Superconducting Power Cables in Denmark 82
Mikkel Blanné writes "Today Denmark put a superconducting power cable to use , beating Detroit to it! (Be careful though, it's in danish). We're talking 3 cables, each 30 metres in length and produced in cooperation between Nordic Superconductor Technologies, NKT Research and DTU.
This makes it the first superconducting cable in actual use, ie. not in a laboratory. The purpose of this project is of course still research, but I am right now typing this on a computer running on power that came through those cables ;-)
Further descriptions are here and in this rather old RISØ newsletter. Sorry about everything being in danish, but apparently this hasn't come to the world's attention yet..."
Re:some info (Score:1)
As opposed to the really hot liquid nitrogen?
some info (Score:2)
Three 30 metre supercooled cables Copenhagen's new supercable is only 30 metres long, but that is ample for practical full-scale testing in the public supply grid. The cable is installed at 'Amager Substation', a central hub in the Danish capital's energy supply system. The supercable is capable of supplying electricity to the whole of Amager district and will be tested under all operating conditions. No operating experience exists elsewhere of superca-bles installed in a public supply grid, and in particular the use of extremely cold liquid nitro-gen to cool the cable is a totally new element in electricity supply. The new cable has three phases, ie. it consists of three separate superconducting cables each 30 metres long spliced into the grid where the voltage is 30 kV. The supercable has a 2000 Amp current rating.
A real-world test (Score:5)
At first only about 20% of the power in the station is led through the cable, but later (if everything goes well) the cable is supposed to take more power.
If this project turns out fine, a 4-6K meter cable is next.
Power for cooling to keep the cable below -160 degrees celcius is expected to be about half the power loss of a traditional cable.
Re:To really put it in perspective... (Score:2)
Remember though, that long distance fiber optic cables are power cables. All those repeaters along the way need power, and that is usually supplied with one or more 10,000 volt conductors in the same jacket as the fiber.
Re:laboratories aren't actual? (Score:1)
No - They plan to operate the 30 meter at 100% but have started with only 20% usage (yesteday). They expect that all the power for the ~150000 citizen on Amager will go trough this kabel if all go well...
And its a DANISH installation - not Dutch.
Re:To really put it in perspective... (Score:2)
Re:To really put it in perspective... (Score:2)
Re:To really put it in perspective... (Score:3)
This is going to be used to transmit power. Right now, in the US, when power is transmitted from the Hoover Dam to cities several states away, power losses can be well above 50%. A fiber optic cable over the same distance would have losses on the order of a fraction of one percent.
This won't be a replacement for the cabling between your house and the transformer in your neighborhood. The costs of supercooling the wire would be too great. This is going to be used to transmit power from the power source to the power station. BIG wires. Big current. High voltages.
So, if you're a comm company, you don't have to worry about this. This won't affect you one bit. In fact, none of the wiring for power in neighborhoods will be uprooted, either. Only the big high voltage, high current cable (actually, if your cable can take higher voltages, you'll gladly trade a higher voltage, lower current cable, as losses are related to current, not voltage). This will be far less than 1% of all power lines (probably smaller than
Re:A real-world test (Score:1)
But in exchange for that, the failure modes are twice as spectacular!
If the cooling system goes out, the cable will become non-superconducing, start to produce heat, and quickly explode.
If the cable is overloaded, it won't just melt away, but at a certain point the superconductivity will stop to work (you can only carry that much current through a superconducting cable) and again, heat forms, and superconductivity stops alltogether really quickly.
Roger.
Re:Only 30m long! (Score:1)
Right.......... And wrong.
The "V" you need to take is the Voltage over the cable. This is not a nubmer that is easily user-accesible. Moreover, the "R" becoming 0 (superconduction!) means that we start dividing by 0. Fun formula to use in this case.
The right formula is:
P = I^2 * R
This shows that the current used is very important. By increasing the voltage on the long distance lines, the current is reduced, therefore the losses in those lines. In this case, the R is reduced to 0, so the loss should be 0 in the superconducting cable.
Roger.
Re:Only 30m long! (Score:3)
Actually, 30 meters is just over 98 feet, 5 3/32 inches. :-)
--Joe--
Economic value? (Score:2)
Does anyone know how much these cables would save (in the way of line loss) over ordinary copper power mains?
