This level-5 vital article is rated C-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
|
|
Right now, I think it doesn't get clear enough how the HVDC is put back to AC. An explanation would be great, especially see Static inverter plant - i think that would be a good reference. Thanks, --Abdull 09:22, 22 July 2005 (UTC) It is much like the inverter you connect to a 12 volt battery, but much larger components and many of them connected in series.Ccpoodle (talk) 18:13, 7 January 2009 (UTC)
Corona dicharge does not depend on an electromagnetic field neccessarily ( unless you are talking about RF corona when of course it does) So, to keep thing simple and improve accuracy, I ve changed electromagnetic to electric. Any comments. Please reply here initially. I watch this page. Light current 16:41, 5 August 2005 (UTC) "electrostatic field" is possibly still better than electric field. Ccpoodle (talk) 18:17, 7 January 2009 (UTC)
I don't really understand one of the advantages of HVDC: Reducing I²R losses and line cost since HVDC transmission requires less copper conductor (i.e 2 conductors one is +ve another is -ve). Less copper means more resistance, not less, so at a given I, the losses should increase! -- CyrilB 13:24, 18 April 2006 (UTC)
Hmm... I didn't exactly understand this either. Perhaps what the other user meant to imply was that, by using bipolar DC transmission, the effective transmission voltage would be twice the transmission voltage (versus ground), and by using DC you'd also reduce line reactive, skin effect, and corona losses. The combination should allow smaller conductors to be used versus a HVAC transmission system of similar power handling capability?? Bert 14:26, 18 April 2006 (UTC)
I think the I²R=P refers to power lost in charging and discharging of the line vs. ground(mono) or other conductor (bipolar) —Preceding unsigned comment added by 81.166.130.9 (talk) 09:24, 3 May 2009 (UTC)
Yes, this para needds to be re-written. Its confued. Fact 1 -The I2R losses are identical for AC and DC. P(lost) = I2R and P (lost) = V2 (square)/R
The losses are identical if Vac RMS = Vdc . There is no difference.
Fact 2 - The V in V2/r is NOT the total V applied to the line (refrecned to ground). Rather, its the voltage DROPPED across the line. Its not relative to ground, instead its the V dropped across the 2 ends of the line itself.
So the I2R arguements re HVDC being efficient are bunk.
However, HVDC is better for specific reasons 1) No Losses due to Line Impedence. Z is immaterial to HVDC 2) No Capacitance Losses. Line only needs ot be charged once on startup. 3) Crona losses are less because Vpeak for AC is > Vdc for identical power transfer. —Preceding unsigned comment added by 61.95.167.91 (talk) 06:00, 10 July 2009 (UTC)
Yay!, armchair critics. You can talk all you like about corona discharge and what-ever, with HVDC, I've never seen it in 20 years as a chopper pilot/Line Mechanic over here. The guy above me that says there is no line impedance had better do his maths again, all wires have a finite resistance, even at DC voltages.
The additional copper in AC lines is used to transmit the reactive power due to inductance. Since DC lines are not subject to reactive power, you can use less copper. Ac power lines act as a transmitting antenna, so there is significant 60 hertz electromagnetic energy lost, plus small skin effect losses. Three phase ac requires at least three conductors. HVDC monopole one conductor, bipolar two conductors. The voltage can be 140% or more higher without serious arcing, corona losses and environmental hazard. Higher voltage means less current and/or more power capacity. Is HVDC more vulnerable to EMP = electromagnetic pulse than properly transposed ac power lines? Ccpoodle (talk) 01:39, 8 January 2009 (UTC). Rubbish, All HV stuff uses ACSR wire, this is aluminium outer and a steel centre tensioning wire or pure aluminium wire Trumpy (talk) 11:52, 22 October 2011 (UTC)
I don't want do edit this page, but I'm afraid the second Itaipu converter is located at Sao Paulo, not at Brasilia. Take a look at http://www.transmission.bpa.gov/cigresc14/Compendium/Itaipu%20Pictures.pdf. Brasilia is not shown, but it is at the heart of the country, while Sao Paulo is much closer to Foz do Iguacu, where Itaipu is located.
