共查询到20条相似文献,搜索用时 15 毫秒
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J. Zhang S. Dai Y. Teng D. Zhang N. Song Z. Zhu X. Xu T. Ma Z. Zhang Z. Gao Q. Bao H. Li F. Zhang L. Lin L. Xiao 《Journal of Superconductivity and Novel Magnetism》2014,27(10):2195-2203
There are many irreplaceable advantages of high temperature superconducting (HTS) fault current limiter, applying in electric utilities. It is expected to be able to solve excessive fault current problems and to enhance safety and stability of power systems. In this paper, the R and D of an improved bridge-type 10.5 kV three-phase superconducting fault current limiter (SFCL) was present. Each phase adopted a HTS coil with inductance of 6.2 mH. The three coils wound with 8,571 m Bi2223/Ag tapes totally. After installation at a 110 kV/10.5 kV substation in Hunan Province of China, the performances of the whole SFCL were tested, including a three-phase-to-ground short circuit experiment at the pre-setup short circuit point. And then, the SFCL was put into operations in the 10.5 kV power grids for more than 11000 h. About 3 years later, the SFCL was moved, reinstalled, and put into operation again since February 16 of 2011 at a 10.5-kV superconducting power substation located in Baiyin, Gansu Province of China. In this paper, the redesigned and manufactured cryostats with nonmagnetic stainless steel, tests, and long-term operations of the SFCL in 10.5 kV power grids were also described in detail. 相似文献
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C. A. Baldan J. S. Lamas A. A. Bernardes C. Y. Shigue E. Ruppert Filho 《Journal of Superconductivity and Novel Magnetism》2013,26(4):1241-1245
A superconducting fault current limiter (SCFL) consisted of a transformer with low reactance connected to the power line and with the secondary winding short-circuited by a modular superconducting limiter device with 16 elements connected in series was constructed and tested. The designed coupling transformer has low dispersion reactance in order to limit the voltage drop in the power line within the range of 5 % to 10 %. The experimental results showed that an insertion of a 0.125 Ω resistance limited the peak current to a factor of 2.5 times of the unlimited current. The power dissipation reached 39 kW during 100 ms, with an energy density of 380 J/cm3. Based on these results, the SCFL will be further tested in a 3 MVA (15 kV/380 V) generator for currents up to 10 kA. 相似文献
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J. Sheng Y. Chen B. Lin L. Ying Z. Jin Z. Hong 《Journal of Superconductivity and Novel Magnetism》2014,27(6):1353-1357
A multi-physics finite element model of high-temperature superconductors (HTS) will be presented in this article. The electrical-thermal model is mainly based on Maxwell’s equation and basic heat transfer equation to calculate the temperature propagation along the length of the superconducting tapes. According to the calculated temperature profile during quench, the surface thermal stress of the tape is obtained by a structural model. This model can be used to evaluate the degradation of tape performance due to the surface thermal stress, and the results can be used to minimize these effects in the SFCL system. The proposed model is used to investigate the uneven tape, the thickness of the copper layer and YBCO layer which is non-uniform. Methods of smoothing the degradation effect by adding auxiliary fixed points to the tape and changing the basic thickness of copper layer are discussed. 相似文献
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Peng-Bo Zhou Guang-Tong Ma Huan Liu Chen Yang Zhi-Tao Wang Tian-Yong Gong 《Journal of Superconductivity and Novel Magnetism》2016,29(7):1747-1753
A novel concept of cloaking, concentration and transferring of the static magnetic fields by the combination effect of the superconductor (SC) and ferromagnet (FM) has been recently presented. The performance of these hybrid structures strongly depends on the properties of the involved materials as well as its geometrical parameters. In this work, we have practically demonstrated a magnetic hose, which is developed by a FM core wrapped by a SC layer. Meanwhile, a finite-element simulation with experimentally derived permeability of both SC and FM constituents was also established. Based on the verified simulation, further investigations were carried out to systematically examine the dependence of the transfer efficiency of the magnetic hose on its dimension and magnetic properties of the involved materials, both of which are difficult to be varied in practical case, especially for the magnetic properties. 相似文献
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以自制埋管换热器换热实验台为原型建立模型,用Fluent软件进行数值模拟,模拟进水40℃、45℃、50℃三种工况下连续运行8小时后,埋管换热器周围土壤的温度分布,并用埋管换热器换热实验台做相同工况下的换热实验,取埋深4m、埋深3m、埋深2m处共计12个测温点进行比对,验证数值模拟结果的正确性,并指导数值模拟模型的修正,最后利用数值模拟计算结果分析埋管换热器周围土壤的温度场特性。 相似文献
