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Aluminium production needs the most energy‐intensive technologies among all the metal processing sectors. During the process of aluminium profile extrusion, the whole production line needs bulk electricity, and the mold inside the extrusion equipment needs robust cold energy for rapid cooling of the metal surface. This paper presents a new combo‐transmission that can simultaneously deliver cold energy together with electricity to the aluminium profile extrusion line. Thanks to the superiority of virtually zero loss and compact size, the powerful superconducting cable is used to replace the conventional copper cable. The entire superconducting cable assembly is fully installed into a cryogenic pipeline and cooled by liquid nitrogen at 77 K. In addition to keeping a favourable cryogenic environment for the superconducting cable, liquid nitrogen can also provide a large amount of cold energy for cooling the metal surface. For a typical 100 MN aluminium extrusion production line, the design and optimization of 10 kA class superconducting cable with the pipeline cooling system for aluminium production are presented in detail. The simulation results and comparisons show that the total energy loss of superconducting transmission is about 46% of conventional copper cable, and the energy saved in a year can be up to about 240.6 MWh. Moreover, the net profit increases almost linearly along with the increases of the extrusion speed when the liquid nitrogen cooling is applied to the 100 MN production line. For the case of 23% increase in extrusion speed, the net profit can be up to 1.48 M$ in a year. Overall, the novel design, technical evaluation, and economic analysis of the combo‐transmission system (cold energy + electricity) can provide a promising solution for future high‐dense aluminium production sectors. [ABSTRACT FROM AUTHOR]

High-temperature superconducting materials have shown great potential for the design of large-scale industry applications. However, they are complicated under AC conditions, resulting in penalties such as power loss or AC loss. This loss has to be considered in order to design reliable and efficient superconducting devices. Furthermore, when superconductors are used in rotating machines, they may be exposed to rotating magnetic fields, which is critical for the design of such machines. Existing AC loss measuring techniques are limited to measuring under one-dimensional AC magnetic fields or transport currents. Therefore, it is essential to develop and investigate robust experimental techniques to investigate the loss mechanism in HTS machines. In this paper, a new and novel experimental technique has been presented to measure AC loss in rotating magnetic field conditions. The loss under rotating magnetic fields is measured and compared by numerical modeling methods, and the results show a strong correlation with the numerical modeling and show the effectiveness of the experimental setup. [ABSTRACT FROM AUTHOR]

The evolution from low-temperature superconductors (LTSs) to high-temperature superconductors (HTSs) has created a great amount of opportunities for superconducting applications to be used in real life. Dynamic voltage is a special superconducting phenomenon, and it occurs when the superconductor takes a DC transport current while simultaneously exposed to an AC magnetic field. The dynamic voltage is crucial for some superconducting applications as it is the energy source by which to energise the load, such as flux pumps. This article investigates the missing aspects that previous studies have not deeply exploited: the optimisation of energy efficiency for the dynamic voltage in an HTS tape with different working conditions (e.g., currents and magnetic fields). First, the mechanics of superconducting dynamic voltage were explicated by typical analytical solutions, and the modelling method was validated by reproducing the behaviours of the Bean model and analytical solutions of dynamic voltage. After the feasibility of the modelling was proved, in-depth modelling was performed to optimise the energy efficiency of an HTS tape with different DC transport currents and AC magnetic fields. Owing to the physical limitations of the superconducting tape (e.g., quench), a safe operating region was determined, and a more delicate optimisation was performed to discover the optimal operating conditions of the HTS tape. The novel conceptualisation and optimisation approaches for the superconducting dynamic voltage in this article are beneficial for the future design and optimisation of superconducting energy/power applications under complicated electromagnetic conditions. [ABSTRACT FROM AUTHOR]

