Talk:Overhead power line

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Needs work

This article needs a lot of work. I don't even have enough understanding of what the article is supposed to be saying to correct the problems. Maybe somebody could look at the German version and try to get more accurate translation on some of this. Atomiktoaster 03:24, 17 Jun 2005 (UTC)

Running Trails

In the section that describes how the area near a power line is used, can someone include the fact that those areas are often used for running trails and other recreational uses (ie soccer fields). When there is lightning, does that area have a greater or lesser risk of a lightning strike? (ie is it safer or are you at greater risk when you're underneath one of these lines and you're caught in a thunderstorm?)

68.110.237.188 (talk) 04:36, 15 July 2010 (UTC)[reply]

It's probably safer to be under one, than not under one. The power line will act as a lightning conductor and you're less likely to be hit. Still, if you're in a thunderstorm, being inside a car is safer, and dryer.- Wolfkeeper 14:11, 15 July 2010 (UTC)[reply]

Helicopters

What does it mean when the term 'helicopters' are used in this context? I can't imagine that aircraft are used in this case?

The pylons (or sections of) are lifted into position by helicopter, particularly useful on difficult terrain or inaccessible locations. --86.43.202.77 (talk) 12:05, 20 October 2013 (UTC)[reply]

Merge

I agree with the merge proposal...I'd do it now if I had time. Text needs work, the history is redundant with the power transmission article and would be well merged there, and there's the usual Wikitis to clear up - the article isn't very authoritative sounding, and needs input from people with relevant experience. There's a good reason why mechanical translations aren't recommended on Wikipedia. --Wtshymanski 03:54, 20 Jun 2005 (UTC)

I'm not so sure (but I'm new here, too). Content is slim right now, but needn't be. Overhead power lines are a big, big subject area if somebody wants to get technical with it; I'd like to add at least a little bit about modelling, etc. Maybe clean up a bit and leave for somebody to expand? John Fisher 03:36, 1 January 2006 (UTC)[reply]

I oppose the merge. There's a lot of information in this subject that can't be covered in the big electric power transmission article. However, there should be a link in the first sentence or two to the other article. Also, the article needs to be cleaned up. -- Kjkolb 10:23, 16 January 2006 (UTC)[reply]

Moved out telecomms portion

Telecommunication

Overhead powerline structures may also be used to support cables for telephone, communications, television, and other services. An overhead line in telecommunications is a line run on telephone poles, whose wires are not isolated. In order to fasten it to the poles; glass, ceramic or plastic insulators are used. Short-circuits between the wires are avoided by the fact that a minimum distance between them is kept. The telephone network in Germany was re-equipped at high cost to underground cable (and occasionally also overhead cable) since overhead lines are often disrupted by weather; storms damage poles, lines can ice up and collapse due to the weight of ice or snow.

In the United states, a similar system of local and Radio Frequency (on copper wire) carrier circuits were used to provide long distance communication between cities. Open wire was the term given to any wire on an insulator. Local circuits had anywhere from 2 to 20 wires on a pole, with a two wire lead being attached to a pole with wooden brackets, and anything above six wires were typically constructed on a crossarm, with 10 or 20 positions per arm. A typical pole was able to carry up to six crossarms, making for a possibility of up to 30 circuits (for 10 pin) or 60 circuits for a 20 pin configuration. 20 Pin arms were typically found in urban areas. Toll (long distance) lines use a special configuration of crossarm with the space between wires being 8 inches and 18 inches between other circuits. Sometimes the individual pairs were connected with copper pieces between each insulator and the wooden pins to help stabilize capacitance issues. None of the metal pieces were ever grounded, otherwise capacitive coupling would leak energy from the line to earth. Beginning in the 1950s, however, the open wire began to come down and multi-pair cable became the favoured choice of telephone companies. in the 1960s, microwave and fiber optic technology was put into service, with modern day open wire being nearly extinct today.

