Experimental Study On Electromagnetic And Mechanical Properties Of A Novel HTS Square Wires

External magnetic field would influence the performance of HTS wires including critical current,AC loss and so on,especially when the magnetic field is perpendicular to the HTS wire’s surface.In order to reduce the effect of external magnetic field,many studies have been done,which mainly focus on stack or twist multifilament structures: tapes stacked and transposed according to the Roebel Assembled Coated Conductors technique,tapes stacked and twisted along the longitudinal direction,round strand composed of coated conductor cable and so on.However,these studies are usually based on HTS tapes with more than 4 mm width,and their dimensions are significantly limited by the widths of the HTS tapes used in fabrication.Different from above studies,we proposed a novel wire with a square cross section of 1 mm × 1 mm which is named novel HTS square wire.Due to the low width-to-thickness ratio and small square dimension,HTS square wire has great advantages in cabling,but it is inevitable to endure twisting,bending and stretching in actual applications.Therefore,it is necessary to have further study on the mechanical properties of HTS square wire.we firstly fabricate several HTS square wire samples through narrowing,soldering and stacking process,and then we investigate the basic electrical characteristics for the HTS square wires include critical current and AC loss.Finally,We can also conclude the rules that what influence mechanical properties such as axial tension,bending diameter and twisting pitch have on critical current of HTS square wires.The results show that the critical currents of the HTS square wires are decreased approximately 10% after the stacking and soldering process.Measured AC losses are independent of frequency and are in good agreement with the thin strip theoretical values.When the critical current of the HTS square wires samples decays within 90%,the twist pitch is about 60 mm,the bending diameter is approximately 60 mm,and the axial tensile force is about 350 N.These electrical and mechanical properties of HTS square wire can be well applied in power system applications.