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Utility poles

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141–150 of 213 posts

Re: Utility poles

#141

Post by toast0 »

zwieback wrote: post #7
pan69 wrote: post #6

I have always wondered about utility poles, they always seem very fragile. Why not just stick everything in the ground?

I think it's cost, mainly. Also, in my neighborhood of older homes it would be hard to get all the easements. http://www.elp.com/articles/powergrid_international/print/vo...

Many of the easements for above ground utilities also contain provisions for underground utilities, so getting easements may be easier than you would think. However, having the easement, and having it be feasible to use are two different things. In my neighborhood, some sections have the utilities in line with the sidewalks and there is easy access; others have the utilities behind the homes, over many years many buildings have been built encroaching the easement. The encroaching buildings aren't legally there, but it would be messy to remove them to underground the utilities.

Re: Utility poles

#142

Post by toomanybeersies »

dustinmoorenet wrote: post #81

I was looking at the transmission lines one day and was curious about why there are always 4 wires. Basically, 3 lines carry equal voltage phased 120 degrees apart from one another. This kind of power is easily generated from 3 phase power generators at the power plant. The 4th wire is a common return for all three wires. It is normally smaller than any single load wire because, if the power is distributed evenly, no…

Is that an American thing?

I've never seen 4 lines on a power line in New Zealand unless they're also carrying telephone lines.

Re: Utility poles

#143

Post by ThrustVectoring »

Pyxl101 wrote: post #140
Animats wrote: post #95

Earlier quoted context omitted.

Yes. One of Tesla's more useful inventions was figuring out an simple way to get a synchronous motor started. Pre-Tesla schemes involved auxiliary starting motors and clutches. Tesla figured out how to run a synchronous motor in induction motor mode during starting.

To clarify, do you mean Tesla the person or Tesla the car company? I figure the answer should probably be obvious to me, but I'm not an electronics person and it's not.

Nikola Tesla, the late 19th / early 20th century inventor. Induction motors have been around for over a century.

Re: Utility poles

#144

Post by eptil »

Caveman_Coder wrote: post #137
eptil wrote: post #109

Earlier quoted context omitted.

This is only true at dysfunctional utilities. We dont even have paper maps and havent since the 90s. GIS is the standard for all our employees.

Do your system operators us GIS to sectionalize lines and troubleshoot transmission/distribution issues, or are you talking about the engineers/planners?

Both sides use GIS to do their jobs. The scada part is a little different since one-line diagrams are all that is needed for that. But the dispatching is all GIS based.

We make significant revenue based on accurate maps and good data as well. Just fixing our attachment rental inventory and keeping it accurate pays for all of the GIS system and upkeep with money to spare.

Re: Utility poles

#145

Post by kijiki »

pan69 wrote: post #6

I have always wondered about utility poles, they always seem very fragile. Why not just stick everything in the ground?

Underground power lines can get complicated in ways that are very expensive to remedy compared to aerial power lines. For example: https://www.jwz.org/blog/2002/11/engineering-pornography/

Re: Utility poles

#146

Post by PhantomGremlin »

limaoscarjuliet wrote: post #87
dnm wrote: post #63

Earlier quoted context omitted.

> the voltage in those two power-carrying wires is constantly switching directions I'm not buying this (in the USA). I've been in my breaker box. For a typical 110 volt outlet, the black (hot) wire is connected to the breaker, which is connected to one of the wires coming into the house from the street. The white (neutral) wire is connected to the same ground bracket that the bare (ground) wire is connected to. 240 v…

There are two phase wires and one neutral. Diff between phases is 240V, the diff between any phase and neutral is 120V. In Europe, you have three phases (R,S,T) and neutral. Here the diff between any phase and neutral is 250V, and the diff between any two phases is 380V.

In Europe, you have three phases (R,S,T) and neutral.

Is that everywhere, to every building?

In the USA, of necessity, power generation is three phase, large scale power distribution is three phase. What's confusing is that the previous discussion didn't differentiate between residential and commercial.

In USA residential areas nobody gets all three phases to their house or apartment. As discussed in previous comments, a house gets two hot wires and a neutral. In fact, to save money, sometimes entire neighborhoods only get one or two phases[1]: "spur lines" branching off the main line to provide power to side streets often carry only one or two phase wires, plus the neutral

In commercial and industrial settings it's common and necessary to deliver all three phases to the building. E.g. large electric motors require all three phases.

