First Russian long length HTS power cable

Volkov, E. P.; Vysotsky, V.S.; Firsov, V. P.

doi:10.1016/j.physc.2012.04.024

Cited by 20 publications

(4 citation statements)

References 11 publications

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“…The operating temperature of superconducting power components is commonly in the range of 65-77 K [11]. Hence, the investigations on the dielectric parameters and the electrical conductivity are performed within this temperature range.…”

Section: Generation Of Lnt-rangementioning

confidence: 99%

Investigation on the Dielectric Material Parameters and the Electric Conductivity of Syntactic Foam at the Liquid Nitrogen Temperature Range

Winkel

Puffer

Schnettler

2015

IEEE Trans. Appl. Supercond.

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Liquid nitrogen (LN 2 )-based insulation systems for superconducting components of the electric distribution network are state of the art. As the dielectric strength of LN 2 -based insulation systems can be significantly reduced if bubbles occur, an alternative insulation system could be a solid insulation system using LN 2 only for cooling but not as electrical insulation material. This paper discusses syntactic foam as a solid substitution of LN 2 -based insulation systems. Syntactic foam consists of a polymer matrix with embedded hollow microspheres (HMS) that have diameters of several 10 μm. Compared to the pure matrix material, the HMS filled matrix features a lower density and a significantly reduced thermal contraction when being cooled to cryogenic temperatures. Several syntactic foams are investigated regarding their dielectric parameters (relative permittivity, loss factor) and electric conductivity at liquid nitrogen temperature (LNT). The results show that the investigated parameters of syntactic foam are almost constant in the temperature range of LNT. Furthermore, the loss factor and the relative permittivity at LNT are lower than at room temperature. These effects can be explained by the existence of a secondary glass transition of polymers. At cryogenic temperatures, a decrease of the electric conductivity of syntactic foam is detected presumably due to the rise in required energy to lift valence electrons to the conduction band of the polymer at lower temperatures.Index Terms-Cryogenic temperature, dielectric parameters, electrical conductivity, liquid nitrogen, syntactic foam.

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Section: Generation Of Lnt-rangementioning

confidence: 99%

Investigation on the Dielectric Material Parameters and the Electric Conductivity of Syntactic Foam at the Liquid Nitrogen Temperature Range

Winkel

Puffer

Schnettler

2015

IEEE Trans. Appl. Supercond.

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“…Type II superconductors are essential for large bore or highfield magnets [1][2][3][4] and are promising for power applications, such as motors for aeroplanes [5,6] or ship propulsion [7,8], generators [9][10][11], grid power-transmission cables [12,13], transformers [14][15][16][17], and fault-current limiters [18][19][20][21][22]. The critical current density, J c , of type II superconductors depends on the magnitude and angle of the local magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…The prism model presents current paths with 3D bending for all angles θ. The average current density over the thickness agrees very well with the thin film model except for the highest angles.The prism hysteresis loops reveal a peak after the remnant state, which is due to the parallel component of the self-magnetic-field and is implicitly neglected for thin films.The presented numerical method shows the capability to take force-free situations into account for general 3D situations with a high number of degrees of freedom.The results reveal new features of force-free effects in thin films and prisms.Type II superconductors are essential for large bore or high-field magnets [1][2][3][4] and are promising for power applications, such as motors for air-plane [5,6] or ship propulsion [7,8], generators [9][10][11], grid power-transmission cables [12,13], transformers [14][15][16][17], and or fault-current limiters [18][19][20][21][22]. The Critical Current Density, J c , of type II superconductors depends on the magnitude and angle of the local magnetic field.…”

mentioning

confidence: 99%

3D modelling of macroscopic force-free effects in superconducting thin films and rectangular prisms

Kapolka¹,

Pardo²

2019

Supercond. Sci. Technol.

