At present, the long-distance large-capacity power transmission generally uses overhead bare aluminum cable and wires, and the power transmission in large cities generally uses underground cables, and the conductors are copper wires or aluminum wires. Using these traditional wires or cables, electrical energy will lose 5% to 10% during the transmission process. In order to reduce the loss of electric energy during the transmission process, the voltage should be increased as much as possible during long-distance transmission, such as using 500kV or 750kV and above ultra-high voltage lines. UHV lines have very high requirements on the insulating porcelain bottles of transmission towers and the use of space, especially the materials and production technology requirements of line terminal accessories, which greatly increase the construction cost of UHV lines. At present, my country cannot produce terminal accessories for ultra-high voltage lines, and imported ultra-high voltage line terminal accessories are very expensive.
If a superconducting cable is used, its AC impedance is only 1/10 of that of a conventional aerial bundled cable ASTM B231 standard, which can reduce the line loss of the power grid by about 50%; the application of superconducting cable will also reduce the system voltage for long-distance transmission, and the overall cost of other equipment in the system will follow It is reduced.In the long run, the application of superconducting cables also makes long-distance DC transmission technology easy and economical. For direct current transmission, superconducting cables will reduce the power grid line loss by more than 70%, showing better economic benefits. Since the power transmission capacity of superconducting cables is 3 to 5 times that of traditional conventional cables, the use of superconducting cables can also save the area and space of the power transmission system, save a lot of valuable land resources, and protect the ecological environment accordingly.
The smooth grid-connected operation of China’s first group of practical superconducting cables indicates that the technology of my country’s superconducting cables has become mature and has a profound impact on the development of my country’s power system. The application of superconducting cables in the main lines of my country’s power grids and transmission bottlenecks will help improve the safety and reliability of the power grid. In the long-distance and large-capacity transmission, superconducting cables have incomparable advantages in the overall performance of the system, and will fundamentally solve the problem of long-distance and large-capacity transmission such as my country’s “West-to-East Power Transmission” in the long run. In the near future, high-temperature superconducting cables may soon show advantages in the following aspects:
(1) In dense urban residential areas, skyscrapers, conventional cable capacity is insufficient, and there is no room for aerial bundled cables BS 7870;
(2) High current, short distance, and small space applications such as metal smelting equipment;
(3) High-current transmission bus in power stations and substations;
(4) In large cities with rapidly developing power demand, the required power supply capacity is constantly expanding. Due to the congestion of the city and the high cost of excavation, it is impossible to expand the scope of cable laying. With the help of superconducting cables, it can be replaced in the original pipeline to increase the power supply capacity. Increase 3-5 times.