Within Alcatel Alsthom Group, Alcatel Cable and Alcatel Alsthom Recherche Center have undertaken a HTc research program, with support from EDF : the aim was to develop conductors suitable for ac applications, where major market opportunities are expected. For ac applications at 50 Hz low ac loss conductors with a resistive matrix material and a twist length of the superconducting filaments of less than 10" are required. Bi-2223 and Bi-2212 conductors are fabricated up to lengths of 200 m of 64 filaments tape by the patented rectangular Alcatel Alsthom route. Recently Bi-2212 conductors for 20 K applications have been tested at liquid helium temperatures. Different Bi-2212 conductors with a twist length of 7 to 9 mm, with a silver-alloy matrix and a cross section of 0.5 mm x 3 mm have been realised. In such conductors transport currents of 400-500 A have been measured at 4 K in self fields with a very good reproducibility. The engineering current density in the wire has reached the threshold value of Je = 30'000 A/cm2. The superconducting volume fraction of the conductor is 18 % which results in a critical current density in the superconductor of Jc = 170'000 A/cm2. At liquid nitrogen temperature transport currents of 18 A are carried in this conductor. For this temperature range the development of a Bi-2223 conductor is under progress. For instance, different untwisted conductors with transport currents up to Ic(77K) = 60 A and critical current densities up to are realised.
Six partners from five European countries are cooperating within a R&D BRITE EURAM project named SHIFT" (Superconducting High Tc Coils for High Field Technologies). The objective of this 3-year project is to develop basic technologies for manufacturing magnets producing high fields operating in the temperature range 20-30 K: HTS wires, coils based on bulk parts, coil structures and cooling system. The potential applications are pulsed magnets for power quality SMES and DC magnets for MRI, instrumentation and laboratory use. Specifications and designs of SMES for the voltage sags smoothing application have been performed and will be presented together with SMES designs for flicker mitigation. Main deliverables are the realization of a 6 Tesla demonstration coil cooled by closed cycle refrigeration and the design of a SMES coil for power quality applications. Target performances, conductors, test coil developments and designs will be discussed in this paper.
In 1.995 the PIT conductor development was strengthened at Alcatel and important progress has been achieved since. During 1997 the patented rectangular Alcatel route was upscaled and pre-industrial conductors have been fabricated in a wire drawing mill. After the successful transfer the first high performance conductors have been realized in kilometer lengths. The conductors are realized in cooperation with Aventis Research & Technologies using precursor powders optimized for the Alcatel conductor route. The simpler Bi3212/AgPd matrix conductor is used as a working horse where engineering current densities of Je = 65 kA/cm2 have been reached at 4 K, 0 T. Significant progress has also been achieved on Bi-2223 conductors where critical current densities of J c = 3 0 kA/cm2 at 77 K, OT are reached. First solenoids generating a field up to 2.3 Tesla have been realized using Bi-2212 conductors. In a background field of 3 Tesla this magnet still generates a field of 2 Tesla. The results on test coils are consistent with Jc(H) measurements on short samples showing that an important step towards high homogeneity conductors has been achieved.
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