Don't have a wire table handy and the answer should be generally interesting.
Power 101 (Score:2)
Axtually, as someone else has already pointed out, it it just under 100 ft.
Partly true. The longer the line, the more you gain from reducing the resistance. However, the load current also plays a a large part in this (see below)
The formula is correct, but the v (or more properly e for EMF) is the line drop, which is proportional to both the current, the length, and the resiatance/length. In this case, the more appropriate forumula would be P = I^2 * R, where I is the load current and R is again proportional to cable lenght.
Consider a local main that delivers 200A, is 1000 ft long (300M) and has a resistance over its length of 0.01 Ohm. The drop in each each leg ot the main will be 2V. So if the substation feeding the main delivers 120V, only 116V will be seen at the other end. Further line loss (which will be heating the main) will be 400W in each leg of the main, or 800W. (My reistance value may be way off, I have no real idea what the resistifity of local power mains is.)
Long distance power lines are extremely high voltage (on the order ot tens of KV) and carry relatively low current. Local mains carry only 100 .. 240 V and (relatively) more current.
Also, there are probably more miles (total) of local mains than of
long distance transmission lines.
Useful in dense downtowns (Score:2)
The Detroit cable is 1% the weight of the copper
it replaces, and almost twice as efficent.
One very interesting ascpect is.. (Score:2)
TA (I read the article)
Re:VVVVV's (Score:1)
110V @60Hz VS. 230V @50Hz has it's pro's and cons. The US has due to the low Voltage and high current a FAR higher incidence of fires. (As well partially due to aluminium wiring)
Europe has (had in most countries) due to the higher Voltage and lower frequency a higher number of electrocutions. In most of Europe this danger has been overcome by putting earth-fault relais in every home and installation.
And sure the losses in a 110V line are quadratic higher than in a 230V line but then the US system far ofter uses (3000V?)transformers right on the doorstep.
So when can I buy superconducting speaker cables? (Score:2)
I'm suprised the audiophile market doesn't have any superconducting products. It seems these people will buy anything as long as it costs enough.
laboratories aren't actual? (Score:3)
I think the author (Chick) is a little confused on the term 'actual use.' Just because a superconducting cable is used in a laboratory doesn't mean that the cable itself is the subject of the experiment, and could easily be seen as a case of 'actual use.'
More to the point, the 30m cable is a 20% load experiment which, if successful, will lead to a 100% 'actual use' implementation of several Km, so this Dutch installation isn't really specifically for 'actual use' either.
Kevin Fox
--
Re:Translation of http://www.ing.dk/... (Score:1)
Uh, it's superconducting. No resistance. So, there should be no maximum current, and no minimum size!
What am I missing here?
Re:VVVVV's (Score:1)
higher amperage does.
As for Electrical fires, the amount of power used in a typical U.S. home, in comparison to a typical U.K. home would probably level out the statistics. (Is Aluminum wiring even allowed anymore? scary)
Re:To really put it in perspective... (Score:1)
Re:Eeek! (Score:2)
Re:VVVVV's (Score:1)
more power to the end user. Simple arithmetic will
tell you 230V x 16A is alot more than 117V x 15A.
The 50Hz issue is an interesting one. There has
been talk of taking it to 60Hz here in Europe. By
doing just that, you get a few percent more
capacity from the power system and don't yet need
those expensive super-conducting cables for a
while longer. Except for a few obsolete clocks,
there would be little or no side effects in going
to 60Hz.
As for the higher voltage, the handling is done in
a much more safe manner. You cannot touch 230V by
plugging something in as you can with the North
American plugs. They are alot larger here however.
Anyone moving from the US to Europe that works
with electrical equipment quickly learns to have
a bit more respect for the "low voltage" mains!
It is hard to say which voltage is safer. Tesla
said that 230V was the best compramise between
power deliverable and safety. He also suggested
55Hz while Westinghouse suggested 130Hz. IMO, 60Hz
appears to be the best frequency: A compramise
between transmission distance and transformer
size.
