburke261, on 10/12/2007, -1/+0Gee, looks like it can power my friends Quad G5.
- spacebar14, on 10/12/2007, -1/+0Sweet mother of God -- that's intense!
ps: nighthawke -- your link didnt work. i couldnt find diddly squat - WaterDragon, on 10/12/2007, -1/+0Now THAT's a Bad Shutdown!
SEE?
That's why you should always log off Windows first. by using the start button . - zenghost, on 10/12/2007, -1/+0awesome....just like the movies... +digg
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