Why metal poles 2?

I went a mile north of where I first saw

Metal poles. Like I suspected, they are tying into the high voltage lines from the natural gas power station on the west side of the Wabash river. The natural gas plant was built before anyone mentioned carbon. Natural gas is cheaper.

I asked the guys installing the metal poles why metal . They said last longer. Also installing copper wire.
I told him they must have rubber Male parts. They said just polymer coated.

Now on the north side of Terre Haute, they are installing new wood poles. They are just as tall. Running new lines to connect to the power grid sub station.

In the middle of town metal poles have replaced a few damaged wood poles.

Ground wire on top of metal poles. Wood poles 3 power wires on top. Ground wire underneath.

I'm guessing the metal poles are used for the highest voltage coming from the power station.
Wood poles for lower voltages from sub stations. Just guessing.

They are busy up grading poles and wires.
Also appears they are no longer building coal plants, in favor of natural gas.

The coal power plant just north of town has been demolished.

George

There are at least 5 different voltages in the image you provided. I don't think any are connected together.
The far right pole has the lowest voltage on its lowest wires running from right to left, and supported by the (appearing) tallest single pole with the sign on the bottom. it probably runs 2 to 4000 volts.
On that right pole is also the next level on its top cross arm, could be 8+ thousand volts. It goes out of the image away and to the right.
The next level is the 6 conductors on that tallest (appearing) pole with the sign. maybe 20,000ish.
The next is the double pole three wire also going away in the image. Maybe 80 to 120Kv.
and last is the actual highest towers using angle iron open structure. they probably carry 500K to 750K volts.
that confluence of wires is nasty.
There remain large coal deposits in the area that range from the former Snow Hill underground mine, to the Peabody stripping south of Seelyville.
My mother's cousins mined there in the 40s and 50s with the walking draglines. Jim

Lots of poles and wires there George lol... Yep we pretty well beat that horse to death already not sure what else there is left to say ??? the utility and their engineers and bean counters choose which poles based on such factors including but not limited to, supply, initial cost, long term cost, availability, durability, longevity, installation costs, safety, length, particular application, voltage, etc etc etc and they know their needs and the industry more then ourselves. They didn't ask us which to use and with all the brain power here geeeeeeeeeeeeee

If there are to be more electric cars requiring charging they need power plants be it coal or natural gas or nuclear or hydroelectric or wind or solar or tidal power TAKE YOUR PICK the market and politicians Im sure will figure that all out without asking this Forum grrrrrrrrr lol We all would be happy to tell them right ??

Take care neighbor

John T

George, in Iowa we had a tornado break the high voltage line that ran from Des Moines Northwest to the Sioux City area. Where they crossed State Highway 141, they changed from wooden poles to steel. The steel poles buckled like Dominoes while the wood poles stood firm. Several miles of steel poles needed replacing and the area was without power for days until it could be re-routed from undamaged areas. This made the news as many thought the steel poles were stronger than the wooden and there were photographs at the time.

Like trees that can give and sway a certain degree and still survive, wood poles can offer benefits in certain conditions and situations.... I wouldn't doubt weather wind and climate are among some of the many factors the utility considers when making their choices.....

John T

Yup, natural gas is so cheap that they are still flaring it in the oil fields as it doesnt pay to build the pipelines to collect and transport it.

Coal on the other hand, can be stacked in a pile and stored so the power plant has a reserve supply. As was proven a couple months ago, all the NG generating capacity in the world doesnt do you any good if you dont have the delivery system in place to supply the demand of gas.

Here is an alternative to metal and conventional wooden poles.

Saw one of the new laminated wood posts. They used them with the new 34 kv lines and poles where there is a change of direction or curve in the road. Engineer told me they don't need guy wires and I said yeah but when a car hits them they don't break.

We've had issues with lightning strikes, animal shorting out the wires, old insulators, and bad fuses that when they short out, they all end up burning down the wood pole. Problem is that those are the short, low power poles that aren't being replaced with metal.

I'm going to bet that the big metal high voltage poles don't snap off during ice storms causing major power losses to highly populated areas.

I had noticed 40 years ago that utility poles in downtown Toronto were actually made of concrete full of rebar. Remember seeing a truck turn too short and rub a utility pole, and the pole bent and flex, and cracked. Shooting small chips of concrete showering to the ground, but it didnt break off. And once the truck drive off, it went back into shape, only missing a few chips. I got to looking at utility poles in the city after that, and found many poles with chips even chunks missing, with rebar showing, still standing strong doing their job.

I wonder why they just dont bury power lines. No more wind, ice, drunk driver or hot-air balloon damage. It sure would hide all those ugly lines running every which way with tennis shoes hanging from them. Plenty of work for Miss Dig too!

High voltage does not like the idea of conductive earth so close to the lines. It might need 2 meter diameter (or smaller if insulated) conduit to operate a single wire voltages less than 2000 are often buried. Mu electricity goes under the Mississippi river and then 1 mile under ground at 3800 volts to transformers. Jim

I agree with Jim, while for low voltage secondary direct burial is often used, when you get up into thousands of volts its not as much favored due to the size quality and durability the necessary insulation to avoid HV breakdown. There was some buried HV cable where I practiced but only for short distances.......and the type of soil made a difference.....

John T

Heat. Electric transmission lines generate heat. The higher the amperage, the more heat. That heat disipates into the air. With burried lines you need bigger conductors to handle the same amperage because they cannot disipate the heat as readily.

Because they can't get people to call before they dig. Somebody gets fried digging up a high voltage line they would be sued for a gazillion dollars.

Soil type makes a difference.

Or lack thereof. Where I grew up in Maine, there were lots of places with less than 12 of cover over bedrock.

Where I am now in ND, many of the rural distribution lines are buried. But then I have to drive 5 miles to find a rock. They can just plow the wires in with no worries.

CIPS / AMERON installed double wood pole H shaped structures in our area & the woodpeckers have ruined a few!

Interesting post, questions and answers. Now here is a question, an electrician and I were discussing today. Neighboring counties are acquiring some rather impressive wind farms. They're meeting quite a bunch of resistance in putting them in in our county. But probably coming in the near future.

NOW, WITHOUT GETTING INTO THE POLITICS OF WIND FARMS, here is my question. How are they getting the power from the towers to the substations? No visible overhead wires, so must be underground. What kind of transmission lines can they run wind mill power through? Voltages? Wire size? Frequency? (assuming 60 Hz, but not necessarily)? What depth and separation? I'm sure there is someone here that has some experience with this technology that can describe power transmission from these large windmills.