[1] https://en.wikipedia.org/wiki/Utility_pole#Power_distributio...

Re: Utility poles

#147

Post by ars »

m4x wrote: post #139
ars wrote: post #89

Earlier quoted context omitted.

> Both prongs absolutely carry power. Both carry current . But not power. Power is volts * amps, and the neutral is defined as zero volts (if you ignore the voltage drop). > you can get shocked when working on junction boxes for the neutral line Only from the voltage drop on that wire. It's not the full 120v. (Unless it's cut of course, but that's a whole different story.) > Here you use voltages as a relative measur…

If you are going to take the view that the neutral does not carry power, then the phase wire does not either. Ignoring volt drop, both wires have a 0V difference between each end and so no power is dissipated in them. Power is only dissipated in the appliance (except in reality, where volt drop is responsible for significant losses between generator and consumer)

> both wires have a 0V difference between each end

Obviously voltage is relative. So I'm measuring with respect to me. With respect to me the hot has power, and the neutral doesn't.

i.e. If I attach a light bulb between me and either of the two electrical wires, will it light?

But you're right "carrying power" is a poorly defined term. The problem is that it's hard to use a term that is both clear, and strictly correct.

Re: Utility poles

#148

Post by stevenwoo »

dogecoinbase wrote: post #130
mirimir wrote: post #99

Earlier quoted context omitted.

Yes, PCBs have high thermal conductivity and low electrical conductivity. Also better thermal stability than hydrocarbons. But unfortunately, quite toxic as well. And they tend to be contaminated with dioxins, which are far more toxic. Seriously, PCB/dioxin contaminated oil sold for frying? That is insane. But then, people sometimes adulterate sugar with lead acetate :(

It's kind of astonishing how far people will go in the absence of a punitive regulatory environment. One of my favorite books in Project Gutenberg is this 1820 treatise on the adulteration of foods: http://www.gutenberg.org/ebooks/19031 Everything from copper to make pickles green, to molten lead to clarify wine.

Don't need to go that far back, only five years for the gutter oil (the most famous of many in the area) phenomena to make the news. https://www.theatlantic.com/china/archive/2013/10/chinas-fri...

Re: Utility poles

#149

Post by gunzel »

toomanybeersies wrote: post #142
dustinmoorenet wrote: post #81

I was looking at the transmission lines one day and was curious about why there are always 4 wires. Basically, 3 lines carry equal voltage phased 120 degrees apart from one another. This kind of power is easily generated from 3 phase power generators at the power plant. The 4th wire is a common return for all three wires. It is normally smaller than any single load wire because, if the power is distributed evenly, no…

Is that an American thing? I've never seen 4 lines on a power line in New Zealand unless they're also carrying telephone lines.

I think New Zealand is the same as Australia with 5 wires: the 3 phases, neutral (the central return wire) and earth. Grabbing a random location in Auckland off Street View shows 5 wires:

https://goo.gl/maps/wz1W73uWAiz

Re: Utility poles

#150

Post by mirimir »

js2 wrote: post #133
adonovan wrote: post #47

Those cans are filled with transformer oil, which until relatively recently consisted mostly of polychlorinated biphenyls or PCBs. Imagine how many of those cans exist across the United States and you get a sense of how big the PCB industry used to be, and why rivers such as the Hudson in New York [1] and the Housatonic in Massachusetts [2] are polluted with olympic swimming-pool sized quantities of the durable oily…

There's a nice recreational lake here in Raleigh, NC. People run on paths by it, sail on it, and used to fish out of it. Sadly, it’s also an EPA Superfund site because a company long since out of business, Ward Transformers, saw fit to dispose of PCB-laden transformer oil right into a ditch behind the plant. The PCBs ran off into the lake and streams for miles. All the nearby waterways warn not to eat the fish caught…

Dirt and gravel roads were commonly oiled to keep down dust, and eventually create something like macadam. But they tended to use the least expensive oil available. Such as used motor oil. Which, back in the days of leaded gasoline, contained considerable lead.
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