Links to description in English (Score:4)
In the US ? (Score:1)
Re:In the US ? (Score:3)
Translation of http://www.ing.dk/... (Score:5)
Danish research, industry and power supply in unified world record.
For the first time in the world superconducting wires are moved beyond the laboratories and into the power grid. It happens monday at Amager Koblingsstation located Irlandsvej 95. The Italian/American competitor Pirelli is believed to be at least a month delayed.
Since february engineers from Copenhagen Energy, NKT Cables, NKT Research and DTU have worked on installing three pieces of superconducting wire at Amager Koblingsstation, monday they're ready to supply great parts of Amager with power.
This is a demonstration project (proof of concept) that through daily maintenance will show whether superconduction techniques are read for the terms of reality. the cables need to withstand the large fluctuations in power and voltage, that occur from time to time. Three cables at each 30 meters of length have been spliced into a section of the normal power grid, on the distribution side, where the voltage is 30 kilovolt.
The initial phase is careful, but as Amager Koblingsstation is capable of supplying power to all of Amager's 150000 inhabitants, the supercables will have theirs to see to.
"Initially the supercables will be in charge of 20 percent of the ordinary power, for as long as we're comfortable using them. Later the load will be increased", says integrational project manager Svend Korning of Copenhagen Energy.
Waste is halved
Not only the cables are on test. An important part of the cooling facility that's needed to keep the superconductors below their critical temperature, minus 160 degrees celcius (-256F), where electrical resistance disappears.
When the test phase is over, the new supercables are to be used across larger distances, typically 4-6 kilometers (1.6-3.75 miles). This is where money is to be made in comparison to traditional power cables, that become 70-80 degrees celcius hot (158-176F) when fully loaded. The dug down cables heat the surrounding ground to no use, that waste will disappear completely when using superconductors.
"In stead there's going to be an extra power usage in the maintentance of the necessary cooling facilities, but that usage is only half the wast of the traditional cables" says project manager Dag Willen of NKT Research.
"The society can save energy on superconductors, but to the power companies it's more interesting that the cables are cheaper to install, as this helps then to be competitive on price. So far things look good. With cables that are several kilomneters in length, expensive high voltage transformers which have been necessary so far, can be saved when the power is to be transported. Furthermore, the supercables are smaller and bend easier" he says.
The demonstration project at Amager has costed 10 million danish crows (~$1.25m), but there are more possibilities of doing this cheaper next time. For examnple, the cables can be produced to take up less space, and allow larger maximum current.
"But for the first round, we've purposely produced a simple cable with the same dimensions as the old" says Dag Willen.
To really put it in perspective... (Score:1)
And of course it's a cool thing to do.
What will be interesting to see is what the price difference is between super-conducting & standard copper cable when produced in bulk, because this is the real make or break for it. If it doesn't produce a high enough medium term saving, then I can't see very many power/comms companies rushing out to pull up their existing cables.
However, assuming that the wholesale price doesn't cancel medium term savings then perhaps we'll see it being installed in all the new cabling contracts in 2/3 years.
Re:Rat-resistant wires (Score:1)
--
Re:To really put it in perspective... (Score:1)
--
Re:To really put it in perspective... (Score:2)
--
Re:To really put it in perspective... (Score:2)
--
Re: (Score:2)
Re:laboratories aren't actual? (Score:1)
Or maybe not.
Just because a superconducting cable is used in a laboratory doesn't mean that the cable itself is the subject of the experiment
Granted. However, you then concede:
the ... cable is a ... experiment which ... will lead to a ... 'actual use'
So now you're agreeing with the author, and refuting the applicability of your objection to the case at hand. What was the point of that?
Size and heat are the significant savings (Score:3)
The refrigerators that keep the liquid nitrogen liquid make a lot of waste heat, but that heat doesn't end up in the conduit with the cable.
Switch to superconducting wire in an existing tunnel, and there is both more electrical capacity and more space for communication cables.
Cables in Detroit (Score:2)
Rat-resistant wires (Score:2)
Power loss != (V^2)/R (Score:1)
Try it: plugging in 120V for a .001 Ohm line gives you a ridiculously high power loss, a wrong answer that is to be expected since you hardly expect power loss to increase with decreasing R! The other way to look at it is to notice that the only power loss is due to the voltage that drops across the resistance. Here, that would be Vdrop = IR. We need a value for I (can't derive it, for the same reasons as above). So using an arbitrary I=200A (pretty high), Vdrop = 2V which is much better: 400W power loss instead of 1440000W! QED.
