The Preparation of MgB2 Conductors for Magnet Application of SMES in WST

Due to the low cost, high critical current density (J_c), low anisotropy and a critical temperature of about 40 K, MgB₂ tapes/wires is promising to operate in the High-temperature Superconducting Magnetic Energy Storage (SMES). Based on the development of the world's first 10 MJ/5 MW class High-temperature SMES prototype in China Southern Power Grid, the MgB₂ wires prepared in Western Superconducting Technologies (WST) Co., Ltd is used to wind coils. This paper mainly introduces the preparation progress of MgB₂ wires in WST. The round MgB₂ wires consisted of 30 superconducting filaments and 7 copper filaments is prepared by In-situ PIT (Powder in Tube) technology, the metals (Nb, Cu and CuNi alloys) acted as stable matrix. For batch prepared MgB₂ wires, the length of single one was greater than 2000 m, the MgB₂ fraction of wires was 0.15, the average J_c value of wires reached to 3265 A/mm² (4.2 K, 3 T). The tensile strength was more than 800 MPa. In addition, the decrement of I_c value is less than 2% for the single MgB₂ wire after stranding.