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Why Aren't Powergrids Underground?
jonging asks: "It is common knowledge that an underground power grid is less susceptible to the effect of a large thunderstorm. The American Transmission Company cites numerous reasons why it (and other power companies I assume) do not bury their transmission lines underground (e.g. environmental concerns, cost of installation and repair, etc.). Exactly how detrimental are underground transmission lines to the environment? Wouldn't the time spent without a power outage generate more than enough revenue to offset initial costs? Aren't the need for repairs in cities with successful underground power grids rare?" The linked article goes into extensive detail about the disadvantages in initial costs of putting in underground lines, but doesn't go into any detail about the maintenance costs of either option. With storms getting worse and worse (Maryland, DC and Northern Virginia have weathered torrential downfalls this week), might underground lines prove more resistant to storm-related power outages?
Sure, it would be nice to put it underground, but it costs more that way...
This issue is a bit more complicated than you think.
Though I'm not addressing TFA directly, let me comment on the DC thing. Yes. We have been utterly hammerered unto oblivion with rain in the last 5 days. But even at that, the power grid in DC is remarkably stable.
My office, which is about 3 blocks from the White House, has never had a major event that would have an effect on our network. In about 10 months of running monitoring 24/7 on our UPS, I've never seen a major "power event" (outage, surge, something else big). I've never seen a big spike or dip. Hell, I've barely seen any variation at all in the signal.
Perhaps it's a function of living in the big city. Perhaps it really is the fact that I'm on the same power grid as the White House. Perhaps it's just a coincidence and some really nice wiring, and me with a little too much tinfoil in my hat. Regardless, I think something is special about the power grids in the DC area.
ACs are modded -6. I don't read you, I don't mod you, I don't see you. Don't like it? Don't be a coward.
More expensive to dig, harder to cross roads/othershit when digging, MUCH easier to repair above-ground lines than below-ground lines (all you need is a cherry-picker truck), and what would squirrels walk on if there weren't above-ground power lines?
A computer once beat me at chess, but it was no match for me at kick boxing.
It's true that underground lines require less maintenance. A lot less maintenance. If we changed all our lines from overhead to underground, NES would have to layoff 4/5 of their maintenance team. Rather than realizing that it would take years to convert every powerline in Nashville from overhead to underground so they'd have excellent job security until they retired, they have decided not to convert to underground lines. I wouldn't be surprised if this is true in other areas, but I know that's the deal here. So everytime there's a thunderstorm the power goes out, and the cable goes out with it, cause the cable lines follow the powerlines.
just some guy
And you know what? I'd say it looked pretty damned nice.
You know what else? I sound like a old rambling grandpa. I remember in my day to get to Taliesin we had to walk 5 miles uphill both ways in the snow...
A guy walks into a bar... well, I forgot the joke, but the punchline is that he's an alcoholic.
Each cable that transports AC is subject to drain by the capacity the parallel lines themselves represent. The closer the wires, the higher the capacity. At about 30 km on a regular high voltage cable, you reach a point where the reactive power drain reaches the maximum power the cable can transport - the cable is saturated without draining a single watt at the end.
DC does not have this issue however then you have all the problems that killed Edison's original DC power distribution in favor of Telsa's AC distribution.
Peter.
My apartment complex has its power fed in through a buried line, and I can attest to one good reason why power companies may not want to bury all (or even most) of their power lines: water.
My power has gone out three times already, this year, due to water seeping in where it shouldn't and causing a major short. Aside from the obvious risk of losing power, there's also the possibility of pedestrians and pets being electrocuted.
~UP
Eat the Path.
Underground powerlines would suffer higher capacitive losses than overhead lines, and losses between the generating plant and the user would be power that the utility company can't (directly) bill for.
With all the public concern about EMF exposure, the situation would be made much worse when all those distribution transformers move from 40' up a pole to concrete pads at ground level. And then there is the everpresent problem of "backhoe fade"...
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In the Southeast United States fire ants are a big problem. The just love low- and medium-voltage electricity.
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Downtown Washington rarely has power outages because the power lines are underground.
Here in Australia, or at least large (for big values of large) amounts of it, it's all above ground too. Where I'm coming from, the Netherlands, it's all below ground.
