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Archive 1Archive 2

Miscellaneous

Just a query about one of the picture captions. It meantions that this tower transposes the phases.

In my opinion this is incorrect. To me it looks like a single-phase transmission line supplying 16.7Hz for railways (otherwise the conductors would be a multiple of 3). The cross-connections are not phase transpositions but just cross-connections between the same phase (maybe for distribution reasons?)

Can anybody comment please?

10:57, 28 September 2007 (UTC)

Looks like a double-circuit single phase traction line. So if we label the conductors from left to right A, B, C & D then A & B would make one line and conductors C & D another line. It is a tension tower. When I expand the picture, the bridges look like transpositions A to B and C to D.

Neddy53 (talk) 11:51, 9 September 2008 (UTC)

This article starts talking about ELFs in the Health Concerns section without ever establish what the acronym stands for. rowley

Article should mention that transmission lines sag under power load. (This was a large contributor to the cause of 2003 North America blackout.) Here's a quote from that article:

Power lines normally grow longer and sag between their towers when they get hotter as they carry more power, reaching a designed lowest height above the ground at a specified power level. To prevent the sagging lines from coming too close to trees and causing a short circuit the trees are pruned, often on a five-year cycle. If the lines touch the trees the lines are disconnected by systems which detect the sudden change in power flow from the short circuit.

Article should mention both FERC and NERC as well as a map of the utility grid. US government map available at http://www.ferc.gov/industries/electric/gen-info/transmission-grid.pdf#xml=http://search.atomz.com/search/pdfhelper.tk?sp_o=12,100000,0 —Preceding unsigned comment added by R Stillwater (talk • contribs) 18:03, 4 September 2008 (UTC)

--Jeffrey Sharkey 21:37, 30 April 2006 (UTC)

Reverted to previous version as the additions were not NPOV and referred to a web page soliciting funds to promote their ideology Tiles 06:11 31 May 2003 (UTC)

could anyone add details on transmission losses to the article? I gather they are rather high. Rmhermen 15:23, Dec 11, 2003 (UTC)

I removed the sentence "The universal method of supply from distribution lines to small end users is via single phase or three phase connections. " as this is incorrect - there are other supply configurations than single and three-phase. updated reference to electricity distribution as this is where this stuff belongs. --Ali@gwc.org.uk 14:10, 6 Nov 2004 (UTC)

I would be interested to learn of any public supply systems where the configuration is not either 3 phase or 1 phase Tiles 05:24, 7 Nov 2004 (UTC)
there's two-phase (apparently still in occasional use in the US) and split phase (though I suppose this is really a variant on single-phase). But really, this belongs under electricity distribution - see what I put there re supply characteristics. --Ali@gwc.org.uk 10:17, 7 Nov 2004 (UTC)
Thanks for the reply. You are right up to a point. Two phase supplies are sometimes run in rural ares from the 3 phase main. This is to reduce the costs of running 3 wires for low loads and allows for more capacity than a SWER line would provide. Effectively, though, the system is 3 phase with occasionally two phases used for reticulation. The older 2 phase systems must be gone or going. The electricity distribution article is the right place for this stuff and it seems to be developing well. Tiles 00:10, 8 Nov 2004 (UTC)

"Some jurisdictions prohibit a power transmission company from selling surplus communication bandwidth or acting as a telecommunications common carrier." Which jurisdictions? Tiles 04:57, 19 Dec 2004 (UTC)

The Arrowhead-Weston line in Minnesota is one place where the transmission line constructor had extra "dark fibres" in the overhead ground conductors, but was prohibited from selling that capacity. --Wtshymanski 05:01, 19 Dec 2004 (UTC)
As a practical matter, if the utility does not own the land outright, landowner agreements may also limit the utility's ability to resell fiber capacity, depending on the language. --A. B. 16:35, 30 July 2006 (UTC)

Highest voltages used for AC and DC transmission are still missing

More informations about special power grids, as the traction current network

The material on transmission lines to radio-frequency antennas is not really related to the purpose of the article, in my opinion. It at least needs to be rewritten. These transmission lines are short compared with electric power networks, and handle relatively small amounts of energy. --Wtshymanski 05:04, 1 Apr 2005 (UTC)

Generation and transmission voltages

The range of typical kV for generation and high-voltage transmission need to be corrected (expanded). I'll do it soon if nobody else beats me to it. -- Fingers-of-Pyrex 23:48, 2005 May 1 (UTC)

On a similar note, distribution line voltages are frequently higher than 25 kV. 26.7 kV is becoming more common.

Why the power line voltages are multiples of 11(22kv, 33kv, 66kv...)?

Proposed merger of Overhead powerline article

I don't agree with the proposal. This article is not about electricity transmission lines. Tiles 03:01, 22 Jun 2005 (UTC)

I think that Overhead Powerlines are just one example of power transmission, and need to be kept as a seperate article. I'd like to see a seperate entry for subsea power transmission lines. --jmd 06:10, 7 August 2005 (UTC)

I'd like to see a seperate entry for underground power cables as well. --81.188.94.63 (talk) 12:48, 30 May 2008 (UTC)

because there is a generation of 11kv so that there is a multiplaying of 11kv. —Preceding unsigned comment added by 59.162.119.252 (talk) 07:45, 26 October 2008 (UTC)

Control

This article badly needs some explanation of how transmission grids are controlled. Why do they become unstable? Who controls them, and how? How do HVDC links help stabilize AC grids? What is meant by a "weak" grid?

Also, HVDC links are not the only way to connect AC grids. Variable frequency transformers have recently been used. Is there any other way, besides a motor-generator set? I presume motor-generator sets haven't been used in a large scale.

Iain McClatchie 23:04, 11 August 2005 (UTC)

The size of an synchronous AC grid is limited by the speed of light. Arnero 11:29, 13 April 2007 (UTC)

Motor-generator sets (or salient pole machines) have been used on the UK National Grid for a long time now. The pumped storage at Dinowigg and Ffestiniogg are examples of this.

Grids are controlled by the Grid System operator in the case of a Private Company, or it was the CEGB pre privatisation. Control is done on the basis of a balance between demand and generation which system frequency plays a part, and voltage and VArs. aquizard 22:50, 23 July 2007 (UTC)

When is a grid?

Someone seems to be under the misapprehension that power plants are built in the US and Canada with only a single line connecting them to load centers. This turns out not to be the case. Even remote power projects invariably have more than one transmission line circuit connecting them to the outside world. I would venture that the parts of the US network that precipated the Aug. 2003 blackout are at least as well interconnected as in the UK - the topology of the network was not at fault, the factors are deeper than that.--Wtshymanski 17:36, 25 August 2005 (UTC)

Powering control equipments in a rotating machine

I am facing a problem in my controllers (230 V 50 hz) powered by the slip rings of a rotating machine. Power Supply board of the controllers often blows out even though we have taken necessary maintenance acts such as UPS supply, proper maintenance of slip rings etc..., can you help me by providing a proper solution..........

Merging

I've read the introduction to this article a few times now, and I don't think there's anything in Electrical power grid that isn't basically covered in the introduction. The main thing that might be done to help the merger is to make the introduction a bit less technical. I think judicious use of some bold terms might also help the intro to this article. Anyway, in summary, I vote that Electrical power grid be turned into a redirect; there's just not that much there. —HorsePunchKid→龜 19:14, 25 October 2005 (UTC)

I agree. --D0li0 06:34, 26 October 2005 (UTC)

As for the Overhead powerline merge, I simply found it there and un-commented it, not sure where this is at or how similar their content actually is. --D0li0 06:34, 26 October 2005 (UTC)


Health Effects

I made a change in this section regarding the effects of power lines on cancer. I don't think the article did justice to how much of an old wives tail this belief is. Specifically I noted that there isn't even a proposed biological mechanism for non-ionizing radiation to cause cancer. -wagsbags

Actually, the subject of old wives' tails, though interesting, is way off-topic. rowley 13:50, 14 June 2007 (UTC)

This section certainly seems to need some balancing. From reading it one gets the impression that the evidence strongly supports the conjecture that power lines cause health problems, which is, from where I'm sitting, inconsistent with what the medical establishment and governments are saying: namely that the evidence is weak at best. -Nathan Baum

Actually, I think the evidence for Childhood Leukaemia is extremely good. Certainly here in the UK it is now pretty much accepted as being true. There is various conflicts on belief with miscarriage, depression, adult leukaemia and other health effects, but these are also quite fairly reported on in this article I feel.
There are now two widely circulating theorised mechanisms on how the increase in cancer could occur:
* Suppression of melatonin. There is a wealth of literature showing that melatonin acts as an extremely powerful antioxidant, and is suspected to be very radioprotective. Magnetic fields have been shown in a number of animal studies to suppress melatonin production in the pineal gland [1] and this could therefore contribute to the increase in leukaemia risk.
* Corona ions. Bristol university have found that powerlines create charged particles (corona ions) that attract heavy metal and other particulate pollutants. These fall to the ground (from the ~30 height of their creation) anywhere between the powerlines and about 1 km away, and when inhaled the charge on the pollutants make them far more likely to be deposited in the lung.
Neither of these are conclusive, but it is mechanistic support for the increasing epidemiological evidence showing the increase in risk. Topazg 08:45, 12 June 2007 (UTC)
Way too much on health effects here - should be a separate article --Wtshymanski 01:36, 15 August 2007 (UTC)

The WHO Factsheet and article from Sciencemag.org are irrelevant and outdated. Current research has shown a connection btwn cancer and powerlines which is all that is relevant to this page. http://news.bbc.co.uk/2/hi/talking_point/4606045.stm 24.196.82.10 (talk) 07:10, 2 July 2008 (UTC)

History

The history section has a number of "firsts". Are these "world firsts" or are they related to the countries mentioned i.e. USA, Canada and Germany?

