Application of the FDM-ADI Method for Simulating SFCL Under Inrush Conditions

Advances in superconductor technology make the prospect of economical operation of high temperature superconducting (HTS) power cables a practical concept for grid applications in urban centers. With more advanced cable designs being developed and commercialized, their geometrical features and dynamic behavior are becoming increasingly complicated to be modeled. This brings new challenges as the complex structure of HTS power cables significantly increases the computation power needed to perform simulations. In this paper we develop a two-dimensional open source simulation code based on the finite difference method which is solved by means of the alternating direction implicit routine. The algorithm has been written in MatLab programming language. The method improves computational performance and simulation time. In addition, this enables the creation of open-source simulation codes. A three-phase concentric HTS cable design has been chosen for the development of the code, nevertheless the model can be employed for any cable design. The results indicate an efficient, stable and powerful simulation code. During the development no numerical instabilities have been found. Besides that, the model is able to deliver quantities that are experimentally difficult to access. Simulation files are available for the scientific community on the HTS Modeling Workgroup webpage. 1 1 Simulation files can be downloaded.here.

Section: Ln 2 Returnmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An open-source 2D finite difference based transient electro-thermal simulation model for three-phase concentric superconducting power cables

Sousa

Shabagin

Kottonau

et al. 2020

“…This method has the advantages of possessing better numerical stability than the explicit method, and relying on fast solvers of the tridiagonal system thus requiring lower computational efforts in comparison with the implicit methods [48]. The ADI method has been successfully utilized for simulations of superconducting fault current limiters [49,50] and power cables [51] in recent years.…”

Section: Introductionmentioning

confidence: 99%

Quench analysis of a no-insulation REBCO magnet based on the ADI method considering the coupling effect of the cryostat

Zheng,

Liu,

Song

et al. 2023

A no-insulation (NI) REBCO superconducting magnet is under development at Wuhan National High Magnetic Field Center, China. The magnet with the liquid helium cryostat system has a compact structure to reduce the space required for operation. During a quench, the fast-changing spatial magnetic field around the NI magnet may induce a strong eddy current in the conductive parts of the cryostat. The eddy current and its associated Lorentz force will generate mechanical stress on the cryostat, especially on the thermal shield (TS). The mechanical strength of the cryostat needs verification in the preliminary design. Furthermore, the degree to which the electromagnetic coupling between the cryostat and NI magnet might impact the quench behaviors of the NI magnet remains uncertain. In this paper, a multi-physics quench model is newly developed for the NI REBCO magnet, and the alternating direction implicit method is employed for the solver of the thermal model to improve computational efficiency. This simulation model can consider the electromagnetic coupling effect between the NI magnet and cryostat by constructing a partial element equivalent circuit. A quench analysis has been performed and we found that: (1) The cryostat can function as a secondary shorted circuit to the NI magnet and slow down the quench speed to a certain extent. (2) During the rather fast inductive quench phase, the cryostat will experience an attraction force towards the quench propagation frontier. (3) A quench propagation from one end of the magnet can cause a significant z-axis unbalanced force on the TS. (4) Cryostat materials with drastically changed electrical conductivity can significantly affect their mechanical responses during a quench. However, the eddy current density and maximum Von Mises stress on the TS are barely affected by the thickness of the TS and the contact resistance of the NI REBCO magnet.

“…when the current is above the critical current I c ) of the superconducting material, and other models remain empirical [7][8][9][10][11][12]: for instance, they use a piecewise power-law in which the overcritical current regime is modeled as the flux creep region, but with a lower n-value [13]. Accurate knowledge of the E − J relation can help improve the reliability of the models, and thus, the performance of the simulated devices working in the overcritical current regime or where the electro-magnetothermal aspects must be studied carefully, for instance a hotspot scenario [14][15][16], a non-insulated coil [17,18] or a superconducting dynamo [19].…”

Section: Introductionmentioning

confidence: 99%

A wide range E − J constitutive law for simulating REBCO tapes above their critical current

Riva¹,

Sirois²,

Lacroix³

et al. 2021

When modeling superconducting devices based on rare earth barium copper oxide (REBCO) tapes and operating near or above the critical current value I c , the power-law is not always accurate. In our previous works, we proposed the overcritical current constitutive law, based on a combination of fast pulsed current measurements and finite element analysis. The overcritical current constitutive law was provided in the form of look-up tables and was validated experimentally. We showed that the overcritical current constitutive law could better reproduce experimental measurements than the power-law, and that the power-law predicts a faster quench than the overcritical current constitutive law. In this contribution we use a mathematical expression based on the collective pinning model to analytically describe the overcritical current regime of REBCO tapes based on measurements performed between 77 and 90 K in self-field conditions. The wide-range constitutive law is verified by comparing DC fault measurements with the results of numerical simulations using the overcritical current constitutive law to represent the electrical resistivity of the superconducting layer of REBCO tapes.