Finite Element Study On AC Loss Of Superconducting Cables Composed Of High-temperature Superconducting Tapes With Different Geometric Structure

As a new type of transmission carrier,superconducting cables can reduce losse,increase transmission capacity and save transmission corridors.With the success of superconducting cable demonstration projects at home and abroad,high-temperature superconducting cables,the most mature application of superconducting technology,are moving from the laboratory to the industrial field.However,AC power loss analysis and optimal design are particularly important for superconducting cables applied in AC environments because superconducting materials generate AC losses in the AC power system industrial frequency environment,and the energy is released energy in the form of heat generation and are carried away by the low temperature system which consumes energy.In the design process of superconducting cables,accurate analysis of AC loss distribution can help improve the manufacturing process of superconducting cables,reduce the transmission losses,improve cable performance,reduce the need for cryogenic systems,and save operating costs throughout the equipment life cycle.Since superconducting cables usually generate a complex electromagnetic environment due to its multilayer structure when energized,and the overall system thermal load is influenced by heat leakage,it is difficult to accurately evaluate the AC loss by experimental methods,but the finite element analysis method can be used to well analyze the AC loss of superconducting cables from the simulation perspective.Therefore,this paper uses the finite element simulation software to model and analyze superconducting cables with different geometries to simulate the AC losses of superconducting cables with different structures under different electromagnetic environments.First,for first generation of superconducting strips with Bi-2223,the AC losses of dodecagonal single-layer,double-layer and triple-layer high-temperature superconducting cables are studied with changing geometric spacing.The effects of superconducting layer and superconducting strip spacing on the loss of each layer and the total loss are analyzed.The simulation results show that the total AC loss of superconducting cable can be reduced by increasing the distance between layers,shortening the superconducting strip spacing,and increasing the number of layers of superconducting layers.Secondly,for the second generation superconducting strips with YBCO,single-layer hightemperature superconducting cables from pentagonal to dodecagonal are studied.The AC losses of superconducting cables with different geometries are analyzed for three cases: different transmission currents,at different applied magnetic fields,and at different transmission currents plus applied magnetic fields.The variation of losses is analyzed in terms of the magnitude of loss values,distribution of AC losses,flux density distribution,and magnetic field distribution.The results show that the closer the strip arrangement is to the circular dodecagonal arrangement,the smaller the superconducting strip spacing and the AC loss of the superconducting cable.For the circular arrangement of superconducting strips,the loss is mainly concentrated at the gap of the strips.The closer to the circular strip arrangement,the more the interaction of the magnetic field between the superconducting strips will make the AC loss of the superconducting cable lower.Finally,the loss of three identical-axis superconducting cables is simulated by applying three-phase AC current,and it is found that the staggered arrangement form can reduce the leakage of magnetic field and avoid electromagnetic interference.It is found that the staggered arrangement can reduce the leakage of magnetic field and avoid electromagnetic interference.And the loss of staggered arrangement is smaller for the same structural parameters.The induction of the leaked magnetic field by the external superconducting layer can prevent electromagnetic interference.