The conductor on round core (CORC) cable wound with second-generation high-temperature superconducting (HTS) tapes is a promising cable candidate with superiority in current capacity and mechanical strength. The composing superconductors and the former are tightly assembled, resulting in a strong electro-magnetic interaction between them. Correspondingly, the AC loss is influenced by the cable structure. In this paper, a 3D finite-element model of the CORC cable is first built, and it includes the complex geometry, the angular dependence of critical current and the periodic settings. The modelling is verified by the measurements conducted for the transport loss of a two-layer CORC cable. Subsequently, the simulated results show that the primary transport loss shifts from the former to the superconductors as the current increases. Meanwhile, the loss exhibited in the outer layer is larger than that of the inner layer, which is caused by the shielding effect among layers and the former. This also leads to the current inhomogeneity in CORC cables. In contrast with the two-layer case, the simulated single-layer structure indicates stronger frequency dependence because the eddy current loss in the copper former is always dominant without the cancellation of the opposite-wound layers. The core eddy current of the single structure is denser on the outer surface. Finally, the AC transport losses among a straight HTS tape, a two-layer cable and a single-layer cable are compared. The two-layer structure is confirmed to minimise the loss, meaning an even-numbered arrangement makes better use of the cable space and superconducting materials. Having illustrated the electro-magnetic behaviour inside the CORC cable, this work is an essential reference for the structure design of CORC cables. [ABSTRACT FROM AUTHOR]

With regard to the state-of-the-art technologies in the fields of applied superconductivity and electromagnetic devices, research and development highlights are presented. The recent progress and achievement described with principle and technical details include mainly i) applied superconducting materials; ii) superconducting magnets and their applications such as in ITER and Tokamaks; iii) high Tc superconducting (HTS) magnetic levitation and applications; iv) HTS smart grids; v) superconducting and electromagnetic material modelling and characterization; and vi) advanced electromagnetic devices. The applied superconductivity technology and availability are especially focused and verified with the trend of development prospection. [ABSTRACT FROM AUTHOR]

The Bi-2212 round wire has a multifilamentary structure, and the use of numerical method to study ac loss of such multifilamentary superconducting wire requires a long calculation time and large memory. Adopting a homogenization method at low frequency to study the ac loss of multifilamentary structural wire/tape has been proven to have high enough accuracy and can save a lot of calculation time. With the expansion of the application range of superconducting materials, however, superconducting power devices exceeding the frequency of tens of kHz have huge potential applications in the future such as wireless power transfer. Therefore, it is necessary to study the applicability of the homogenization model at high frequencies. This article mainly presents an ac loss numerical study of Bi-2212 round wire at wider frequency (50 Hz–500 kHz) by homogenization method. The homogenization is achieved by two different methods. The first method is to treat the superconducting bundle and the Ag matrix between the bundles as a superconducting domain (bundle-matrix homogenized model, BHM). The second method is to regard the Ag matrix between the superconducting filaments and the filaments as a superconducting domain (filament-matrix homogenized model, FHM). In order to evaluate the feasibility of the two different homogenization methods, we compare the calculation results of the two different homogenization models with the original model, OM. The results show that the FHM can effectively improve the calculation speed while satisfying the high calculation accuracy. This conclusion can be used to quickly evaluate the ac energy loss of large-scale superconducting devices at wider frequencies. [ABSTRACT FROM AUTHOR]

Based on conventional approaches for the integration of resistive-type superconducting fault current limiters (SFCLs) on electric distribution networks, SFCL models largely rely on the insertion of a step or exponential resistance that is determined by a predefined quenching time. In this paper, we expand the scope of the aforementioned models by considering the actual behaviour of an SFCL in terms of the temperature dynamic power-law dependence between the electrical field and the current density, characteristic of high temperature superconductors. Our results are compared to the step-resistance models for the sake of discussion and clarity of the conclusions. Both SFCL models were integrated into a power system model built based on the UK power standard, to study the impact of these protection strategies on the performance of the overall electricity network. As a representative renewable energy source, a 90 MVA wind farm was considered for the simulations. Three fault conditions were simulated, and the figures for the fault current reduction predicted by both fault current limiting models have been compared in terms of multiple current measuring points and allocation strategies. Consequently, we have shown that the incorporation of the E- J characteristics and thermal properties of the superconductor at the simulation level of electric power systems, is crucial for estimations of reliability and determining the optimal locations of resistive type SFCLs in distributed power networks. Our results may help decision making by distribution network operators regarding investment and promotion of SFCL technologies, as it is possible to determine the maximum number of SFCLs necessary to protect against different fault conditions at multiple locations. [ABSTRACT FROM AUTHOR]