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When the magnetic field has a parallel component to the current density J there appear force-free effects due to flux cutting and crossing. This results in an anisotropic E(J) relation, being E the electric field. Understanding force-free effects is interesting not only for the design of superconducting power and magnet applications but also for material characterization.This work develops and applies a fast and accurate computer modeling method based on a variational approach that can handle force-free anisotropic E(J) relations and perform fully three dimensional (3D) calculations. We present a systematic study of force-free effects in rectangular thin films and prisms with several finite thicknesses under applied magnetic fields with arbitrary angle θ with the surface. The results are compared with the same situation with isotropic E(J) relation.The thin film situation shows gradual critical current density penetration and a general increase of the magnitude of the magnetization with the angle θ but a minimum at the remnant state of the magnetization loop. The prism model presents current paths with 3D bending for all angles θ. The average current density over the thickness agrees very well with the thin film model except for the highest angles.The prism hysteresis loops reveal a peak after the remnant state, which is due to the parallel component of the self-magnetic-field and is implicitly neglected for thin films.The presented numerical method shows the capability to take force-free situations into account for general 3D situations with a high number of degrees of freedom.The results reveal new features of force-free effects in thin films and prisms.Type II superconductors are essential for large bore or high-field magnets [1][2][3][4] and are promising for power applications, such as motors for air-plane [5,6] or ship propulsion [7,8], generators [9][10][11], grid power-transmission cables [12,13], transformers [14][15][16][17], and or fault-current limiters [18][19][20][21][22]. The Critical Current Density, J c , of type II superconductors depends on the magnitude and angle of the local magnetic field. There are three types of anisotropy which we call "intrinsic", "de-pinning", and "force free" anisotropy.The "intrinsic" anisotopy is the following. Certain superconductors present an axis with suppressed superconductivity, where the critical current density is lower. In cuprates, for instance, the critical current density in the c crystallographic axis is much smaller than in the ab plane. There is also important anisotropy in REBCO vicinal films due to flux channeling [23,24].The "de-pinning" anisotropy of J c is due to anisotropic maximum pinning forces caused by either anisotropic pinning centres or anisotropic vortex cores [25]. When the current density J is perpendicular to B and the electric field E is parallel to J, the anisotropy of J c is always due to de-pinning anisotropy. This kind of anisotropy is important for High-Temperature Superconductors (HTS), such as (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 and ...

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“…Recently, the application of a high-capacity refrigerator with a cooling system that has a large cooling capacity per unit is being researched as the length of superconductivity power cables increases [3,4]. Although the reverse Brayton refrigerator, JT refrigerator, and Claude refrigerator can be considered as large-capacity cryogenic refrigerators, taking into account the reliability and efficiency of the system, the reverse Brayton refrigerator is the most competitive cooling system [5].…”

Section: Introductionmentioning

confidence: 99%

Conceptual design of cryogenic turbo expander for 10 kW class reverse Brayton refrigerator

Lee¹,

Kim²,

Yang³

et al. 2015

Progress in Superconductivity and Cryogenics

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Recently, the development of the HTS power cable is actively promoted. As the length of HTS power cable increases, there have been many efforts to develop large capacity cryocooler. Among the various cryocooler, the Brayton refrigerator is the most competitive for HTS power cable. The Brayton refrigerator is composed of recuperative heat exchangers, a compressor, and a cryogenic turbo expander. In these components, the cryogenic turbo expander is a part to decrease the temperature and it is the most significant component that is closely related with overall system efficiency. It rotates with high speed using a high-pressure helium or neon gas at cryogenic temperature. This paper describes the design of a 10 kW class Brayton refrigeration cycle and the cryogenic turbo expander. Flow and structural analysis are performed for the rotating impeller and nozzle to verify the efficiency and the design performance.

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First Russian long length HTS power cable

Cited by 20 publications

References 11 publications

Investigation on the Dielectric Material Parameters and the Electric Conductivity of Syntactic Foam at the Liquid Nitrogen Temperature Range

Investigation on the Dielectric Material Parameters and the Electric Conductivity of Syntactic Foam at the Liquid Nitrogen Temperature Range

3D modelling of macroscopic force-free effects in superconducting thin films and rectangular prisms

Conceptual design of cryogenic turbo expander for 10 kW class reverse Brayton refrigerator

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