When I discuss it with the people here, they give me all kind of reasons why it should be above ground (limited but not only to unable to quickly repair, the famous cable cut from people digging and, believe it or not, the people who are doing the repairs now would be jobless).
Just a quick glance about how it could be done and you'll see that it would be quite a trick anyway: All footpaths in Australia are large blocks of concrete or asphalt, and the nice small tiles you see in shopping centers are also just laying above a concrete layer. Opening up that would be a major++ operation. Compare it to the Netherlands where all footpaths (and most of the bicyclepaths) are just 30x30 cm tiles laying on top of yellow or black sand, you'll see that it has a historical tradition to put things underground and have them easily accessible.
bash$
We could continue to debate this endlessly, but maybe you could save time and just read the official report?
I'll also mention that 4 of the 5 NYC boroughs (Manhattan, Brooklyn, Queens, and the Bronx) have their electricity distribution almost entirely below ground. It was a massive investment, but it was long ago.
I work for an electrical contractor in Eastern Iowa and we regularly have to work near these high lines and work with the power companies. As far as I can see, it is exceedingly expensive to bury these wires. There are alot of farmers around here and they regularly hit buried power lines when digging in their fields. This is a often an expensive and timely problem to fix involving the power company, an electrician and usually a whole day. I noticed the article doesn't say maintenance issues. From my experience, they need less maintenance, but the particular maintenace is very costly in money and time.
"Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive." - C.S. Lewis
Not exactly. Here's some good information on it:
State's utility system in better shape now
Some key points:
Since 1966 new neigborhood's have been built with underground electrical cabling.
Since hurricane Iniki devestated the island of Kauai in 1993 a lot of utility wiring has been moved underground.
Only about 40% of Hawaiian Electric Company power lines are underground.
At least here on Oahu we have plenty of power lines and during bad storms some areas of the island often lose power.
Sometimes my arms bend back.
The same reasons most houses in coastal areas of Florida and other sandy-soil areas near water don't have basements. Water pushes right into them.
Try putting underground *anything* in gulf-coast Florida, etc.
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In urban areas in Sweden it's all below ground. It's in part, I believe, because of snow; rural areas (where underground cables become far too expensive) have a predictable power outage mess every winter as some storm weighs down lines enough to break them (cue predictable news images of army units clearing snow off calbe poles and some farmer with no backup generator milking his cows by hand). It's also because of zoning laws - power companies have no choice. I believe much of nothern Europe at least is similar in this regard?
Here in Japan, on the other hand, it's all above ground. In part because of the relative lack of zoning laws (Japanese city architecture is delightfully, ah, surprising as a result), but according to people here it's mosty because of the prevalence of earthquakes, the one thing buried cables are not protected against. Sure, overhead cables will break too, but it'll be easier to fix.
I can understand the situation here in Japan, but really, it's a pretty hideous sight. So your power may end up getting slightly more expensive as a result (though this is dwarfed by other factors), but it's worth it. If saving money is all there is about city living, why not allow people to dump their trash in the street as well?
Trust the Computer. The Computer is your friend.
How's about designing roads and sidewalks with utilities in mind in the first place. Bolt down slabs which can be lifted to lay cables and pipes underneath instead of digging up roads continuously bringing traffic to a halt.
Deleted
I come from a telecommunications background. Putting in a pole-route is quicker and easier than digging a trench. No question.
Nowadays, most telecoms cables are buried, which puts them witin reach of problems you'd probably not consider likely.
Termites, we discovered, will eat lead sheathing and just about anything else. So will rats. In fact rats will gnaw at anything. Then there are chemicals in the ground. Water is an issue. All our cables were pressurised with air to keep the water out. In short, you can't just bury cables and ignore them.
Something no one has brought up is the ability to upgrade technology. With above-ground poles, it's fairly simple to string along additional wires as needed. If you're undergound and you run out of phone lines, the telco may just say too bad, wait 6-18 months until there's enough demand to dig up the neighbourhood. If the city is rolling out fiber-to-the-home, the undergound neighbourhoods are likely to be the last to get it. Most likely they won't get it until the road needs to be dug up anyways to replace the surface, or sewer or water lines.. That can take 20-30 years, or even longer sometimes.
