Power Lines – Mar 2018

Some of my readers have been asking me, “Brad, when are you going to do a post on high tension electrical power lines?” Well, your wait is over!

When I am towing our trailer over the open roads, my mind is busy. That is probably not a good thing because I contemplate some crazy shit. Like, what kind of tools do they use to affix those reflectors on the road? Or, why did they choose yellow for the centerline?

Recently I happened to fixate on power lines that ran near the highway, and I got to think about what goes into those bad boys. I just heard two readers click off my blog.

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Knowing close to nothing about power lines, I gathered a little background. So, from the person voted least likely to be confused as an engineer or an electrician, here goes.

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Power lines, of course, carry electricity. If you really want to learn about electricity, this blog is the LAST place you want to go to educate yourself. But if you aren’t too fussy about facts or accuracy, read on. Three more readers just departed.

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Electricity is, in its most basic term, a flow of energy or electric charge. And really, to understand electricity you need to go to sub-atomic particles. Oh yeah, sub-atomic particles, says the man who failed high school science.

Do you remember terms like neutrons, protons and electrons? Well those sub-atomic particles are integral to understanding electricity.

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Diagrams courtesy Sparkfun

All atoms have some number of neutrons, protons and electrons circling its core. The number of protons defines each atom, and that number represents an atom’s atomic number. For example, copper has 29 positively charged protons – and 29 negatively charged electrons. The key to electricity is to get those electrons to move by applying a negative charge and getting those electrons to move to another atom. It is this movement that is essentially electricity.

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Most home and business electrical wiring uses copper as its primary material.  Why? Copper, if you remember from the periodic table (that I know we all carry with us), has 29 free electrons, and having that many electrons means you can push energy through a copper wire easier than many other materials. Those electrons just move from one atom to another – like dominos or musical chairs. And copper is relatively inexpensive, pliable, doesn’t shrink, all that kind of stuff that becomes important to people trying to run wiring through tiny places – like electricians.

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So if you have a copper wire, a complete circuit, a load (like a lightbulb), and some kind of energy to get those electrons moving, you now have electricity! See? That wasn’t so bad! It probably isn’t right, but it wasn’t bad.

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As I watched those power lines, I got to thinking about electricity relative to other utilities. Water to your home gets stored in tanks, wells or reservoirs for when it is most needed. Fuel tanks perform the same task.   But what about electricity? Are there like big storage tanks of electricity, held in abeyance until we all need our coffee machines to crank out a little joe?

There is a thing called electrical potential. In fact all energy exists in either kinetic (in use) or potential (stored) form. With water, potential sits in the reservoir; fuel potential sits in fuel tanks. With electricity, electrical potential sits in the pile of coal sitting next to the furnace, or the amount of nuclear fission that waits to gets released in the reactor, or the water that sits behind the dam ready to be released to turn the turbines and thereby generate electricity, or in an open circuit waiting to be closed.

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This idea of electrical potential is what makes alternative power sources like wind and solar a bit different. Wind and solar are like the wild west of power generation because there is much less control over their potential being turned into electricity. I mean, some days are cloudy, and some days the air is still. Shit happens, but electric customers don’t really care that shit happens; they just want to turn on the switch and see their light come on.

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And that discussion leads back to power lines.  New power lines need to be erected to connect these new sources of power to the grid. According to Wikipidia, as of 2015 more than half of all new power generation came from renewables! And now we start talking about the smart grid and technologies being created and used that treat the power grid in more efficient and intelligent ways. And then we’re talking about increased electric demands such as electric and driverless cars and trucks. Holy crap! My head is going to explode!

Anyway, we need something to transport electricity from the power sources to users, and that is where power lines come in. It would be fantastic if there were other ways to deliver that energy other than power lines, and I am sure technology will make power lines obsolete some time in the future, but for now that is the method we are left with.

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Now I mentioned copper as a great element to transmit electricity, but there are other elements as well, such as gold and silver. These get just a wee bit expensive to use for carrying electricity. Alas, there is aluminum! Many of my readers are familiar with aluminum because they drive around pulling aluminum trailers!

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Aluminum happens to be (largely) the element of choice for power lines. While it only has 13 electrons compared to copper’s 29, it is light (very important), flexible, relatively strong (to withstand long distances, temperature changes, snow, ice – and sneakers), doesn’t require a coating to protect it from corrosion, and does a yeoman’s job of transmitting electricity.

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In fact, aluminum is preferred because it can withstand enormous amounts of voltage. We’re talking voltages from 150,000 – 750,000 volts! Thar’s alotta power.

Typically one of these wires is constructed of aluminum strands with a steel centerpiece that adds strength to the cable and can withstand high voltages. The size of these cables depends on the load, but some of these cables can be 3-4 inches in diameter – even though they look like tiny wires from several hundred yards away.

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Photo courtesy Wikipedia

According to Scientific American, the US electrical grid is composed of about 200,000 miles of high voltage transmission lines, and about 5.5 million miles of local distribution lines.

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Anyway, I thought you might be interested in having a little back story the next time you get in your vehicle on the open road and see high tension electrical power lines.  Maybe the sight of a power line will bring a smile to your face.

“Hey, didn’t Brad do a post on those bad boys a while back?”

“Yeah, is he full of shit or what?”

Like I said, my mind works in strange ways.

Next month’s post? How to watch water boil. Stay tuned!

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