> Thicker wires will heat up less for a given amount of current, increasing the carrying capacity of the circuit. One solution to increasing the effective thickness of a conductor is to “bundle” several conductors a few inches apart from one another, allowing for a larger increase in current for less cost than a conductor that is simply double the size.<p>In power engineering at university we were taught that the separation of the wires within a conductor, to increase the effective diameter, is primarily about reducing the self-inductance rather than dissipating heat. From memory, it's along the lines that the separation effectively increases the diameter of the conductor, which in turn reduces the intensity of the magnetic field, reduces the self-inductance and allows more power transfer for a given voltage and current.<p>The article got it right in saying spacing the wires gives an increase in current for a given cross-section of conductor, but the main reason is reduced inductance rather than the reduction in resistance due to it running cooler. There will be some reduction in resistive losses due to cooler conductors, but the main gain is the reduction in reactive power, which otherwise causes current flow with no power transfer.
I saw this linked from the comments, and agree with the commenter that if you liked that, you'll love this:<p>"Why three prongs?"<p><a href="http://amasci.com/amateur/whygnd.html" rel="nofollow">http://amasci.com/amateur/whygnd.html</a>
Here in California, the State government has maps of all of the transmission infrastructure, from the generating stations to the utility substations, and the transmission lines in between.<p><a href="https://www.energy.ca.gov/maps/" rel="nofollow">https://www.energy.ca.gov/maps/</a>
From the end of the piece:<p>>Moving into the future, it’s hard to say how much more modern the power grid can get since the underlying principles are so simple: three phases per circuit and structures large enough to keep them from sagging into something that could cause a fault. There is a lot of talk of the smart grid, but the solution to most of the issues with the power system is often simply to build more circuits as the demand for electricity rises. It’s a difficult problem to engineer ourselves out of, especially with the increasing age of the power grid itself, and at some point is simply becomes a numbers game of how many watts can be moved from place to place.<p>Technological progress could change the landscape quite a bit: <a href="https://en.wikipedia.org/wiki/Space-based_solar_power" rel="nofollow">https://en.wikipedia.org/wiki/Space-based_solar_power</a>
There is a book from the mid 1960s (I think the last revision, a few older ones) that is still basically current (hehe) by Westinghouse called "Electrical Transmission and Distribution Reference Book"<p>If you liked this you will like it:
<a href="https://www.amazon.com/Electrical-Transmission-Distribution-Reference-Book/dp/B000AOMQV2" rel="nofollow">https://www.amazon.com/Electrical-Transmission-Distribution-...</a>
Well this was an educational read, thanks for sharing. I particularly enjoyed finding out about surface transmission characteristics of alternating current and ACSR bundles. More on HVDC would be good.<p>It was uncomfortable too: I feel about power lines the way some people feel about snakes or heights. I find being near or under them extremely disconcerting. I even have an infrequently recurring nightmare where I find myself having to crawl near one of the thick cables. They make my skin crawl.
In France i saw some pylons which reminded me of sleeping owls:<p><a href="https://www.flickr.com/photos/128452384@N02/43626380385/" rel="nofollow">https://www.flickr.com/photos/128452384@N02/43626380385/</a>
The transmission towers might be easy to design for flat lands and plateaus but not so much for hilly areas. I am a always fascinated by transmission towers in the mountains, wether I’m driving on the highway and see them far away or I’m hiking and run into one. I’m amazed by how they get such big structures up and running in those areas.<p>Edit: I just think the author kind of rubbed them off is all.
In 2015 the Center for Land Use Interpretation did a bus tour of high-voltage infrastructure in Southern California. The write-up has some interesting photos:<p><a href="http://www.clui.org/newsletter/winter-2015/high-voltage-bus-tour" rel="nofollow">http://www.clui.org/newsletter/winter-2015/high-voltage-bus-...</a>
If only Mr Tesla got the investment and we wouldn’t have to see these things.<p><a href="https://teslaresearch.jimdo.com/wardenclyffe-lab-1901-1906/connection-to-earth/" rel="nofollow">https://teslaresearch.jimdo.com/wardenclyffe-lab-1901-1906/c...</a>
Title should say "Power Transmission Lines", because transmission lines are a broader concept.<p><a href="https://en.wikipedia.org/wiki/Transmission_line" rel="nofollow">https://en.wikipedia.org/wiki/Transmission_line</a>