Re:Economic value? (Score:1)
Actual cost? (Score:1)
BTW, sorry if it actually has this info in the article - I don't speak Danish, my connection is really slow, and I'm just too lazy to use The Fish or whatever.
30m (Score:5)
What happens if the cooling cuts off? (Score:1)
Re:What I want to see now... (Score:2)
[Homer stands outside Mr. Burn's office door. He knocks and peers inside.]
Homer: "Ummmm...Mr. Burns?"
Burns: "Yes?"
Homer: "I read on Slashdot this morning that there these Danishes we can get now that are made of superconductors."
Burns: "Hmmmm....If you read it on Slashdot, it must be true!
[Under his breath] (Or so I've heard.)
I'll look into it."
[Homer leaves.]
Burns: "Smithers, who was that neanderthal?"
Smithers: "Homer Simpson, sir. One of your trolls from Section 7-G."
Burns: "Simpson, eh? He raises a good point. As the local energy concern, I've got maintain my competitive edge. Hire more Danes."
Smithers: "But I think he meant..."
Burns: "Enough chatter! Get me more Danes. We'll rend their superconducting little bodies into superconducting wires. Get me more Danes!"
[Pause]
"And Smithers? No Germans. I'm still trying to fix the damage they did to my plant while trying to bring it up to code."
Re:Links to description in English (Score:2)
Re:Links to description in English (Score:4)
Well here is the text anyway.
Today, for the first time in the world a superconducting cable enters service in a public electricity supply grid.
Energy savings, increased grid capacity and cheaper electricity for consumers are in prospect as a result of new technology that is about to undergo full-scale testing in Copenhagen. From 11.45 today, for the first time anywhere in the world, superconducting cables will be used to supply electricity to consumers. Some 150,000 residents in the Amager district of Co-penhagen will in future have their electricity supplied by this new technology. Until now, superconducting cables have only been tested - by laboratories and by the organisations across the world that have been competing for more than a decade to develop the technology for practical application. "We have focused on placing ourselves among the five technologically leading manufacturers of supercables. Not specifically on being first past the post", says Dag Willén, Project Manager of NKT Research. And indeed, for a long time it looked as though first place would go to a project in Detroit. But in the end Danish technology proved quickest to overcome the legion of theoretical and practical challenges posed by supercable development. 5-7% energy savingDiscovered as far back as 1911, the phenomenon of superconductivity occurs at extremely cold temperatures and causes almost all electrical resistance - and thus also energy loss - to disappear. However, within the last 15 years new materials have been discovered that only require cooling with liquid nitrogen (minus 196 Celsius). The Danish technology group NKT has been involved in the research race since the end of the 1980s. With widespread use of superconducting technology in grid 'highways' energy consump-tion can be reduced by 5-7%, which means an equivalent reduction in CO2 emissions from electricity generation. But supercables can also become part of a simplification of the electrical infrastructure. This is because they can transmit massive currents, something which can further be utilised to reduce the number of voltage levels (fewer transformer substations). At the end of the day this will enable cheaper electricity for consumers. Three 30 metre supercooled
cables Copenhagen's new supercable is only 30 metres long, but that is ample for practical full-scale testing in the public supply grid. The cable is installed at 'Amager Substation', a central hub in the Danish capital's energy supply system. The supercable is capable of supplying electricity to the whole of Amager district and will be tested under all operating conditions. No operating experience exists elsewhere of superca-bles installed in a public supply grid, and in particular the use of extremely cold liquid nitro-gen to cool the cable is a totally new element in electricity supply. The new cable has three phases, ie. it consists of three separate superconducting cables each 30 metres long spliced into the grid where the voltage is 30 kV. The supercable has a 2000 Amp current rating. The future electrical infrastructure
