1,721,091 research outputs found
HTS dc transmission and distribution: concepts, applications and benefits
No full textThe advantages of using HTS cables for dc transmission and distribution are quantitatively
investigated. 2G-HTS cables with LN2 cooling are considered. MgB2 cables with LH2 cooling or
with two stages LH2/ LN2 cooling are considered as well. A design procedure is first set up to
arrive at the sizing of the cryopipes in order as to have a realistic estimation of the cooling power
required. Losses and right of way of HTS cables are calculated and compared with those of
conventional solutions by following a system approach, which takes into account the possible
different power architectures of the two cases. Cost comparison is also carried out. Bulk energy
transmission by means of HTS HVDC link is dealt with. Feasibility of medium voltage HTS dc
connection of a large offshore wind park is assessed. Finally, low voltage HTS dc distribution for
data centers, aluminum smelters and ships is investigated
EUCAS 2023 Conference Co-Chairs’ Introduction
No full textThe 16 th European Conference on Applied Superconductivity (EUCAS) 2023 was held from 3–7 September 2023 at the Palazzo della Cultura e dei Congressi in Bologna, Italy under auspices of the European Society on Applied Superconductivity (ESAS). The event marked 30 years since the first EUCAS in Göttingen, Germany in 1993. Since then, EUCAS has become a first-rate, world-class event for the sharing of knowledge and latest advances in all areas of Applied Superconductivity, from materials and conductors to large scale applications for medicine, research, and energy transition, as well as electronics for novel devices and quantum computing
In-Depth Induction Heating of Large Steel Slabs by Means of a DC Saturating Field Produced by Superconducting Coils
No full textThe feasibility of an innovative in-depth AC induction heating method for large steel slabs is investigated. Aside from the AC field, which induces the heating currents, a large DC magnetic field is also applied, which brings the material to saturation. Due to saturation, permeability is reduced by orders of magnitude and the penetration depth is drastically increased, thus enabling much faster and more uniform heating. In order to produce the field needed for the saturation of common steel workpieces, lossless DC superconducting magnets need to be employed. A possible layout of an AC induction heater employing magnetic saturation (saturated AC induction heater) is discussed. The conceptual design of the superconducting magnet needed is carried out based on present state-of-the-art superconducting materials. The performance of the saturated AC induction heater is numerically investigated and compared with the case without magnetic saturation
Design and performance of a 1 MW-5 s high temperature superconductor magnetic energy storage system
No full textThe feasibility of a 1 MW-5 s superconducting magnetic energy storage (SMES) system based on state-of-the-art high-temperature superconductor (HTS) materials is investigated in detail. Both YBCO coated conductors and MgB2 are considered. A procedure for the electromagnetic design of the coil is introduced and the final layout is arrived at and compared for the two materials. The choice of the inductance of the coil is carried out as part of the design procedure. Both low-field (3 T) and high-field (8 T) designs are considered for the YBCO. AC losses during a complete charge/discharge cycle at full power are estimated and the cooling power needed for continuous operation is derived. The power conditioning system and control algorithms needed to carry out various operations are discussed in detail. Performances of the SMES system during voltage sag compensation, load leveling and power factor correction are investigated by means
of numerical simulation
Supercapacitor Modeling for Real-Time Simulation Applications
No full textSupercapacitor-based energy storage systems have proved their performance in stabilizing the power system, particularly during disturbances, which require high power capability, but low energy density, such as during frequency support services. Several models have been proposed in literature to model the supercapacitors, aiming to maximize the model accuracy in the whole frequency spectrum. However, their real-time modeling has been not deeply studied, in particular, considering the real-time simulation constraints, that limit either the model details or the simulation size. This work introduces a modeling guideline for supercapacitors for real-time simulations, proposing a tradeoff between the model accuracy and the required computational time to simulate it. Compared to existing models, this work assesses their time- and frequency-domain accuracy, estimates required computational time, and recommends which model is suited for a specific power system analysis or application
AC induction heating of ferromagnetic slabs saturated with a DC field
No full textPurpose -This study aims to investigate the feasibility of saturated AC heating of magnetic metals. In AC heating of magnetic steel below the Curie temperature, because of the high magnetic permeability, the penetration depth is in the order of 1-6mmat 50 Hz. Surface heating is then obtained, in practice, if large slabs are processed. The necessity to provide the required surface-To-core temperature uniformity (about 25°C) at the end of the heating process, avoiding excessive thermal stresses which can lead to cracks, thus implies a long heating time. Design/methodology/approach -The penetration depth can be increased if the material is brought to saturation by applying an external DC magnetic field, and a faster in-depth heating can be obtained. The DC saturating field can be produced with no losses over large volumes by means of superconducting (SC) coils. Findings -The feasibility of in-depth induction heating of a 200 1,000 5,000 mm magnetic steel slab with an applied 2 T DC saturating field is numerically investigated. The results show that the use of a DC saturating field leads to shorter processes which fulfil the heating objectives. Practical implications -A DC saturating field cannot be produced by means of copper coils because of the large amount of material and the unaffordable power required. However, this field can effectively be produced by means of SC magnets based on state-of-The-Art materials. Originality/value - Superconductivity may be the enabling technology for fast and efficient induction heating of magnetic steel slabs if the increase in productivity can balance the additional costs due to the SC magnet
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Solid Nitrogen Cooled Linear Levitating System Based on MgB2 Bulks
No full textAn innovative linear levitating system based on MgB2 bulks produced by the Reactive Liquid Infiltration (RLI) method is designed and built. Details of the system are presented. The levitation performance is also evaluated by means of previous experimental data.
The linear levitating system consists of four MgB2 arc-shaped tiles lodged inside a double shells dewar sliding on a guide made of Nd-Fe-B permanent magnets. The magnets on the guide are properly arranged in a flux shaper configuration in order to pro-duce the maximum stiffness. Each MgB2 bulk have curvature radius of 165 mm (arc length 200 mm), thickness 10 mm and width 70 mm The system is cooled by means of a Solid Nitrogen heat sink. Helium gas supply to a heat exchanger is used in order to cool down the MgB2 slabs and the nitrogen at a temperature in the range 20-30 K. When the flow of helium gas is interrupted the temperature of the solid nitrogen remains below 39 K for half an hour. During this time interval levitation measurements can be performed. Experimental verification of the cooling concept has been carried out successfully
A Fast Integral Equation of J−φe Formulation for Superconducting Structures
No full textThis article presents an integral equation method based on the current–potential ( J−φe ) formulation, for the solution of the eddy currents problem in superconducting structures. Two efficient methods for storing and manipulating the fully populated matrices resulting from the discretization of the integral equation are proposed in this work. These approaches leverage hierarchical ( H ) matrices and the fast Fourier transform technique, tailored for voxelized structures. These techniques drastically reduce the computational cost of the numerical simulations. The proposed approach is compared to existing methods, as the H−φm formulation, and is efficiently applied to calculate the power losses for a realistic high-temperature superconductor coil
The proposed approach is compared to existing methods, as the formulation, and is efficiently applied to calculate the power losses for a realistic High-Temperature Superconductor (HTS) coil
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