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This paper presents the characteristics of novel high temperature superconducting (HTS) twisted square wires with different structure. First, the HTS tapes of 4 mm width are cut into 1 mm width HTS narrow tapes. Then, different numbers of HTS narrow tapes and narrow tape of copper are stacked to prepare a HTS square wire with three structures of 1 + 5c, 2 + 4c and 4 + 2c. Finally, the HTS square wires of these three structures were twisted, and the critical current characteristics of HTS tapes were tested under different twist pitches. The test results show that the twist pitch of the three structures is about 100 mm. The experimental results show that the preparation of HTS square wire with twisted characteristic better, which has broad application prospects in superconducting power equipment.

High temperature superconducting (HTS) maglev train running in the evacuated tube is a new kind of transportation with great potential, and its guidance performance is crucial to the ability of passing through curves. Therefore, it is necessary to study the guidance force of the bulks YBCO under a low-pressure environment. Based on the test platform of magnetic levitation characteristics under a low-pressure environment, the liquid nitrogen super-cooling state is realized by the method of evacuation and depressurization. The guidance force of YBCO superconductor in the lateral displacement above a Halbach permanent magnetic guideway (PMG) was measured under different pressure values (100 kPa, 60 kPa, 40 kPa, 20 kPa). Results show that decreasing pressure improved the guidance performance of YBCO bulks. Compared with the maximum guidance force and its hysteresis under 100 kPa, there are about 23.1% increase for guidance force and 40% decrease for hysteresis under 20 kPa. So, the lateral stability of the HTS maglev system has been enhanced during the evacuation process. The experimental results provide basic references for the research on the evacuated tube transportation (ETT) HTS maglev system.

This paper focused on the effects of antioxidant on the resistance to electrical tree degradation in EPDM under liquid nitrogen. In the study, a needle-plane electrode system was used to investigate the electrical treeing characteristics under liquid nitrogen. In the test, the pulse amplitude was 25 kV with pulse frequency of 200 Hz. The results showed that the electrical tree was deaccelerated under liquid nitrogen in EPDM. Moreover, the antioxidant was served as the degradation inhibitor in EPDM, which restrained electrical treeing process in both room temperature and liquid nitrogen environment. This research has substantial commercial significance in high temperature superconducting insulation areas.

Due to high power density, high efficiency and outstanding dynamic characteristics, high temperature superconducting (HTS) machine shows a good application prospect in ship proportion and new energy generation. To ensure the safe operation of the HTS machine, the wireless online monitoring system to determine that whether HTS has failed is necessary. An online monitoring system was designed by detecting the voltage, environment temperature and liquid nitrogen level and the system was applied to the 500kW HTS machine. The experiment result shows that the wireless online monitoring system designed in this paper sufficient accuracy and reliability.

The research of Bitter-like high temperature superconducting (HTS) magnets is potential for producing strong magnetic field, which can operate in persistent mode. Based on the formula of the magnetic field generated by the uniform current circle and anisotropic critical current density model at 77 K, the magnetic field distribution in a single ReBCO annular plate can be simulated by using MATLAB software. According to the magnetic field, the distribution of the critical current density could be calculated, which provides essential reference for Bitterlike HTS magnet made from ReBCO annular plates.

Up to now, the lapped insulation is the insulation measure for most high temperature superconducting cables, whose material is mainly insulating paper. As superconducting cables should be operated under low temperature environment, low temperature characteristics of the insulating cable have become important indexes for the insulation design of the high temperature superconducting cables, and it is indispensable to conduct the experiment for the low temperature characteristics for the insulating paper. This paper has conducted the AC voltage withstanding test and analysis under the low temperature environment (LNG, 77K), has come to the conclusion of the insulation parameters of the PPLP based on the Weibull distribution under the characteristic experiment illustrated above according to the PPLP, and has provided reliable foundations for the application of the insulation materials in the insulation design of high temperature superconducting cables.

