Current Density Distribution in 2G HTS Tape in an External Magnetic Field

AbstractThis paper describes the method of study of the critical current density distribution across a tape in a background magnetic field. We measured the current distribution by the scanning Hall probe method. Then we measured field across a tape by a set of 10 Hall probes placed on a single substrate. By comparison of data from these two experiments we determined positions of Hall probes at a tape. Then we measured the current distribution of current density across a tape inside a magnet in parallel and perpendicular magnetic field of 30 mT. The details of measuring method and results are presented

Influences of voltage–current characteristic difference on quench development in low-Tc and high-Tc superconducting devices (Review)

We review the approaches in analysis of quench development in LTS and HTS superconducting devices. Considering description of quench from very general point of view, we analyze how the change from sharp voltage–current characteristics with high-index n to smooth characteristics with low n and other material parameters affects quench dynamics. We compare traditional approaches for the description of the quench development in LTS devices with new approaches suggested for HTS devices. Reduction of index value n and high-operating temperature leads to a change of the quench development time, temperature rising rate that make it unnecessary to use the term “normal zone propagation” for describing quench in HTS devices

Analysis of stability and quench in HTS devices—New approaches

R&D of HTS devices are in their full steam—more magnets and devices are developed with larger sizes. But analysis of their stability and quench was still old fashioned, based on normal zone determination, analysis of its appearance and propagation. Some peculiarities of HTS make this traditional, quite impractical and inconvenient approach to consideration of HTS devices stability and quench development using normal zone origination and propagation analysis. The novel approaches were developed that consider the HTS device as a cooled medium with non-linear parameters with no mentioning of “superconductivity” in the analysis. The approach showed its effectiveness and convenience to analyze the stability and quench development in HTS devices. In this paper the analysis of difference between HTS and LTS quench, dependent on index n and specific heat comparison, is followed by the short approach descriptions and by the consequences from it for the HTS devices design. The further development of the method is presented for the analysis of long HTS objects where “blow-up” regimes may happen. This is important for design and analysis of HTS power cables operations under overloading condition