China's First Three-phase Coaxial Superconducting Cable Passed the Large-load Test
Recently, China's first three-phase coaxial superconducting cable, developed under the leadership of Shenzhen Power Supply Bureau of China Southern Power Grid, successfully passed the large-load test in the central area of Futian, Shenzhen. This is also the first time in China that the superconducting cable directly connected to the user has been tested for large loads.
In the test, the 10kV Binxing superconducting cable of Shenzhen Power Supply Bureau has been operated with a large load of more than 1000 A and a maximum of 1212 A for 12.5 consecutive hours. The power supply area was expanded from Shenzhen Ping'an Financial Center to the central area of Futian within about 5 square kilometers, which was 31 times larger than that of conventional cables. The ability of the three-phase coaxial superconducting cable to supply users directly with large capacity was verified in stages. The test lasted 54 hours. During this period, various indicators of superconducting cable are normal and stable in the process of the sudden increase of current from 700A to 1100A, the sudden drop of current from 1000A to 500A, and the switching of the liquid nitrogen pump.
It is reported that the superconducting cable is the first three-phase coaxial superconducting cable commercially operated in a high-load density area in China. It was officially put into operation in September 2021, crossing through the central business district of Shenzhen, with a total length of 400 meters. It has been in continuous and stable operation for more than 16 months.
Dai Shaotao, a professor at Beijing Jiaotong University, pointed out that the large-load test of the superconducting cable comprehensively tested the capabilities of the three-phase coaxial high-temperature superconducting cables from design to manufacturing and installation, from the body to the system, from operation to scheduling and other aspects. The test achieved the expected results, enhanced the confidence in the long-term stable and reliable operation of the superconducting cable, and also laid a good technical and operational foundation for the subsequent application and popularization of superconducting transmission technology in large cities with high-load power supply density like Shenzhen.
The power transmission principle of superconducting cables is to use the characteristics of superconducting materials in a liquid nitrogen environment of minus 196 °C to make power transmission close to zero resistance, to achieve large-capacity transmission at low voltage levels. Under daily operation conditions, the transmission loss of superconducting cables is only one-fourth to one-fifth of that of conventional cables, and the current carrying capacity can exceed 5 ordinary cables, which can solve the power supply problems of high-density power consumption areas in large cities.
Huang Weizhao, a technical expert in the asset management department of Shenzhen Power Supply Bureau, introduced that compared with three-phase discrete cables, three-phase coaxial superconducting cables save half of the superconducting materials and more than one-third of the cable laying space. It can be widely used in urban power grids, high-speed rail power supply networks, data centers, and other scenarios. It has important economic and social value and also lays a solid technical foundation for the popularization and application of superconducting transmission technology in China.
Source: http://www.cinic.org.cn/zgzz/cx/1408702.html
