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New York Sky Turns Bright Blue After Transformer Explosion

nytimes.com

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Re: New York Sky Turns Bright Blue After Transformer Explosion

#41

Post by mirimir »

lvs wrote: post #32
Cthulhu_ wrote: post #22

How dangerous is that light? I know welding arcs contain a lot of dangerous UV light for example. It should be fine indirectly (clouds would let the UV pass or absorb it), but directly being exposed to it seems dangerous.

It's a good question. It depends on whether we're observing arc discharge or just combustion. If it's arcing, it could surely have a significant UV component. But I suspect this is burning copper or aluminum. HV transformers are filled with some kind of cooling oil, and I suspect that just has to burn off. If it were totally uncontrolled arcing, I'd guess there would be lots of reports of broadband interference that…

With that sort of light, there clearly was arcing. But most of the billowing smoke was from burning transformer oil.

And about radio interference. This is 60 Hz, so I doubt that's an issue.

Re: New York Sky Turns Bright Blue After Transformer Explosion

#42

Post by dschuetz »

lvs wrote: post #31

Someone with HV experience should probably know better, but I'm curious if the color is due to burning copper and/or aluminum. Copper salts used in fireworks burn at nearly this color.

Excited copper ions inside the discharge plasma emitting blue->UV light, sounds plausible to me.

Re: New York Sky Turns Bright Blue After Transformer Explosion

#43

Post by opless »

groestl wrote: post #33
antome wrote: post #16

Here's a pretty good view from above, from reddit: https://old.reddit.com/r/Damnthatsinteresting/comments/aa632...

I think the battle is lost, but I'm a little bit sad seeing the sky over a city being filmed in vertical video.

Though it makes sense if you're watching it on your phone maximised in its natural orientation.

Re: New York Sky Turns Bright Blue After Transformer Explosion

#44

Post by ben_w »

mirimir wrote: post #41
lvs wrote: post #32

Earlier quoted context omitted.

It's a good question. It depends on whether we're observing arc discharge or just combustion. If it's arcing, it could surely have a significant UV component. But I suspect this is burning copper or aluminum. HV transformers are filled with some kind of cooling oil, and I suspect that just has to burn off. If it were totally uncontrolled arcing, I'd guess there would be lots of reports of broadband interference that…

With that sort of light, there clearly was arcing. But most of the billowing smoke was from burning transformer oil. And about radio interference. This is 60 Hz, so I doubt that's an issue.

A spark’s RF interference isn’t limited to the frequency of the power supply. I don’t know the mechanism, but when I was a kid I found I could hold a lightswitch in a halfway state and hear the interference on the nearby FM radio. (Classic FM, so ~101 MHz compared to UK mains at 50 Hz).

Re: New York Sky Turns Bright Blue After Transformer Explosion

#45

Post by snowwindwaves »

ars wrote: post #13
miiiiiike wrote: post #12

I live about two blocks away. The lights dimmed and one of our breakers flipped. Then it got bad. My phone suddenly lit up, brighter than the night's electric blue sky, as everyone I've ever known called and texted to ask about what was going on. Nothing interesting. Astoria is a pretty great neighborhood tho. We have a 24-hour fruit market next to another 24-hour fruit market.

That's interesting. What would make the breaker trip? Was it a regular overcurrent breaker, or some other kind?

A load could draw more current when the voltage sags and therefore trip. Like a fan on a motor that rotates at a fixed speed. Or a pump.

Re: New York Sky Turns Bright Blue After Transformer Explosion

#46

Post by eigenvector »

DaOne256 wrote: post #27

I have never seen a transformator explosion in Germany or Europe. What is different in the american power grid?

Distribution transformers (i.e. the small ones that serve homes or individual businesses) are run-to-failure components and they fail all the time. Most of the time, the failure is not as catastrophic as an explosion, because a protection system isolates the circuit and limits the amount of energy discharged through the fault.

For various reasons, it can be impractical or not economic to provide very sensitive, very fast protection schemes for distribution systems. An example would be single-wire Earth-return distribution systems which still exist in rural areas of the USA.

But rest assured, there are transformer failures on a daily basis all around the world.

Re: New York Sky Turns Bright Blue After Transformer Explosion

#47

Post by eigenvector »

ggm wrote: post #18

What happens to the fluids in the transformer? PCB breaks down in very high heat, into much more benign things. Hopefully a long persistent arc helps make conditions right to get rid of a lot of it. Otherwise.. it's a nasty contaminated site. Be kind rewind...

Nowadays, large power transformers like those that would be found in a generating station or large substation are surrounded by an oil containment pit to prevent release of oil directly to the environment.

Re: New York Sky Turns Bright Blue After Transformer Explosion

#49

Post by eigenvector »

Cthulhu_ wrote: post #22

How dangerous is that light? I know welding arcs contain a lot of dangerous UV light for example. It should be fine indirectly (clouds would let the UV pass or absorb it), but directly being exposed to it seems dangerous.

Directly observing an electrical arc can cause serious eye damage.

At close proximity, the huge amount of heat that can be produced by a high-current arc as well as the blast wave (known as arc blast) is much more dangerous, and can be fatal. It is a serious hazard for utility and electrical workers.

https://www.youtube.com/watch?v=ePiTODvl_vk

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