The T-A formulation: an efficient approach to model the macroscopic electromagnetic behaviour of HTS coated conductor applications

Huber, Felix; Song, Wenjuan; Zhang, Min; Grilli, Francesco

doi:10.1088/1361-6668/ac5163

Cited by 71 publications

(42 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where t is the thickness of the whole HTS wire, including the copper stabilizer, silver overlayer, HTS layer, buffer stack and substrate [59]. FEM (finite element method) models [60]- [63] implemented in COMSOL Multiphysics [64]- [67].…”

Section: B T-a Homogenization Methodsmentioning

confidence: 99%

Combined Impact of Asymmetric Critical Current and Flux Diverters on AC Loss of a 6.5 MVA/25 kV HTS Traction Transformer

Song

Wimbush

et al. 2023

IEEE Trans. Transp. Electrific.

Self Cite

View full text Add to dashboard Cite

A 6.5 MVA/25 kV high temperature superconducting (HTS) transformer for the Chinese Fuxing high-speed train has been proposed to replace the oil-based transformers while achieving higher efficiency, lighter weight, and minimized volume. The high targeted efficiency (> 99%) makes AC loss reduction a vital issue. HTS coated conductors generally exhibit asymmetric critical current characteristics as a function of magnetic field angle Ic(B, θ), leading to a non-trivial influence on the AC loss of coil windings. The fastcomputing T-A homogenization method is proposed to calculate the AC loss of the 6.5 MVA/25 kV traction transformer with large turn numbers. The variables, T and A, are the current and magnetic vector potentials, respectively. The AC loss of the transformer windings is analyzed for various coil configurations with and without flux diverters considering Ic(B, θ). At the rated current and 65 K, employing the flux diverters with a square-shape cross-section, the total AC loss is decreased by 73.7% and an extra 150 W loss reduction was also obtained. Moreover, an additional reduction of 37 W is realized upon utilizing the asymmetric Ic(B, θ) characteristic. The reduced 187 W in AC loss at 65 K corresponds to a reduction in ambient power requirement of over 5.6 kW. Therefore, considering asymmetric Ic(B, θ), can lead to a non-trivial reduction in AC loss, even incorporating flux diverters.

show abstract

Section: B T-a Homogenization Methodsmentioning

confidence: 99%

Combined Impact of Asymmetric Critical Current and Flux Diverters on AC Loss of a 6.5 MVA/25 kV HTS Traction Transformer

Song

Wimbush

et al. 2023

IEEE Trans. Transp. Electrific.

Self Cite

View full text Add to dashboard Cite

show abstract

“…This method couples T and A formulations and can effectively solve the analysis of large-scale HTS systems. With the further study of T-A formulation [15], the application field of T-A formulation has become more and more widely, including superconducting motor [16][17], superconducting fault current limiter [18], superconducting cable [19], superconducting flux pump [20]. However, the application of T-A formulation in superconducting transformer has not been involved.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Electromagnetic Characteristics of 6.5 MVA/25 kV HTS Traction Transformer Using T–A Formulation

Liao

Fang

Zhao

et al. 2023

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

Low AC loss of the winding of high-capacity high temperature superconducting (HTS) traction transformer is a very important link to introduce large capacity traction transformer into commercialization. A new winding structure is proposed for the transformer. The HV windings are made of double pancake coils (DPCs), which are wound by 4.8 mm-wide tapes, and the LV windings, which are wound by 12 mm-wide tapes, are solenoid coils. The electromagnetic characteristics of the new winding structure of the traction transformer are analyzed by H-formulation homogenization method and T-A formulation homogenization method respectively. Significant HTS tape cost reduction could be achieved without compromising AC loss by using hybrid windings into the new winding structure. We report that the H-formulation homogenization model and T-A formulation homogenization model are used to calculate the AC loss of the new winding structure with flux diverters (FDs) at the end. The results meet the design requirements of less than 2 kW, which shows the feasibility of the new winding structure. Due to the good convergence of H-formulation and poor convergence of T-A formulation under the homogenization model of the transformer, no one has used T-A formulation to calculate the electromagnetic characteristics of the transformer before. Due to the simplicity of T-A formulation applied to large-scale superconducting system, a new form of mesh generation is proposed to improve the convergence and accuracy of T-A formulation homogenization model calculation of the transformer in this paper. This paper verifies the correctness of the calculation of HTS transformer by T-A formulation, and provides a reference for the application of T-A formulation in more superconducting fields.

show abstract

“…The T -A formulation, originally proposed in [1], has emerged as a popular approach to efficiently and accurately simulate the electromagnetic behavior of devices made of HTS coated conductors [2]. The main appeal of this formulation is that, by assuming that the superconducting layer can be considered as an infinitely thin sheet [3], [4], it leads to short computation times, especially for 2D problems where only the transverse cross section of superconductors is encountered.…”

Section: Introductionmentioning

confidence: 99%

2-D Modeling of HTS Coils With $T$-$A$ Formulation: How to Handle Different Coupling Scenarios

Santos

Santos²,

Sirois

et al. 2022

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Numerical models based on the finite-element method (FEM) are popular tools for investigating the macroscopic electromagnetic behavior of high-temperature superconductor (HTS) applications. This article explains how to use the T -A formulation for modeling HTS coils in 2D with different coupling scenarios between the turns. First we consider a racetrack coil wound from one piece of superconducting tape. Then we consider a coil obtained by winding a cable composed of different HTS tapes. In the latter case, the tape turns are either electrically connected along their entire length or just at the two ends of the coil: in the model, these two different types of electrical connection are implemented with the help of the electrical circuit module. The current density distributions and the AC losses of the coils in the different coupling scenarios are compared and discussed. The limits of applicability of the presented approach are pointed out. The model is developed for the straight section of racetrack coils, but can be easily adapted to axisymmetric geometries.

show abstract

The T-A formulation: an efficient approach to model the macroscopic electromagnetic behaviour of HTS coated conductor applications

Cited by 71 publications

References 46 publications

Combined Impact of Asymmetric Critical Current and Flux Diverters on AC Loss of a 6.5 MVA/25 kV HTS Traction Transformer

Combined Impact of Asymmetric Critical Current and Flux Diverters on AC Loss of a 6.5 MVA/25 kV HTS Traction Transformer

Analysis of Electromagnetic Characteristics of 6.5 MVA/25 kV HTS Traction Transformer Using T–A Formulation

2-D Modeling of HTS Coils With $T$-$A$ Formulation: How to Handle Different Coupling Scenarios

Contact Info

Product

Resources

About