Design And Research Of Conductor For ±10kV/6kA Bipolar Coaxial High Temperature Superconducting Direct Current Cable

Compared with traditional cables,superconducting cables have many advantages,such as high current density,low line loss,improving system stability,environmental friendliness.They are more suitable for the long-distance and large-capacity transmission situation in China.Superconducting power transmission is currently in the stage of engineering demonstration and many pilot projects have been launched at home and abroad.The planning of Tong Li New Energy Town in Jiangsu Province includes the construction of a 260m HTS DC transmission system demonstration project.The main work of this graduation project is to design,manufacture and test a 13m,10kV/6kA bipolar coaxial HTS DC cable,and to conduct type tests for the 260m cable construction.Firstly,based on the current transmission situation in China,the advantages of using superconducting cables to transmit electricity are briefly analyzed.According to the situation of superconducting tape spiral winding in cable,the current carrying capacity of the second generation HTS tape provided by the tape supplier is tested after spiral deformation.The influence of the two deformation parameters of spiral angle and diameter on the critical current and safe current of the tape is analyzed.The three-dimensional magnetic field finite element simulation of the conductive layer of superconducting cable is carried out.Combined with the critical current anisotropy of the superconducting tape in the external magnetic field,the influence of helix angle on the upper limit of non-stop current of the conductive layer is analyzed.To meet the requirement of voltage and current level in the project,the main structures of bipolar coaxial HTS DC cable,such as support skeleton,insulating layer,semi-conducting layer and superconducting layer are designed.Especially,the helical angle of superconducting layer is optimized based on the previous experiments and simulation results to improve the current capacity of the cable.After the steps of cable winding,copper head welding,the sample cable has been manufactured.The voltage withstanding test and critical current test have been carried out respectively according to the national standard.The rationality of the design has been proved by testing.