High temperature superconducting (HTS) materials including HTS bulks and HTS wires become available to apply in some transportation applications. In this work, two different types of hybrid HTS magnetic suspension and linear propulsion systems have been designed and modeled for the evacuated tube transportation (ETT) and electromagnetic aircraft launch system (EMALS) respectively, and their performances have been analyzed by finite element time–stepping transient method. With the principal parameters’ verification up to 3000 km/h in principle, this work forms a basis for the structural and electromagnetic design of a hybrid HTS magnetic suspension and linear propulsion systems for practical high speed driving applications.

New superconductor materials have been constantly found since the discovery of superconductivity in 1911. With the critical temperature and inherent flux-pinning property improved continually, the practical high temperature superconducting (HTS) magnetic levitation (maglev) technology in rail transit became possible. The development history and the current state of the HTS Maglev in Applied Superconductivity Laboratory (ASCLab) are elaborated in detail. On the basis of the test vehicle “century” born in 2000, improvements and new technologies need to be investigated. First of all, a 45-m-long HTS Maglev ring test line, named “Super-Maglev”, was successfully developed focusing on the high-efficiency and low-cost. Then, aiming to eliminate the obstacle of air resistance, a test platform for HTS Maglev-Evacuated tube transport (HTS Maglev-ETT) was established in June 2014, in which the HTS Maglev and the ETT had been successfully combined. Recently, a hybrid maglev vehicle with both permanent magnetic levitation (PML) and superconducting magnetic levitation (SML) was proposed for enhancing load capacity. We continue to promote the HTS Maglev technology, and offer a new rail transit tool with high speed, energy efficiency, environmental friendly and low cost.

Soldered-Stacked-Square (3S) high temperature superconducting (HTS) wire is a novel structure of second generation (2G) HTS wire which has been developed through narrowing, stacking and soldering processes. AC loss is one of the most important parameters that needed to be confirmed when the 3S wires are applied in alternating current or magnetic field circumstances. In this paper, we proposed a three dimensional (3D) finite element method to calculate the AC loss of the 3S wire. A homogenization method is introduced to simplify the simulation process and improve the simulation speed. The model is based on E-J power law and H-formulation in 3D space. The simulated 3S wire is made of six narrow HTS tapes. The validity of the model is verified by the experimental results. Moreover, the simulated results are also compared with the theoretical results obtained from the elliptical and thin strip equations of Norris model. In conclusion, the AC loss of 3S wire lies between two theoretical values. The work in this paper would be meaningful to understand the electromagnetic characteristics of 3S HTS wire. It is also a preliminary study on the twisted 3S HTS wire and 3S HTS wire solenoid coil.

The critical current of 2G high temperature superconducting (HTS) wire is attenuated by the influence of external magnetic field. And the degree of attenuation is decided by the direction and magnitude of the magnetic field. In order to narrow the high temperature superconducting wire, a novel HTS square wire with 1 mm width was proposed. In this paper, the critical currents of HTS tapes with 4mm,1mm width and the novel HTS square wire were measured under the temperature of 77K, different magnitude and direction (0 ~ 1.2T, 0 ~ 360 °) of magnetic field, respectively. The results show that the critical current of the novel HTS square wire attenuates with the increase of external magnetic field strength, and has obvious anisotropy. The dependence of critical current of the novel HTS square wire on magnetic field angle is obtained. The tested and analyzed results are providing data reference for the simulation of the novel HTS square wire.

The paper mainly focuses on bending properties of a novel Soldered-Stacked-Square (3S) high temperature superconducting (HTS) wire with 1 mm width [1], which is designed to decrease the effect of external magnetic field [2]. The critical currents of the prepared several 3S samples before and after being bended are tested and compared in this paper. The results reflect that the samples could maintain a good stability with various bending diameters. There is also almost no degradation in critical current within limitation. Based on the above mentioned summaries, it is effectively confirmed that 3S HTS wires can satisfy the demand of contemporary electrical equipment.