My parents live in an area with everything undergound. It definately looks nicer, but their cable reception is on some channels is terrible, and has been that way for years. They've had the line going up to the house replaced and all the inside wiring replaced, but it's still not as good as it would be. Replacing the main line in the road would mean digging up the bottom couple feet of 50-60 driveways (most paved, some interlocking brick.. you usually can't find the exact same replacement bricks either, so it would never look the same). It's just not practical to do to fix a few snowy channels for a handful of houses (I'm not sure exactly how many people have the problem, but their immediate neighbours do at least).
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I've been building power plants and other industrial projects for 15 years now. We encase all cabling in ductbanks (conduit & rebar in concrete, usually dyed red) and only a determined idiot will knock these lines out of service.
To address the issue with power loss through induction, yet it happens and it's dangerous. We had a run of pipe being welded up directly under a 100+ kV line leaving a substation. After getting several hundred feet welded up, they started having spot fires in the area. After several calls to the local FD, the FD Chief was getting pissed so they were walking the area down, heard a zzzzzssshhhtt (best I can describe) and sure enough the lines were inducing a current into the pipe (creating a large cap) and once the charge was large enough it arced to the ground, sometimes in a area with dry leaves & pine needles.
Also on another project we had a 12kV line in a ductbank piggybacking a 100pr data cable which fed our T1/T3 lines and we kept blowing the phone companies coils on their end and causing havoc with our digital phone system. Finally one day I was re-wiring the phone system and got zapped. Voltmeter showed 60V, not sure of amerage but it smarted. Idiots who installed the 12kV line didn't bond the shield so we had a current inducted into the 100pr.
So, yes power can be run underground but you better encase it and know what you're doing or hire someone who does.
Reminds me of this thread
The Backhoe, The Internet's Natural Enemy
Always carry a length of fiber-optic cable in your pocket. Should you be shipwrecked and find yourself stranded on a desert island, bury the cable in the sand. A few hours later, a guy driving a backhoe will be along to dig it up. Ask him to rescue you.
[Fuck Beta]
o0t!
Out in the air the water drips off and broken cables are easier to get to.
Companies like this rarely ever build infrastructure unless they can get an enormous government grant for it they can milk mercilessly while providing something that doesn't work or barely works - so are unlikely to be involved anyway.The Western Australian christmas tree (Nuytsia floribunda) is parasitic, and apparently its 'tenticles' wrap around cables and sever them.
New Orleans had all kinds of power systems underground, including powering their pumps. When Katrina hit, they flooded and failed, just like they did for years in smaller storms.
If New Orleans didn't learn to do it different before Katrina, why should we learn to do it different after Katrina?
--
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that has nothing to do with community or competition. it has to do if the city engineering office is organized or not and how many lawyers get involved. For new subdivisions, usually what you described for the "German senario" happens if the city is on the ball. in other cases, the road may be there for years or decades before it is determined that utilities need to be run into that area.
the good ground has been paved over by suicidal maniacs
Not sure if Nashville is an extreme case or if it is rather representative of the reliability of overhead lines, but after I moved here I felt like I was living in a developing country in terms of power supply. Back in Germany, where all power lines are underground, I would experience a power outage every 3-5 years. Here in Nashville, it's more like 3-5 per year. Oh well, at least now I finally understand what a UPS is useful for.
I used to work for a NSW power company, and as I left they were completing the south sydney project. The city CBD needed more power than the current lines could provide, but there was no way to put in overhead high tension lines. Instead, they started in the inner south-west suburbs (the nearest new power source) and ran 3 x 330kV cables under the back-street asphalt. When they got close, they started digging (ie tunnel boring machines) and ran it underground. At Haymarket, they built an underground substation, and connected it up to the grid. 330kV overhead lines in NSW are bloody huge and very high, with lots and lots of insulation and separation. Putting them underground was a challenge.
Switching to underground power would require not just the upkeep of underground wires:
Underground wires will require insulated wire to replace much of the uninsulated wire used in overhead lines.
Underground wires will require that thousands of miles of trenches be dug.
Underground lines will require that houses have power inlets underground rather than on the roof, as present.
Underground lines will require that Millions, if not billions, of towers and poles be constructed.
Underground lines will require pole-top transformers be moved to ground level or below.
The costs of converting are staggering, and will take probably at least a decade.
As a resident of the DC suburbs (southern MD to be precise) we aren't having too many power outages due to these recent storms. Mostly flooded roads.
