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June 24, 2020
A superconducting electrical transmission line developed for the High-Luminosity LHC has set a new intensity record
Image above: The innovative electrical transmission line, designed for the HL-LHC, has been undergoing tests since mid-June (Image: CERN).
Intensity is rising at CERN. In the superconducting equipment testing hall, an innovative transmission line has set a new record for the transport of electricity. The link, which is 60 metres long, has transported a total of 54 000 amperes (54 kA, or 27 kA in either direction). “It is the most powerful electrical transmission line built and operated to date!” says Amalia Ballarino, the designer and project leader.
The line has been developed for the High-Luminosity LHC (HL-LHC), the accelerator that will succeed the Large Hadron Collider (LHC) and is scheduled to start up at the end of 2027. Links like this one will connect the HL-LHC’s magnets to the power converters that supply them.
CERN - Electricity transmission reaches even higher intensities
Video above: Interview with Amalia Ballarino, the superconducting link project leader, during the insertion of the line into its cryostat in February 2020 (Video: CERN).
The secret to the new line’s power can be summarised in one word: superconductivity.
The line is composed of cables made of magnesium diboride (MgB2), which is a superconductor and therefore presents no resistance to the flow of the current and can transmit much higher intensities than traditional non-superconducting cables. On this occasion, the line transmitted an intensity 25 times greater than could have been achieved with copper cables of a similar diameter. Magnesium diboride has the added benefit that it can be used at 25 kelvins (-248 °C), a higher temperature than is needed for conventional superconductors. This superconductor is more stable and requires less cryogenic power. The superconducting cables that make up the innovative line are inserted into a flexible cryostat, in which helium gas circulates.
The strands of magnesium diboride of which the cables are made were developed by industry, under CERN’s supervision. The cable manufacturing process was designed at CERN, before industrial production began. As the strands of magnesium diboride are fragile, manufacturing the cables requires considerable expertise. The current is transmitted from the power supply at room temperature to the flexible link by ReBCO high-temperature superconducting (HTS) cables.
Image above: A team member connects the superconducting link cables before the electrical transmission tests begin (Image: CERN).
Last year, an initial prototype transmitted a 40 kA intensity over a distance of 60 metres. The link that is currently being tested is the forerunner of the final version that will be installed in the accelerator. It is composed of 19 cables that supply the various magnet circuits and could transmit intensities of up to 120 kA! “We started the power tests by connecting just four cables, two at 20 kA and two at 7 kA,” explains Amalia Ballarino. New records are therefore expected to be set in the coming months.
This new type of electrical transmission line has applications far beyond the realm of fundamental research. Links like these, which can transfer vast amounts of current within a small diameter, could be used to deliver electricity in big cities, for example, or to connect renewable energy sources to populated areas.
Note:
CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.
The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.
Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.
Related links:
High-Luminosity LHC (HL-LHC): https://home.cern/science/accelerators/high-luminosity-lhc
Large Hadron Collider (LHC): https://home.cern/science/accelerators/large-hadron-collider
Superconductivity: https://home.cern/science/engineering/superconductivity
For more information about European Organization for Nuclear Research (CERN), visit: https://home.cern/
Images (mentioned), Video (mentioned), Text, Credits: CERN/Corinne Pralavorio.
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