Publications by Francesco Grilli

Optimization Method for Extracting Stabilizer Geometry and Properties of REBCO Tapes

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, Arooj Akbar, Nicolo' Riva

A good knowledge of material properties is a critical aspect for modeling high-temperature superconductor (HTS) devices. However, the electrical resistivity of coated conductors above the critical current is limited. The major challenge in characterizing t ...

2021

Superconductors for power applications: an executable and web application to learn about resistive fault current limiters

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, Nicolo' Riva

High-temperature superconductors (HTS) can be superconducting in liquid nitrogen (77 K) at atmospheric pressure, which holds immense promises for our future such as nuclear fusion, compact medical devices and efficient power applications. In a power system ...

2021

Resistivity of REBCO tapes in overcritical current regime: impact on superconducting fault current limiter modeling

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, Frédéric Sirois, Nicolo' Riva

A detailed knowledge of the resistivity of high-temperature superconductors in the overcritical current regime is important to achieve reliable numerical simulations of applications such as superconducting fault current limiters. We have previously shown t ...

2020

Non-twisted stacks of coated conductors for magnets: Analysis of inductance and AC losses

Rainer Wesche, Francesco Grilli, Davide Uglietti

Almost all present High Temperature Superconducting (HTS) cable designs for magnets are based on twisted or transposed concepts that were developed for Low Temperature Superconducting (LTS) cables. However, requirements for LTS materials (like filament twi ...

2020

Overcritical Current Resistivity of YBCO-Coated Conductors Through Combination of PCM and Finite-Element Analysis

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, Nicolo' Riva

Understanding the electro-thermal behavior of high-temperature superconductor (HTS) materials is a critical aspect for designing efficient and reliable applications. In order to optimize cost and performance, one needs to understand the role played by the ...

IEEE Institute of Electrical and Electronics Engineers2019

Magneto-thermal finite element modeling of 2nd generation HTS for FCL design purposes

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, François Roy, Frédéric Sirois

Coated conductors are very promising for the design of novel and e±cient Fault Current Limiter (FCL). However, before considering using them in a power grid, their thermal and electromagnetic behaviors in the presence of over-critical currents need to be i ...

Iop Publishing Ltd, Dirac House, Temple Back, Bristol Bs1 6Be, England2008

Magneto-Thermal Modeling of Second-Generation HTS for Resistive Fault Current Limiter Design Purposes

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, François Roy, Frédéric Sirois

Coated conductors are very promising for the design of novel and efficient resistive Fault Current Limiters (FCLs). However, a detailed knowledge about their thermal and electromagnetic behaviors in the presence of over- critical currents is crucial for th ...

IEEE Institute of Electrical and Electronics Engineers2008

Evaluation of two commercial finite element packages for calculating AC losses in 2-D high temperature superconducting strips

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, François Roy, Frédéric Sirois

This paper compares the speed and accuracy of two commercial packages based on the finite element method (FEM) for calculating the AC losses in high temperature superconductors (HTS). The softwares investigated in this paper were COMSOL Multiphysics and FL ...

2008

Finite-element modelling of YBCO fault current limiter with temperature dependent parameters

Bertrand Dutoit, Bertrand Dutoit, Joseph Duron, Francesco Grilli

In this paper we present a numerical model in which both the thermal and the electromagnetic aspects of the over-critical current regime of HTS materials are taken into account. The electromagnetic and thermal equations have been implemented in finite elem ...

2007

Computer Modeling of YBCO Fault Current Limiter Strips Lines in Over-Critical Regime With Temperature Dependent Parameters

Bertrand Dutoit, Bertrand Dutoit, Joseph Duron, Francesco Grilli

We present the results of an advanced numerical model for fault current limiter (FCL) based on HTS thin films in which both thermal and electromagnetic aspects are taken into account. This model allows simulating the behavior of FCL in the over-critical cu ...

IEEE Institute of Electrical and Electronics Engineers2007

Finite-element modelling of superconductors in over-critical regime with temperature dependent resistivity

Bertrand Dutoit, Bertrand Dutoit, Joseph Duron, Francesco Grilli

In this paper, we present a new numerical model, in which both the thermal and the electromagnetic aspects of the over-critical current regime of HTS materials are taken into account. The electromagnetic and thermal equations have been implemented in finit ...

Institute of Physics Publishing2006

Finite-element analysis and comparison of the AC loss performance of BSCCO and YBCO conductors

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli

The AC loss performance of two BSCCO and two YBCO conductors of different geometry, characterized by the same self-field critical current of 150 A, is analysed and compared quantitatively. The comparison is made using the finite-element method with a non-l ...

Instutute of Physics Publishing2006

Dynamic field mapping for obtaining the current distribution in high-temperature superconducting tapes

Bertrand Dutoit, Bertrand Dutoit, Joseph Duron, Francesco Grilli

The magnetic field profile on the surface of Bi-2223/Ag tapes has been dynamically measured across the width of the samples. The experimental technique uses a Hall-probe array with 7 sensors connected to a multiple channel lock-in amplifier especially prog ...

2005

Comparison of the AC losses of BSCCO and YBCO conductors by means of numerical analysis

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli

This paper presents a quantitative comparison of the AC loss performance of two BSCCO and two YBCO conductors, characterized by the same self-field critical current of 150 A. In particular, compared are a 37-filamentary BSCCO tape, a 16-filamentary BSCCO s ...

2005

Analysis of magnetic field and geometry effects in the design of HTS devices for AC power applications

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli

The performance of HTS devices is strongly influenced by local values of the current/field distributions. In this paper, we investigate the influence of the magnetic field and of the geometrical configuration on the loss behaviour of a 200kVA FCL prototype ...

2005

3D Finite Element Simulations of strip lines of a YBCO/Au Fault Current Limiter

Bertrand Dutoit, Bertrand Dutoit, Joseph Duron, Francesco Grilli

Geometrical aspects of the design of fault current limiters (FCL) have a great impact on their performance. Recently, the University of Geneva have presented optimized geometries obtained by splitting the FCL into many small dissipative lengths in order to ...

IEEE Institute of Electrical and Electronics Engineers2005

Comparison of Numerical Methods for Modelling of Superconductors

Bertrand Dutoit, Bertrand Dutoit, Francesco Grilli, Yong Yang

Different FEM formulations have been developed in order to model the electromagnetic behaviour of type II super-conductors. The paper presents a comparison between simulations with A-V formulation models implemented in two FEM software packages (FLUX2D and ...

Institute of Electrical and Electronics Engineers2002