You like your new Mac more than you like me, don't you, Dave? Dave? I asked...She said Yes.
Oh, stop whining. He's talking about urban areas. I live in an urban area comparable in density to a common American suburb, and I couldn't find a single power line if I spent a whole day looking, and that's not because we don't have electricity, it's because they're all underground ;)
As weird as it may sound, quite a number of small towns here, in Ukraine have their powergrids (mostly) underground. It is so because in the 90s it was not uncommon for every piece of cable/wiring to get stolen sortly after being installed. So, back in day it used to be financially effective. Now with crime rates down it, probably, would not be worth the price, thought. But it stays as it was.
"Long term it still costs more."
I'd say that's debatable. My power bills were more in Denver than an hour north. In Fort Collins, Colorado, a study found that the quality of life was higher because the skyline lacked the unsightly transmission lines. I can say, being here, that it is a benefit to creating an overall, less-clustered atmosphere (I like to see the mountains when the pollution isn't in the way). The plan to bury lines was started before the town started growing, so various infrastructure was already well established to handle a growing population, e.g., roads, schools, etc. The cost of labor, materials and fuel was also cheaper when they started the program over a decade ago. They continue to add more buried lines to new neighborhoods and are still burying exposed lines in the back of older neighborhoods to this day. I'd like to note that our city handles water and electric, not a privately-held utility, like our gas company, Xcel.
Sure, our town is in a budget crunch. Well, more like we have a six million dollar deficit, but there's other reasons for that. I've often wondered why places like Florida don't bury their lines as they suffer so many storm-related disruptions. That's got to take a bigger hit on the economy, but when you think that every person has to start over to some extent, they will spend their insurance money on a new PS2 as much as a new house (unless the insurance company goes broke trying to settle claims). The Miami Herald has an article about the debate to bury or not to bury:
http://www.miami.com/mld/miamiherald/12502044.htm
The long-term cost of maintaining the conduit may be offset by increased services the government can give in the event of crisis because they don't have to bear the cost of repair and/or the cost of lost productivity when responding with reduced public services. I admit that the environment here is completely different than Florida. I would imagine, because it is dry here, we don't have to worry too much about drainage/plant related problems with our conduits, but ICBW... I also notice that our utility crews seem very well-prepared and, at least, look like they're working!
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There's a slight difference between the two jobs. When you're working on something, you're standing on the ground. So when you touch something not-at-ground-potential, a current flows through your body (killing you instantly ;). When you're working on the high tension lines, you touch the line, and you too become charged to whatever potential the lines are at. As long as you don't touch anything else (like the ground), you're perfectly fine.
My other car is first.
I presume that the Germans, because of the constraints of their language's syntax at the end of which their sentences most of their verbs must put, cultural constraints that ahead they must think required are.
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In general, it is safe and legal to kill your children. -- POSIX Programmer's Guide
Why this is modded +5 informative shows how bad the average person's logic is. Unless you pegged my sarcasm meter (which is possible) it seems more plausible that keeping the nations government stably powered is a more significant factor than the placement of the lines.
Power has gone out at least once a year for the past five years to my (Downtown San Francisco) neighborhood. Due to underground power lines. A couple months ago an underground substation exploded and burned the hell out of a woman walking on the sidewalk. A couple years ago directly in front of my apartment a short underground ignited flammable (sewer) gases which blew the manhole covers 40 feet in the air (And the power out for the whole day). No one was hurt, but one of the covers did go most of the way through a car.
My UPS gets a good work out.
Why does this discussion suddenly demand an anti-european outburst? Is it wrong to point out Europe's good experience with underground powerlines?
You yanks can have as lousy an infrastructure as you please. The rest of the world doesn't care how poorly you arrange your society. In fact, the US neglect of it's infrastructure gives the rest of us a competitive advantage (and even more so in the future).
However, the original post talked about power outages from thunderstorms, which -- excuse me -- is a HUGE problem in the US. I have lived in your country for several years, and been on numerous visits, and my experience is that power outages happen frequently in the US, whereas in Europe, it is a rare event. I remember one ice-storm in New Haven that brought down all the city's powerlines and it took weeks to repair. What you have to ask (and the original poster does) is whether the electricity companies across the country are scooping the profits from consumers without making investments that will ensure/improve the supply for the future. The electricity company does not pay the economic losses of thousands of other companies due to power outages.
