Tests of the 15-kV Class Coreless Superconducting Fault Current Limiter

Kozak, J.; Majka, M.; Błażejczyk, T.; Berowski, P.

doi:10.1109/tasc.2016.2524504

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…This increases the impedance of a short-circuit loop, allowing the fault current value to decrease. Numerous papers concentrate on the subject of inductive type fault current limiters [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], limiters with saturated core [20][21][22], resistive SFCLs [23], flux coupling SFCLs [24], transformer type SFCLs [25], comparisons of various types of SFCLs [26][27][28], integration of SFCLs in a power grid [29][30][31][32], and fault detection and analysis [33][34][35][36][37]. Magnetic core limiters are large and very heavy.…”

Section: Introductionmentioning

confidence: 99%

Forces and Stresses in the Windings of a Superconducting Fault Current Limiter

Kozak

2022

Energies

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This paper presents the design of a Superconducting Fault Current Limiter (SFCL) and calculation results of forces and stresses in the windings of a resistive fault current limiter. The design of the fault current limiter consists of two parallelly connected and magnetically coupled windings, cooled by a single stage cryocooler. Magnetically compensated windings made of HTS tape give a very low voltage on the limiter at a nominal current. Limitation of the short-circuit time and the value of the maximum initial fault current reduces the thermal and dynamic effects of the passage of a fault current. Using devices which limit the value of a fault current can lower the level of required short-circuit capacity of the elements in a system. However, selected means of fault currents limitation must maintain the power quality standards. A perfect fault current limiter is required to have substantial impedance in fault conditions and zero impedance at work currents. Such requirements are met by a SFCL. An increase of current caused by the occurrence of a fault current results in the transition of the superconducting material from the superconducting state into the resistive state. This increases the impedance of short-circuit loop, allowing the fault current value to decrease. During a short-circuit, the forces generated from the short-circuit current also act on the limiter windings. Short-circuit current causes stresses in the superconducting tape. Exceeding the permissible stress value results in an irreversible reduction in the critical current of the superconducting tape. Calculations of the forces and stresses in the HTS tape for the maximum value of the short-circuit current were carried out using the finite element method. The constructed limiter was tested and the winding design ensures that the tape stresses are at a safe level even for short-circuit currents.

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Section: Introductionmentioning

confidence: 99%

Forces and Stresses in the Windings of a Superconducting Fault Current Limiter

Kozak

2022

Energies

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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.…”

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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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