Lorentz Force Electrical Impedance Tomography (LFEIT) is a hybrid diagnostic scanner with strong capability for biological imaging, particularly in cancer and haemorrhages detection. This paper presents the design and simulation of a novel combination: a superconducting magnet together with LFEIT system. Superconducting magnets can generate magnetic field with high intensity and homogeneity, which could significantly enhance the imaging performance. The modelling of superconducting magnets was carried out using Finite Element Method (FEM) package, COMSOL Multiphysics, which was based on Partial Differential Equation (PDE) model with H -formulation coupling B -dependent critical current density and bulk approximation. The mathematical model for LFEIT system was built based on the theory of magneto-acoustic effect. The magnetic field properties from magnet design were imported into the LFEIT model. The basic imaging of electrical signal was developed using MATLAB codes. The LFEIT model simulated two samples located in three different magnetic fields with varying magnetic strength and homogeneity. [ABSTRACT FROM AUTHOR]

The dynamic voltage is a unique phenomenon of superconducting materials. It arises when the superconductor is carrying a DC transport current and spontaneously in subject to an AC magnetic field. This study excavates the aspects that previous studies have not comprehensively investigated: the dynamic voltage in a DC-carrying superconducting tape exposed to different oscillating AC magnetic fields. First, the fundamental physics of dynamic voltage/flux of superconductors is reviewed and further analysed in detail. We used the superconducting modelling method using the H-formulation merged into the finite-element method (FEM) software, to re-produce the typical dynamic voltage behaviour of a superconducting tape. The modelling was verified by both the analytical and experimental results, in order to precisely prove the reliability of the modelling. Afterwards, the modelling was performed for a DC-carrying superconducting tape under four different oscillating magnetic fields (sine, triangle, sawtooth and square), and their corresponding dynamic voltages and energy losses were analysed and compared. Results show the sinusoidal magnetic field can lead to the optimal combination of reasonable dynamic voltage but relatively lower loss, which is suitable for those superconducting applications requiring dynamic voltage as the energy source, e.g., flux pumps. This article presents novel investigation and analysis of the dynamic voltage in superconducting materials, and both the methodology and results can provide useful information for the future design/analysis of superconducting applications with DC transport currents and AC magnetic fields. [ABSTRACT FROM AUTHOR]

• Multi-energy vehicle charging/refueling station using 100% renewable and liquid hydrogen. • Hybrid LH 2 /electricity energy pipeline based on cryogenic and superconducting technologies. • A 100 MW-class hybrid hydrogen/electricity supply station is designed. • Energy management strategy is carried out with static/dynamic economic feasibility. • It offers a technically/economically superior solution for future vehicle charging/refueling systems. Renewable energies such as the wind energy and solar energy generate low-carbon electricity, which can directly charge battery electric vehicles (BEVs). Meanwhile, the surplus electricity can be used to produce the "green hydrogen", which provides zero-emission hydrogen fuels to those fuel cell electric vehicles (FCEVs). In order to charge/refuel multi-energy vehicles, we propose a novel scheme of hybrid hydrogen/electricity supply using cryogenic and superconducting technologies. In this scheme, the green hydrogen is further liquefied into the high-density and low-pressure liquid hydrogen (LH 2) for bulk energy storage and transmission. Taking the advantage of the cryogenic environment of LH 2 (20 K), it can also be used as the cryogen to cool down superconducting cables to realize the virtually zero-loss power transmission from 100 % renewable sources to vehicle charging stations. This hybrid LH 2 /electricity energy pipeline can realize long-distance, large-capacity, and high-efficiency clean energy transmission, to fulfil the hybrid energy supply demand for BEVs and FCEVs. For the case of a 100 MW-class hybrid hydrogen/electricity supply station, the system principle and energy management strategy are analyzed through 9 different operating sub-modes. The corresponding static and dynamic economic modeling are performed, and the economic feasibility of the hybrid hydrogen/electricity supply is verified using life-cycle analysis. Taking an example of wind power capacity 1898 MWh and solar power capacity 1619 MWh per day, the dynamic payback period is 15.06 years, the profitability index is 1.17, the internal rate of return is 7.956 %, and the accumulative NPV is 187.92 M$. The system design and techno-economic analysis can potentially offer a technically/economically superior solution for future multi-energy vehicle charging/refueling systems. [ABSTRACT FROM AUTHOR]