Where there is the longest superconducting cable?Superconductivity are open more than hundred years ago. The longest in the world the superconducting cable connects two transformer substations in the city of Essen, Germany. Its extent about one kilometer, it is made of superconducting material and special ceramics. The cable is capable to transport five times more energy, than copper, and is calculated on transfer of the power of 40 megawatts.
Superconductivity was opened in 1911 by the Dutch physicist Heyke Kamerling. This remarkable physical phenomenon allows to transfer the electric power to any distances almost without loss. In one of experiments the electric current induced in the closed conductor did not fade within 2,5 years. Would flow to itself further and the strike of the workers providing supply of the cryogenic liquid necessary for maintenance of the required conditions prevented.
It would seem, long ago it is time to introduce the invention of the beginning of the last century widely. But, unfortunately, not everything is as simple as it would be desirable. Not all materials possess superconductivity, besides, it is impossible without extremely low temperatures. Nevertheless under certain conditions superconductors can be effective in the commercial relation already today.
The longest in the world the superconducting cable is officially put into operation in Germany. “Superprovodnik“ about one kilometer long connected two transformer substations in the downtown Essen in the spring of 2014.
The event marked the beginning of the practical test focused on reorganization in the future of all city power supply system. Advantages of a superconductor are obvious. In comparison with usual cables, it possesses considerably bigger efficiency and the compact sizes.
The Institute of technology of Karlsruhe acted as the scientific partner of the AmpaCity project (Karlsruhe Institute of Technology, KIT). Researchers comprehensively studied technical and economic feasibility of superconducting city power networks and support work of a cable. Conclusion of scientists: high-temperature superconducting power cables are ready to commercialization.
In household understanding high-temperature superconductivity differs from low-temperature a little. Incredibly low temperatures are necessary for one and for another. But if “usual“ superconductors show the properties approximately at a temperature of liquid helium - 287 degrees Celsius, then superconductivity is possible already at a nitrogen boiling temperature - 196 degrees. In physical and economic aspects the difference is huge.
The first connection possessing properties of high-temperature superconductivity is opened in 1986. Authors of opening - Karl Muller and George Bednorts - were conferred for the work of the Nobel Prize.
About 30 years that high-temperature superconductors passed a way from the idea conferred the Nobel Prize to the industrial appendix were required. Researchers managed to find the most suitable materials to create a cable of the increased mechanical durability and to minimize losses of electric current.
The three-phase concentric cable of the AmpaCity project of 10 kilovolts is calculated on transfer of the power of 40 megawatts. In comparison with a copper cable of the same size the superconductor can transport five times more energy.
The cable consists of superconducting material and special ceramics and is in the thick protection cover in which temperature minus 200 degrees Celsius is maintained. Thanks to ideal properties, the superconducting cable of 10000 volts replaces the usual line of 100000 volts.
Today superconducting cables are the most reasonable alternative to high-voltage lines in city distributive networks. Introduction of superconductors reduces energy losses, simplifies infrastructure and allows to refuse a large number of transformer substations, releasing the city earth and resources.
The decision on full modernization of power supply networks is final it will be made in Essen upon termination of the two-year period of trial operation of a superconducting cable.