So why not leave your flag-waving patriotism behind for a few moments and relate to the actual problems?
Let's assume (though this is far from obviously true) that underground lines are indeed more reliable. Having a reliable electric supply generates lots of positive externalities--and of course unreliable power has large negative externalities.
The problem is that the positive externalities generated by the underground lines would not be captured by the power company. Even if the buried lines generate benefits to society far in excess of their high costs, the power company would see only a fraction of those benefits (e.g. less money spent on repairs, assuming that's even true.) The cost, though beneficial to society, is prohibitive to the utility.
Possible solutions of course involve government subsidies to bury the power lines, or perhaps requiring them to be buried and allowing the higher cost to be passed to consumers (for instance in Maryland, where electricity has been deregulated, it's only the generation of power that's deregulated. Retail delivery is still regulated.)
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Put fiber optics underground, and no matter how well you try, someone is going to hit them. Whether by contractor laziness/mistake, or due to utility locates being off by more than 20 feet, it's going to happen. Also, you have the problem of lazy install contractors who will find the softest dirt, and bury fiber optics right smack dab on top of existing utilities. And repairing overhead is more cost efficient than repairing underground utilities. I work in this field, so I know what I'm talking about.
In my opinion, string that garbage up in the air where it can be seen, and make a "treefall" zone around any above ground utility (nothing shall remain standing that can at any time fall and interupt service. There are plenty of trees, and what would be cut can be replaced).
Why do we use fiber optics anyway when there's wireless? The only thing that should be in the ground are gas, storm drains, and water and sewer lines.
This experiment in burying wires has gone on long enough, time for it to end.
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Germany has 1/3 the people of the USA crammed into a space 1/27th the space.
That might suggest that a single US utility consumer might be paying for a bit more infrastructure.
It is not the full 9x factor that the numbers imply since you can localize your sources, but it is a SIGNIFICANTLY larger distance that must be covered to convey the same service.
This is true of highways.
I find it absolutely amazing that our prices are even in the same ball park as those of Europe on goods and services that are impacted by population density. In most cases in the US it is cheaper even if you do not take government subsidies into consideration.
Ok, train travel is MUCH cheaper in Europe, but electricity, water, septic, garbage, postal, trucking, auto and air are all cheaper in the US.
Slowly waving my hand - "This is not the sig you are looking for."
Speaking as the son of a retired rural co-op lineman, underground counduit is a very bad idea in most situation. Whatever conduit you put the lines in breaks down and can leak. You would have to insulate the lines, buy new excavating equipment that most utilities don't own (and train/hire people who know how to operate them), shut down surface streets for extended periods of time. You'd also have to punch holes in the basements of all the hosues served by this underground line and move most, if not all of the meters. It'd be a nightmare, and in many rural environments like ours the terrain would absolutely prohibit it.
Overhead lines are cheap and easy to break, sure, but they're also cheap and easy to repair. Which would you prefer? Having your heat and lights go out in the dead of winter maybe once or twice every year, but you get to have it back in an hour or two; or having your heat and lights go out once every couple of years and not being able to have it back for a day or more (i.e. after grandma's dead because she's frozen to death or because she fell down the stairs or couldn't find her pills in the dark or her respirator's backup batteries died)?
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It's more because being ineficiant will annoy any good German. In the town I spent my high school years in they repaved one of the main roads only to dig up a section less than a week later to upgrade the water lines. A German city planner would have a stroke seeing that.. a North American city planner would just shrug and just not worry about it.
In Florida, after Hurricane Wilma, all of Broward county lost power for 1-4 weeks...except for my town. The only difference is that our power lines are underground. The cost of repairs to the rest of the power grid was estimated at close to $6 billion. At least in hurricane prone areas, the extra investment is well worth it.
Here's one article about a mole robot for digging conduit tunnels.
And another about a robot for laying conduit in sewers.
And those are just the first two hits on a google search for "underground conduit robot."
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Powerline transmission in the US covers vastly more distance per end user than in most of the world. At the same time, the pace of change and growth in virtually every town in city in the country is so very rapid that underground placement would require much more frequent changes and retrenching. Above ground transmission is better suited to this environment.