The following paragraph:

"A power transmission system is sometimes referred to colloquially as a "grid". However, for reasons of economy, the network is rarely a grid (a fully connected network) in the mathematical sense. Redundant paths and lines are provided so that power can be routed from any power plant to any load center, through a variety of routes, based on the economics of the transmission path and the cost of power. Much analysis is done by transmission companies to determine the maximum reliable capacity of each line, which, due to system stability considerations, may be less than the physical limit of the line. Deregulation of electricity companies in many countries has led to renewed interest in reliable economic design of transmission networks. The separation of transmission and generation functions is one of the factors that contributed to the 2003 North America blackout"

...is not accurate.

1. The transmission system is an interconnected network. Whether it fits the mathematical definition of a "grid" is not terribly important. 2. Power is not, and cannot be, "routed" except via very expensive phase angle regulators that are used only in special circumstances. 3. That said, there is congestion on the transmission system, which can only be relieved by altering the dispatch of the generation. 4. While transmission contracts are based on "paths," this is only for tariff purposes. The relationship between a contract path and the actual electricity path is purely coincidental. 5. I don't believe the separation of generation and transmission functions was not a factor that contributed to the 2003 blackout. The blackout had four root causes identified in the U.S.-Canada Power Outage Task Force: 1.) Lack of understanding of grid operations, 2.) lack of situational awareness, 3.) poor tree trimming procedures, and 4.) inadequate reliability coordination.

You can change the flow of power by switching in and out capacitor banks or by changing taps on transformers not just be mving the real sources arround.

Health effects again

I think that the mainstream scientific view (ie, the majority opinion) should be mentioned first, before the health concerns. —Preceding unsigned comment added by 59.92.80.75 (talk • contribs) 08:16, 5 May 2006 (UTC)

Done. —Viriditas | Talk 08:21, 5 May 2006 (UTC)


NPOV? Future of the power grid

This reads like its an advertisement for that superconductor company

Bulk Power Transmission

Removed paragraph:

Long-distance transmission of electricity is usually more expensive than the transportation of the fuels used to make that electricity. As a result, there is economic pressure to locate fuel-burning power plants near the population centers that they serve. The obvious exceptions are hydroelectric turbines—high-pressure water-filled pipes being more expensive than electric wires. The unvarying portion of the electric demand is known as the "base load", and is generally served best by facilities with low variable costs but high fixed costs, like nuclear or large coal-fired power plants.
The "long distance ... more expensive ... cheaper to transport fuels ... better local" comment is unsourced and inconsistent with grid economics. Likewise the "high fixed costs" comment (also known as sunk costs) applies equally well to essentially all renewables (wind, solar, ...). Revised (with source) to say transmission costs are usually (relatively) trivial; local sources can minimize grid fault problems; and usually prefer to use the cheapest running cost. Also added discussion of renewables transmission. Scimike 05:27, 24 April 2007 (UTC)

Extended the HVAC vs HVDC discussion to more strongly express the grid isolation benefit of HVDC. Includes an intuitive analogy of AC electrons moving up-and-down vs DC isolation by smoothing. Scimike 07:34, 24 April 2007 (UTC)


OK, I edited this paragraph to read as the following, which is factually correct:
"The unvarying (or slowly varying over many hours) portion of the electric demand is known as the "base load", and is generally served best by large facilities (and therefore efficient due to economies of scale) with low variable costs for fuel and operations, i.e. nuclear, coal, hydro. Renewables like solar, wind, ocean/tidal, etc..are not considered "base load" but can still add power to the grid. Smaller- and higher-cost sources are then added as needed."

What I did is to remove the confusion that solar and wind were some how 'base load' which the article clearly indicated previously. This is wrong and no one in either industry suggests that either sources, at least for this time, can be considered "base load" for the obvious reasons. I moved hydro to base load which it is.Tialsedov (talk) 17:57, 26 February 2008 (UTC)David

Increasingly, hydro is being used for peaking rather than base load, by installing 'surplus' generators and running them all through the day and curtailing at night. Works ok if you have sufficient head pond capacity. How about something to that effect such as "Hydro generation is traditionally used for base load, but is gaining favor for peak loading, allowing other thermal sources to operate continuously as full capacity". I'll find you a reference or too if needed. —Preceding unsigned comment added by Tinfoil666 (talk • contribs) 14:44, 2 January 2009 (UTC)

Reddi vs ScienceApologist - Tesla

Wireless bulb. Light bulbs are measured in watts. This buld is lit with power sent wirelessly!
One design of his bulb.

Please can we not have a big edit-war on something that is pov and controversial from both points of view. If there is contention, which clearly there is, can it be discussed and some general consensus agreed. I have attempted a compromise within the section itself with the secondary aim of making you comment in the talk. Hopefully we can get to a point that both parties can accept. Topazg 23:16, 21 May 2007 (UTC)

I would be willing to talk about things. The wireless thing was well document. Tesla displayed to this audiences at lectures. And to guests at his lab. J. D. Redding 23:31, 21 May 2007 (UTC) (PS., this is jsut a brief mention, something that should be acceptable here .. and comved more at the main article. J. D. Redding 23:32, 21 May 2007 (UTC))

Tesla did have his radio patent upheld, but signal transmission is not the same as power transmission. One needs to demonstrate a work output in the latter while one doesn't in the former. There is no evidence that Tesla demonstrated work output. --ScienceApologist 02:04, 22 May 2007 (UTC)
Read:
Martin, T. C., & Tesla, N. (1894). The inventions, researches and writings of Nikola Tesla, with special reference to his work in polyphase currents and high potential lighting. New York: The Electrical Engineer.
Please pay attention to Page 188.
I'll be back with some of hte lectures that he demonstrated this. J. D. Redding 02:26, 22 May 2007 (UTC)
Fluorescent lamps and, alil different, his wireless bulb were lit remotely. The Image is him holding his wireless bulb ... still getting the lecture stuff ... J. D. Redding
There's no doubt that Tesla believed that wireless transmission of electrical power was possible. He developed patents for harnassing power transmitted by his Colorado Springs station. However, no successful demonstration of him actually accomplishing this is documented by the sources. --ScienceApologist 13:07, 22 May 2007 (UTC)

My personal feeling on this is that the documentation is cited appropriately, to documents which should be verifiable. I would propose that the commentary remains, with caveats if appropriate, unless someone can demonstrate why the citations linked are not valid to be used - My own understanding of the background of Tesla's work is insufficient to make this judgement, but I think evidence should be treated as evidence unless proven to be flawed. Are people happy with the current wording or do either sides have a further suggestion? Topazg 09:44, 22 May 2007 (UTC)

I think we need to be crystal that Tesla believed in his idea but there was never any effective demonstration of it. --ScienceApologist 13:07, 22 May 2007 (UTC)
You are wrong.
Stop the ignorant POV pushing. J. D. Redding 02:15, 23 May 2007 (UTC)
One demonstration : Experiments with Alternate Currents of High Potential and High Frequency
There are plenty of other lectures and demonstrations too. J. D. Redding 02:18, 23 May 2007 (UTC)
Sorry, that's not a convincing source for your claim. Tesla gave all sorts of lectures throughout his career where he purported to do things we know now he wasn't actually doing. A successful demonstration requires not only the person demonstrating but also the acceptance of those who review the demonstration. Tesla believed he had created an electrostatic "radiant" field with his devices: a complete violation of Maxwell's equations. What Tesla was demonstrating with his wireless electro-radiance is hard to say, but it is far from being an uncontroversial example of electric power transmission. --ScienceApologist 12:44, 23 May 2007 (UTC)
Topazg: The sources that I have checked are primary, which are more than sufficient to support the "claimed" part, but I haven't seen any secondary, independent scientific sources suitable for supporting the claim that he actually succeeded, and that he failed to push this to his investors not because they weren't convinced, but because a particular person wanted to suppress it (that point actually concerns me more than the succeeding experimentally part). You might want to read the Acceptable Sources criteria of the WP:ARB/PS decision, if you haven't already. —Philosophus T 02:33, 27 May 2007 (UTC)
@Philosophus: Thanks for the input. Yes, I agree that there should equally be a level of citation to support that such a suppression existed as that is quite a claim, yet there also appears to be some citation of that now. It seems to me that the truth of this matter is unlikely to be resolved, and should probably be left with a caveat that such claims are controversial and may not in fact be true. To omit them entirely would be as unjustified as claiming them to be hard fact IMHO. Topazg 11:20, 28 May 2007 (UTC)
Inductive effect strong oscillator:Three lamps find themselves in a square turn of 50 foot of side length, which is from the primary excited by the oscillator 100 foot discharger-harvested. The turn contain a condenser and is exactly co-ordinated with the frequency oscillator.