Bifilar coil is one of the most significant components for high temperature superconducting (HTS) fault current limiters (FCLs). We studied a bifilar stack composed of two coated conductors (CCs) without ferromagnetic substrate, where upper and lower conductors carry current in opposite directions. Three bifilar stack arrangements were designed, depending on the adjacent CCs facing each other by HTS to substrate side (H-S), HTS to HTS side (H-H), or substrate to substrate side (S-S). Numerical calculations, by means of a B-dependent E-J power-law relation and non-uniformity $J_{\mathrm {c}}$ distribution along tape width, were carried out to investigate the effect of stack arrangements mentioned above on AC loss reduction and the dependence of AC loss value on bifilar turn number N.

The idea of insulating individual high-temperature superconducting (HTS) tapes was explored as a dielectric design to reduce the risk and complexity of HTS cable manufacturing. Applying insulation on individual HTS tapes is amenable to continuous manufacturing processes and opens up material choices for the insulation. In this study, heat shrink insulation was selected as the material choice for exploring the possibility of this design philosophy because of its commercial availability in multiple thicknesses. A systematic set of selection criteria was developed for the selection of appropriate heat shrink for given HTS tape dimensions. The cryogenic dielectric characteristics of insulated HTS tapes were evaluated both in liquid nitrogen and gaseous helium environments at 77 K. Dielectric characteristics of tapes with a single layer of thicker insulation were compared with those insulated using multiple layers of thinner insulation to evaluate the relative merits of each method. Several model power cables were fabricated using the PET insulated tapes, and their dielectric behavior was evaluated at 77 K in gaseous helium environment. The results suggest that the explored method is useful for HTS power cables operating at low voltages (

International audience; In this article, we report on the fabrication of very long YBa2Cu3O7 nanowires in a meander shape patterned in a CeO2-capped thin film by high-energy oxygen ion irradiation. DC and RF characterizations outline the good superconducting properties of the nanowires whose geometryapproaches the one used in single photon detectors. Their inductance, which mainly sets the maximum speed of these devices, has been measured on a wide range of temperature by mean of a resonant method. The extracted values are in agreement with the ones calculated from the geometry of the meanders and from the known London penetration depth in YBa2Cu3O7 thin films.

The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.

Locating of normal transitions in high temperature superconducting (HTS) coils is important for protection and safety design of HTS apparatus. A general method to locate the normal transitions is to measure resistive voltages along HTS windings by many voltage taps directly soldered to the HTS coils. However, electrical insulation characteristics of the HTS coils are deteriorated because it is necessary to remove electrical insulations of the HTS wires for the soldering. It is a serious problem especially for AC HTS coils to which high voltages are applied. Therefore the authors have presented a non-contact voltage measurement method that can detect the resistive voltages without removing the insulations by voltage dividing capacitors. So far the authors have verified the principle of the non-contact method. In this paper, a method to locate the normal transitions in a Bi2223 HTS coil based on the non-contact method is proposed. The proposed method can not only detect the normal transitions but also locate their positions. It is experimentally confirmed that the proposed method is useful for locating the normal transitions.

High temperature superconducting (HTS) maglev technology is becoming more and more mature, and many key technologies have been deeply studied. However, the transition curve plays a key role in HTS maglev system, and related studies have not been carried out. In this paper series of simulations were conducted to test the lateral and vertical vibration of HTS maglev when passing through curves. Two magnetic guideways, of which one has transition curves but the other does not, are designed to test the vibration characteristics of a mini HTS maglev model running though curves. Results show that after adding transition curves between straight line and circular curve the vibration of HTS maglev model in lateral and vertical directions are all weakened in different degrees. It proves that adding transition curve into HTS maglev system is favorable and necessary.