As a firefighter, I have had on many occasions to stand by near broken transmission lines or transformers to wait for power company repair trucks. While it seems to the person sitting at home to take a very long time, let me assure you it seems longer for the poor bastard standing in the rain or snow waiting. That said, when there is a problem that is isolated they usually show up within minutes. During a storm, they make every effort to prioritize based first on danger, second on the number of outages that can be fixed in a single repair, and dead last based on cost. When we have a reported fire, they drop everything to get to where we are as quickly as possible to disconnect service to the location -- so that we can be able to do our work more safely.
I've never met a single careless or lazy power company lineman. I suppose any that start out as such are soon quit or dead.
The problem with quotes on the internet, is that nobody bothers to check their veracity. -- Abraham Lincoln
Andrew points out two important factors -- distance per customer and the need for ongoing network changes due to regional growth. These make the U.S. power situation different from many other countries. There are other issues as well.
Finally, Andrew's comment about the caliber of power company field people matches my own experience. I have constantly been amazed at how dedicated and public-spirited these people prove to be. When there's a bad storm or other emergency, nobody in the company sleeps, and everybody sweats the details. Having worked with clients in many different industries, I was quite surprised to find that most electric and gas utilities are full of conscientious people striving to make the right decisions. (This was very different from my experience with telecommunications vendors, for example, where many are good but many are appalling.)
Bottom line: This is an important topic, but I don't believe it is a no-brainer.
-- We all have enough strength to endure the misfortunes of other people. La Rochefoucauld
Georgetown's power outages happen not because the lines are underground, but because the lines that were put underground in decades past are now overloaded ...
Burying cables makes them harder and more expensive to upgrade, so it brings a risk of inadequate capacity planning.
Exactly, so indirectly the parent to your post is in fact correct. If Georgetown did not bury its transmission lines they could've afforded to upgrade them as peak demand increased. Now, these people face the prospect of digging a very large trench and causing a very long, very intrusive disruption to the area where the cable is buried...or they could just build another (overhead) transmission line.
...NOT Distribution lines. There is a HUGE difference.
Part of the thing *not* discussed here is that there are huge amounts of the power distro system in DC which *is* underground
That is because the *distribution* systems are not even part of this discussion. Transmission lines present a whole different set of challenges. Firstly, they are longer, second they are MUCH higher voltage--hundreds of kV, and third a transmission line serves a much larger area than distribution lines.
In most scenarios, they actually wait for the equipment to fail (eg. ignite and/or blow up) before they can do anything because the alternative is that they take down multiple city blocks for hours...
Thus these problems are magnified orders of magnitude for transmission lines. Working with live transmission lines requires very specialised safety equipment--expensive and bulky. With lower voltage distribution lines it is merely cumbersome to open a manhole and crawl into a confined space--with transmission lines the practical constraints as well as the increased danger make it basically impossible to repair or upgrade without digging out a big pit. In any case not much could be done live so they'd have to disconnect the line...and when you suddenly disconnect a transmission line you don't take down city blocks...you yould take out *cities*.
I think there are a few people with experience in transmission that appreciate what is involved in the installation and maintenance of high-tension lines, however I don't think the general public really has a grasp of it--they aren't the same as telephone or the power lines coming into your house. Very high power, high current electricity behaves very strangely sometimes.
Another consideration is that reparing downed lines doesn't take all that long or even cost all that much. The real costs from storm damage, with regard to power, is replacing blown transformers and juctions. These things would still be above ground, and still be blown regardless if the lines were above or below ground.
The primary cause for blown transformers and junctions is abnormal load conditions on the power grid, and the primary cause for abnormal loads would be the problems created when exposed overhead wiring is grounded or shorted unexpectedly due to contact with foreign objects. Like blowing trees, falling branches, and similar problems which are much less likely to affect buried lines. The transformers may still be above ground level, but when properly installed, they should not be as vulnerable as exposed power lines.
When combined, problems can propagate outward as local load conditions cause failure on the local circuits, in turn causing abnormal load on nearby circuits and leading to a cascade effect from a large number of otherwise-local problems with last-mile lines.
The bottom line is that buried power lines are massively less susceptible to storm damage, despite the inherent difficulties of underground installation. It's not even close to being comparable.
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