Tesla did it. J. P. Morgan shut him down. Sad really. J. D. Redding 02:45, 27 May 2007 (UTC) ( ... [ponders hanlon's razor] ...)

Secondary source:

J. D. Redding

Poor sourcing, Reddi. What this source indicates was that Tesla created strong direct electrical currents as a sort of cross between a capacitor and a Tesla coil. Not electrical power transmission in the same way as described in this article, lest we include lightning! ScienceApologist 14:49, 28 May 2007 (UTC)

No. It's describing the picture to the right.

Wireless transmission of power and energy demonstration during his high frequency and potential lecture of 1891.

J. D. Redding 21:53, 29 May 2007 (UTC)

Looks like there is both a capacitor and a Tesla coil in that picture. Good work. Still isn't wireless in the modern sense of the word. --ScienceApologist 22:03, 29 May 2007 (UTC)

Yes it is. And there is the Image:Experiment in wireless power transmission by Nikola Tesla at his laboratory in Colorado Springs in 1899.png you seem to be ignoring. It is wireless in the modern sense of the word ... you jsut have convoluted definitions. J. D. Redding 23:01, 29 May 2007 (UTC)

No reliable source for this claim, Reddi. As has been stated, there was not independent verification that Tesla was actually transmitting power rather than transmitting signals. --ScienceApologist 23:23, 29 May 2007 (UTC)
There has been several reliable sources presented. Please stop pushing your POV. J. D. Redding 15:46, 30 May 2007 (UTC)
There has been precisely zero reliable sources presented. I don't know why you think images prove your point or why Tesla apologists and primary sources are reliable, but regardless, it is clear that your version is inappropriate and it will be resisted until you find critical reviews that support any of your assertions. I won't be holding my breath. --ScienceApologist 15:47, 30 May 2007 (UTC)
What?!?!?! Sorry your POV is clouding your preception but there is plenty of reliable sources ... I do not thing that any source would be "reliable" enough in your eyes ...
Calling things "Tesla apologists" is not NPOV ...
the statements are from the available information ... please find facts from primary and secondary sources to counter these ... I implore you to ... but try to be NPOV and allow the primary and secondary sourced information ...
I am trying to insert facts and data from primary and secondary sources ... and you cannot seem to grasp that. DO NO REMOVE the information because of your POV ... please, please, please try to be NPOV ....
What is clear is that you have a bias, it is clear that the current version is inappropriate with the associated primary and secondary sources, and actions should be taken to reverse your actions and "assertions". J. D. Redding 00:13, 31 May 2007 (UTC)

Could this wireless transmission of power perhaps be explained by Electromagnetic induction or Electrostatic induction? I mean I used a 6.6kW Magne Charge on an EV1 which transmitted power wirelessly, but not over much of a distance. I have also managed to light a fluorescent bulb with static electricity, is that the same thing as the photo above? Don't get me wrong I admire Tesla as much as the next guy but there is a lot of misunderstanding and misinterpretation surrounding some of his work. --D0li0 09:11, 2 June 2007 (UTC)

You are indeed correct. I've been studying Tesla Coils and Tesla's work for over 40 years as an electrical engineer and as a Tesla Coil experimenter. All of Tesla's documented demonstrations involved "near field" induction (or "reactive") effects, through transformer (electromagnetic) coupling, capacitive (electrostatic) coupling, or a combination of the two. That's one reason why I have a problem with the term "Tesla Effect" as a distinct phenomenon. Near field effects are simply due to localized electrostatic or magnetic fields that are associated with the capacitance and inductance "seen" by the Tesla Coil and topload. Within the near field, energy is being exchanged between local electostatic and electromagnetic fields as a natural consequence of resonance within a Tesla Coil. The near field is considered "reactive" (lossless) since the energy stored within the local fields is continually transferring between the transmitting device and nearby surroundings. This also means that energy is being transferred back into the transmitting device - in fact, it is this reactive energy interchange that causes oscillations to continue within an oscillating system! However, once you get significantly beyond the near field region, energy transfer occurs only via radiated electromagnetic waves acting through the intervening media.
The problem here is semantics. Reddi contends that he has provided numerous demonstrations of wireless energy transfer. To a very limited extent, these demonstrations are indeed "wireless" since there were no direct electrical connections to the load. However, near field induction effects are also limited to a maximum of a few wavelengths (i.e., a few miles at the frequencies used by Tesla) around an oscillating system. To my knowledge, Tesla was never able to demonstrate wireless transmission of any significant power beyond the near field. This would seem be a requirement for any practical wireless power system. BTW, by using identically tuned Tesla Coil secondaries, one acting as a transmitter, and the other a receiver, one can easily detect an output from the receiving coil many miles away. The receiving is being "rung" (building up amplitude over many cycles via Q multiplication) by the faint fields from the transmitter. However, useful levels of power have never been obtained using this approach. Scaling this to Wardenclyffe proportions does not appear to change the overall physics of the system. At present, none of Tesla's proposed methods have been demonstrated to transfer significant amounts of power outside of the near field. Bert 14:56, 2 June 2007 (UTC)
I didn't realize there was an edit war going on here. I did quite a bit of research on Tesla some years ago (http://www.mentallandscape.com/Tesla.htm) and read virtually everything he ever wrote. I believe he lit some lights by induction, close to a massive Tesla coil in Colorado. However, it is doubtful that he really resonated the Earth or transmitted power efficiently to any distance. You have to be careful about Tesla (and Edison and Marconi and many other inventer/entrepreneurs of that era), he was part scientist and part showman. He loved publicity and was always trying to get people to give him money, so take his statements with a grain of salt. Note for example, he swindled the power company in Colorado Springs and was later sued by them. I found that in the Colorado newspapers (see the citations in my report). Tesla is an amazing guy, but be realistic about him and about certain new-age followers of him today. DonPMitchell (talk) 21:33, 22 January 2008 (UTC)

Poll: moving health effects to separate article

Comment copied from above:

Way too much on health effects here - should be a separate article --Wtshymanski 01:36, 15 August 2007 (UTC)

I agree. Let's have a small poll for the proposal to move the health section to a separate article. I propose the title "Health effects of extremely-low-frequency electromagnetic fields" (it's a bit long, though). Han-Kwang (T) 10:25, 15 August 2007 (UTC) -- no wait, to a section in Electromagnetic radiation and health. Han-Kwang (T) 23:23, 15 August 2007 (UTC)

I moved the section since there were no objections. Han-Kwang (t) 14:19, 26 August 2007 (UTC)

Corona on HVDC Lines?

I noticed the comment in the article: "at high AC voltages significant (although economically acceptable) amounts of energy are lost due to corona discharge" -- with the implication that HVDC lines don't suffer from this problem.

I have a BSEE but never worked professionally on power electrical, so I may be naive about its peculiarities -- however, it would seem that corona discharge is due to voltage gradient and would also occur with DC lines. The only thing I could think of is that, for an AC line carrying the RMS power equivalent of a DC line, the peak voltages are higher -- but then again they're not continuous.

This item seems to need clarification. Anybody with professional standing who knows the details? MrG 4.225.208.2 02:32, 23 August 2007 (UTC)


I dont know either but someone once mentioned that zero crossing in AC helps mitigate stuff in datacentres and hence there is no arcing. —Preceding unsigned comment added by 220.227.207.194 (talk) 06:38, 4 February 2008 (UTC)

Corona discharge is dependent upon the electric field gradient, but also to some extent upon other factors of the gaseous surrounding -- such as density, humidity, and pollutant content. The alternating field of the AC voltage causing the vibration of the air molecules would have some stripping effect upon the electrons, but I don't know the contribution of that factor. 65.119.61.193 (talk) 23:08, 25 August 2008 (UTC)

Removal of cited material

I have reverted this edit, on NPOV grounds. Unless it can be shown that this was not fraudulent, or unequivocal and powerful evidence can be found then it cannot be out of date, and even if it was, it would still be notable for historical reasons.- (User) WolfKeeper (Talk) 12:09, 8 January 2008 (UTC)

