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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)
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:
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)
"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)
Highest voltages used for AC and DC transmission are still missing
More informations about special power grids, as the traction current network
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...)?
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)
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)
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)
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..........
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)
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)
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
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
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)
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.
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)
This reads like its an advertisement for that superconductor company
Removed paragraph:
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)
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
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))
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)
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:
No. It's describing the picture to the right.
J. D. Redding 21:53, 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)
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)
Comment copied from above:
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)
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)
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 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)
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)
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)
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)
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)
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)
I don't think the extra length makes the passage any clearer. Sentence fragments. -- Wtshymanski ( talk) 15:26, 31 December 2008 (UTC)
<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).
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.
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
(Oh, and love the additional murkification of the photo caption. Let's rub the reader's nose in it good and hard.)
Is there no English language equivelent of File:ElectricityUCTE.svg
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?
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). S B H arris 21:25, 6 August 2011 (UTC)
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)
I've removed the RfC tag since this appears to be settled. Jc3s5h ( talk) 10:12, 8 August 2011 (UTC)
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)
"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)
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 undid this change for several reasons.
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
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)
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)
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)
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 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. Tigraan Click here to contact me 17:25, 16 September 2016 (UTC)
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)
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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