Study On Properties Of YBCO High-T_c Superconducting Tapes

YBCO high temperature superconducting tape with superior current carrying capacity and zero loss has very broad application prospects and research value in power transmission and new energy technologies.The key to get large-scale commercialization of YBCO superconducting tapes is its performance and preparation technology.Therefore,it is very important to study the performances of YBCO superconducting tapes and improve their fabrication technology continuously.In this paper,the main factors that affect the electrical properties of YBCO high temperature superconducting tapes will be analyzed,as follows:1.The pinning mechanism of YBCO superconducting tapes was investigated.The electrical properties of different Gd-doped YBCO superconducting tapes were investigated,especially the changes in magnetic field.With increasing doping concentration,the critical transition temperature Tc increases slightly,and the critical current I_c increases.After reaching a certain concentration,continue to increase the doping concentration,I_c will decline.2.A critical current test device with adjustable strain conditions was designed,which can be used to test a variety of strain levels by configuring the power system.The device is suitable for liquid nitrogen condition and it also has many advantages,like operation simplicity and good repeatability.It is not subject to sample length and does not require repeated sampling.I-V curves under tensile stress condition and compressive stress condition can be achieved in one measurement cycle.3.The electrical characteristics under strain condition of YBCO high temperature superconducting strip were analyzed.The tapes involved in this paper were prepared in lab,whose reversible strain degree was 1.3%.When the strain degree is more than 1.3%,the strip is irreversible.The I_c of YBCO superconducting tape increases with the thickness of the strip,the thicker the strip,the smaller the maximum irreversible strain.I_c decreases with the increase of Ba concentration,and the higher Ba concentration,the slower the I_c decreases in the irreversible strain range.4.The microscopic mechanism of YBCO superconducting tapes on electrical properties under bending strain condition was analyzed.The results show that the lattice structure of YBCO superconducting tapes changes under strain condition.The lattice in a axis and b axis were stretched when the current transmitted through the YBCO tape,the resistance increases,then the critical current decreases.In addition,the initial deformation during the tapes preparation process can't be ignored.Through the research of this paper,the YBCO high temperature superconducting tapes were analyzed under different application conditions to find high performance YBCO tapes as new type of electric power equipment,which will lead the new transformation in the transmission cable,transformer and electric power lead.