I have just removed the paragraph again, as it is simply factually incorrect. For a start, referring to a 9 year old reference on a topic as hotly researched as ELF EMFs and cancer as still notable is strange, unless to say that "once upon a time people thought..."! It's also a refutation of an old Liburdy paper which was not the strongest evidence back in 1999, and most certainly isn't now. With Albohm and Greenland's meta-analysis papers both pointing towards a strong association, and the latter having largely ruled out selection bias and other confounding factors, an indication that the association is unlikely is inappropriate in a Wiki article. As it stood, the paragraph was factually incorrect, highly misleading, and offered nothing to the article. Topazg (talk) 08:27, 3 July 2008 (UTC)
Regarding your last edit comment: It _is_ factually incorrect as it refers to one not particularly notable paper as "the strongest evidence" so far, which it was anything but. It's a criticism of a minor reference that itself would not be notable in the article, yet the criticism of it makes the whole issue look unlikely, which is highly misleading. Topazg (talk) 17:22, 3 July 2008 (UTC)
First you say it's factually incorrect, then you say it's misleading. Which is it?- (User) WolfKeeper (Talk) 18:10, 3 July 2008 (UTC)
The paragraph is factually incorrect. It's presence makes the section misleading, so both. Topazg (talk) 08:17, 4 July 2008 (UTC)
Without it, the whole section is completely unbalanced.- (User) WolfKeeper (Talk) 18:10, 3 July 2008 (UTC)
With it, the section is completely unbalanced. I can happily write a more balanced version of the paragraph, but it will be substantially changed. Topazg (talk) 08:17, 4 July 2008 (UTC)
You're seriously claiming that the WHO isn't notable on this???? I'm probably going to report you on WP:ANI this just isn't valid.- (User) WolfKeeper (Talk) 18:15, 3 July 2008 (UTC)
This has nothing to do with the World Health Organisation. What do you mean? Topazg (talk) 08:17, 4 July 2008 (UTC)
I have updated the section with 2 very notable papers, one that should have been in there a long while ago, one which is recent (and the only currently meta-analysis / review paper on Alzheimer's). The removed paragraph was citing a news story older than the publishing date of all 11 of the papers cited in the section on health effects, referring to a paper even older (Liburdy paper was from 1992!!) - How can you honestly claim that it is relevant in context with the rest of the section? No one was referring to the paper in the first place, and that ScienceMag link isn't even notable. The information on http://en.wikipedia.org/wiki/Electromagnetic_radiation_and_health#powertransmission is much more thorough, and the section on here as it currently stands is a good summary of it. Topazg (talk) 08:38, 4 July 2008 (UTC)

Birds and powerlines

I have added a link (as annotation) that deals with the problem in Hungary. Someone ought to do a write-up about the problem of bird collisions/electrocutions on powerlines. Dysmorodrepanis (talk) 02:44, 28 March 2008 (UTC)

"wayleave" links to "easement", but waylink is not found on the easement page. Makes it look like an error. Wayleave is not in the Mirriam-Webster online dictionary. Using Google to search for it points to wikiepedia/easement. Must be an old page. c.pergiel —Preceding unsigned comment added by 71.117.248.179 (talk) 20:49, 2 September 2008 (UTC)

Pictures

One or two pictures of overhead lines suffice - this isn't the Overhead powerline article and the additional pictures (especially without explanation) don't impart a lot more knowledge to our proverbial bright 12-year-old Wikipedia reader. How about a picture of an operations control center? --Wtshymanski (talk) 15:36, 2 November 2008 (UTC)

I'll see what I can find; however, security restrictions usually prohibit the taking of such photos – I know they do for my own control centre. — BillC talk 15:55, 2 November 2008 (UTC)

Incorrect Source Cited -- I looked at the pdf cited for the power distribution picture and there is no picture on page 13. I think the reference for the power grid diagram is incorrect. —Preceding unsigned comment added by 68.160.143.233 (talk) 13:38, 8 May 2009 (UTC)

Confusion in WP regarding use of the term Grid

This is notice. Please Discuss on this page Issue: The Grid connection article attempts to define general term "Grid" which applies to both Electricity transmission and Electricity distribution articles. The proposal is to clarify the name of the article as "Grid (electricity)". Confusion exists in WP with the generic meaning of grid in the electrical power networks context which is sometimes taken to mean transmission (provoking a proposed merge) and sometimes distribution, and sometimes both. Note that Power grid redirects to transmission, whereas Electricity grid since 2006 redirects to distribution, whereas the definition of Smart grid talks of a "grid" that does both. This rename is intended to clean up the contradiction in WP's handling of the term. Any generic use of the term "grid"- eg the "super grid" concept of both Unified Smart Grid (US) and SuperSmart Grid (EU) projects would refer to the newly named article. -Mak (talk) 17:16, 21 November 2008 (UTC)

The phrase power transmission.

As power is the rate of energy transmission with respect to time, can power be transmitted? I strongly suspect this article should be entitled 'Electric Energy Transmission' Chris Hill 25th December 2008 02:09hrs (GMT) —Preceding unsigned comment added by 87.112.74.87 (talk)

Merge/redirect with grid connection

The merge proposal has been discussed on the grid connection talk page since March, with no consensus reached. I don't really care which way this is decided, but if there is no comment for a week, I shall retire the label without prejudice. Anyone who wants to drive the issue may reintroduce it at any time. -J JMesserly (talk) 19:04, 28 December 2008 (UTC)

Shorter, grammatically correct, is better

I don't think the extra length makes the passage any clearer. Sentence fragments. --Wtshymanski (talk) 15:26, 31 December 2008 (UTC)

Your blanket revert destroying many additions which have nothing to do with your criticism. For example, your revert replaced the citation on hughes with this:
 <ref> Hughes </ref>

Please explain why this reference is better. -J JMesserly (talk) —Preceding undated comment was added at 16:01, 31 December 2008 (UTC).

History section improvements

It has been stated by authoritative sources that the transmission system as it exists today has progressed so little that the original implementers of these systems would feel very familiar with the systems being used today. The concepts and problems developed at the turn of the 19th century are still the dominant ones today, so understanding them very much tells us where we are today. This is why this period deserves far greater attention in the main transmission article rather than be buried in the historical sub article. Goal definition: Let's enumerate the who what why and how questions that need to be answered by the history section.

  • 'What was the shift in this period? answer: DC-> AC. (we do this ok)
  • Why was the change necessary? Answer: 2 problems were addressed: 1) DC encouraged proliferation of multiple lines. With AC it was possible to cheaply use a common transmission system. The reason why was that it was much cheaper to transform AC from one voltage to another. 2) Both AC and DC could go long distances. AC could go longer distances more cheaply because transforming them was cheaper.
  • Does consideration of the history of transmission have any relevance for today? If so, why?
  • Who were some of the pioneers of the period. Is there a personal interest angle that can be used to further deepen the readers understanding of concepts? You bet- there are several to pick from the rivalries between westinghouse and edison, the collision of tesla with edison and so on. The main article should be a jumping off place to these articles.
  • What were the killer applications for electricity and what influence did they have on transmission?


Replacing Intro topic statements

Topic statements should give a clear description of what will be explained. The following is the original topic statement.:

#1 In the early days of commercial use of electric power, transmission of electric power at the same voltage as used by lighting and mechanical loads restricted the distance between generating plant and consumers.

Unclear. How many problems are there? one or two. The reader only knows about one problem- limited transmission distance. The original sentence conflates multiple concepts that become mixed. Did lighting and mechanical loads use the same voltage? The sentence suggests this is the case. It wasn't. Brush's street lights ran at 10 kV. Motors for mechanical loads ran at much lower voltages. Edison used a three line system to send DC so that you could get both 110 and 220 volts without transforming, but if this is what the sentence was describing, the reader would have no idea.

Next, the old passage states of the source of the problem.

#2 In 1882 generation was with direct current, which could not easily be increased in voltage for long-distance transmission.

We have learned that DC cannot be increased in voltage cheaply. The reader might wonder why the emphasis on increasing- Maybe it can be decreased in voltage cheaply? (Well, no.) Also, The sentence underscores the transmission problem described in the "topic" sentence. Is distance transmission the only problem? No. But the reader is not let in on that.

#3 Different classes of loads, for example, lighting, fixed motors, and traction (railway) systems, required different voltages and so used different generators and circuits.

Non sequitor- what does this have to do with transmission distance? The author is attempting to introduce the second problem that they didn't cover in the topic sentence. Worse, the topic sentence contradicts it, stating that electric power was transmitted at the same voltage used by lighting and mechanical loads. The reader is baffled. Which was it? Sloppy organization, and lack of clarity of thought.

This mess is closed off with a lift of one of my added sentences:

#4 Due to this specialization of lines and because transmission was so inefficient that generators needed to be close by their loads, it seemed at the time that the industry would develop into what is now known as a distributed generation system with large numbers of small generators located nearby their loads.

This ties together specialization problem with the distance problem, but why did it take so many sentences to even mention that there are two problems? And why does the reader at the close of the section still not know why one system one over the other?

The reader has no idea that cheap voltage transformation is at the heart of the technology shift. It has a great deal of relevance today. Cost voltage transformation happens to be the key obstacle to broad use of HVDC, which is crucial to both the climate change and energy independence issues. For this reason, WP deserves greater clarity and depth on this little bit of history in the Main transmission article. You could throw most of the rest out and if the reader understood the innovations and challenges of the period they would have an essential understanding of transmission and its challenges today.

