Study of BSSCO/Ag Tapes With the Help of Voltage Signal Analysis

Abstract

Properties of BSSCO/Ag tapes transporting AC current were studied by the Fourier analysis of the accompanying voltage signal. Particularly, the electrical signal in the measurement loop that is used in the standard AC loss measurement has been investigated. BSSCO/Ag tapes were studied starting from the characterization of the filament configuration, ( ) dependence and inhomogeneity of distribution. These data were used as the input parameters for the numerical simulations. Initial simulations showed the necessity of replacing the simplified geometry model with detailed mutlifilamentary structure. Consequently, the higher harmonics turned out to be extremely sensitive on characterization parameters. After such refinement, the results of simulations give good agreement with measured higher harmonics of the voltage signal. This means that the analysis of higher harmonics could provide relevant information about the structure and other basic properties of the measured tape.

Theoretical and experimental study of AC loss in high temperature superconductor single pancake coils

“…The properties of the superconductor can be qualitatively studied from the voltage signal [13][14][15][16][17][18][19]. However, the voltage in a coil where it circulates an AC current I = I m cos ωt has a very large inductive component (proportional to sin ωt) which does not depend on the material properties; neither does it contribute to the AC loss.…”

“…This is a bit surprising when taking into account the simplifications used in the AC loss calculation. For example, the superconducting zone of the BiSCCO tape is replaced by a bar with elliptic cross-section, ignoring the nonhomogeneity effects originated by the actual filamentary structure [17]. The dependence on the number of turns N of the AC loss is shown in figure 13 for a specific current (I rms = 19.4 A).…”

“…Furthermore, in addition to the AC loss, the shape of the voltage signal in the coil is also interesting for both the understanding of the loss mechanisms and applications [13][14][15][16][17][18][19].…”

AC Loss and Voltage Signal in a Pancake Coil Made of Coated Conductor With Ferromagnetic Substrate

“…However, its height is lower than expected. There are several factors that could explain this, like a smooth relation (where is the electrical field), and a nonuniform with larger values at the tape ends [17], [18] 2 . Since the magnetic material does not produce any signal at the current peak, the voltage there must be caused by the superconductor.…”