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Evan
08-06-2010, 02:58 AM
On my way home from town today I decided to take the back road into our valley. The smoke was dense. Coming in that way you drive under the quadruple set of half million volt power lines that feed the power from the Bennett Dam to Vancouver and points south. Smoke is ionized and therefore conductive. The lines were hissing and crackling loudly with corona discharge when I took this image this afternoon.

http://ixian.ca/pics7/fire12.jpg

Sitting relaxing this evening and working on some of the pictures I have taken lately it occurred to me that I might be able to take a picture of the intense corona discharge. I have never seen an image of corona from the actual lines, only around the insulators. Because of how the lines cross the gravel road as they slope down the side of the hill they are only about 30 feet above the road. I drove down to that end of the valley and parked under the lines at about 11:00 pm. They were still hissing and snapping as before but even after my eyes adjusted I couldn't see anything.

I set up the camera and took several time exposures of about 1 minute as ISO1600 with my Canon 350D. It was spooky as hell with my hair standing on end because of the strong electrical field. Every time I touched the truck I could feel a tingle of electricity. The combination of desert dryness and conducting smoke is causing a far stronger field than normal.

When I examined the images I was very surprised. The corona is very obvious and different than what I expected. I imagined that it would be a more even faint glow but instead it shoots out in jets from various and numerous points on the lines.

http://ixian.ca/pics7/corona1.jpg

A closer look from another image:

http://ixian.ca/pics7/corona2.jpg

This is another first for my collection of night photography.

hardtail
08-06-2010, 03:50 AM
Trying times produce some interesting conditions........great shots, I think the sun photos were outstanding......as good as all this is I hope for a quick improvement on your situation.

Astronowanabe
08-06-2010, 03:52 AM
so in a sense, you DID get aurora of sorts.

[edit] if you took several shots (or a movie) would they be moving or stationary?
if stationary do they come and go from the same spot?

Todd Tolhurst
08-06-2010, 08:27 AM
Wow -- world's largest smoke detector!

Your Old Dog
08-06-2010, 09:12 AM
Hell, you may as well move to LA and take a machete with you to slice your way over to Hollywood and Vine .

rkepler
08-06-2010, 09:34 AM
I saw a program that covered the problems in long line power transmission in South Africa. Problems with grass fires giving ionized paths to ground caused them to monitor weather to try and predict where the next trouble spot might be.

A large chunk of Albuquerque's power comes in on HV lines from the northwest, an area prone to grass fires. A couple of years ago one fire was close enough to the lines that they started a nice conductive path to ground, and the arc was sustaining. I didn't see it but wish I had - something like 30MW was involved IIRC.

Evan
08-06-2010, 09:43 AM
I quickly discovered that if I crouched down directly in front of the truck it acted as a partial shield from the intense electric field. I would have taken some longer exposures but it was just too creepy being that close to such high voltage on the loose. I might go back tonight if conditions are right but this time I will rig a mount for the edge of the window and stay in the truck.

ldn
08-06-2010, 10:42 AM
Hey Evan,

Neat pics of the discharge. I've never seen anything like that.

Have you ever tried holding a fluorescent tube under the high tension power lines? It will light up right in your hands!

Evan
08-06-2010, 10:48 AM
I considered taking a few with me but I didn't want to alarm the few people that can see that part of the road.

BTW, IT"S RAINING!!!!

Evan
08-06-2010, 08:37 PM
Today I spoke to the Transmission Assets Managing Engineer at BC Hydro Corp. He looked at my pictures via internet and was highly impressed. He asked for precise details of which lines they are and the exact time of day for the images, which I provided. He explained that the images are very valuable to determining the maximum loading of the circuit under these unusual conditions and in his opinion they may have been overloading the circuit based on the amount of corona and my reports of the intense electrical field near ground level. As the load increases the amount of energy coupled to the ground increases dramatically and transmission efficiency drop quickly.

He asked in a round about way if I could/was planning to take pictures of the tower insulators tonight. I explained I would be happy to do that. I have a feeling there might be a nice little well paying side line here. He explained that they can't be everywhere at once.

Incidentally, protecting the transmission line from the fires is top priority only exceeded by lives and structures.

Tony Ennis
08-06-2010, 09:08 PM
Incidentally, protecting the transmission line from the fires is top priority only exceeded by lives and structures.

I'm surprised structures come before the power lines.

Glad you're hanging in there. I assume the danger of fire consuming your place has now passed?

dp
08-06-2010, 09:30 PM
I've always been amazed how you could be centered between the towers and hear that hissing and crackling, and wondered what it might look like. I've never seen any flashing even on the darkest nights except at the insulators, so this is quite an eye opener! Nice. I wonder what might happen if you use your "priming the pump" method of sensitizing the camera.

And what a great example of right time, right place, well equipped.

Evan
08-06-2010, 09:39 PM
I assume the danger of fire consuming your place has now passed?

