Prospects for HTS applications

Gamble, B.; Snitchier, G.; Schwall, Robert E.

doi:10.1109/20.511435

Cited by 11 publications

(3 citation statements)

References 8 publications

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“…The cost of the CS is about 15% of the total [1]. It can be reduced to some level when a low-temperature superconductor (LTS) is replaced by a high-temperature superconductor (HTS) with a cryogen-free and conduction-cooled system, since the HTS will result in a reduction in refrigeration power [27]. Hence, many studies and developments of HTS SMES have been carried out.…”

Section: Introductionmentioning

confidence: 99%

A study of the status and future of superconducting magnetic energy storage in power systems

Xue¹,

Cheng²,

Sutanto³

2006

Supercond. Sci. Technol.

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Superconducting magnetic energy storage (SMES) systems offering flexible, reliable, and fast acting power compensation are applicable to power systems to improve power system stabilities and to advance power qualities. The authors have summarized researches on SMES applications to power systems. Furthermore, various SMES applications to power systems have been described briefly and some crucial schematic diagrams and equations are given. In addition, this study presents valuable suggestions for future studies of SMES applications to power systems. Hence, this paper is helpful for co-researchers who want to know about the status of SMES applications to power systems.

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Section: Introductionmentioning

confidence: 99%

A study of the status and future of superconducting magnetic energy storage in power systems

Xue¹,

Cheng²,

Sutanto³

2006

Supercond. Sci. Technol.

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“…In the present paper is discussed an R&D activity aiming at developing a reliable technology for small-size superconducting magnets, to be operative at temperatures ranging from 4.2 up to 77 K. The first part of the paper is devoted to the design and construction topics. From the beginning it appeared clear that a serious problem for application in coils of SC tapes comes from the anisotropy of critical current [6][7][8][9]. The critical current, when the magnetic field is applied normal to the wide face of the tape, is substantially lower than the critical current measured with the field parallel to the wide face [10].…”

Section: Introductionmentioning

confidence: 99%

Field distribution effect on the performances of coils wound with Ag/Bi-2223 tape

Fabbricatore

Priano

Testa

et al. 1998

Supercond. Sci. Technol.

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A small coil (35 mm bore) was made by winding a superconducting Ag/Bi-2223 multifilamentary tape. The coil, composed of eight pancakes, showed reduced performance in the pancakes placed at the sides with respect to central ones. This effect was attributed to the radial field at the coil ends. In order to explain this behaviour, a general method for predicting the critical current of a coil, starting from basic information on short samples, was developed. The method was used to understand the possible advantages from a reduction of radial field in the coil through a suitable iron yoke for flux return. The measured performance (in terms of critical current) of the coil with iron improved by 10%. The central field at 77 K was 1100 Gauss and 6000 Gauss at 4.2 K.

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“…Compared with their LTS counterparts, HTS materials have less cryogenic requirements and better performance in high magnetic fields. These advantages promise HTS materials a broad prospect in practical applications [70]- [72].…”

Section: High-temperature Superconductorsmentioning

confidence: 99%

AC Loss Reduction in HTS Coils and Armature Windings of Fully Superconducting Motors

You¹

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High AC loss in armature windings is one of the greatest barriers to achieve practical fully-HTS (high-temperature superconducting) motors. At present, AC loss estimation for HTS armature windings is one of the core technical challenges. AC loss behaviours and AC loss reduction methodologies have not been fully investigated in REBCO (REBa2Cu3O7-x, RE: rare earth) HTS armature windings carrying AC current under rotating magnetic fields. Many open questions need to be studied, of which this thesis addresses the three most prominent: can significant AC loss reduction be achieved by using low-loss MFDs (magnetic flux diverters); is it feasible to apply MFD structure to the HTS armature windings; and what kind of REBCO conductor types for armature windings generate less AC loss. The goal of this thesis is applying experimental and numerical methods to investigate AC loss behaviours and AC loss reduction methodologies in the HTS windings wound with REBCO wires. Specifically, it includes investigating AC loss reduction in HTS coil assembly by using low-loss MFDs; building numerical models for fully-HTS motors; and developing methodologies to achieve AC loss reduction in the HTS armature windings. We firstly explored the effectiveness of AC loss reduction on a REBCO four double-pancake coil assembly by using low-loss MFDs, MPP (Molypermalloy powder) MFDs and HF (High flux) MFDs. These have not been studied with HTS coils before. The measured and simulated results show that both MFDs can significantly reduce the total loss (the summation of the losses in the HTS windings and MFDs) in the system. At 77 K and 40 A coil current, compared with the coil assembly without MFDs, the total loss with HF and MPP MFDs is reduced by 77% and 81%, respectively. Although MPP MFDs show slightly better performance in reducing total loss at low coil current, HF MFDs are the more obvious option for AC loss reduction in high magnetic field applications owing to their relatively high saturation field. Next, we developed numerical models to investigate the AC loss reduction in the armature windings of a 50 kW fully HTS motor by applying pole shoes, which function as MFDs. For comparison, two motor designs with and without pole shoes have been considered in the finite-element method (FEM) models. REBCO coated conductors were considered for both the armature and field windings, and 2D FEM models of both designs were built using the T-A formulation (T: current vector potential, A: magnetic vector potential) and rotating meshes. The simulation results show that flux diverting pole shoes reduced the perpendicular magnetic field in the armature windings and provided a 51% AC loss reduction, without weight penalty or motor power rating reduction. Finally, AC loss simulation in HTS armature windings of a 100 kW HTS motor wound with different types of REBCO conductor arrangements were carried out. Three types of conductors, 4 mm-wide REBCO conductors, 14/2 (14 strands, each strand is 2 mm wide) REBCO Roebel cables and striated REBCO conductors with four 1 mm-wide filaments, were considered in the armature windings. The simulation results show that both Roebel cables or striated conductors can significantly reduce the AC loss in the armature windings compared with 4 mm-wide conductors. Further, a 2% AC loss reduction can be achieved in the armature winding wound with REBCO conductors with asymmetric Ic(B, θ) characteristics by simply flipping the direction of the conductors. This work provides a method to achieve large AC loss reduction in HTS coil windings by using low-loss MFDs. Also, it supplies practical implications for designing armature windings of fully-HTS superconducting rotating machines. The methodologies of AC loss reduction in this thesis also can be applied to other HTS applications, such as transformers, and fast ramping magnets.

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Prospects for HTS applications

Cited by 11 publications

References 8 publications

A study of the status and future of superconducting magnetic energy storage in power systems

A study of the status and future of superconducting magnetic energy storage in power systems

Field distribution effect on the performances of coils wound with Ag/Bi-2223 tape

AC Loss Reduction in HTS Coils and Armature Windings of Fully Superconducting Motors

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