The Development of Second Generation HTS Wire at American Superconductor

Development of the second generation (2G) YBCO high temperature superconducting wire has progressed rapidly and its performance is approaching, and in some areas exceeding, that of first generation (1G) HTS wire. American Superconductor´s approach to the low-cost manufacturing of 2G wire is based on a wide-strip (4 cm) process using a metal organic deposition (MOD) process for the YBCO layer and the RABiTS (rolling assisted biaxially textured substrate) process for the template. In addition, the wide-strip RABiTS/MOD-YBCO process provides the flexibility to engineer practical 2G HTS wires with architectures and properties tailored for specific applications and operating conditions through slitting to custom widths and laminating with custom metallic stabilizers. This paper will review the status of the 2G manufacturing scale up at AMSC and describe the properties and architecture of the 2G wire being developed and tested for various applications including in cables, coils and fault current limiters. Performance of 100 meter class, 4 mm wide wires at 77 K, self-field has reached 100 A (250 A/cm-width) with single-coat YBCO and 140 A (350 A/cm-width) with double-coat YBCO. A 5 cm inner diameter coil fabricated from the latter wire achieved 1.5 T at 64 K, confirming the capability of the wire for coil applications.