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Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsREVOLUTIONARY NEW DEVICE? Insulated Cross Arms could speed up connection of new electricity supplies
TUE JAN 22, 2013 AT 09:05 AM PST
The simple innovation that could make wind power a big player
Increasing the voltage by a factor of 2.5 would reduce powerline losses by a factor of six. And that's a BFD, as Joe Biden would say.
by Keith Pickering
.........................
....recent announcement from the University of Manchester (UK) leaves you with a forehead-hitting "doh!" moment: why didn't anyone think of this before?
http://www.manchester.ac.uk/aboutus/news/display/?id=9384
Insulated cross-arms? Yes!
?1358871793
A typical high-voltage powerline looks like this. There's a tower (called a pylon) made of steel, with (typically) three pairs of cross-arms at different heights. At the end of each cross-arm hangs an insulator made of a type of plastic that won't allow electricity to flow. The wire that carries the power is hung from the insulator.
It's the job of the insulator to keep the powerline itself far away from the steel of the cross-arm or the pylon, because if the line gets too close, electricity could short from the powerline to the grounded cross-arm. That means the insulator has to be long, to keep it away from the cross-arm. But that long insulator then could sway in the wind toward the pylon, which might also cause a short. All of which means that there's a limit to how much voltage the line can carry, based on the minimum distance the line could get to the pylon or the cross-arm.
The "Doh!" moment comes when you realize that all you have to do is make the cross-arm itself from insulator material, as in the photo below:
?1358873199
We're looking at the middle cross-arm on the right. Notice how short the hanging insulator is. That's because the cross-arm itself is made of insulating material, so the line can't short to the cross-arm. The line could still short to the pylon, but since the insulator is so short, the amount of wind-sway is going to be very very small. And that means that this line is capable of higher voltages than its sisters, because it can never get as close to the pylon as they can.
Cross-arms could speed up connection of new electricity supplies
22 Jan 2013
A revolutionary device developed by engineers at The University of Manchester and EPL Composite Solutions Ltd. could dramatically increase the capacity of the UKs electricity network, enabling rapid increases in renewable generation and lower bills for consumers.
Insulated Cross-arms, manufactured and sold by University of Manchester spin-out company Arago Technology Ltd., have been installed on pylons in some of the most stark and remote areas of the UK to test their resistance to extreme weather and are also being tested for an eventual use with 400,000 volt systems at a coastal site in Scotland.
Tests have also been carried out at the Universitys High Voltage Laboratory which has subjected them to lightning strikes of more than 1.4 million volts.
Modelling shows that in some cases the new Cross-arms are capable of increasing the power carrying capability of a pylon by up to 2.5 times.
22 Jan 2013
A revolutionary device developed by engineers at The University of Manchester and EPL Composite Solutions Ltd. could dramatically increase the capacity of the UKs electricity network, enabling rapid increases in renewable generation and lower bills for consumers.
Insulated Cross-arms, manufactured and sold by University of Manchester spin-out company Arago Technology Ltd., have been installed on pylons in some of the most stark and remote areas of the UK to test their resistance to extreme weather and are also being tested for an eventual use with 400,000 volt systems at a coastal site in Scotland.
Tests have also been carried out at the Universitys High Voltage Laboratory which has subjected them to lightning strikes of more than 1.4 million volts.
Modelling shows that in some cases the new Cross-arms are capable of increasing the power carrying capability of a pylon by up to 2.5 times.
MORE:
http://www.manchester.ac.uk/aboutus/news/display/?id=9384
http://www.dailykos.com/story/2013/01/22/1181120/-The-simple-innovation-that-could-make-wind-power-a-big-player
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REVOLUTIONARY NEW DEVICE? Insulated Cross Arms could speed up connection of new electricity supplies (Original Post)
kpete
Jan 2013
OP
mike_c
(36,214 posts)1. doesn't the additional current increase the likelihood of sagging...
...in the middle of the span though, and shorting to objects beneath the wires?