A novel approach to quench detection for high temperature superconducting (HTS) coils is proposed, which is mainly based on phase angle between voltage and current of two coils to detect the quench resistance voltage. The approach is analyzed theoretically, verified experimentally and analytically by MATLAB Simulink and LabVIEW. An analog quench circuit is built on Simulink and a quench alarm system program is written in LabVIEW. Experiment of quench detection is further conducted. The sinusoidal AC currents ranging from 19.9 A to 96 A are transported to the HTS coils, whose critical current is 90 A at 77 K. The results of analog simulation and experiment are analyzed and they show good consistency. It is shown that with the increase of current, the phase undergoes apparent growth, and it is up to 60° and 15° when the current reaches critical value experimentally and analytically, respectively. It is concluded that the approach proposed in this paper can meet the need of precision and quench resistance voltage can be detected in time.

Three types of high temperature superconducting current leads (HTSCL) are designed to carry 68 kA, 55 kA or 10 kA to the ITER magnets. Before the supply of the HTS current lead series, the design and manufacturing process is qualified through mock-ups and prototypes. Seven mock-ups, representing the critical technologies of the current leads, were built and tested successfully in the Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP) in 2013. After the qualification some design features of the HTS leads were updated. This paper summarizes the qualification through mock-ups. In 2014 ASIPP started the manufacture of the prototypes. The preparation and manufacturing process are also described.

Recently, extensive studies have been carried out on developing a high voltage superconducting apparatus as a substitute for the conventional one. superconducting wires used for a high voltage superconducting apparatus can be damaged under high voltage condition due to electrical breakdown and the damaged superconducting wires may result in the degradation of the critical current (Ic) and index number. Therefore, a study on the degradation characteristics of superconducting wires in accordance with the electrical breakdown should be performed. In this paper, the degradation characteristics of second generation high temperature superconducting (2G HTS) wires with respect to electrical breakdown tests are studied. The applied electrical breakdown voltages to 2G HTS wire are AC and lightning impulse (Imp) ; 50, 60 and 70 kV. The electrical breakdown test is successively repeated five times. The Ic and index number of 2G HTS wires were measured. The relationship between electrical characteristics such as the Ic and index number and the electrical breakdown was analyzed.

This paper described the medium voltage high temperature superconducting cable thermal simulation and its application. New simulation method for HTS cable modeling using PSCAD/EMTDC is introduced in this paper. The developed simulation method consists of electrical model part and thermal model part. In electrical model part, power loss and thermal capacitance can be calculated in each layer, then the temperature of each layer can be calculated by power loss and thermal capacitance in thermal model part. This paper also analyzes the electrical and thermal characteristic in the case of normal operating condition and transient including single line to ground fault and line to line ground fault using new simulation method.

The high temperature superconducting (HTS) magnet has been developed for the high magnetic field applications such as NMR , MRI and other industrial machinery. In designing process of these HTS magnets, the accurate estimation on the critical current ( Ic ) is essential to predict and secure electromagnetic performance.the The critical current of 2G HTS tape has anisotropic Icdegradation characteristics with the application of magnetic field angular dependency of critical current. It is known that the – perpendicular magnetic field to the face of HTS tape makes dominant degradation on the critical current for conventional 2G HTS tape. However, recently developed 2G HTS tapehas more complex characteristics due to the artificial pinning center. Therefore, the method for estimation reflecting such characteristics of 2G HTS tape needs to b Ic e devised. The method considering the angular dependency is introduced in this paper. And the result of newly devised method is compared with that of previous method.

The transient characteristics of the tri-axial High Temperature Superconducting (HTS) power cable are different from those of a conventional power cable depending on whether the cable is under a steady or transient state due to the quench. Verification using simulation tools is required to confirm both the characteristics of the cable and the effect of the cable when it is applied to a real utility. However, a component for the cable has not been provided in simulation tools; thus the RTDSbased model component of the tri-axial HTS power cable was developed, and a simulation was performed under the transient state. The considered properties of model component include resistance, reactance and temperature. Simulation results indicate the variation of HTS power cable condition. The results are used for the transient characteristic analysis and stability verification of the tri-axial HTS power cable. In the future, the RTDS-based model component of the cable will be used to implement the hardware-in-the-loop simulation with a protection device.