(This isn't about a power line so belongs somewhere else, in a more telecomms-oriented article.) --Wtshymanski 17:54, 11 April 2006 (UTC)[reply]

conductor spacers

Could someone comment in more detail on the use of conductor spacers, briefly mentioned here? 132.70.50.117 (talk) 09:41, 23 April 2009 (UTC)[reply]

Bundle conductors are used because they decrease reactance compared to a single conductor, due to skin effect; having them right next to each other would totally defeat the purpose.— Preceding unsigned comment added by 70.189.170.229 (talk) 21:37, 31 July 2011 (UTC)[reply]

Insulator photo

Oops! I almost forgot, because the question was raised in my own talk page rather than here where all concerned editors would see it. Searching thorough Commons:Category:Electric insulator a few days ago for a good illustration, I found commons:File:Endmast_Bernhausen_-_20090909-05.jpeg and chose it for the relatively large size of its disks and their clear outline. Other pictures from that category or elsewhere have other merits, for example when you click and see the larger version they show color and other details. I rejected those on grounds that those merits only apply to the larger version, not the small version an ordinary reader sees who doesn't know to click to see the details. Perhaps I was mistaken and other editors can suggest a picture I didn't see, or can offer better reasons for choosing another. Jim.henderson (talk) 13:37, 3 January 2011 (UTC)[reply]

Additional citations

Why, what, where, and how does this article need additional citations for verification? Hyacinth (talk) 08:38, 26 June 2011 (UTC)[reply]

Merge 2012

We have Compact overhead powerline which is very short, unreferened, and really could be merged here for context and comprehensiveness. --Wtshymanski (talk) 22:17, 30 January 2012 (UTC)[reply]

Baffling Sentence re Insulated Conductors Needs Clarification

I can't make sense of this sentence at the beginning of the section on Insulated conductors:

While overhead lines are usually bare conductors, overhead insulated cables are rarely used, usually for short distances (less than a kilometer).

Is this supposed to mean that overhead insulated cables are sometimes used or that bare conductors are usually used for short distances?

Or is it supposed to mean that "Overhead lines are usually bare conductors but for some short distances of less than a kilometer, insulated cables may be used."

Someone who understands how overhead power lines are installed needs to clarify this section.

DDugan (talk) 19:30, 7 April 2013 (UTC)[reply]

I took out the "bare conductors" clause which confounded this sentence...how does it read now? --Wtshymanski (talk) 20:52, 7 April 2013 (UTC)[reply]

Thank you so much. It is much easier to understand now.

DDugan (talk) 22:03, 7 April 2013 (UTC)[reply]

Changing Bundle conductors section

I added information about geometric mean radius (GMR) to show more in depth why some of the benefits of having bundling occurs. It could be improved by adding equations of inductance of a line. --Jaebinju 20:56, 27 November 2013 (UTC)[reply]

Comment about capacitance in bundled conductor lines

Is there any reference for following sentence: "Bundled conductor lines will have higher capacitance in comparison with single lines. Thus, they will have higher charging currents, which helps in improving power factor."

My understanding is that: more charging current = more loss; but also capacitance can improve power factor if power lines are predominantly inductive (which I believe they are). I also guess that one cannot reduce reactance by a lot, as LC circuit will become better at oscillating, defeating the purpose. I have tried to find concise explanation of this aspect elsewhere, but to no avail. — Preceding unsigned comment added by 145.94.217.110 (talk) 13:07, 22 September 2016 (UTC)[reply]

Added section, inconsistent citations

I added a section about representing short length of power line. Noticed while citing my source that the Standard Handbook for Electrical Engineers is referenced twice in this article, two different editions but with slightly different formatting. Not sure which one is more proper, so I followed the format of the first one. -Icybears (talk) 22:44, 27 November 2013 (UTC)[reply]

Notes for expansion

Some things that could be added:

Environmental impact(lots of articles could use an enviromental impact section), effects on birds, migratory animals (wolf predation on caribou)
Vulnerabilities, icing, wind damage, a place to inline Operation Outward
Controversy, land owners protest, link to the "boltweevils" and the CU project controversy
Underground vs overhead, discuss economics, transmission operators, bottlenecks,
Right of way, eminent domain, PICON
Planning process, construction methods, foundations
Show power conveyed vs. right of way used, limits to power transmission
Mention HVDC vs AC.