We wish. I am afraid it is closer than before. It is breaking through the southern end of the fire line because it has been too smoky for the water bombers to fly. It is now 8 miles distant from us.

http://ixian.ca/pics7/fire15.jpg

arkiehilbily
08-06-2010, 09:55 PM
Evan, if you don't feel it would be invading your privacy, would you give us your GPS coordinates so we could "find" you on Google Earth?
Jim (Warm in Mississipi but no fires)

aostling
08-06-2010, 10:53 PM
We wish. It is now 8 miles distant from us.


I'm following the Williams Lake weather report with much interest: http://www.wunderground.com/cgi-bin/findweather/getForecast?query=williams%20lake,%20bc&wuSelect=WEATHER.


Cloudy with 40 percent chance of showers this evening and after midnight. Showers beginning after midnight. Risk of a thundershower this evening. Local smoke.

They need to change that word risk to chance or hope.

Evan
08-06-2010, 11:06 PM
Sure. 53 3 50.9 N, 122 9 15.9 W

Google Earth won't show the fire though. If you want to see the fire map also then go here. Use the zoom feature by drawing a rectangle around the Meldrum fire in the lower centre of BC.

http://webmaps.gov.bc.ca/imf5/imf.jsp?site=pub_fireinfo

Black_Moons
08-06-2010, 11:06 PM
Evan, if you don't feel it would be invading your privacy, would you give us your GPS coordinates so we could "find" you on Google Earth?
Jim (Warm in Mississipi but no fires)

Only evanlike people can find evan! its rule #1 of evanclub.
*Cough cough, Corner of map picture cough cough*

Seriously though, cool pics evan, hope the fire turns out allright!

rockrat
08-06-2010, 11:49 PM
Thanks for the photos Evan. These are indeed a few sweet shots.

There are a set of high power lines on my route to the local observatory here. On late nights home I noticed that there was a crackling sound as I passed under one section. I would stop on occasion and just listen to the random noise that it would generate. Yes, my life can be that boring on occasions, but I think its cool.

I never thought that on a high temp, high humidity night I might be able to snap a photo like that. Now I have one more mission to try out.

Good luck with the fires up there Evan. I have been hoping that things will work out for you and your family.

Cheers
rock~

Peter.
08-07-2010, 04:36 AM
Evan.

Forgive my ignorance as I know nothing about photography. How is it that you can see nothing of the flashes with the naked eye but can capture them on time-exposure film? How does time-exposure help with something that surely must last just an instant?

arkiehilbily
08-07-2010, 12:35 PM
Thank you for the coordinates. The Google Earth view was taken back in
2005. The Forest Service photo looks like there might be a few less trees.
Boy, if you set out to cut enough trees to make sure nothing got near your house, you would need help for at least a week from Paul Bunyan and Babe.
Jim

fredf
08-07-2010, 01:55 PM
I expect its not that bad, there are no houses anywhere near that link. I think maybe a typo has occurred . . .
I think I found his place, but not at all sure

fred


Thank you for the coordinates. The Google Earth view was taken back in
2005. The Forest Service photo looks like there might be a few less trees.
Boy, if you set out to cut enough trees to make sure nothing got near your house, you would need help for at least a week from Paul Bunyan and Babe.
Jim

Evan
08-07-2010, 02:02 PM
I took out a bunch last year for fire safety but there is no easy way to take out the ones between the road and the house. There is a gulley about 20 to 30 feet deep that acts like a forested moat (which I like) and falling trees in that gulley is almost impossible. It's also full of brambles and raspberry bushes and parts of the gulley are kinda cliff like.

Back when our daughter was still at home a couple of young studs came sniffing around her bedroom window to take her out for an after midnight drive. I stepped out on the porch and fired a load of #7 shot into the air. They ran for the closest edge of the property which happened to be straight to the small cliff on the gulley that was over grown with the raspberries.

<BIG GRIN>

They next morning my very good friend and neighbour called and asked if I had any idea how his son might have gotten so seriously scratched and banged up last night. His son wouldn't tell him, so I did. Dave thought it was hilarious and a good lesson too.

I took some photos for BC hydro last night. The engineer was interested to see if there were any problems with the insulators. There aren't but the photos turned out well.

http://ixian.ca/pics7/corona4.jpg

http://ixian.ca/pics7/corona5.jpg

http://ixian.ca/pics7/corona6.jpg

http://ixian.ca/pics7/corona7.jpg

dp
08-07-2010, 04:36 PM
Sure. 53 3 50.9 N, 122 9 15.9 W



That should be 52 3 50.9 N, 122 9 15.9 W, no? If not, I was very lost but met a nice couple who put me up for a night :)

wierdscience
08-07-2010, 04:44 PM
Cool pics,any theories as to why they are flashing only at certain points and not along the entire run?

