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Question

How do linemen deal with clearing wet-snow/ice on medium voltage power lines? I need real life stories

Snow is different according to the region. There is snow and then there is snow, wet-snow, dry snow, ice etc. New York Pennsylvania linemen must be dealing with it differently than Michigan linemen, or Alaksa people must have different stories than polar vortex survivors. I need to know so many things, like do they do anything before it covers the lines? Once it is on the powerlines and iced real quickly, how do they clean it? Robots? other means? sticks hitting the line? How about the people up in the mountains, at night, looking for snapped lines? How do they even know where the line snapped? Or what if the whole line is down? How do they get the poles back up? How do they work? 

Purpose for Question: 

I am working on an article on the invisible lives of linemen who are out there working on frozen power lines trying to get power to homes but never get acknowledged. It is always the company who gets the blessings, but the real people are the linemen. We are also developing a technology that is supposed to prevent ice on power lines. However, without talking to the linemen/people who suffer fro this pain, we cannot know if our technology will actually help them eventually. We are not selling anything because we are still at the very early stage. Plus, the technology we need to be developing will depend on the local circumstance. Therefore, we need to get close to people at utilities. I have been a faculty member, so I know nothing about the industry. That is why, I am working on this paper, where I can put all the stories together, and create a 'real life'-based story, where not the companies but the people are the main actors of the game.

Answers

Best Answer

This is a good question and it is good to recognize the different forms of frozen water that accumulate on overhead cables and concurrent wind loading in general.  In western Oregon we typically would mostly worry about freezing rain rather than snow, which is obviously has a different density and characteristics of loading than other forms.  I would say the first step would be to contact some specific utilities about this.  Portland General Electric , PacifiCorp and Bonneville Power Administration have some lines in the Columbia River Gorge which has some of the worst concurrent wind and ice loading conditions per ASCE 7-10 anywhere in the U.S. Also look at the west side of Lake Superior (1.25" ice and 80 mph wind, is pretty extreme). As a transmission line engineer we engineer for a set of loading conditions, however there is always the risk that these conditions will be exceeded in an extreme weather event.  If engineering can't solve the problem, then in known problem areas, one way I have heard of clearing transmission lines is heating them up intermittently by running a large current through them. I don't think this is necessarily possible on distribution level lines which is likely what you would be focusing on.

I need to know so many things, like do they do anything before it covers the lines? -  This would best be answered by direct contacts with different utilities operations and maintenance departments.

Once it is on the powerlines and iced real quickly, how do they clean it? Robots? other means? sticks hitting the line? - I might be wrong but I get the feeling for distribution level lines, it is more prepare for the worst, hope for the best.

How about the people up in the mountains, at night, looking for snapped lines? - The utilities know their facilities, and are typically prepared to deal with potential outages as quickly as reasonably possible.  Again prepare for the worst, hope for the best.

How do they even know where the line snapped? - Depending on the location and equipment on the line the utility can get a pretty good idea of where the fault is remotely, and send a crew out to investigate, triage, and repair. Someone may be able to provide more detail on how they do this if necessary.

Or what if the whole line is down? - Worst case scenario, and not too typical hopefully.  But temporary lines can be constructed or other lines rerouted as quickly as possible to get power back.  Then the line can be rebuilt, likely designed to larger weather loading requirements.

How do they get the poles back up? This is a question that could be answered best by lineman themselves and in much more detail. But if the poles have failed, they are hauled away and new poles are installed. Typically in Oregon, this would be with a bucket truck with an auger for wood poles. New holes would be augured, the poles would be pre-drilled or drilled on site, equipment would be remounted and the pole would be set in the ground.  The cables would then be rehung or restrung on the structures depending on the overall damage.  

How do they work? - How do the lineman work? Again best answered by a lineman but generally, they have strict safety measures, great training and experience.  They recognize their importance to the grid and are prepared to work through extreme weather events as soon as it is safe to do so.

I hope this helps a little.  I think your best bet would be to get into contact with some of the utilities/owners that have these issues and see if they can get you an interview with the O&M groups.

Elissa Elif Kalaycı's picture
Elissa Elif Kalaycı on Oct 10, 2019 6:37 am GMT

Wow!!! This is so much valuable information.. You have answered them one by one.. Can't appreciate enough.. I will directly write to the utililites, maybe their PR people could make me talk with some linemen, if not anyone I can get hold of. But certainly I am not at point zero now!! Thanks Steve.. I did not know the freezing rain happened in Portland area. That point about prepare for the worst and hope for the best is soooo diggable!!. I should include that in the questions. If you were in my shoes, what other questions would you ask in particular to the utilities in northwest? You are good!!! Thank you very much...

That is the big question : why many of faculty members, know nothing about the industry ? How to bridge this gap?

Elissa Elif Kalaycı's picture
Elissa Elif Kalaycı on Oct 9, 2019 2:07 pm GMT

I guess it is because academics can get literature from journals, but real life stories is a different case. As for bridging the gap, mine is a small step :) towards closing the gap. What do you say?

Dr. Amal Khashab's picture
Dr. Amal Khashab on Oct 9, 2019 7:12 pm GMT

That is right from academics side , but ,what the industry side has to do ? I gues proper ways to continuous education will help . Who can take the lead ?

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