The following passage clearly states the problems but a similar version was reverted to the above muddled introduction for reasons that are entirely unclear.

In the early days electric power usage, transmission of electric power had two obstacles. Firstly, devices requiring different voltages required separate generators with their own separate lines. Street lights, electric motors in factories, power for streetcars and lights in homes are examples of the diversity of devices with voltages requiring separate systems. Secondly, generators had to be relatively nearby their loads (a mile or less for low voltage devices). It was known that long distance transmission was possible the higher the voltage was raised, so both problems could be solved if transforming voltages could be cheaply performed from a single universal power line.

My earlier statement #4 is included later in my edit and will be discussed in a later post.

I propose that the introductory statements in red be replaced with the passage in above. Comments?-J JMesserly (talk) 18:33, 31 December 2008 (UTC)

Early history- examples of the problem

Following the topic paragraph, we elaborate on its summary statements. It is longer than the former treatment for a good reason. By the end of the 19th century, the present day concepts in transmission had been developed and were being implemented. But the treatment of the period from 1880 to 1890 is much too brief in relation to its significance for main article on transmission.

The current second paragraph on early history:

In 1886 in Great Barrington, Massachusetts, a 1kV AC distribution system was installed. That same year AC power at 2kV of 30km was installed at Cerchi, Italy.

Why is the 1886 system significant? If there were clear advantages to AC, then why does it matter who was first? Everyone would be beating a path to its door, and whoever was first is simply a random event of who got financing for a project of electrification first. So if the early history is not going to even mention Edison, Stanley, or offer a link to the War of Currents, then the 1886 Barrington plant is particularly odd. I propose explaining mentioning Barrington in the context of a fundamental technological challenges and inventive responses.

At an AIEE meeting on May 16, 1888, Tesla delivered a lecture entitled A New System of Alternating Current Motors and Transformers, describing the equipment which allowed efficient generation and use of polyphase alternating currents. The transformer, and Tesla's polyphase and single-phase induction motors, were essential for a combined AC distribution system for both lighting and machinery.

Ok, we point the reader to an in depth technical lecture from Tesla, and the reader correctly understands that polyphase was important. But why was it important? The reader doesn't know. If the motivation is conciseness, why not spend the sentence on explaining why polyphase is important rather than pointing the reader to a lecture that explains only what it is, without explanation of its significance for the history of transmission? The passage is not connecting the dots, and like the 1886 event is instead reciting what to the reader cannot be anything but unconnected facts.

Because of the significance of the period, the proposed replacement text fleshes out the specialization problem with examples. This also provides further breadth of connectivity to the luminaries of the period. By providing personal interest, we employ a known hook for many readers to serve our pedagogical purpose.

In 1882 generation was with direct current, which could not easily be increased or decreased in voltage either for long-distance transmission or sharing a common line for multiple types of electric devices. Companies simply ran different lines for the different classes of loads their inventions required, for example, Charles Brush's New York voltaic arc lights required 10,000 volts, Edison's incandescent lights used 110 volts, streetcars built by Siemens or Sprague used about 500 volts [1], whereas fixed motors in factories used still other voltages[2]. Due to this specialization of lines and because transmission was so inefficient that generators needed to be closeby their loads, it seemed at the time that the industry would develop into what is now known as a distributed generation system with large numbers of small generators located nearby their loads. [3]

If there are no comments, then this shall be the replacement text for the passages in red, and the facts in the replaced text will be covered later. -J JMesserly (talk) 18:36, 2 January 2009 (UTC)

Hold on there. Great Barrington was the first AC distribution project. AC is a more important concept that polyphase because AC allows transformers. The explanation should be brief and accurate, and gramatically correct. the proposed replacement text is nothing if not longer. --Wtshymanski (talk) 20:23, 2 January 2009 (UTC)
OK. I have worked Great Barrington into the explanation of the history of the fundamental ideas of transmission. BTW- I have explained why greater detail is needed for the 1880s. The description should not be brief because after the development of cheap transformers and cheap polyphase generation, you have of the modern transmission system. It's all over after the decade of the 1880s. The rest is incremental refinements. You appear to believe these are unimportant fluff that should be buried in the history article. This only promotes the reader's ignorance and hides the information that would illuminate their understanding of the fundamentals of transmission. If there are no objections or refinements, then I propose the text above be inserted in place of the text in red. -J JMesserly (talk) 21:02, 2 January 2009 (UTC)

Early history- Inventive responses to the problem

I propose that the following passage explain the solutions that were developed, properly referencing the who, what and why's of Westinghouse, Stanley, Tesla, and the Barrington event. The reader should understand from these why westinghouse's AC won out over Edison's DC in the war of currents, and may have gotten a taste of the drama of the 1880's, and the interaction of some of the titanic personalities of that remarkable period for transmission.

When George Westinghouse became interested in electricity, he quickly and correctly concluded that Edison's low voltages were too inefficient to be scaled up for transmission needed for large systems. Understanding that inexpensive AC transformers had been developed in Europe, he purchased the patents and asked his employee William Stanley to refine them. The concept that is the basis of modern transmission using inexpensive step up and step down transformers was first implemented by Westinghouse, Stanley and Franklin Leonard Pope in 1886 in Great Barrington, Massachusetts. Westinghouse next purchased patents by Nikola Tesla which described the highly efficient and inexpensive polyphase design for AC generators and motors used today. Development of efficient polyphase generation and low cost step up and step down transformers would mean decisive victory for AC in the War of Currents, since a single universal system could provide electricity for both light and power for machinery. This "universal system" is today regarded as one of the most influential innovations for the use of electricity[2].

If there are no objections or refinements, this passage will be added to the main article following the "examples of the problem" passage proposed in the section above. -J JMesserly (talk) 21:02, 2 January 2009 (UTC)

Loss figure in National Geographic

In the latest issue of Natural Geographic there are a number of interesting factoids about power use in the US. One that jumped off the page was the claim that for every Watt you "burn" in your home, 2.2 Watts are burned up delivering that power. As a result, the total electricity used is by far the largest use of power in your home. However, looking here I see that losses are about 10%, which strikes me as much more reasonable. Can anyone explain the NatGeo number? Maury Markowitz (talk) 12:18, 10 March 2009 (UTC)

They may be meaning (or have confused) the energy costs of generating, rather than transmitting, electricity. The figures they provide suggest an efficiency of 31.25%, which is comparable to the combined efficiency of generation, transmission and distribution. The figures I am looking at on a screen right now suggest losses of 2.25% for HV transmission. Distribution losses are proportionally higher, but still of the same order of magnitude, and on par to give the 10% overall figure you mentioned. —BillC talk 12:54, 10 March 2009 (UTC)
That makes perfect sense. Thanks! Maury Markowitz (talk) 21:21, 10 March 2009 (UTC)
My paper gave the figure of 10% line loss when reporting what Vermont would lose when purchasing electricity from other New England states. I don't seem to see the "ten percent" (10%) in the article as clearly as the previous editor did. Can you direct my weak eyes? Thanks. Student7 (talk) 12:20, 23 March 2009 (UTC)

spacers

Could someone comment in more detail on the use of conductor spacers, briefly mentioned here? 132.70.50.117 (talk) 15:31, 27 April 2009 (UTC)

Underground vs overhead reliability

Check out [[2]] which quotes CEA studies of the reliability of overhead and underground circuits. Overhead has the great advantage of many faults clearing after a reclosure, whereas any fault on a buried cable requires a repair; it also takes longer to fix buried cables than overhead lines. Certainly Transpower New Zealand is not clamoring to bury a lot of circuits. --Wtshymanski (talk) 15:32, 25 November 2009 (UTC)

'Radio frequency power transmission' Removal

  1. I believe that the section 'Radio frequency power transmission' has no place in this article. The articles first line states "Electric power transmission is the bulk transfer of electrical energy, a process in the delivery of electricity to consumers". RF transmission lines are for communication, and therefore have noting to do to with "delivery of electricity to consumers".
  2. The section on 'Wireless power transmission' (WPT) should probably also go. It is speculation, Wikipedia is NOT a crystal ball? The entire article has 40 citations, WPT provides 6 of them (mostly relating to Tesla), but only has ≈8 lines of text! The 3 lines that refer to Microwave Power TX, which has a scienfic basis is uncited. The last para. is also uncited. ('Crystal radio' ?? Miniscule energy involved. IRRELEVANT!) WPT could also be described as a fringe theory.
    --220.101.28.25 (talk) 19:51, 24 November 2009 (UTC)
Well, the article does point at "wireless power transmission" which presumably is a Good Article with Reliable Sources and Brilliant Prose - we don't need to recap it all here in the wired transmission article. I've taken out the Tesla stuff altogether - his notion of a conductive ionized layer in the atmosphere turned out to be harder to use than wires on poles (one has a vision of carnival bumper cars sparking away with antennas brushing the ionosphere). Don't know about the Yagi stuff, doubt he was the same sort as Tesla. Agree that RF transmission lines are of dubious relevance to power-frequency transmission. --Wtshymanski (talk) 15:55, 25 November 2009 (UTC)

health hazards ref 19

Midwest Today, April/May 1996 "DO HIGH-VOLTAGE


Cover-Up?