Bird crap on the wire acting as terminals maybe?

arkiehilbily
08-07-2010, 05:13 PM
I expect its not that bad, there are no houses anywhere near that link. I think maybe a typo has occurred . . .
I think I found his place, but not at all sure

fred
For Google Earth, you have to convert the coordinates Evan gave. Divide the seconds by 60 and add that decimal to the minutes. Try entering 53 3.848' N and 122 9.265'. I can even make out the gully.
Jim

Evan
08-07-2010, 05:26 PM
The outer part of the cable is pure aluminum strands. They are very easily damaged when handled. The slightest nick, scratch or ding can leave a sharp edge or point that acts to concentrate the electric field past the breakdown voltage of air.

The corona lasts for a good part of each AC cycle and repeats in the same place 60 times per second (not 120). A negative corona is much easier to create than a positive corona and has a much brighter and larger extent. If there are significant numbers of ions already present this makes it much easier for a coronal discharge to form. I have found that an exposure time of around 60 seconds is about optimum when it is very dark. It's never completely dark though and in this case there were quite a few bright yard lights both sodium and mercury vapour in the vicinity. That made the "sky" seem quite bright.

The corona discharge light is mostly in the near ultraviolet. The eye is insensitive to this wavelength but the silicon based sensors in a digital camera can detect it well. Most colour films will not detect it as they are intentionally kneecapped at that end of the spectrum to reduce haze effects. With a digital camera capable of producing RAW image format the raw sensor data is present with no post processing in the camera so the UV can be visualized.

Incidentally, corona physics was a big part of my training at Xerox.

Sorry about the typo. 52 03 50.59 N, 122 09 16.14 W is my roof top. It's 500 meters along the dashed line.

http://ixian.ca/pics7/property.jpg

Evan
08-10-2010, 12:32 AM
I sent the pictures of the towers to the power company this AM and almost immediately recieved a reply.



Evan,

Thank you for these and the previous set you provided. The capabilities of your equipment are very impressive. Normally we would require a Corona Camera to capture similar information.

We don't have a need for additional photography at this time but I have passed these on to others in the company who may be interested.

Thanks again

Regards,

Les XXXXXXXXX
Transmission Line Program Manager
BC Hydro Project Delivery


So, a corona camera eh? I looked up just what a corona camera is like. It is a very specialized unit that has UV filters to allow only the short wavelength UV from the corona through. The better units are "bi spectrum" which means they can also take a visible light image and overlay it on the corona image, just like my images except monochrome.

I was curious how much one costs as it sounds like something that is only targeted to very large corps with very deep pockets. The moment I found them offered as rentals I knew they weren't cheap. All the companies that make them don't list any prices until I found a used corona camera dealer.

That's when I damn near choked on my own tounge. The cheapest one is around 30 grand and a decent dual spectrum model is 95 thousand dollars. :eek: No wonder Les is impressed. The only thing special about my equipment is my very sharp modified Japanese telephoto that I used to take the pictures. I also used my astrophoto manipulation techniques to improve the image diagnostic values. I am hoping that this might turn into a nice little side line in the future. All that needs to happen is for an insulator in this area to develop a crack or two that they can't find. I work a lot cheaper than the $3000 per week corona camera rental.

aostling
08-10-2010, 02:43 AM
I looked up just what a corona camera is like. It is a very specialized unit that has UV filters to allow only the short wavelength UV from the corona through.

I don't know much about UV photography, but Pentax made some very rare and expensive Super-Achromatic Takumars for this. There was also a Quartz Takumar, for use on a bellows for close-ups: http://www.aohc.it/tak06e.htm.

http://photographyoftheinvisibleworld.blogspot.com/2007/09/ultra-achromatic-takumar-300mm.html shows a photo taken with the 300mm, in the ultra violet, with more here: http://www.pbase.com/kds315/uv_photos. Those lenses are virtually unobtainable, but I'd love to have one.

dp
08-10-2010, 02:55 AM
That's when I damn near choked on my own tounge. The cheapest one is around 30 grand and a decent dual spectrum model is 95 thousand dollars. :eek: No wonder Les is impressed.

I wonder if the power company has ever published the photos taken with one of those cameras. My guess is electricity may be a lot like making sausage - you don't want the public to see it! :) I'll bet some of those runners in UV video are quite spooky.

Evan
08-10-2010, 04:26 AM
The spectrum of interest is really short wavelength, from 240nm to 280nm. Quartz lenses are a requirement. However, an aluminum coated mirror has no problem with short wavelengths. Aluminum has about 85% reflectance at 250nm. Even silver falls short at that wavelength. It falls off dramatically at around 350 and at 250nm is almost black. A small wide angle short focal length telescope with a bandpass filter over a silicon sensor would make a fine corona camera. The most expensive part is the filter. I priced them at Edmond Optics and a 12.5mm 254nm with 40nm half power bandwidth is about $200. This arrangment will allow for corona images in full daylight as UV from the sun in that range is blocked almost entirely by the atmosphere.