Well, maybe not 2 inches to strike the arc, but more than an inch, but again this is from sharp points. Although this source says that it is about 3.7 kV/mm for point electrodes:
On the other hand, this report (page 17) shows a (measured) breakdown voltage of 26 kV for a 4 cm gap (from a point source), which is only 650 V/mm (even when adjusted to standard conditions, it is only about 10-15% higher); and even for spherical electrodes (page 13) the voltages are much lower than 3 kV/mm.
Aren’t most European (or at least German) power lines buried?
That review is listed on the CDC page here: EMFs In The Workplace (96-129) | NIOSH | CDC, but I wouldn’t read too much into it. As even that page admits, it doesn’t account for the “welder exception.” Welders are exposed to huge amounts of EMF, but don’t have the increased prevalence of disease. High-power electrical line workers are similarly unaffected. “there is something there” seems very premature at this point; especially since it’s basically a meta-study of a small number of other studies, which is infamously prone to data-gathering anomolies in any of the contributing studies affecting the result of the meta-study. “Needs more study” seems more like it; although reducing exposure for high-EMF workplaces is probably a good step even without real evidence. It shouldn’t be a problem for the OP, though, who’s talking about much lower levels.
As to the OP, the main problem I see is that there are a lot of folk who believe that power lines are going to make their children have additional heads and/or become supervillians. Thus, it’s something you’d have to disclose on a home report if you were going to sell the property (assuming you’re in the US, where you have to disclose anything that could make a potential buyer choose not to buy the property), and it might limit who’d be willing to buy it.
There are different types of power lines. The OP seems to know the difference between a transmission and a distribution line. For the benefit of others, a transmission line carries very large amounts of electricity from one location to another, like from a generating plant to a neighborhood substation. Overhead transmission lines are usually not insulated, and operate at very high voltages (50,000 volts and above, typically). Distribution lines are used to carry the power around the neighborhood and such. These operate at much lower voltages, typical somewhere between 3,000 and 10,000 volts. Overhead distribution lines are sometimes insulated and sometimes not. Transformers are attached to distribution lines, and each transformer will typically supply electricity to three or four houses.
In older areas, transmission and distribution lines will all be overhead. People think this is kinda unsightly, and overhead lines swaying in the breeze are more likely to be damaged in storms and such. As a result, in most newer neighborhoods (at least that I’ve seen) the distribution lines are underground. Transmission lines though are typically still overhead, except in rare cases like crowded cities where running overhead lines isn’t practical.
I believe the same is true in most of Europe. Distribution lines will usually be underground and, except in crowded cities, transmission lines will be overhead.
As for health effects, back in the late 60s or so some insurance guys noticed that folks who live next to power lines didn’t live as long as folks who didn’t (insurance guys get paid big bucks to figure stuff like this out, since it determines how they set their rates). Nobody except insurance guys really cared though, until the leukemia study in the 70’s that Cecil’s article mentioned. Then everything went nuts. That study was later discredited, but it gave folks the idea that power lines were somehow bad. This led to the idea that if electric fields from power lines are bad, radio waves from cell phones and such must also be bad (this was at a time when cell phones were roughly the same size and weight as a brick). At that time, there hadn’t been a whole lot of research done, but folks were going absolutely nutso. People in charge wanted science to say what was safe and what wasn’t, so folks used rectally generated numbers (i.e. pulled out of their a$$) and walked around with field strength meters proudly proclaiming what areas were safe and what areas weren’t.
Lots and lots of money poured into research. Several decades later, we can conclusively say that folks who live next to power lines statistically don’t live as long as folks who don’t. We can also conclusively say that we still don’t have a freaking clue why. Despite oodles of money and tons and tons of research, no one has been able to conclusively prove anything. Sure, there are studies that pop up once in a while and say POWER LINES KILL AND WE PROVED IT! but the problem is the follow-up studies don’t actually prove it. To date, as far as I am aware, there has never been any studies that have held up to peer review and follow-up studies that have conclusively proven a link between either power lines or cell phones and anything bad.
Anyone who tells you any such effects have been conclusively proven is full of hooey.
It’s hard to prove a negative, but health-wise, the huge mountain of studies that haven’t been able to find anything is really making it look like there just isn’t anything there to find.
So health-wise, a 345 kV line running down your street probably isn’t anything to get excited about.
As far as radio interference goes, though, the news isn’t quite so good. high voltage lines tend to suffer from corona discharge, which makes a lot of radio noise. I would expect corona discharge problems to get worse as the line ages as well. Expect interference with anything that uses radio waves, like your TV, radio, cell phones, etc. A pacemaker could technically have problems, but modern pacemakers are designed pretty well to reject radio noise.
Why would they use DC? I was under the impression that DC HV lines were pretty rare and mainly used under saltwater.
DC lines are getting more and more common. They always run at peak voltage, where AC lines have to be designed for peak but effectively all you get out of them is RMS. DC lines don’t suffer from reactive losses like AC lines do (a very big issue for underground and underwater cables).
There are disadvantages to DC lines as well, though. An AC transformer is dirt simple. DC transformers are much more complicated (and therefore much more expensive). DC also has problems with switch gear. If you try to shut off an AC line, any arcing that occurs when the switch contacts separate will naturally extinguish when the voltage drops to zero, which occurs twice during every AC cycle (120 times a second for 60 Hz). DC switches require special arc suppression because the voltage is constant, which means you can draw a really long arc once you get one going.
The extra equipment needed at both ends of the line adds expense, but this is offset by the greater efficiency of DC. This means that there is a break even point. Shorter than that, and the efficiency bonuses are too small to be worth the extra expense of the extra equipment required. Once you go a certain length, though, DC becomes more cost effective in the long run.
As you’ve noted, underwater and underground cables tend to realize a benefit to DC pretty quickly. There are quite a few overhead DC lines these days, though. They are getting more and more common as the extra equipment required for them is getting cheaper, as this makes the break-even point where DC becomes more cost effective much shorter.
Thanks. The research I’ve done today suggests that lines like this are put into continuous welded steel pipes, with a coolant gas surrounding the actual conductors. So it sounds like there’s a continuous Faraday cage to limit corona discharge or inductive effects. Correct?
With a little careful digging, this could be a great opportunity for you to get free electricity for your whole house.
And you won’t even need to install conduit from the main to your house, as you will be it.
Thank you, that is very interesting. Gotpasswords mentioned in post 2 that the cabling is like coax and I figured it would couple like coax: optimized and pretty efficiently largely regardless of environmental dielectric. But no, it looks like the jacket is for protection from local hazards and thermal conduction and that three parallel legs are run like any other transmission line.
This is a good site: Underground transmission cables
The intersection of transmission lines and transmission lines. 
Remember the time you found out the TLines course was NOT going to be fun and outside with lots of time on a tower?
I’m not saying you’re wrong, but this makes little sense to me. I don’t see why a seller should have to anticipate every possible irrational thing a buyer may think. Do you have to disclose ley lines as well?
Depending where you live, your jurisdiction may require you as a seller to disclose certain stigmas that may devalue your home. It doesn’t necessarily matter whether the stigma is real (your house was built on land contaminated with dangerous waste) or imaginary (your home is haunted). However, as far as I know the stigmas you must disclose are codified and I’ve never heard of transmission lines being one. An easement for transmission lines through your property would be different. I could be wrong though…