Alvaro Augusto alvaro@daelt.sh06.com
This stuff is all irrelevant without cost informatn and comparison with AC. Also what about losses? Cam;t see them anywhere yetEngineman 18:48, 8 April 2007 (UTC)
I’ve heard HVDC lines are better for long-distance transitions because the ac current reflects from the end points when the length of the line approaches 1/2 of the wavelength of the power. Given a 50 Hz line, the length is c/ν = (3e8 m/s) / (50 s-1) = 6e6 m = 6 thousand km, and if the line is exactly 3000 kilometers in length, the potential difference at the recipient’s end will be exactly zero. Is that true? Zero and double voltage is for a theoretical transmission line loaded at the characteristic impedance. The voltage is however different at the half wave length and quarter wave length points of ac power lines, but not by enough to cause serious problems in most cases. Ccpoodle (talk) 02:05, 8 January 2009 (UTC)
---isn't that true for any EM wave? find the equivalent LC of the circuit thus made and see if it can resonate. I think it has more to do with mixing of circuits and no phase matching needed which make HVDC easier
"Between each" makes no sense. I tried to correct the grammar of that section, and hope that in the process I didn't change the intended meaning. Please, would somebody who is familiar with the subject verify that the rewording is accurate? D021317c 00:46, 10 June 2007 (UTC)
Why is that non-existent source credited on this page? He may not want to be named, but it is the same as an unsourced comment as far as articles go... (#11)
I read (e.g. 50 hz is used in Canada while 60 hz is used in the United States) and was made very sad. I'd like to think that someone who's bold enough to edit an article can speak with some reliability about the topic he or she chooses to edit; but if you're missing on the fundamentals, it really undercuts the reliability and credibility of the whole process. --Wtshymanski (talk) 13:24, 21 May 2008 (UTC)
"HVDC cables can carry more power for the same thickness of cable compared with AC lines"
Can we have an explanation in the article for why this is?
Rtdrury (talk) 06:21, 24 July 2008 (UTC)
I took out the link to the breathless article claiming HVDC underground costs no more than overhead lines. The author of that piece seems (how to put it gently?) ill-informed, at the very best. He seems unaware that every HVDC converter must also have a power transformer (or two), and that because of their multiple windings and special construction they are more costly per MVA than an equivalent AC line transformer. He seems also uninformed about the relative costs of digging in a cable vs. overhead lines. Yes, overhead right of way is expensive too, but you don't get to bury cables along the highway for free either. Buried cables always cost several times as much as an overhead run...that's why we don't bury cables more often.
It would be a good practice when picking external links to make sure that the linked material is credible, authoritative, and well-informed; not some puff piece written by an "expert" who wouldn't know the difference betweeen a kw and a kwh. --Wtshymanski (talk) 14:26, 12 March 2009 (UTC)
Due to Texas wind farms now feeding presumably the USA EAST grid is it correct to still list TEXAS as being a grid unto itself? —Preceding unsigned comment added by 151.198.55.135 (talk) 18:20, 3 May 2009 (UTC)
Can be used, a explanatory image, to improve the article.
This scheme has no harmonic filters at one terminal. Can a machine delivering reactive power make harmonic filters obsolete?
Inga-Shaba has intermediate switching stations. Under which circumstances is such equipment sensitive?
Can someone please make a photograph of the crossing of HVDC CU and Square Butte situated at 47°2′48″N 100°5′49″W / 47.04667°N 100.09694°W? It would be the unique chance to take a photograph showing 2 different HVDC lines!
what inherent properties of the transmission line is used now in a.c. networks to regulate the power? Wdl1961 (talk) 22:03, 15 October 2009 (UTC)
here are a few references about control of HVDC.
these do not appear to use properties of transmission lines
Stability analysis of HVDC control loops The influence of HVDC control loops on the dynamic stability of an overall HVDC- HVAC system is discussed. The eigenvalue decomposition is used for the ...
cat.inist.fr/?aModele=afficheN&cpsidt=1795072 - - Similar pages
ANFIS based HVDC control and fault identification of HVDC converter of ANFIS for HVDC control is given in Section 4. Section 5 presents use .... train ANFIS based control, training data is obtained from HVDC system, ...
www.hit.ac.il/jse/B/vol0236B/jse19.pdf - - Similar pages
[hal-00407666, v1] HVDC Control Strategies to Improve Transient ... 27 Jul 2009 ... First, the HVDC control settings are unchanged during the disturbance. ... This paper focuses on four control strategies for the HVDC- ...
hal.archives-ouvertes.fr/docs/00/40/76/66/PDF/Phulpin_Proc_09_2.pdf - - Similar pages
Welcome to IEEE Xplore 2.0: A Model of HVDC Control System Based ... This paper describes the hybrid characteristic of HVDC control system, which consists of continuous dynamic behaviors and discrete event behaviors. ...
ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1547096 - - Similar pages
Welcome to IEEE Xplore 2.0: Modeling HVDC control and protection ... According to the hardware configuration used for HVDC control system and operation mechanism of MACH2 (modular advanced control for HVDC) from ABB company, ...
ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4523685 - - Similar pages
First CIGRE Benchmark for HVDC control studies | Opal RT This demo models the first CIGRE benchmark for HVDC link protection studies rated at 1000 MW with a DC voltage of 500 kV and a DC current of 2 kA. ...
www.opal-rt.com/demo-application/first-cigre-benchmark-hvdc-control-studies - 13k - Similar pages
ABB HVDC Classic control system - HVDC Classic technology (HVDC ... 5 Feb 2009 ... A modern HVDC station is equipped with a well integrated microprocessor based control and protection system. In the normal mode, the control ... .aspx - 56k - Similar pages A nonlinear robust HVDC control for a parallel AC/DC power system ... With recent developments of HVDC electronics and with improvements of HVDC control devices, the proposed control can be practically implemented to have a ...
linkinghub.elsevier.com/retrieve/pii/S0045790601000192 - - Similar pages
Adaptive Granular Control of an HVDC System: A Rough Set Approach control in an HVDC system. This control strategy can be easily extended to ... In a typical HVDC control system, a proportional ...
www.springerlink.com/index/NCLP8B6NEVT3G2EM.pdf - - Similar pages
Method and control for maintaining optimum performance of HVDC ... Patent Abstract: A new and improved control subassembly for HVDC power converters and method of its use during transient faults affecting the AC system ...
www.patentstorm.us/patents/4177507.html - - Similar pages
there is more.Wdl1961 (talk) 01:26, 20 October 2009 (UTC)
regulation and control goes from zero to max cap sim to a gaspedal .max cp is limit. Wdl1961 (talk) 02:08, 19 January 2010 (UTC)
thumb|right|200px| Stability equation 14-56 out of Fink and Beaty.
quote """In contrast to AC systems[citation needed], realizing multiterminal systems is complex, as is expanding existing schemes to multiterminal systems. Controlling power flow in a multiterminal DC system requires good communication between all the terminals; power flow must be actively regulated by the inverter control system """" how is this done,not how it is not done???Wdl1961 (talk) 15:41, 19 January 2010 (UTC)
The essence of editing is easy come easy go. Unless you can really say to yourself, "What the hell. There's plenty more where that came from, let's throw it away." you can't really edit. You have to be a big spender?
Editing must be cut-throat. You must wade in with teeth gritted. Cut away flesh and leave only bone. Learn to say things with a relationship instead of words. If you have to make introductions or transitions, you have things in the wrong order. If they were in the right order they wouldn't need introductions or transitions. Force yourself to leave out all subsidiaries and then, by brute force, you will have to rearrange the essentials into their proper order.
Every word omitted keeps another reader with you. Every word retained saps strength from the others. Think of throwing away not as negative-not as crumpling up sheets of paper in helplessness in rage-but as a positive, creative, generative act. Learn to play the role of the sculptor pulling off layers of stone with his chisel to reveal a figure beneath. Leaving things out makes the backbone or structure show better.
Editing means being tough enough to make sure someone will actually read it.
Peter Elbow, Writing Without Teachers, Oxford University Press, 1973; as quoted in American Journal of Physics 44(8), p740, August 1976
,
try for ac current(i) = voltage / impedance(i) i=1,2,3,4,---,n . usually the voltage is regulated instantly by powerplants.Wdl1961 (talk) 20:00, 31 January 2010 (UTC)
It is possible to go from one frequency to another without rectification. It is used in motor drives. Wdl1961 (talk) 15:18, 1 November 2009 (UTC)
Am I the only one who cannot parse this?:
"For an 8 GW 40 km link laid under the English Channel, the following are approximate primary equipment costs for a 2000 MW 500 kV bipolar conventional HVDC link... "
The cited reference cannot be "reasonably well relied upon" given that the quotation is pretty well garbled. What is the point it is trying to make? An anonymous reference is no reference at all, because it is unverifiable.
