High-temperature superconducting power transmission is one of the most revolutionary engineering technologies in the current power industry. The so-called high-temperature superconductivity refers to the use of superconducting materials in a liquid nitrogen environment close to minus 200 degrees Celsius relative to absolute zero, so that the power transmission medium is close to zero resistance and the power transmission loss is close to zero.
A large amount of power is actually wasted on the transmission line during long-distance power transmission. The use of high-temperature superconductor (HTS) cable will greatly save energy. But superconductivity requires absolute zero that is too low to achieve. In the late 1980s, scientists discovered high-temperature superconducting materials. This high temperature is relative to absolute zero, absolute zero is -273.15 degrees and this high-temperature of superconductivity is close to -200 degrees. In the vicinity of this temperature, the special copper-based oxides have superconducting properties. This discovery has made a breakthrough for the realistic application of HTS cables.
A HTS cable consists of four parts: cable core, cryogenic vessel, termination and cooling system. The cable core is the core of HTS cable, including the main components such as the skeleton layer, the conductor layer, the insulation layer and the shielding layer(armado). Inside the outer sheath of HTS cable is a double-layer stainless steel high-vacuum adiabatic Dewar tube. Liquid nitrogen flows in the Dewar tube and the superconducting cable core is immersed in liquid nitrogen. A cryogenic chiller acts as a system auxiliary to drive the liquid nitrogen cycle and cool the entire system. The use of HTS cables can change the traditional transmission method by using low voltage and high current to transmit electrical energy. As a result, high-temperature superconducting cables can significantly reduce the losses in the power system and improve the total efficiency of the power system, which has considerable economic benefits.
The global market for superconducting applications reaches $244 billion in 2020, with HTS cables accounting for about 5% of the share. A total of about 130,000 km of existing underground cables worldwide will likely be replaced by HTS one after another. Therefore, the market for HTS cables is very promising.