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In the scenario I'm envisioning, my group is in a city. They've got a source of hydroelectric power, but a few downed power lines/utility poles are making it difficult for them to transmit the electricity. We're far enough post-apocalypse that they don't have any petroleum and can't use a car with a crane attached to it. Would it be feasible for them to design a crane or simple pulley system that could get the pole upright again (using the materials that might be readily available to them in a city, of course)? Is there another way they might get the job done?

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  • $\begingroup$ Hi, Peter A, welcome to Worldbuilding! Do you want a simple low-voltage wire that hangs on posts, or a big, high voltage transmission line? $\endgroup$ – Alexander Oct 31 '18 at 19:57
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    $\begingroup$ Google "how to raise an obelisk". Just as important... where did you get your generator from, and how are you regulating the voltage and amperage? (Technology has a 1000x more vital details than you can imagine.) Also, the transmission lines: were they scavenged ages ago? $\endgroup$ – RonJohn Oct 31 '18 at 20:00
  • $\begingroup$ Hi Alexander, thanks! I'm thinking low-voltage wire. The community isn't that big and they only plan on using the electricity for a few key items, e.g., refrigeration. $\endgroup$ – Peter A Oct 31 '18 at 20:03
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    $\begingroup$ @Peter A Low voltage lines are distribution lines, not transmission lines. Unless the settlement is at the hydro-electric dam, they won't be able to transmit power to the settlement using LV. $\endgroup$ – Arkenstein XII Oct 31 '18 at 20:06
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    $\begingroup$ Low-voltage power lines are typically running for a distance less than 1 km. There is no problem maintaining those lines manually, except for the required amount of work. $\endgroup$ – Alexander Oct 31 '18 at 20:43
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One of the issues with doing this is that righting the pole is not enough. They're likely working with 11kV or even 33kV lines (depending on the country, but it'll be in this ballpark), which are under high tension. They would need not only to put the pole back up, but the re-tension the lines. Without the proper equipment, this going to be difficult. Furthermore, when the poles fell down, some of the lines probably snapped, which means they'd have to repair or replace those lines too.

My suggestion is, that they'd want to have access to the correct equipment, and a working knowledge of how high-tension transmission lines work before attempting this.

That's not to even begin on the issue of replacing and broken insulators, fuses, or switchgear...

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    $\begingroup$ And then they gotta regulate the grid somehow. Too little power and you get brown-outs/black-outs. Too much and you fry your equipment. This project is just way too big for one engineer, no matter how good he is. It's probably too big for 100 engineers. $\endgroup$ – Ryan_L Oct 31 '18 at 20:06
  • $\begingroup$ "High tension" as used WRT power lines does not mean what you seem to think it does. It simply means high voltage. The power lines are under no tension other than that of their own weight. (And wind, ice, &c.) $\endgroup$ – jamesqf Nov 1 '18 at 18:03
  • $\begingroup$ @Jamesqf Technically true, however they have enough weight to make specialist equipment a necessity. $\endgroup$ – Arkenstein XII Nov 1 '18 at 19:13
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    $\begingroup$ @Arkenstein: Depends on the size of the line, of course. But when the OP says "power poles", I think of the standard wooden ones that are used in rural distribution lines. The lines used for these aren't very large, and could be pulled sufficiently taut with a simple hand winch. $\endgroup$ – jamesqf Nov 2 '18 at 4:46
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Even to this day, people are lifting objects even heavier than an electrical utility pole to upright them in this manner. Think of the stereotypical Amish barn-raising scene where an entire wall of a building might be raised into place and held there while worked on. Yes, you could use a pulley system, but you probably don't need to.

You start with your utility pole on the ground. If there is not already a hole in the ground for its bottom to rest in, then dig one.

An "=" represents the tree
A "+" represents the hole
A "," represents the ground (the comma is grass)

==========
,,,,,,,,,,,,+,,,
            +

Make 3 or more ropes, tie them all to the top end of the pole you want to raise. Then make a smaller pole that will help you lift the top end of the utility pole up by pushing on it. With the bottom end of it inserted into the hole in the ground (or at least partially in it) to stabilize the location of the bottom, push up on the top to get it as high as you can.

A "-" is the smaller pole that you are pushing the bigger one up with
A "." is rope

==...
  == ...
  - ==  ...
 -    ==   ...
-       ==    ... <--(people, animals, or devices pulling on end of rope here)
,,,,,,,,,,,=,,,,,,,
           +

Then have people with ropes on the other side of it start to pull to raise it the rest of the way.

With ropes in place, minimum 3 at 120 degree angles from each other, you should be able to stabilize the pole so that it does not fall over since it is held back from each direction.

Once it is upright and in place, just make sure that it has good footing in the hole in the ground you have put it in. If you are unsure, leave the ropes in place and anchor them to act as guy lines to support the pole.

Here is a video of practically the same thing being done, though not for electric utility: (Thanks to @Bald Bear for the comment suggesting this video)

https://www.youtube.com/watch?v=jEBA1UvmntM

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  • $\begingroup$ Correct answer. here is an illustration: youtube.com/watch?v=jEBA1UvmntM if you do not have enough people to pull, use horses, or hand-cranked winches. $\endgroup$ – Bald Bear Oct 31 '18 at 20:09
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    $\begingroup$ @Bald Bear: Enough people? Given sufficient incentive, I think I could erect a standard utility power pole single-handed. $\endgroup$ – jamesqf Nov 1 '18 at 18:05
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    $\begingroup$ @jamesqf I agree; if given sufficient time a lot can be done even by 1 person. However, if you have a small community of people willing to work together to restore power, you might as well gather them and work together. Working together, they could get a bunch of poles up per day, maybe their entire local network of poles in a week or month. $\endgroup$ – Loduwijk Nov 1 '18 at 18:16
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@Aaron above has correct answer on raising the electric poles without a crane. But there are a few other solutions to the broader problem of restoring electric service.

There are large cranes that work off electricity, for use in arctic conditions. They do trail a cable behind them, but it only needs to be long enough to reach the next pole. Even if they do not have such a crane handy, they can modify an gas-powered crane (using the same tools and skills that they used to fix the generator).

Electricity can be carried without poles, by a heavily insulated cable, that is typically buried in the ground, but could be left just laying on the ground in the short term (you just do not want any human or animal to break it accidentally). There are few cables big enough to power a large city, but there are plenty that can power a small village. Poles are used more IRL b/c they are easier/cheaper, but that is only true if you have a crane.

If it's a small community, it makes sense for them to live at or near the hydroelectic dam. River & reservoir are good for fishing, transportation, irrigation. Moving the community might be easier than fixing a long power line.

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  • $\begingroup$ Though cables that can power (a significant part of) a large city do exist. See e.g. the Pacific DC intertie en.wikipedia.org/wiki/Pacific_DC_Intertie#Components which runs up to 3.1 gigawatts over two cables. $\endgroup$ – jamesqf Nov 1 '18 at 18:09
  • $\begingroup$ My only issue with this is "they can modify an gas-powered crane (using the same tools and skills that they used to fix the generator)". They might be able to modify a gas powered crane, but that would be much more complicated and not necessarily within their capability. If they could though, then ok. 2) Moving closer to the source of power would be great if they have nothing else holding them back from doing so; that doesn't really answer OP's question as asked but it is probably the best answer in reality. $\endgroup$ – Loduwijk Nov 1 '18 at 18:22
  • $\begingroup$ @Aaron I agree modifying a propulsion system of a large crane is a lot of work. On the other side, portable electric winches are common and could be used in the usual pulling method $\endgroup$ – Bald Bear Nov 1 '18 at 19:00

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