On September 28, my country’s first self-developed new superconducting cable was put into use in Shenzhen. This is also the world’s first superconducting cable used in the central area of a super-large city, marking that my country has fully mastered the design and manufacturing of new superconducting cables. , The key core technology of construction.

The new superconducting cable has a diameter of only 17.5 cm and a length of 400 meters, with a transmission capacity of up to 43 MVA, which is equivalent to meeting the electricity demand of four 350 kilometers per hour high-speed rail at the same time, achieving a transmission capacity 5 times that of conventional cables. Bring high-reliability power supply to Shenzhen Ping An Financial Center, the tallest building in the Guangdong-Hong Kong-Macao Greater Bay Area.

As a major science and technology project of China Southern Power Grid, the project is a powerful measure to implement the innovation-driven development strategy and promote scientific and technological self-reliance. It not only realizes 100% localization of key equipment, but also provides power for the global solution to the high-load density areas of super-large cities. Problems provide new solutions.

High-temperature superconducting power transmission technology is known as the next generation of power transmission strategic technology, which has the advantages of low line loss, large transmission capacity, small corridor area, and environmental friendliness. This technology takes advantage of the conductive properties of superconducting materials, so that the power loss during low-voltage transmission is almost zero. The transmission capacity of superconducting cables is much larger than that of conventional cables. The power transmission capacity of a 10-kV triaxial high-temperature superconducting AC cable is larger than that of a conventional 110-kV cable, but the transmission loss is only 1/4 to 1/of that of conventional cables. 5. Very suitable for power supply in high load density areas.

In recent years, the power supply in the central areas of super-large cities around the world is facing challenges. The load demand in central urban areas continues to grow, the demand for "double reduction" in energy consumption is increasing year by year, the saturation of urban corridors, and the difficulty of land use for power grid construction have been exposed year by year. Shenzhen is the city with the largest power load density in China, and the load density of its central business district is even "peak on the peak". The "package" of this project solves high power supply reliability, high load density, high power quality, and limited land resources. The reality of the puzzle.

"If the existing power supply method is adopted, it is necessary to supply power to the important loads in the Futian central area, especially the newly added loads, and use conventional technology to achieve expansion, which is very difficult in Shenzhen, which is very expensive." China Southern Power Grid Shenzhen Power Supply Bureau Innovation and According to Lu Zhining, general manager of the Digitalization Department, 10 kV superconducting cables can reduce the use of high-voltage cables in the urban power grid while meeting power supply requirements, simplify the grid structure, reduce the construction of 110 kV substations, and save 500 square meters of land.

The superconducting cable developed and put into production this time adopts the three-axis configuration, which is the superconducting cable with the most compact structure, the least amount of strips, and the most difficult research and development. After 4 years, the project team has made major breakthroughs in the overall design and manufacture of superconducting cable systems, and the development of domestically-made high-cooling GM refrigerators through independent innovation, and achieved 100% localization of key equipment, filling the domestic technology. blank.

Only when superconducting cables are made at a reasonable cost can they have the possibility of sustainable promotion. It is understood that the cost of superconducting tape accounts for about 50% of the cost of the entire superconducting cable, and the three-concentric superconducting cable saves nearly half of the superconducting tape compared with other configurations of superconducting cables.

In addition, the superconducting cable put into operation this time uses a superconductor that can be cooled in a liquid nitrogen environment (about 70°C higher than absolute zero, so it is called "high temperature") instead of conventional copper and aluminum conductors to transmit electricity. Liquid nitrogen is a relatively simple and inexpensive cooling medium, so high-temperature superconductivity has important application value. In order to solve the "stuck neck" problem of superconducting cable low-temperature refrigeration equipment, the project team successfully developed a nationally produced large-capacity GM refrigerator for the first time in the country, and realized the online "plug and play" of the refrigerator, allowing the superconducting cable to be below zero. Long-term high-reliability operation can be maintained under a 200 degree liquid nitrogen environment.

The reporter learned from the Innovation Management Department of China Southern Power Grid that compared with conventional technology, the high-temperature superconducting demonstration project put into production this time has basically reached an economic equilibrium point. In the next step, China Southern Power Grid will further increase investment. , Actively promote the construction of scientific research and demonstration projects for superconducting applications in distribution networks.