High temperature superconductors (HTSs) have the potential to impact the future development of superconducting applications for research magnets in physical sciences and industrial products. A compact spherical tokamak of major radius 25 cm has been designed and engineered using the second generation HTS material, REBCO tapes. It was developed with the primary objective to test out the feasibility of a fully superconducting device made entirely from HTS materials and hence be the first tokamak to demonstrate the practicality of this new medium operating at temperatures above 4.2 K. The tokamak has 6-D shaped toroidal field coils, and two poloidal field coils, each of which is wound in a pancake geometry. Each coil is made in one continuous winding and the coils are assembled together. Results of initial coils and magnet cooling and energisation will be presented.

The compact magnet for NMR device that consists of a stacked high temperature superconducting (HTS) Gd-Ba-Cu-O bulk annuli was trapped by a held cooling method. However, it was difficult to trap the uniform magnetic held above 4.7 T (200 MHz-class NMR magnet) and held homogeneity under 0.01 ppm/cm3 at liquid nitrogen temperature (77.4 K) because of the low Jc-B characteristics of present HTS bulks. On the other hand, the strength and homogeneity of the magnetic held required for NMR relaxometry device are 1.5 T and 150 ppm/cm 3 respectively. It is easily to generate the trapped magnetic held over 1.5 T at 77.4 K using the stacked HTS bulks, but it is still hard to obtain 150 ppm/cm 3 held homogeneity with the conventional superconducting magnet (SCM) as the magnetizing magnets. Therefore, we have studied the compensation methods to improve the held homogeneity. In this paper, we proposed the packaged HTS bulk magnet consisted of HTS bulks annuli and various iron rings as the held compensation, and investigated it in analysis and experiment.

We proposed an HTS wind power generator that has armature windings in the rotor. Field windings in the stator make a slightly higher magnetic field than the field windings in the rotor if both windings have same size of armature windings and field coils. In addition, we split the field windings into two and installed one of the split ones inside the armature, i.e., the so-called dual field windings. This structure is mechanically complex because the armature windings rotate between two stationary field windings. However, the output voltage of the 10-MW generator is 12% higher than that of the rotating field with this structural modification. We set up six different types of field winding arrangement and analyze the field magnitudes and field distributions in the armature and field windings of each one. Finally, the output voltages are calculated by a finite-element method at full load.

Electric joints are an essential part of every current carrying device. In the field of high temperature superconducting applications, quality of a contact between superconducting tapes and electric terminations is crucial for the device performance. When connecting tapes to each other, soldered contacts are commonly used. Recent reports have demonstrated that the resistance of this contact depends on the pressure applied during a soldering process, and the soldering temperature. When superconducting tapes are used in cables or in other applications, they have to be connected to copper terminations, e.g., to a current lead. Thus, tape-to-copper contacts are important. In superconducting cables, tapes are stacked together having a resistive electrical contact from tape to tape. The resistance of this contact depends on the pressure applied on the stack due to, for example, jacketing of the cable or during cool down. In this paper, the dependence of resistance between tapes on the applied pressure is reported. In this contribution two kinds of contacts, soldered ones and mechanical pressed, are presented and discussed. They are realized, respectively, between two superconducting ReBCO tapes from SuperPower, Inc. (SPI) and SuNAM, which were used for manufacturing HTS cable, and between superconducting tapes and copper.

Concept design and optimization for a high-temperature superconducting (HTS) rotor of a 100-kW generator is studied in this paper. The rotor has eight HTS magnets constructed by air-cored racetrack coils. The HTS magnets with a unique circular cross-sectional shape can produce a gap field over 2.0 T. The present design is based on a new graphical method developed to estimate the maximum operating current of an HTS magnet that takes both I c -B characteristics and angular dependence into consideration. The optimized stepped shape design saved more than 8% of the HTS material compared with the rectangular one without sacrificing the gap field.