The increased energy consumption expected in the future would demand expansion of the power network and in many cases - especially in the industrialised part of the world - also investments in replacement of existing networks. As technology evolves high capacity super-cables at still more competitive prices will gradually play a more important role in the future infrastructure. City of Copenhagen's Environmental Mayor Bo Asmus Kjeldgaard stresses the importance of Copenhagen pressing ahead with development of new environment-friendly technology: "All new technology is expensive at first. Like solar cells in the past, superconducting mate-rial is currently very expensive. That means it will have to come down in price to compete with conventional technology. But I am certain that if this project produces the right results, we will see the superconducting material used not only in cables but also, for instance, in coils and transformers." The supercable project
The actual power transmission in supercables takes place through superconducting tapes. These tapes are the key component of the cable, and the NKT subsidiary company NST (Nordic Superconductor Technologies) is among the world's three or four leading manufacturers of these products. The tapes are used in a large number of electrical applications, such as engines, generators, current leads and MRI scanners. The high tech superconducting cable was fa-bricated by NKT's cable company NKT Cables, and will now undergo full-scale testing by Copenhagen Energy. Please address any questions relating to this press release to: Bo Asmus Kjeldgaard, Environmental Mayor, City of Copenhagen, phone + 45 26 15 58 21
Svend Kvorning, Project Manager, Copenhagen Energy, phone + 45 33 95 31 21
Asger Bundgaard-Jensen, CEO, NKT Cables Group, phone + 49 221 676 22 22
Dag Willén, Project Manager, NKT Research, phone + 45 43 48 35 77
Re:Only 30m long! (Score:1)
Only 30m long! (Score:4)
As i recall the loss in a cable is P=(v^2)/R so the lower the resistance the lower the loss in the line. As the resistance of a wire is proportional to it's length P=(v^2)/(al) so the greatest losses are on long lines.
None the less this is still a fantastic acheivement and will hopefully pave the way to more widespread use.
There's no Eeek! in Danish (Score:1)
Eeek! (Score:2)
What's wrong with it being in Danish? Has the danish language suddenly become volatile when viewed by a non-dane? Is this another security feature -
YOU ARE NOT AUTHORISED TO VIEW THIS LANGUAGE
YOU WILL NOW SELF-DESTRUCT.
What if some of our readers can actually parse danish themselves? You need a disclaimer on your disclaimer: "Be careful though, it's in danish* (does not apply if you can read Danish.)"
Jeez.
Alex
Re:30m (Score:2)
According to the article, they want to be sure that the cables can cope with the power spikes before making the real investment.
Re:VVVVV's (Score:1)
Online Translation, etc. (Score:3)
Here is the original web page as auto-translated to English [tranexp.com]
On another note, there are these stories previously seen on Slash
- Superconducting Power Cable in Detroit [slashdot.org] by michael on Sunday May 20, @08:21PM EST 221
- Nitrogen Semiconductors [slashdot.org] by timothy on Thursday May 10, @01:23PM EST 14
- High-Temperature Metal Superconductor Beckons [slashdot.org] by timothy on Monday February 26, @03:21PM EST 179
I note that the Detroit Story was just a week or two ago, but it is nice to see europeans getting a jump on the US.Check out the Vinny the Vampire [eplugz.com] comic strip
Re:60,000KVA is a good test (Score:1)
Well, there's probably a cable temperature interlock.
Power goes out, cables get warm, breaker trips on cable overtemp, power stays out....
Liquor
Re:Links to description in English (Score:1)
Tom.
Re:Links to description in English (Score:1)
Well, under Mozilla at least, when you go into the site it jumps into a mad state where it keeps refreshing to itself continuously with the graphics jumping all over the page. I guess the moderators thought the destination site was funny. Annoying more like....
Re:Only 30m long! (Score:2)
P = (v^2)/R
or
P = (I^2) R
it's just the same...
the story (Score:2)
In the beginning the cables will only take about 20% of the power in the line they have been connected to, but once they feel confident in the cables, they will turn it up.
The power used to cool the cable should be less that 50% of the power lost in a normal cable.
Hmm it just strikes me that I am getting power from those cables, cool, they seem to wo.#%Ffbfkhg
--------
Re:VVVVV's (Score:1)
Re:VVVVV's (Score:1)
Re:VVVVV's (Score:1)
Re:some info (Score:1)
Re:To really put it in perspective... (Score:1)
Well, maybe not, but we do sell an awful lot of power to the Americans. Lots is generated at hydro dams in northern Quebec and Labrador, and shipped to New England.
