Germany builds the world's longest high temperature superconducting transmission line

The Karlsruhe Institute of Technology (KIT), the German energy company RWE and the French cable manufacturer Nexans are currently conducting a high-temperature superconducting (THS) power transmission test project “AmpaCity” in the city of Essen in western Germany. A high-temperature superconducting transmission circuit with a length of 1 km is planned to be laid out in the center of Essen, Germany. The transmission cable is built between two substations in the center of Essen. The transmission voltage is a transmission power of 10 kV medium voltage transmission cable. For 40 MW, to complete such a power transmission capacity requires the laying of five medium-voltage copper-core cable transmission lines, or switching to high-voltage transmission lines, which is a very difficult task in the central part of the city.

The superconducting cable used is in the form of a coaxial cable. The conductor is a concentrically distributed three-layer superconducting material with an insulating medium in between. The center and the outer layer of the core of the superconducting conductor have a loop and interlayer for the flow of liquid nitrogen, and the insulation is used. The insulation layer made of a material located on the outermost layer of the cable works together to maintain the superconducting core of the cable at a temperature of -180 degrees Celsius to ensure its superconducting properties. The diameter of the cable is not greater than the current universal copper cable. With the same diameter of cable, the power transmission capability of the high-temperature superconductor cable is more than 5 times that of the ordinary copper core cable.

This is currently the world's longest test circuit for high-temperature superconducting cables. The project began on January 19 this year for a period of four years. Different high-temperature superconducting materials and insulating and insulating materials will be tested. The goal of the medium-term plan is to use a high-temperature superconducting cable to construct a city's transmission network to replace high-voltage transmission lines, and to achieve the goal of improving the efficiency of power transmission, reducing the cost of operation and maintenance, and reducing the occupation of land resources. At the same time, this test transmission line will also be used to test superconducting overvoltage protection technology, this technology can automatically start and restore the normal state of the transmission line faster than the existing protection device in the event of a fault such as a short circuit on the transmission line.

Experts from the Karlsruhe Institute of Technology (KIT) believe that the application prospects of high-temperature superconductor cables are determined by continuously improving the cost-effectiveness of high-temperature superconductor materials, improving the cable manufacturing process, and optimizing the cost and reliability of related cryogenic technologies. In the near future, Breakthroughs will be made in these areas.