Lending credence to claims that there is, indeed, a public health risk from EMFs and that the government knows about it is that an EPA report a few years ago raised suspicions of a causal link between electromagnetic fields and leukemia, brain tumors, breast and prostrate cancer, even birth defects.

Less-publicized but still significant are some of the foreign studies. Last July, Canadian researchers told the Lancet medical journal they had found a high rate of leukemia among children whose mothers had worked at sewing machines while pregnant.

Checks showed the operators were exposed to more electromagnetic radiation than people who work on power lines or in power stations. In another study, Swedish researchers assessed the long-term exposure of people living near high-voltage transmission lines by taking spot measurements of the field strength in each home, and using them to confirm the accuracy of a computer model that calculated the strength of the fields emitted by each of the lines, according to distance from the lines, the wiring configurations, and the current level the lines were known to be carrying.

Then they programmed a computer with records of past current loads that had been maintained over the previous 20 years for each of the transmission lines. They were thus able to pinpoint with great accuracy EMF exposure for each cancer victim. What they found was a clear dose-response relationship between exposure to even weak power-frequency electromagnetic fields and the development of cancer, especially acute and chronic myeloid leukemia.

A second Swedish study, which also employed cases and controls, was conducted by epidemiologists. It confirmed that average magnetic field exposure over time was the critical factor in the development of disease. Interestingly, these studies were funded in part by the Swedish utility industry.

Maria Feychting of Swedens Karolinska Institute looked at 127,000 children who lived near big power lines for over 25 years and found twice the risk of leukemia.

"In our study we found about a two-fold increase in the risk if the children were living close, within 50 meters (yards) of a big power line," she told Britain's Channel Four television.

The new study by the University of Bristol showing that power lines can attract cancer-causing gases like radon has heightened concerns.

Even scientists who have failed to find a reason for the apparent link refuse to say it is safe to live near a high-voltage power line.

Warning to Parents

Of critical importance to all parents is that some studies have suggested that children exposed to magnetic fields of between two and three milligauss or above experienced a significantly increased risk of developing cancer. Since ambient levels of two to three milligauss can routinely be measured in buildings within 50 to 150 feet of wires carrying strong electric current, these findings are especially troublesome.

The report leaked last October by the mellitus National Council on Radiation Protection recommended a safety limit of 0.2 microteslas, a very weak field compared to those generated by household appliances. A person standing one foot away from a vacuum cleaner or electric drill can be exposed to anywhere between two and 20 microteslas.

There is no way to block EMFs (they even penetrate lead shielding), and the only protection is distance from the source.

In our electronic age, its almost impossible to eliminate exposure to the myriad of electrical sources with which we come in contact on a daily basis.

Thousands of electric company substations are scattered throughout our cities large and small and they abut homes, apartments and office buildings -- even schools. Since few of the high-voltage lines that lead into and out of these substations have been buried to prevent harmful emissions, magnetic fields of potent strength can be found virtually everywhere.

Concerns have also been raised about magnetic fields given off by faulty household wiring, by high-current conductors concealed in the walls, ceilings and floors of commercial office buildings and other large structures; and by high-voltage transformers that can be found in almost any large building.

The EPA Raises Questions

Concerns about so-called non-ionizing radiation began to mount in 1979, when a study of cancer rates among Colorado school children determined that those who lived near power lines had two or three times as much chance to develop cancer. The link seemed so improbable that power companies eagerly paid to have the study replicated. To their surprise, the subsequent scientific inquiry supported the original findings, which have since been buttressed by a variety of additional studies and reports of increased cancer rates among workers employed in the electric industry.

partial copy Wdl1961 (talk) 01:22, 13 December 2009 (UTC)

OK, there is now a citation. Would you please fix the citation to give the full source, including the URL?
It isn't a very good source:
  • It is 13 years old
  • It is the popular press, not a science journal, and it does not give any specific citations to reliable journals
  • It isn't clear just how good a publication Midwest Today is.
I am going to bring this source to Wikipedia:Reliable sources/Noticeboard to see what others think about this source. --Jc3s5h (talk) 02:07, 13 December 2009 (UTC)

Cut your losses

I've heard new wire technology could reduce losses to heat by 66%. How does this translate into overall system losses? Changing overall losses from 7.2% to 2.4%? Or what? TREKphiler any time you're ready, Uhura 23:34, 22 December 2009 (UTC)

In the same vein, "It has been estimated that the waste would be halved using this method, since the necessary refrigeration equipment would consume about half the power saved by the elimination of the majority of resistive losses." could do with clarification. Does this mean the waste would be cut to 25% what it is now, or 50%? TREKphiler any time you're ready, Uhura 18:59, 28 January 2010 (UTC)

Overhead lines compared to power transmission lines

Just wondered if anybody had any input on this

Wikipedia:Reference_desk/Science#Power_lines_compared_to_Overhead_cables_on_train_lines

Any help would be appreciated. Thanks GregB1968 (talk) 17:00, 2 April 2010 (UTC)

Archived

Threads that have attracted no comment for about a year have been archived under Talk:Electric power transmission/Archive 1. --Wtshymanski (talk) 19:43, 12 August 2010 (UTC)

Several hundred thousand volts

A quick search of Commons does not give any extra-high voltage or ultra-high voltage photos that could be used to illustrate the difference between the transmission lines now shown in the article, and a line carrying "several hundred thousand volts". I may have to get a snapshot of the local 500 kV line, but surely somone in the eastern US, Texas, or Quebec could get pictures of 765 or 730 kV lines. Now, that's a line carrying "several hundred thousand volts". --Wtshymanski (talk) 16:37, 12 August 2010 (UTC)

Nobody looking at the photo is going to identify those exact specific lines, but they are going to correlate it with the overhead lines in their city. It's just an image of power lines being carried by steel lattice pylons to a layman (which is who we are writing for). The concept is not "Here are UHV lines carrying 700,000 volts", its "Wires hung between steel pylons are known as 'high-tension transmission lines'. These lines can [sometimes] carry hundreds of thousands of volts."

Also, continuing to revert after being called out on 3RR is not wise my friend, it's much better to discuss and carry out a consensus. Not every editor is a knowledge-less bum looking to wreak havoc on the encyclopedia after all. - ʄɭoʏɗiaɲ τ ¢ 18:16, 12 August 2010 (UTC)

400kV line
EDIT: Found this picture of a 400kV line. I can also go and take a nice picture of the field near my place carrying four sets of (IIRC) 320kV lines. There's a bunch (mostly terrible) in Category:Pylons. - ʄɭoʏɗiaɲ τ ¢ 18:32, 12 August 2010 (UTC)
Not every editor, no. Just most of them. We should make photo captions descriptive of the picture. --Wtshymanski (talk) 19:03, 12 August 2010 (UTC)
Observe the differences. One circuit per tower, not two (for reliability - system operators don't ever want to lose that many MW at one time). Bundled conductors, not single conductors (to limit corona). Longer insulators (more disks, since each disk only stands off about 10 to 30 kV depending on utility standards and local environment). V-string insulator used to control swing and limit clearance requirements. *That's* what a line carrying "several hundred thousand volts" looks like. At least this one has the voltage class identified - at least one Commons image just says "High voltage?". Many Commons images have useless descriptions. --Wtshymanski (talk) 19:16, 12 August 2010 (UTC)
Floydian, I agree with Wtshymanski. If the caption says "can carry several hundred thousand volts" then the picture should be of a TL carrying several hundred thousand volts. I know the caption never said "These lines are carrying several hundred thousand volts", but that simply means it wasn't outright wrong; it was still misleading. A picture's caption should describe what's in the picture, not something that might be in some other picture of something similar to what's pictured.
The point that some TLs "can sometimes carry..." is certainly correct, but it belongs in the article, not under a picture of something else. Jeh (talk) 19:27, 12 August 2010 (UTC)
There is no "right or wrong" on Wikipedia, there is only verifiability and consensus. Peculiar way to write an encyclopedia, but that's the ground rules (we're going to vote on the facts and the most popular explanation must be true). This goes a long way to explain the tendancy of articles to sound like the ravings of a cat lady. See also Wikiality. --Wtshymanski (talk) 19:49, 12 August 2010 (UTC)
Ah, but verifiability trumps consensus, always. If enough reliable sources attest to something, it doesn't matter if every editor except one denies it, the one editor will always be correct if the sources back them up. I digress, this is getting off topic. Should we try to find a picture of a power field with lines of various voltages? - ʄɭoʏɗiaɲ τ ¢ 20:07, 12 August 2010 (UTC)
Also wrong; consensus trumps verifiability. There's no such thing as "correct". Get enough of your Wikibuddies to back you up (and it only takes a few...it's not like 100 10 competent editors ever see any given article) and you'll have the Indians discovering Europe. All you need is an admin on your side. After all, the consensus *decides* what sources get to be played. What's a "power field"? I've only been in this business 30 years, I've no idea what that is. --Wtshymanski (talk) 20:41, 12 August 2010 (UTC)

(Oh, and love the additional murkification of the photo caption. Let's rub the reader's nose in it good and hard.)

