video of 500KV line being opened under load

[guava]

interesting link.

 

[klenger]

All three phases opened at the same time. Interesting.

 

[Peter Campbell]

I think that one of the phases of the breaker were stuck closed. Only one phase arced over, and the arc was only big enough to keep the line charged. An actual motor operated disconnect opening under load instead of just live would have resulted in a large arc and several hundred pounds of aluminum plasma as well as fatalities. We get arcs of a couple of feet just because we are disconnecting a 100' section of busswork from the live side. No current just trying to maintain the line charged.

 

[HoleshotHolset]

That is some $#%& up stuff!



I think I'd soil myself if I ever saw that in person...



Matt

 

[HEMI®Dart]

Cool Video

If somebody has time can you explain to me what they did in Laymen's terms?

 

[NPloysa]

Originally posted by HEMI®Dart

If somebody has time can you explain to me what they did in Laymen's terms?

That's what I was going to ask! I kind of understand it. You can see the two arms seperating and the arc continuing, but yeah, what HEMI Dart said!

 

[Peter Campbell]

What you saw was a motor operated disconnect. A big switch. A circuit breaker is rather large, It would have insulating cones and a type of tank where the contacts are. To break the circuit under a load ( current flow to customers/another part of the system ) the circuit breaker is used. The arc is suppressed inside the tank or an air blast chamber. When you want to do maintenance on the breaker you use one of these switches on each side of the breaker, this deenergizes it with ten feet of "removed" busswork. They are not designed to isolate a current flow, just a small piece of breaker busswork. Utility workers are resistant to climbing on bug zappers that can turn a 200Lb man into bits of hair and teeth in 1/120th of a second. If the breaker failed to open on one out of the three phases, all that is happening is the system or component downstream of the breaker is energized on one phase. The current flow is normally from phase to phase, there is no circuit hence no real load. But that wire/system/component is being charged and discharged 120 times a second 400,000 volts up and back relative to ground. The wire acts lik a capacitor to ground. It stores that energy. So when you use a switch that will not "blow out" its own arc to interrupt that small current flow, you get a nice impressive jacobs ladder type arc. Impressive but not harmfull. If that were opened under 1000 MW of load on all three pahses with no immediate trip the camerman 150 Yards away would have been touch and go at the burn unit, and everyone else in the video would have been bits of teeth. The substation would have been a smoking ruin. They are usually on a multi acre site for that reason.

 

[HEMI®Dart]

If that were opened under 1000 MW of load on all three pahses with no immediate trip the camerman 150 Yards away would have been touch and go at the burn unit, and everyone else in the video would have been bits of teeth. The substation would have been a smoking ruin. They are usually on a multi acre site for that reason. [/B]

Peter,



Would the arch have been bigger or more uncontrollable?

 

[E7mack96]

can't see it, guess site is down?



Anyone that has it, e-mail me @ -- email address removed --

 

[CFast]

Laymen's terms?

 

[dseabaugh]

that was freakin unreal! I bet you could smell that one in the air. Oo. :--)

 

[PJereb]

Laymen's terms? I’ll try, but it is a difficult thing to explain to someone who isn’t familiar with electric transmission equipment.



BIG SWITCH FAILS... .



It is actually a circuit switcher that failed, it is like a motor operated airswitch, but it is designed to break load.



A circuit switcher is a device that can break load, like a circuit breaker. When it opens it first breaks the load in interrupters internally, then the disconnect blades open. When it closes, the blades close first, then the interrupters close, completing the circuit.



Utility companies like them because they are cheap, substation electricians, and other utility workers hate them, because they are dangerous, and a pain to work on.



The horizontal ceramic insulator looking thing to the right of each of the three disconnects is actually supposed to open and break the load internally in an inert gas (sulfur hexafluoride), these things are interrupters.



These interrupters that are to the right of the disconnects are supposed to open a moment before the disconnect does, so there is little or no arc when the blades open.



The closest interrupter failed to open internally, so when the disconnect opened it was energized, hence the BIG arc.



Does that make sense?



If not just tell me and I will take a photo of one, and photoshop a play by play of what failed.



Peter

 

[CFast]

That's ok. I realize I know as much about this as a truck driver knows about an engine.

 

[RHARVEY]

The link wouldnt work! I even tried saving it to my desktop but it still couldnt find it. .



Rick

 

[JPope]

Works great for me on Windows Media Player, IMPRESSIVE!!!!

Sent it to an electrical engineer friend of mine and he could not get it to open, guess maybe he is in need of electrical help!!!!!!!!

 

[Truckie]

Originally posted by CFast

That's ok. I realize I know as much about this as a truck driver knows about an engine.

Hey know thems are frighten words there. I'm not only a truck driver, but an owner operator also. Who works on his own rig.



MIKE

 

[jponder]

Once when I was 18 or so I knocked a big red oak down for firewood, but it hit a pine tree on the way down and threw it into a big poweline, I stood there with my chain saw watching stuff like in that video but eating into the ground as that tree stretched that wire within 5 feet of the ground, it started a big fire and I got the hell out of there

 

[SmokinU]

I couldn't get the link to work either. I believe this is the same video:



http://www.wiredvideo.com/clips/500kv-line-opened-under-load.shtml



Brandon

 

[CFast]

Let me rephrase that then. I know as much about high voltage as MOST truck drivers know about engines.

I've got a question for you then, why do so many truckers lie to the mechanics? "oh it's only happend about 2 miles ago" then I plug into the computer and it's been going on for 20 hours. It just takes longer to dianose if we don't have all the info. Not saying you do this, but I get it alot.

 

[HEMI®Dart]

Smokin,



There are some Good videos from that site.



QVC Ladder is good:



http://www.wiredvideo.com/clips/qvc-ladder.shtml