Fabrication of (6 + 1)-Structure Superconducting Cable Based on 30-Core MgB₂ Superconducting Wire

30-core MgB₂ superconducting wire with a diameter of 1.0 mm has been prepared by the conventional in-situ powder-in-tube (PIT) method. The metallographic analysis results show that the 30-core MgB₂ wire has good uniformity in both transverse and longitudinal directions, and the critical current (I_c) and critical current density (J_c) at 4.2 K and 4 T reach 82.6 A and 7.3 × 10⁴ A/cm², respectively. Furthermore, (6 + 1)-structure MgB₂ superconducting cables have also been successfully fabricated with different twist pitches (T_p) by the twisted and reacted (T&R) route, comprising six 30-core MgB₂ wires around one copper wire in the center. The I_c of the (6 + 1)-structure MgB₂ superconducting cable with 50 mm T_p reaches 467 A at 4.2 K and 4 T, suggesting no degradation of the MgB₂ wire when self-field effects are taken into account.