Elaborate on the last bit of what you said (I won't consider it harassment, don't worry), I do not understand. I used "power field" as I cannot think of a universal term. In Canada they are known as a hydro easement - the right of way occupied by high-tension lines that is left as green-space, or converted into playgrounds so kids can get tumors. There is one near my house with three different styles of pylons and at least two distinct voltages. - ʄɭoʏɗiaɲ τ ¢ 21:11, 12 August 2010 (UTC)

File:ElectricityUCTE.svg

Is there no English language equivelent of File:ElectricityUCTE.svg

Just looking at the image, well, most of the text is just organisational acronyms; so at first glance there shouldn't be much to change.
However, looking at content, I believe the map may actually be out of date and other organisations now cover different areas. (It may have been inaccurate at the time of creation; it doesn't show BALTSO, for a start). I believe an up-to-date organisational map would look a lot simpler as ENTSO-E has absorbed various regional organisations.
A map of grids / interconnections would look different to a map of organisations - which are you after?
bobrayner (talk) 15:08, 18 October 2010 (UTC)

Is faster-than-light power transmission an appropriate topic for the Electric power transmission article?

Is faster-than-light electric power transmission a suitable topic for the Electric power transmission article, bearing in mind that this concept involves tachyons, a hypothetical faster-than-light particle?

No - Without expressing any view on tachyons, I question the relevance and appropriatness of inserting highly technical material in what is a pretty good article describing real world engineering systems. I would equally question it if this article set out in full the equations for: the skin effect, the radiated EM field from finite length conductors etc.
I suspect that this material has an appropriate home somwehere on Wikipedia and would have no objection to a one line reference here.FrankFlanagan (talk) 21:17, 3 August 2011 (UTC)
  • No - The possibility of faster-than-light transmission is, as of yet, a bit too speculative to be in this article, which is most definitely focusing on nuts-and-bolts of real-world engineering. The article Tachyons contains a section on this speculative topic, namely Tachyons#Tachyons_in_Electromagnetic_waves, so WP already discusses it. I suppose a SeeAlso link could be placed in Electric power transmission pointing to that section, but even a SeeAlso link is a bit dubious. --Noleander (talk) 01:59, 4 August 2011 (UTC)
  • No - A bit reluctantly, as a long-time SF buff, but this one is too far outside known science. Prove the existence of tachyons, first, for a start. Or show me Rodney McKay is head of the project team. ;p Radek Zelenka who's smarter now? 03:25, 4 August 2011 (UTC)
  • No Not because this isn't good physics, but because it requires too much qualification to put here. The "low frequency limit" for AC is a static field, which due to Lorentz symmetry, "travels" at an infinite speed (see faster-than-light). This is an old observation which goes back to pre-relativity, as far back as the Liénard–Wiechert potential relations which derived from Maxwell's equations (as does special relativity itself). See also speed of gravity and aberration of light. Note that the supraluminal components of any EM field correspond to the near-field portion of the near and far field of an antenna. Like inductive and static effects (and low frequency changes that approximate static effects), on a quantum level these things are mediated by virtual photons which have no trouble going faster than light (although not infinitately fast, unless they represent a completely static field). For low frequency signals, the "photons" that carry the power are not like the far-field photons that carry EM waves across long distances. Instead, they are more like the "photons" that carry power from one coil to another in a transformer.

    The reason virtual photons can go faster than c is because the information component they "carry" does NOT go faster than c. Nor does it, in a powerline. Consider a thick powerline wrapping around the Earth. The speed of light would demand that a signal would travel around the Earth no faster than in 1/7th of a second. However, it would be no trouble at all to synchronize a 60 Hz signal so that it is in-phase to a far greater degree than that, over its path length of that distance. If you insist that this power is carried by "quanta" then this is how fast these virtual quanta move, since they "tell" the signal to be in-phase over that huge distance. But they carry no information above that, and that pure tone does not "count" as information. If you want to send a signal on the line from one person to another, it must be "surprise" (information) not a pure 60 Hz tone, and for that you need to change the frequency. The modulation to do that, cannot travel on the line from one point to another at greater than the speed of light. There are all kinds of supraluminal things in quantum mechanics (including the QM treatment of simple slow AC fields) but none of them violate relativity, because none of them can send information faster than c.

    See-- I've already exceeded the space of the section being questioned. That's what we'd have to do, if we included it (and it would need to go at the end, along with all those links). SBHarris 21:25, 6 August 2011 (UTC)

Close RfC?

I observe that the editor who added the section in question, User:Zgstehdyp, has been indefinitely blocked [16:24, 4 August 2011 Department of Redundancy Department (talk | contribs) blocked Zgstehdyp (talk | contribs) (account creation blocked) with an expiry time of indefinite ‎ (Abusing multiple accounts: Please see: Wikipedia:Sockpuppet investigations/Bopomofo)]. Since that user is not permitted to offer a defense and no one else supports the presence of this section, is there any objection to closing the RfC and removing the section? Jc3s5h (talk) 22:39, 6 August 2011 (UTC)

Not from me. Section might may an interesting addition at tachyon or virtual particle if it had a cite. Too bad. I don't think it's wrong, just esoteric. SBHarris 01:20, 7 August 2011 (UTC)
Go ahead and remove it Matthew C. Clarke 03:47, 8 August 2011 (UTC)
Since the section in question is now gone, too, close. TREKphiler any time you're ready, Uhura 06:24, 8 August 2011 (UTC)

I've removed the RfC tag since this appears to be settled. Jc3s5h (talk) 10:12, 8 August 2011 (UTC)

Transmission paths

  • Electrical Transmission Path 27 and Path 46 have not been categorized and I don't know how to do it, much less find information on the other 44. I didn't even know they existed until the Great Blackout of 2011 sent me searching for its epicenter, the North Gila substation on Path 46, also called the West of Colorado River, Arizona-California West-of-the-River Path (WOR), a set of many alternating current high-voltage transmission lines located in southeast California and Nevada up to the Colorado River, and apparently employing an Arizona Public Service employee who ran afoul of Murphy's Law. --Pawyilee (talk) 07:52, 18 September 2011 (UTC)

A need for capacity values in power transmission lines

This article is lacking any values or ranges for the capacities of power transmission lines. Is there someone on the Energy project who can supply some theoretic and some actual example values? For example, it is referenced that a 1 inch AC cable has a maximum current due to skin effect - what is that value? What is a source for data on some actual or projected transmission lines, or some rule of thumb values? Is there someone on this project with this information? —Preceding unsigned comment added by Lakotawp (talk • contribs) 02:33, 26 October 2010 (UTC)

I agree. I would also like to see ranges of transmission line capacities in megawatts or gigawatts. Although the text suggests that the capacity is dependent on the length of the transmission line, it seems likely that repeaters must be used on long lines to maintain a general range of capacity. The text says that capacity is proportional to voltage-squared divided by distance. But the constant of proportionality looks like it involves interesting units and otherwise seems unlikely to be close to 1.0.

http://www.idahopower.com/pdfs/AboutUs/PlanningForFuture/ProjectNews/wrep/PresentationTransmissionParamMar2207.pdf Provides an interesting table of MW for a given voltage and distance. http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/nonpgeutility/electrictransmission/weccplanning/finaltacreport.pdf is an interesting report discussing planning for 3000MW of transmission line capacity in the pacific northwest. — Preceding unsigned comment added by 2620:0:1000:3002:BE30:5BFF:FEDB:4C84 (talk) 20:51, 18 March 2013 (UTC)

about one inch diameter is where ampacity ceases to increase with cross-section and more like diameter; this is very roughly 1000 amperes; above this you use bundle conductors —Preceding unsigned comment added by 70.189.170.229 (talk) 02:23, 22 February 2011 (UTC)

Page layout

"Diagram of an electric tra..." is overlapping the contents table a little making the contents table display in the middle of the screen Chrome 1920wide win8 — Preceding unsigned comment added by 193.202.19.36 (talk) 19:55, 5 May 2013 (UTC)

Conflicting and little info on transmission losses

According to the article Storage heater, up to two-thirds of the fuel energy is lost at the power station and in transmission losses.

But this article says it's 7.2%, and only talks about the USA.