This section has nothing to say, except there is no reliably sourced data on HVDC costs. --Albany45 (talk) 13:14, 8 June 2010 (UTC)
While trolling through the Web on a quest for cheap references, I found [2]. It appears to rip off quote extensively from an earlier version of this article. We must be doing something right if it's worth putting on Governor Schwartzenegar's desk. Pity they garbled it somewhat. --Wtshymanski (talk) 20:48, 8 June 2010 (UTC)
There seems to be a mismatch between the descriptions to
http://upload.wikimedia.org/wikipedia/commons/thumb/a/ab/HVDC_Europe.svg/350px-HVDC_Europe.svg.png "On the main article" and http://upload.wikimedia.org/wikipedia/commons/thumb/5/51/HVDC_Europe_annotated.svg/400px-HVDC_Europe_annotated.svg.png "Annotated version"
"Under construction" and "Under consideration" are switched. I think the annotated version has it right, but could someone more familiar with the article take a look at this?
Thanks, Satan_Klaus —Preceding unsigned comment added by 84.160.50.191 (talk) 11:08, 7 August 2010 (UTC)
Hello, I think one more European connection can be added to the map as the SIEMENS company have launched in 2011 the Inelfe-Baixas project on the French-Spanish border with a 2x1000 MW HVDC PLUS (AC 400 kV, DC +/-320 kV) station. 212.160.202.180 (talk) 07:31, 15 December 2011 (UTC)
One additional issue with the map. The France / Spain inter-connector is now built and operational http://www.ree.es/en/activities/unique-projects/new-interconnection-with-france — Preceding unsigned comment added by Jfparis (talk • contribs) 14:08, 17 February 2017 (UTC)
The "AC network interconnections" section is missing citation, which makes it hard to veryfie, and is not usable as a reference.
81.225.97.154 (talk) 18:25, 31 October 2010 (UTC) Gego/XAREN
Could someone who understands the subject rewrite "At such operation mode, it is possible that transmission can be continued, if one conductor fails, however with greater losses and possibly with less transmission capacity, if ground electrodes or lines are not designed for the load of both poles." This sentence does not make much sense, there are a few too many clauses that appear disjointed. 192.16.184.140 (talk) 10:49, 22 November 2010 (UTC)
Now that the second cable from the south of the UK has been opened, perhaps the images should be updated. [3] Esn (talk) 05:25, 4 May 2011 (UTC)
BBC is mentioned, but after a a short confusion about what BBC has to do with high voltage, a quick check reveals the current name of that company is ABB. Article aslo meantions ASEA a lot, that too is now ABB. Is this article really the right place for a history lesson? 83.227.1.122 (talk) 08:59, 8 September 2011 (UTC)
I am not an expert in this area, but found further detailed info (in pretty much this format) at http://www.energy.siemens.com/fi/pool/hq/power-transmission/HVDC/HVDC_Proven_Technology.pdf some of which may be added whist avoiding copyright infringement. Particularly thought that the figures were informative 1-1, 1-2 and section 4. Would an expert in this area be able to compare and see if useful additions may be made to improve the quality of this article. Thanks --DrSteveEllis (talk) 11:22, 26 September 2012 (UTC) Figures 1-1 and 1-2 would certainly be useful. They would need to be re-drawn in order to avoid copyright but that would not be difficult. Clampower (talk) 20:13, 3 October 2012 (UTC)
I have just made quite a large number of text changes to improve clarity, but could not help noticing that the section "Applications" right at the very end seems to be in the wrong place. Shouldn't it be moved to somewhere near the start of the article? Clampower (talk) 20:13, 3 October 2012 (UTC)
I quite agree that "the future" needs to be discussed at the end of the article. My point is just that quite a lot of what is currently in the first two sub-sections under "Applications" is NOT about the future, but actually about the past and present. Things like the ability to inter-link 50Hz and 60Hz networks, efficiently carry power long distances from remote generating sources etc, have been known (and used) for decades. So my point is just that I think those bits ought to appear earlier in the article, around the same point as the section on "advantages and disadvantages". Anything future-looking, like multi-terminal DC grids, using HVDC to transport solar energy from Africa to Europe etc, should rightly be at the end.Clampower (talk) 11:42, 4 October 2012 (UTC)
If you are knowledgeable about HVDC, please take a look at the electrode line article which needs a hand (expansion and references). Katana (talk) 20:41, 30 October 2012 (UTC)
Sunrise Powerlink is an AC line! — Preceding unsigned comment added by 91.46.154.156 (talk) 18:31, 9 December 2012 (UTC)
Cross Channel is still considered a "bipole" even though ground return is not possible, because each end (of each bipole) contains two completely independent converters. A fault in one converter does not shut down the entire bipole (as would happen for NorNed) because the bipole can still operate with the faulted converter bypassed and its HV cable used as the neutral return. Clampower (talk) 19:29, 14 December 2012 (UTC)