--Wtshymanski (talk) 21:12, 15 April 2014 (UTC)[reply]

NIBY

I didn't see anything on the effects of overhead power on people living close to overhead power. Working in residential construction, I know this is a big deal, as many people will not buy a home near transmission. Typically they state that they are unsafe for some reason. I am inclined to believe it is just hype, however I haven't researched it to know for sure. — Preceding unsigned comment added by Blaylocks (talk • contribs) 20:10, 15 December 2015 (UTC)[reply]

Too much detail for an overview

Moved here, might find a home somewhere else. --Wtshymanski (talk) 04:18, 21 February 2017 (UTC) [reply]

Inductance and bundled conductors

Three-conductor bundle with equal spacing

In addition to reducing corona losses and improving the skin effect, conductor bundling also reduces line inductance. Low line inductance is highly desired because it reduces reactive current flow, line heating, and voltage drop across transmission lines. For a non-bundled transmission line, two parameters of transmission lines affect the inductance: the geometric mean radius,

D

, and the equivalent conductor radius,

r x

. The geometric mean radius is the geometric mean of the distance between phases in a bundled or non-bundled transmission line. For example, a 3-phase system with equal line spacing

d

and conductors arranged in a straight line has a geometric mean radius of

D={\sqrt[{3}]{2\,r_{x}\,d^{2}}}

where

2 d

represents the distance between the two outermost phases. The conductor radius

r x

is the effective radius of a single conductor. The equation for inductance is then:

$L=2\times 10^{-7}\,\ln \left({D\,e^{1 \over 4} \over r_{x}}\right)$ where e is the natural logarithm base

Usually, the $r x$ value is tabulated because it depends on the exact composition of the conductor and inductive properties that result—these are hard to describe analytically especially in the case of composite conductors. Typical values of $r x$ range from 6 to 18 mm.^[1] For a bundled transmission cable, two additional factors affect the line inductance: the bundle diameter $D B$ and the geometric arrangement of the bundle. These two parameters can be used to calculate an effective bundled cable radius, $D BE$ .^[2]

Two-Conductor Bundle Equation:

D_{BE}={\sqrt {r_{x}\,D_{B}}}

Three-Conductor Bundle Equation:

D_{BE}={\sqrt[{3}]{r_{x}\,D_{B}^{2}}}

Four-Conductor Bundle Equation:

D_{BE}={\sqrt[{4}]{r_{x}{\sqrt {2}}\,D_{B}^{3}}}

n

-Conductor Bundle Equation:

D_{BE}={D_{B} \over {2\sin({\pi  \over {n}})}}\,{\sqrt[{n}]{2n\,r_{x}\sin({\pi  \over {n}}) \over {D_{B}}}}

^[3]

The resulting line inductance equation is nearly identical, however the equivalent bundle diameter DBE is substituted for the effective cable radius r_x.

$L=2\times 10^{-7}\,\ln \left({D\,e^{1 \over 4} \over D_{BE}}\right)$ where e is the natural logarithm base

Inductance Improvements for Bundled Conductors
Line inductance (per meter) vs. Bundle Diameter for AC power transmission
Line inductance (per meter) vs. Phase Spacing for AC power transmission

Another form of the general equation for calculating inductance is:

$L=2\times 10^{-7}\,\ln \left({D \over r_{x}'}\right)$ ^[4] where D is the effective distance between conductors and r_x' is the effective ratio of an individual conductor, which can be calculated by the following equation: $r_{x}'=e^{-{1 \over 4}}r=0.7788r$