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在磁约束聚变实验装置托卡马克中,第一壁材料直接面对高温等离子体,承受高能粒子的轰击。随着聚变装置等离子体存在时间的延长及辅助加热功率的增加,第一壁材料腐蚀和沉积将会越来越严重。材料的腐蚀一方面会污染等离子体影响聚变等离子体的品质,另一方面将危害装置的安全运行。为了提高材料的物理和化学溅射阈值,超导托卡马克东方超环(EAST)装置上选用掺杂碳化硅涂层石墨作为第一壁材料。本实验通过离子束表面分析方法,研究了EAST装置中限制器石墨材料的腐蚀与沉积特性,结果显示在累计大约36000s的等离子体实验中,安装在限制器上的标记瓦块近1μm的碳涂层基本被腐蚀,其腐蚀速率超过0.0278 nm/s。 相似文献
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Tatnatchai Suwannasit I-Ming Tang Rassmidara Hoonsawat Bumned Soodchomshom 《Journal of Low Temperature Physics》2011,165(1-2):15-26
The Josephson effect in a gapped graphene-based superconductor/barrier/superconductor junction is studied. The superconductivity in gapped graphene may be achieved by depositing conventional superconductor on the top of the gapped graphene such as graphene grown on SiC substrate. In gapped graphene system, the carriers exhibit massive Dirac fermions. We focus on the effect of pseudo-Dirac-like mass on the supercurrent. In contrast to that in the gapless graphene superconductor/barrier/superconductor junction, we find that the supercurrent exhibits dependency of the Fermi energy. Also, the massive supercurrent anomalously oscillates as a function of the gate potential. This novel behavior is due to the effect of electrons acquiring mass in gapped graphene. 相似文献
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L. F. Goodrich A. N. Srivastava T. C. Stauffer 《Journal of research of the National Institute of Standards and Technology》1991,96(6):703-724
The superconductor simulator is an electronic circuit that emulates the extremely nonlinear voltage-current characteristic (the basis of a critical-current measurement) of a superconductor along with its other major electrical properties. Three different types of simulators have been constructed: the passive, active, and hybrid simulator. The passive simulator has the fewest circuit components and offers the least amount of versatility, while the active and hybrid simulators offer more versatility and consequently have more components. Design, characteristics, and applications of the superconductor simulator along with a summary of features are presented. These simulators are high precision instruments, and are thus useful for establishing the integrity of part of a superconductor measurement system. They are potentially useful for testing the measurement method and data acquisition and analysis routines. The 50 A simulator provides critical-current precision of 0.1% at a 1 μV signal. This is significantly higher than the precision of a superconducting standard reference material. The superconductor simulator could significantly benefit superconductor measurement applications that require high-precision quality assurance. 相似文献
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This paper presents a numerical (finite element) analysis of superconductor stability and current propagation under random variations of critical superconductor parameters. Instead of using singular (homogeneous) values, random variations potentially are appropriate to take into account any conductor inhomogeneity that can be considered as an obstacle to current propagation. Traditional assumptions like homogeneous current distribution, critical temperature, critical current density and critical magnetic fields are not justified in general; a local disturbance (for example, release of mechanical stress energy), if not immediately distributed by solid conduction, would generate a transient increase of local conductor temperature. Local critical current density and magnetic field then will be reduced, and current distribution will change. Disturbances may arise also from transport currents that locally exceed the critical current of the superconductor. Disturbances of all kinds may increase the conductor temperature above its critical value. A local analysis of all superconductor states thus is mandatory to safely avoid a quench. As an extension of standard stability models, also flux flow resistive states are taken into account. We will try to find a possibly existing correlation between current propagation and superconductor stability. Fault current limiting is discussed as a special case of current propagation. The analysis is applied to a bundle of high-temperature superconductor (HTSC) filaments. As will be shown, temperature profiles in a superconductor do not allow a clear distinction between Ohmic resistive or flux flow resistive fault current limiting. Though frequently made in the literature, this separation is highly questionable, because Ohmic resistive and flux flow resistive states may locally coexist, side by side, but are not very stable in the superconductor volume. 相似文献
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建筑室内热环境仿真软件已成为室内环境研究的重要手段之一.在VB.NET开发平台下,采用高效的计算语言Visual Fortran与Visual Basic混合编程,开发了一套界面友好、计算速度较快、计算结果可视化的建筑室内热环境仿真软件Indoor Thermal Environment Simulation (ITES),并在重庆大学热环境实验室进行了实验,对特定热湿环境下的室内温度分布进行测试,其测试结果与ITES软件的模拟结果相一致.验证了ITES软件对建筑室内热环境仿真模拟的可信性. 相似文献
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