Hi there. I am completely new to wikipedia, but I found a dead link (currently referece 25 to a pdf of ABB) and I think I found the new location of the reference. I don't know how the procedure is to fix that, but I wanted to let you know, in case someone has the time to fix that. the new location is http://new.abb.com/docs/default-source/default-document-library/hybrid-hvdc-breaker---an-innovation-breakthrough-for-reliable-hvdc-gridsnov2012finmc20121210_clean.pdf?sfvrsn=2 — Preceding unsigned comment added by 129.132.125.221 (talk) 09:17, 13 January 2014 (UTC)
Per this edit, Wikipedia is not a reliable source and the claim that this was the "AC system of George Westinghouse and Nikola Tesla" is incorrect. The Westinghouse AC system was based on the work of many engineers, not just Tesla, including the early work of Lucien Gaulard, John Dixon Gibbs and the developments of Westinghouse engineers William Stanley (who developed the first AC transformer[4]), Vladimir Zworykin, Oliver B. Shallenberger, Stephen Timoshenko, and Benjamin Garver Lamme. Westinghouse started installing AC systems in 1886, two full years before Tesla got into the business and the company was eating Edison lunch by 1887[5], that led into the War of Currents (given a start date of December 1887 (Empires Of Light By Jill Jonnes, page 419). The "War" was a battle of lighting businesses, AC Arc vs DC incandescent (The 100 Most Significant Events in American Business: An Encyclopedia By Quentin R. Skrabec, page 86) so Tesla's July 1888 licensing of his induction motor patents to Westinghouse didn't come into it. The "War" was over by either: 1890 (Edison Machine entered AC biz), or the 1891 International Electro-Technical Exhibition, or the 1892 merger of Edison Electric into GE and the ouster of Edison...... take your pick. Tesla's AC motor was still on the back burner at Westinghouse at that point (George Westinghouse: Gentle Genius By Quentin R. Skrabec page 127). The Tesla induction motor patent did become important to the Westinghouse system in later patent battles but that was after the "War" and a motor is only one quarter of a system, you also have to have lighting, generators, and transformers - none of which were invented by Tesla. Fountains of Bryn Mawr (talk) 04:14, 5 February 2015 (UTC)
I add on one more important applications especially for now and the future, which is the integration of renewable resources such as wind into the main transmission grid. One of the challenges of renewable power generation like wind and solar power is that it can be interrupted, and this variability affects the stability of the power produced. HVDC is so far the best technology for integrating more intermittent forms of renewable energy into the local power grid, particularly over long distances. This is especially significant for large scale offshore wind projects, or large scale solar power production. — Preceding unsigned comment added by (talk) Shenyawang (talk) 01:42, 28 April 2015 (UTC)01:41, 28 April 2015 (UTC)
This article's lead contains some misleading and out-of-date information. Here is the link from which I get my information:[1] (as of June 14, 2015) there are 32 of the total planned 50 turbines operational. (Each with 71.5 MW capacity ...doing the math...) that's 2288 MW (so far, that dam is scheduled for completion in Nov 2016). There are also 3 other hydroelectric dams planned, only one of which is in construction. (I don't know if the others will contribute to the HVDC transmission, based on the claim that a total of over 6000 MW will be transmitted, I assume so -but the total MW claimed seems a bit high to me). The lede needs to change to reflect this information. That is the lede states "which consists of two bipoles of ±600 kV, 3150 MW each..." which is clearly not correct. I know almost nothing about HVDC transmission, but I'm guessing that only one bipole is operational. (No idea about whether both have been constructed).FWIW216.96.78.101 (talk) 17:34, 14 June 2015 (UTC)
Hello fellow Wikipedians,
I have just added archive links to 8 external links on High-voltage direct current. Please take a moment to review my edit. If necessary, add ((cbignore))
after the link to keep me from modifying it. Alternatively, you can add ((nobots|deny=InternetArchiveBot))
to keep me off the page altogether. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true to let others know.
This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template ((source check))
(last update: 5 June 2024).
Cheers. —cyberbot IITalk to my owner:Online 04:57, 4 September 2015 (UTC)
Hello fellow Wikipedians,
I have just added archive links to 2 external links on High-voltage direct current. Please take a moment to review my edit. If necessary, add ((cbignore))
after the link to keep me from modifying it. Alternatively, you can add ((nobots|deny=InternetArchiveBot))
to keep me off the page altogether. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true to let others know.
This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template ((source check))
(last update: 5 June 2024).
