Critical current and AC loss analysis of a superconducting power transmission cable with ferromagnetic diverters

Abstract

Superconducting transmission cables are important for increasing the capability of electricity networks. We analysed monolayer power transmission cable based on high-temperature superconductors, and we propose a new way to improve its performance in this paper. We studied two important parameters of this cable—critical current and AC loss. For the former parameter, the dependence of the critical current density on the local magnetic field is very important. For the latter parameter, the direction of the magnetic field penetration also has a substantial influence. We propose placing ferromagnetic diverters above the gaps between individual superconducting tapes. Ferromagnetic components placed in this position influenced both the critical current density and the AC loss in the superconductor in a positive way. We used a numerical model for magnetic field analysis, and we also prepared a 0.5 m long sample of the cable for experimentation. Our experimental results confirmed the correctness of the basic idea. The critical current of the cable was increased by 14%. However, the AC loss measurement showed differences between the experiment and the calculation.

Influence of soft ferromagnetic sections on the magnetic flux density profile of a large grain, bulk Y–Ba–Cu–O superconductor

“…Ferromagnets can also increase the force in levitation systems [16,17] and close the magnetic circuit, which improves the available flux produced by bulk superconductors [18]. Similarly, ferromagnetic materials are used as sheaths around multifilament wires and tapes [19,20] or as magnetic flux diverters to modify the flux distribution around tapes and superconducting coil magnets [21][22][23][24][25][26][27][28]; thereby improving their electrical properties (i.e. increasing the critical current and reducing ac losses).…”

Numerical study of AC loss of two-layer HTS power transmission cables composed of coated conductors with a ferromagnetic substrate

“…The calculated AC loss results in this work and in [26] are presented in Figure 2. For the comparison between our calculation method and the experimental data, along with the above values, we have exploited the field-dependent critical current density expression [18]: …”

“…The influence of the ferromagnetic (FM) material on the transport AC loss of HTS tapes, monolayer cables, and coils was extensively studied both experimentally and theoretically [17][18][19][20][21][22][23]. For the works on twolayer HTS cables made of coated conductors with a ferromagnetic substrate, Amemiya et al [24] performed numerical AC loss calculations of two-layer superconducting power transmission cables comprising coated conductors with a ferromagnetic substrate concerning the arrangement with respect to the cable axis.…”

Numerical study on AC loss reduction of stacked HTS tapes by optimal design of flux diverter

“…Taking the anisotropic magnetic field dependence of the AC loss into account, one way of decreasing AC loss in HTS coils is using ferromagnetic material to divert magnetic flux orientation to be as parallel as possible to the tape surface. Therefore, magnetic materials have been widely employed in HTS AC applications, such as transformers [7,8], cables [9], superconducting magnetic energy storage [10] and fault current limiters [5,11], in order to reduce the AC loss.…”