China begins work on world-beating MEGA power cables China’s apparently unceasing efforts to lead the world in every conceivable field continued on Sunday after engineers in the western region of Xinjiang began construction of what is claimed will be the largest capacity power line on the planet. The 800 kilovolt (kv) ultra-high voltage power transmission line is being built by …
I make this an average continuous power delivery of 4.2 GW. I assume the 'world beating capacity' of 8 GW is because of a factor of two margin in the design?
How does this compare to other notable power transmission systems?
(Am I the only one who thinks that '37 billion kWh per year' is a clumsy way of expressing energy units?)
Whilst we're here, 8 million kW is a clumsy way of writing 8GW.
My guess is that whoever wrote the English-language press release doesn't actually know what a gigawatt is. That's fair enough, I suppose. I haven't a clue what it is in Chinese. If only there was a "tech news" website which aggregated all these press releases and rewrote them with the proper engineering terminology...
Having worked for The Hamsters for more than 15 years I can state quite categorically that there's NO FUCKING P IN HAMSTER!!!!!
Sorry, just a long-time irk. I feel slightly better now.
Don't apologise matey! I have seriously improved my spelling thanks to the grammar Nazis here in these forums! No P in Hamster - got it! Will add that to no ' in 1980s.
People like you provide a valuable service to those of us unfortunate enough to be educated under a combination of Thatcher, Major and Blair!
Blimey - you learn something new everyday - firstly that you can have 's and Ps and secondly that sometimes grammar Nazis do actually talk out of their arses after-all!
It's good to have a second opinion - thanks guys!
I have completely forgotten what the original point of this thread was now!
A hamster is reasonably capable of 0.15 Watts, and assuming a hamster can only be relied on to run for 3 hours a day... by my calculations (i.e. 1 Watt = 53.33 Hamsters) the El Reg Alternative Unit measurement here would be:
0.224 Terahamsters
Russians tried a 1MV delivery system nearly 20 years ago from Ekibastuz to the European part of the USSR. It was trumpeted very loud and there were even articles describing the designs in their pop-sci magazines (Nauka i Zhizn if memory serves me right).
IIRC, end of the day it was not worth it so they ended up running a couple of 600Kv (which is their de-facto large capacity standard anyway). I may be wrong of course.
In any case - this is _NOT_ earth shattering, it is the usual "Chinese copy Russian or Western tech at reduced capacity and claim world first".
This is a DC line - it's capable of transporting massive amounts of power with low losses and on relatively compact lines.
The Russian 1MV test line was AC. It had massive losses and the towers were absolutely frickin' enormous. I don't think it's still in service.
This is news; no-one has deployed 800kV DC commercially before. This is a fairly epic bit of electrical and mechanical engineering. IIRC, the valve stacks alone are about 60m high...
A standard dual circuit 3 phase 4 conductor 400kV line as used in the main transmission lines in the UK can carry 1kA per conductor for a total power of over 6.7GW. The China link is high voltage but not very high power given the voltage.
The high voltage is probably to reduce the amount of aluminum (or copper) needed for the line (doubling the voltage halves the amount of conductor needed).
Very long distance though. If you use cable materials whose cost is linearly proportional to distance, losses will also be linearly proportional. If your transformers (and rectifiers if DC is used) can handle higher voltages, and if this didn't lose more energy through corona discharge, doubling the voltage would quadruple the capacity of the line without increasing losses which are proportional to current.
Anyone here with expertise about the effect of corona discharges in electric transmission line designs ?
Might be pretty good at thwarting copper thieves, too, no? A would-be-copper-theif-inverted-ito-a-crispy-critter every 200 km might cast the country into a time-warping brownout, hehehe.... Unless these things are very, very buried....
If any get to within the dam-burst zones of the Three Gorges Dams, and got flooded, what might that do to the system overall? Would breakers (or their equivalent devices) be tripping all over the country? IF hey have bad luck restoring power at night, that side of the Globe might look like a bicyclist's strobe to any *nauts who happen to be flying over (assuming the light show penetrates any then-current pollution).
But, it got me wondering whether this is a backdoor prototype for Blue Energy (lol!), to energize a Project Genesis.
Seriously, could this be tapped in to by nuclear reactors later if that 2 trillion tons of coal reserves gets sucked up or is so toxic that burning it becomes untenable? What kind of conversion systems would be candidates to supplant coal plants if/when it becomes necessary?
Higher voltage reduces transmission losses (at the cost of greater clearance distances/insulators), which probably explains where the
"We can reduce 317,000 tons of sulfur dioxide and 267,000 tons of nitrogen oxide which would otherwise be produced during the transportation," quote comes from, though without stating what this is compared to, these figures are meaningless - 800kV Vs. 400kV? 800kV Vs. 1000V?
Work started on Sunday, they aim to be complete in 2014. Lets assume they've 'only' aiming for a 2 year turnaround - 1373 miles in 2 years, 1373 / (365 * 2) = 1.88 m/d
That's nearly 2 miles a day that will be completed. Underground, or over ground, that seems like a pretty damn impressive daily goal.
I'm guessing in the UK we still work in yards per day on a project such as this...?
Building roads and power lines are the kind of public works projects that are easily parallelizable, so while they may do two miles a day on average, its not like there will be one team that makes two miles of progress every day starting on one end and moving linearly to the other.
There's enough people there, enough resources/manufacturing capacity, and more importantly so little red tape in a command economy that they could probably finish it this fall if they really wanted to...
It would be interesting to see the details on the cable for such a project. Western designs usually use spatially separated lines to suppress the corona. Since the corona is dependent upon the electric field, and the electric field is dependent upon the voltage as well as the shape of the conductor, the corona can be reduced by minimizing sharp edges, and maximizing the radius of the conductor. Since it's not practical to suspend a 12 inch diameter conductor, the conductor's diameter is approximated by using a number of smaller wires spatially separated to produce a 12 inch diameter grid (or thereabouts). Thus, the lines (per phase) on high voltage transmission lines, may consist of 2, 3, 4, or even more conductors, spaced apart, rather than a single conductor.
Still, there will be substantial corona, especially in inclement weather conditions.
I used to live near a 250KV AC (or thereabouts) transmission line, and when the fog rolled it, that thing would really sing (Loud enough to be heard several hundred feet away!).
One wonders how much x-ray radiation is produced by the corona from such a power line? Has anyone ever done any studies?
Insulators will also be a bit of a trick. The voltage isn't divided equally across all of the sections. Thus, non-uniform insulator stacks may be required. Complicating the design will be accounting for moisture and/or dirt, which may further alter the voltage division across sections. And, excessive voltage across a section can lead to breakdown, resulting in arcing, heating, and rapid failure.
For that matter, even a tiny air bubble in a ceramic/glass insulator can result in breakdowns at high voltages, resulting in heating and shattering of the insulator.
In any case, it's sure to be a challenging project, and the engineers responsible should be credited with an outstanding design (if it works).
Dave
You're right, the engineering challenges are enormous. Plenty of corona discharge in the wet!
Exposed UHV DC makes a really strange hissing/sizzling sound, quite unlike the heavy crackle/buzz you get on AC stuff.
One big problem is the long-term stability of DC insulators - they tend to degrade over time as the ions all move in one direction. AC is much easier to do in this respect.
No x-rays, though: AFAIK you need a vacuum to generate those...
Have you ever seen this solar power plant near Vienna?
http://upload.wikimedia.org/wikipedia/commons/3/37/Wien_erdkabelstation_400kV_Nordeinspeisung.jpg
Just a tiny solar panel between the 2nd and 3rd while concrete column (from the left) giving enough energy to call for a 400kV line going to it.
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