Cheers.—cyberbot IITalk to my owner:Online 17:10, 27 February 2016 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on High-voltage direct current. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template ((source check))
(last update: 5 June 2024).
Cheers.—InternetArchiveBot (Report bug) 00:13, 27 July 2017 (UTC)
In the article, one should make a comparision on the effiency of HVDC converters and inverters using mercury arc valves, thyristors and IGBTs. Which percentage of the transmitted power is required to steer these different valve types? How depends the amount of steering power from the load current? What is their lose, when the valve is conducting? — Preceding unsigned comment added by 93.236.153.175 (talk) 22:30, 27 September 2018 (UTC)
Hi Wtshmansky, I was slightly worked up in my last revert on the "late completion date" question. Sorry about that. Maybe we can discuss here. 98.216.244.217 (talk) 09:04, 27 January 2019 (UTC)
We can go around and around on the edit summaries with me repeating myself and you playing WP:ICANTHEARYOU. Let's talk about it here instead. I see you're one of those rapid-fire editors who likes to make multiple edits per minute. Does that allow you to pay any attention to what you're doing? I'm thinking you're not paying attention.
If you want to mention that a war caused a delay, you need to provide sources that at least mention a delay in construction. The current source doesn't mention a delay in completion (probably because it's an unreliable PR sheet from a company who had a hand in building it!). Find a better source before replacing the material, see WP:burden. It also needs to be worded better to explain what delay it's talking about.
Mainly, find a ref that actually does the job. If you want to replace, you need to find at least one reliable secondary source (not a PR sheet) that says there was a delay in the construction caused by a Mozambique war -- and says it in a way that makes it notable to the HVDC subject. That's a tall order, but that's what you need to satisfy inclusion requirements and WP:burden. Reactionary WP:ICANTHEARYOU reverts don't cut the mustard.
98.216.244.217 (talk) 23:31, 27 January 2019 (UTC)
I fixed the biggest problem which was that a "late completion date" wasn't established as a thing in the text before it was suddenly referred to, and then it wasn't even mentioned by the ref. Service interruptions resulting from the war were mentioned by the ref so I changed it to that.
It's still off topic, non-notable, ideological digression. It's still supported only by a self-published public-relations propaganda that even has "pressrelease" in its URL. But, at least the wording doesn't stand out as much as it did before for correction or removal. 98.216.244.217 (talk) 05:00, 29 January 2019 (UTC)
"Depending on voltage level and construction details, HVDC transmission losses are quoted as less than 3% per 1,000 km, which are 30 to 40% less than with AC lines" This is a terribly ambiguous phrasing. It could either mean that AC has losses of 33%-43% per 1000km, or losses of 4%-5% per 1000km.
OliverKlozoff (talk) 01:03, 28 June 2020 (UTC)
Which HVDC schemes use Capacitor-commutated converters (CCC)? — Preceding unsigned comment added by 2003:DF:1F25:7650:D7B:5B87:6F99:D1FE (talk) 20:41, 4 November 2020 (UTC)
The first sentence of the lead says, "A high-voltage, direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current (DC) for the controlled bulk transmission of electrical power, in contrast with the more common alternating current (AC) systems." It is unclear to me what we're trying to accompliish with the "controlled bulk" qualifiers here. GliderMaven recently added "controlled". It would seem that we could make things easier for readers by leaving out these qualifiers. If they need to remain, there needs to be some further explaination of this jargon. ~Kvng (talk) 13:47, 1 October 2021 (UTC)
The ABB Power Grid unit (originally part of ASEA) was sold to Hitachi two years ago. Should we switch all references to ABB to Hitachi instead? jax (talk) 10:22, 9 September 2022 (UTC)
An overhead line strung with a bundle of stranded conductors (or indeed any stranded cable) behaves in the same way as a solid conductor of equivalent cross sectional area. The varying magnetic field of alternating current forces the current to the outside of the strands or solid conductor if it is larger in diameter than twice the skin depth . The advantage of stranded cables is solely that they are easier to handle, transport and install because they are much more flexible (and possibly cheaper to make).
If more current capacity is required compared with a single cable (stranded or otherwise) that can carry the current without significantly exhibiting the skin effect (roughly 27 mm or so for the normally encountered utility frequencies in copper conductors), then separate multiple conductors are employed.
Although not relevant to this case, Litz wire does carry the current distributed in all the strands of the bundle, but only because the strands are insulated from each other which changes everything. The magnetic field cannot force the current through the insulation (though, of course, it will try). 109.152.150.247 (talk) 18:28, 14 February 2023 (UTC)