The meaning of r’ is the radius of a fictitious conductor assumed to have no internal flux but with the same inductance as the actual conductor of radius r. Increasing the distance between conductors and decreasing the conductor diameter both increase inductance while doing the opposite decreases it. Because inductance depends not only on the properties of a single conductor but also the geometry of the bundle, the ratio X/R (where X is reactance and R is resistance per unit length) changes with changing distance between conductors. X is given by the equation:

$X=2\,\pi \,f\,L=2\,\pi \,f\,(2\times 10^{-7}\,\ln \left({D \over r_{x}'}\right))$ where f is the frequency

and resistance per unit length is given by:

$R={\rho \over A}={\rho \over \pi \,r^{2}}$ where A is the cross sectional area of the conductor

The ratio X/R is then:

${X \over R}={2\,\pi \,f\,(2\times 10^{-7}\,\ln \left({D \over r_{x}'}\right)) \over {\rho \over \pi \,r^{2}}}={2\,\pi ^{2}\,r^{2}\,f\,(2\times 10^{-7}\,\ln \left({D \over r_{x}'}\right)) \over \rho }$

This means that if the radius the conductor is doubled and the distance between the conductors is also doubled, the ${X \over R}$ ratio will become 4 times larger.

All of the above effects can be attributed to the concept of Geometric Mean Radius (GMR). By putting several cylindrical cables together to attain a single large cable, the action in effect increases the radius of the unit, lowering the inductance of the conductor. The assumption when carrying out this calculation is that the distance between phases are much larger than the GMR of each conductor.

References

^ (Table A4) Duncan Glover et al.
^ Glover, Duncan; Sarma, Overbye (2012). Power System Analysis and Design (Fifth ed.). Stamford, CT: Cengage Learning. p. 828. ISBN 978-1-111-42577-7.
^ Gary, Claude; Moreau, Marcel (1976). L'effet de couronne en tension alternative. France: Eyrolles. pp. 11–12.
^ Cite error: The named reference Grainger, John J 1994 was invoked but never defined (see the help page).

Building a line based on ship and helicopters

Powerline Alaska youtube.com, Wilson Construction Co, 26. April 2016, retrieved 13. Oktober 2017. Video 42:46

Setting the poles solely per heli.(27:40)

Threading the pre-line only per heli-pilot with a double-hooked double-eyed needle underneath the horizontal bar of the towers.(31:00)

My German contribution: https://de.wikipedia.org/w/index.php?title=Hochspannungsleitung&type=revision&diff=169951512&oldid=169918336

--Helium4 (talk) 13:46, 13 October 2017 (UTC)[reply]

Pollution sidebar

To editor Wtshymanski: just to answer your question, the sidebar was included with an uncollapsing of the "Visual" pollution section, where this article is linked, to emphasize that overhead power lines are a form of a specific type of pollution. Figured it would help the article with navigational links for readers and such. Ideally, I thought that perhaps an editor or two would author a section on the subject of overhead power lines as visual pollution and then move the sidebar down to that section, which is what is done in other articles of a more general nature like this one. Since nearly all of the links in the sidebar do have it in their articles, it made sense to me to include it here. However, if you cannot make sense of it, that's okay, too. No harm, no foul. P.I. Ellsworth , ed. ^put'r there 23:04, 14 August 2022 (UTC)[reply]

[1] (Table A4) Duncan Glover et al.

[2] Glover, Duncan; Sarma, Overbye (2012). Power System Analysis and Design (Fifth ed.). Stamford, CT: Cengage Learning. p. 828. ISBN 978-1-111-42577-7.

[3] Gary, Claude; Moreau, Marcel (1976). L'effet de couronne en tension alternative. France: Eyrolles. pp. 11–12.

[Grainger,_John_J_1994-4] Cite error: The named reference Grainger, John J 1994 was invoked but never defined (see the help page).

[1]

[2]

[3]

[4]