Coils on power lines

[PaulInEastTroy]

I've been in electricity and electronics for 50 years, but I have almost no knowledge of the details of the power grid.

On a recent trip to Minnesota, I noticed some power lines that had coils that surrounded the primary conductors. Imagine a few turns wound tightly to the conductor, then an increase in diameter for a time, then a constant diameter, then a decreasing diameter leading to a few turns tightly wound to the conductor. The turns are widely spaced. These coils are affixed to all three conductors, and multiples of them are attached between each tower pair. What the heck are these things? I have only one serious theory -- something about being able to visually locate the location of a lightning strike by the failure -- deformation, evaporation, or whatever -- of the coils when subjected to the massive currents of a bolt from the blue. OK, it's a crazy idea, but I can't stand not being able to rationalize things, and I have at least SOME imagination...

Can anybody tell me what these are?

Thanks in advance,

Paul
Newbie in Wisconsin)

 

[itsmoked]

You CAN include pictures directly into this post now, you know?

Could they have been for allowing expansion and contraction in that thermally challenged state?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Compositepro]

I thought they might be spiral vibration dampers to prevent Aeolian vibrations from wind.

https://www.google.com/search?q=spi...CMQsARqFQoTCKXXr5vmkMgCFYmggAodLLwI1g&dpr=0.9

But this shows a bird flight diverter.

http://www.ecvv.com/product/4056002.html

 

[melspuds]

Paul
In the very early 1970's I worked for an large electrical contractor in central WI. He had several line construction crews and did a lot of work in U.P., N. WI., and iron mines in MN. When I was first reading of the spec's for on a lot of the jobs that could only be done in the winter (frozen ground). I questioned why the loops. They are for for expansion and contraction as "itsmokes" stated above. Remember the temps vary greater than 110F[sup]o[/sup] if not more.
Remember that International Falls, MN. is known to be the coolest spot in the lower 48 states.
I do not know if this is the correct answer for your question or not, but it is a very interesting answer.
Hopes this helps,
Dave

 

[davidbeach]

Having seen what I believe is being described, it isn't for expansion/contraction, but is added after the line is installed; either for Aeolian damping (my initial guess) or as bird diverters as Compositepro suggests. Either is possible, perhaps even both can be achieved with the same device. But in either case it is added after the line is installed.

 

[HamburgerHelper]

I bet they are for aeolian damping as said earlier. I used to live in minnesota and I don't beleive they are for the birds just due to not remembering birds being as plentiful as they are around the gulf during migration. The thing I find kind of funny about you seeing them in minnesota to prevent gallopping conductors is that I beleive that ice build up is actually more of an issue in regions that are slightly warmer. The worst conditions for ice building up is slightly below freezing with a cross wind. The air in minnesota usually is very dry due to the temperature and the air that comes in from canada doesn't passing over water. When I lived in Oklahoma, I went through real ice storm in 2010 and there were rural areas that were without power for well over a week. That though wasn't due to transmission lines coming down. The substations came on line much earlier before distribution got all their poles back up.

 

[melspuds]

I read the question wrong, or what I wanted it to read. MY MISTAKE
What I stated is true, but for coils at every other pole or tower for the expansion/contraction. On long spans required vibration dampers. The owners of the lines with the coils would keep an eye on them for about 2 years, and remove all or part of the coil if everything checked out ok. The strain guages of the that time where not accurated at -30F[sup]o[/sup].
Sorry for the mistake,

Dave

 

[FPelec]

Most probably it is a bird diverter. If so, it should be red or some other bright colour.

Si duri puer ingeni videtur,
preconem facias vel architectum.

 

[jghrist]

I vote for vibration dampers. Normally you don't care if birds sit on the line, and bird diverters are put at the structure where birds can caused outages either by electrocuting themselves or crapping on insulators.

 

[Compositepro]

Apparently, bird diverters are for making the wires more visible to birds so they do not get injured.