Can we have more information about this? --IE (talk) 13:09, 25 January 2010 (UTC)

I see no conflict. The storage heater article says up to two-thirds of fossil fuel energy is lost at the power station and in transmission losses. Fossil fuel plants lose large amounts of energy because the engines are far from 100% efficient. So it is likely that most of that two-thirds figure is due to engine inefficiency. --Jc3s5h (talk) 17:38, 25 January 2010 (UTC)
The section on transmission losses is not well written and probably not very correct — compare, for instance, with Curt Harting's assignment on the same topic. AC transmission is not my field so I cannot contribute easily. Robbiemorrison (talk) 16:32, 21 February 2012 (UTC)
The losses on a reasonably efficient transmission network should be (and are) less than 10% (more like 6 or 7%) of the electricity transmitted. The efficiency of a simple fossil fuel combustion generator in producing electricity will be somewhat less than 40%, as the rest of the chemical energy is released as heat. Some facilities make use of this heat for other purposes (district heating, greenhouses, etc), but the ELECTRICITY component will be on the order of 35% (Source: fundamental property of Carnot's Theorum). Taken together, fossil fuel -> electricty delivered to load can be about 1/3 or less of energy in fuel BUT over 90% of the energy that becomes electricity gets to the far end to perform useful work. Note that newer combined cycle generators can extract close to 60% of the heat in natural gas to produce electricity.Tinfoil666 (talk) 14:28, 22 August 2013 (UTC)

DC vs. AC transmission

I undid this change for several reasons.

  • There is no citation to show that power transmission is usually high voltage DC.
  • The paragraph after the change says transmission lines usually carry three phase AC, which can't be true if power transmission is usually DC.
  • The addition uses poor grammar, suggesting the writer might be unfamiliar with the US. Practices in the US are relevant due to the long distances within a single country, and the relatively high per capita energy use. --Jc3s5h (talk) 15:28, 17 August 2009 (UTC)


I only wanted to know what the average current is in a typical power line, can't find it. Also, difficult to post a question (such as this) to Wiki. 70.70.150.16 (talk) 15:46, 30 August 2013 (UTC) Herb = spsi@shaw.ca

Cost information majorly lacking

As someone researching cost of renewable energy projects, I found this article very unhelpful in understanding the economics of building additional miles of transmission lines. Please add this information, helpful Wikipedians! 98.210.101.88 (talk) 05:26, 15 March 2015 (UTC)

Lede is flawed

This paragraph (and sentence!!) is horrible:"The same relative frequency, but almost never the same relative phase as ac power interchange is a function of the phase difference between any two nodes in the network, and zero degrees difference means no power is interchanged; any phase difference up to 90 degrees is stable by the "equal area criteria"; any phase difference above 90 degrees is absolutely unstable; the interchange partners are responsible for maintaining frequency as close to 60.0000 Hz as is practical, and the phase differences between any two nodes significantly less than 90 degrees; should 90 degrees be exceeded, a system separation is executed, and remains separated until the trouble has been corrected." A single sentence?? It is "The same relative frequency, but almost never the same relative phase as ac power interchange is a function of .." or "At the same relative frequency, but almost never the same relative phase as ac power, dc power interchange is a function of .." ? This makes no sense to me. What does ac power phase have to do with dc interchange?? Is "interchange" even a meaningful concept? It hasn't been defined and isn't obvious. What is being "interchanged"? Isn't power "used"? The lede uses the term "relative frequency". I don't know what that means either. Isn't frequency absolute? (for observers in practically identical frames of reference, ie non-relativistic f.o.rs) Relative phase of what? What is the property which has a phase - is it "interchange"?? Again, I've no idea what this horrible example of English means. If the "equal area criteria" is used to explain stability, No it should be referenced with a link (preferably to a Wikipedia article (or section)). Oh, now we see "absolutely unstable" ...why use the word "absolutely" ? It contains no additional information that "unstable" doesn't convey. (If there is a difference between "absolutely unstable" and "relatively unstable" then it should be explained. Doubtful that its use is needed or appropriate in the lede (lead).) "the interchange partners..." should be a new sentence. (Again, I stress "interchange" hasn't been explained. Is it between the various grids or between transmission and distribution? Or both?) The partners are responsible for maintaining 60.0000 Hz???? That will be news for Europe!! Who thinks that the details of phase as presented in this is useful in the introduction? I don't. If the phase of DC?? AC?? power transmission is > 90°, then its "absolutely unstable" so why is it necessary to add that "separation" occurs?? It isn't, is it? I am guessing that the "phase" discussed here means the difference between current and voltage (as functions of time), and that two different "nodes" (another term which is used without explanation!) may have one synchronized and the other with a phase different from that of the other node. It that correct? If it is, then the "phase difference" being discussed is the difference between phase1 and phase 2, right? (That is, it is the difference of two differences.) And which matches: current or voltage? IDK. In need of a serious rewrite. I find it hard to credit that an English speaking editor wrote this run-on (and on and on) sentence.216.96.78.101 (talk) 18:42, 14 June 2015 (UTC)

Transposition

I chose to add a section to the page to include more information about transmission conductor transposition. I think this is an interesting element of power transmission design that was not well described on supporting pages, or referenced enough on the main page. — Preceding unsigned comment added by Tylernewmancal (talk • contribs) 05:32, 3 December 2015 (UTC)

@Tylernewmancal:: Do you know of a source for the information you added? —EncMstr (talk) 06:21, 3 December 2015 (UTC)

Wireless power transmission, orbit to earth

Can anyone add a picture, mgif, of a flock of gease passing through one of these supposed orbit to earth power links?

Gease honk and wing, then move into the perimeter, heating up, then the feathers fry, one last konk, and then a rush downwards frying, reaching ground level well broiled.

Any? — Preceding unsigned comment added by 201.209.29.60 (talk) 17:26, 19 December 2015 (UTC)

Since the proposed energy density is approximately that of sunlight, not the inside of a microwave oven, no. TREKphiler any time you're ready, Uhura 00:46, 20 December 2015 (UTC)

Addition proposal: simple model of Joule losses

Since I found it nowhere, I have drafted in my sandbox (permalink to its current revision) the usual, first-year-physics demo of why high tension cables are cool: the transformer makes it look like the consumer has a larger impedance than it really has, and hence it takes a larger share of the power division. Is anyone not OK with me adding this to the page somewhere? Otherwise I will proceed. TigraanClick here to contact me 17:25, 16 September 2016 (UTC)

Also, note that while this is certainly not original research, I found no sources on the web with that calculation. I am not sure it could fall under "simple math", so it would be nice to have a source - though I doubt anyone would lose any sleep over this. TigraanClick here to contact me 17:29, 16 September 2016 (UTC)

Changes to 'System' 'Transposition' 'U.S. Energy Policy' and 'Advantages...'

I chose to include in the “System” section a short explanation of power flow studies and their use since they play an important part in managing the system.

I included the following in the “Transposition” section to clarify the consequence of imbalanced inductance, which is referred to frequently but not explained. “An imbalanced inductance among the three conductors is problematic because it may result in the middle line carrying a disproportionate amount of the total power transmitted. Similarly, an imbalanced load may occur if one line is consistently closest to the ground and operating at a lower impedance.

In “Advantage of high-voltage power transmission” section, I chose to include an explanation of the actual advantages, which were not noted anywhere else in this very technical section. “allows for the transmission of a larger proportion of the generated power to the substations and in turn to the loads, translating to operational cost savings.”

The U.S. Energy Policy section was very incomplete. I added a description of the Federal Energy Regulatory Commission, the primary regulatory agency of power transmission. Additionally, I included two key policies 2005 that largely shape today’s power transmission, Order 888 and The Energy Policy Act of 2005. — Preceding unsigned comment added by Kmaslanka1203 (talk • contribs) 09:35, 7 December 2016 (UTC)


Modeling

I've added a section that talks about the transmission matrix and modeling of transmission lines. I explained how the parameters differed between short, medium length, and long lines. Although there is already an article entitled "Two-port network," it does not apply specifically to transmission lines, and because this article does not mention the modeling of transmission lines I thought it would be appropriate to add a section on it. --Tanderson94 (talk) 01:04, 26 April 2015 (UTC) Although the main features of four models are mainly stated, I think the <Modeling: The Transmission Matrix> in Wikipedia is not detailed enough. Firstly this part needs more figures to illustrate some concepts, formulas, differences and phenomenon. Secondly some characteristics of each model should be shown and emphasized, for these four models are of diverse usages. Since we have learned these four models of transmission line in the class, we know them more than relevant content on Wikipedia. And the transmission line is also a very important part in power system, so I chose this topic and added something about modeling. --JasonZhangjc (talk) 17:01, 8 December 2016 (UTC)

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  1. ^ Jim Harter (2005). World Railways of the Nineteenth Century. JHU Press. p. 488. ISBN 0801880890.
  2. ^ a b Thomas P. Hughes. Networks of Power: Electrification in Western Society, 1880-1930. Baltimore: Johns Hopkins University Press. p. 119-122. ISBN 0801846145. {{cite book}}: Text "date-1993" ignored (help)
  3. ^ National Council on Electricity Policy. "Electricity Transmission: A primer" (pdf). {{cite journal}}: |author= has generic name (help); Cite journal requires |journal= (help); Unknown parameter |authorurl= ignored (help)
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