Re:To really put it in perspective... (Score:2)
However, even with a superconductor you'd need a massive cable (and therefore more cooling) to carry high currents, so the old high voltage method is better.
I can't really workout your safety perspective here, it's the current that kills you so it would be even more dangerous. Even with the lowest currents used on the power grid, if you're fried at 4000v or 64,000v you're still fucked either way.
Re:VVVVV's (Score:1)
Aluminum wire is not just fine. It's not just a matter of sizing it properly. Many house fires have been caused by its use. To my knowledge, it is now banned by most local building codes for use within homes. The problem is that it deforms more easily when heated than does copper. When the wire heats up, it extrudes somwhat within its connector (such as a wall socket). After it cools, it leaves a tiny gap which quickly fills with aluminum oxide. After many tempurature cycles, the resistance of the oxide causes even more heating. Eventually it gets hot enough to cause a fire. My house was built in the late 60's and contains aluminum wire. I pay close attention to electrical problems. About twice a year, I have to tighten a connection. It's scary.
As to the relative lethality of the current and voltage ratings of power circuits, I've seen this fallacy before. It amazes me how many people believe this (including many who should know better).
Yes, current is what kills. But the amount of current required to kill is measured in milliamps. The minimum current rating of any residential power circuit I know of is 10 amps. Unless its of the ground-fault interruption type, no circuit breaker is going to pop if you're being electrocuted. Even a ground-fault interrupter won't help if you touch both the "hot" and "neutral" wires simultaneously.
The lethality of a circuit is generally based on its voltage rating. The higher the voltage, the more likely it is to drive enough current into ones body to kill. For example, a 12 volt car battery can easily source more than 1000 amps into a short ciruit and 500 amps into a reasonable load. I've touched both terminals of car batteries many times and usually don't feel it at all. The few times I've been shocked by 120VAC have gotten my attention instantly!
scsg
Re:VVVVV's (Score:1)
http://www.onlineathens.com/stories/121299/new_121 2990009.shtml
My point about current has to do with the rating of actual circuits. I've often heard it stated that a 100A circuit was more dangerous (electocution-wise) than a 20A circuit of the same votage which is false. Looking back at your original post, I see that you didn't actually write that. Sorry for mis-reading.
scsg
What about restarting after failures (Score:1)
I see a potential problem if superconducting cables are used for power distribution.
The cables need to be extremely cold, or else they loose their superconducting properties. The cooling is achieved through liquid nitrogen or something like that, but in the end the nitrogen has to be cooled by some kind of electrical process.
So -- what happens if there if a huge power failure during a long period (several hours or days)? Will it be possible to restart the power distribution without problems when the power lines are no longer cold enough?
Re:60,000KVA is a good test (Score:1)
In News Today... (Score:1)
In another related story, the Chinese are checking the wire for "cameras and other spy equipment."
Re:Economic value? (Score:1)
according to the article the power loss (produced by heating) is about twice as large as the power you'll have to use to cool this cable down.
You'd have to use a lot of power to cool down the system in the beginning, but as superconductors don't emit very much heat this is likely to decrease after the initial freeze.
Re:Power loss != (V^2)/R (Score:1)
Re:30m (Score:1)
Re:some info (Score:1)
Actually the amount of power super-conducting cables can transmit, is a function of temperature. These cables become super-conducting at approx. minus 160 degrees celcius, but they are held at a lower temperature to allow larger currents.
Basically it says this: (Score:2)
Re:laboratories aren't actual? (Score:1)
Re:what?? HELLO?!?!? (Score:3)
what?? HELLO?!?!? (Score:2)
What I want to see now... (Score:1)
Mod-Me-Down (Score:1)
... and I thought to myself, "No shit, it's in fscking Danish."
Re:To really put it in perspective... (Score:1)
p=(i^2)*r (Score:1)
v=i*r and p=v*i
so p=(i^2)*r || p=(v^2)/r.
It's all the same thing.
----
DANGER!Will Robertson!DANGER! (Score:1)
That I don't mind (Score:1)