The development of high temperature superconducting (HTS) dc cable system has been promoted for the land long-term high-capacity power transmissions, submarine cables and renewable energies. Polypropylene laminated paper (PPLP) has been widely used as insulating material for HTS cable. To develop the PPLP-insulated dc cable, it is important to study the dc, dc polarity reversal and lightning impulse characteristics at a cryogenic temperature. In this paper, we discuss the electrical insulation characteristics of PPLP-insulated mini-model cable. We investigate the dc, impulse breakdown strength, dc polarity reversal, and dc voltage (V)-numbers of dc polarity reversal (N). Also, based on these results, the insulation design of 250 kV class HTS dc cable is performed.

Tri-axial high temperature superconducting (HTS) power cables are being developed to maximize their advantages, which include reducing amount of HTS wires, having a low-leakage magnetic field, and being compact compared to different types of HTS power cables. However, a drawback of HTS power cables is their inherent imbalance impedance, which is due to an asymmetrical structure on each phase. To solve this problem, the phases must be transposed. The authors designed a distribution class tri-axial HTS power cable, as well as a transposition-based connection scheme for the cable. The phases of the cable were connected to each other via transposition through their cross-connections. This was achieved with an insulated support structure with three walled-off areas for insulation between three the phases, as well as transposition conductors, including copper base and HTS wires. In this paper, a distribution class tri-axial HTS power cable and a connection scheme for it are designed. The results, including the transposition-based joint box design, are described in detail. The connection scheme will be applied to the joint box of the cable for high-capacity and long-distance transmission.

The engineering critical current (Ic) of the high temperature superconducting coated conductors (HTS-CCs), today available on the market, is not a uniform parameter and varies significantly along the length of the conductors. Moreover, commercial HTS-CCs have a low normal zone propagation velocity (NZPV). This property, together with the Ic inhomogeneity, exposes the HTS-CCs to local thermal instabilities. A crucial challenge for the design of resistive fault current limiters (RFCLs) based on HTS-CCs is to avoid the thermal runaway of the conductors, and in this respect the enhancement of the NZPV is a promising solution. In the recent years, several methods have been proposed and many and various techniques are now available to enhance the NZPV. Whichever will be the best technical solution to improve NZPV of HTS-CCs, our aim is to quantify the impact the enhancement of NZPV will have on the design of RFCLs based on HTS-CCs. For this reason, we used numerical models to analyze the effects of the enhancement of NZPV on the limitation performance of a RFCL integrated in a medium voltage (MV) power grid. In this manuscript, we quantify the benefits the enhancement of the NZPV will have on the next generation of HTS-CC-based RFCLs for MV grids

A Rogowski coil based sensor for current measurement in a cryogenic environment and results of its application for paralleled high temperature superconducting (HTS) coil current sharing are presented. The current sensor consists of a Rogowski coil and an integrator, where the coil output voltage is proportional to the derivative of primary current and the integrator transfers the differentiation to normal state. The Rogowski coil has promising applicability at cryogenic circumstance because its body is made of low temperature materials. The integrator ensures a large bandwidth with feasible magnitude, which is vital for dynamic current measurement during the quench of the HTS coil. The proposed current sensor is used for current sharing measurement of two paralleled Bi2223 HTS coils, and the experimental results show that the measurement precision is better than 0.5%.

This paper introduces two on-going projects for DC high temperature superconducting (HTS) cable systems in South Korea. This study proposes the application of DC HTS cable systems to enhance power transfer limits of a grid-connected offshore wind farm. In order to develop the superconducting DC transmission system model based on HTS power cables, the maximum transfer limits from offshore wind farm are estimated and the system marginal price (SMP) calculated through a Two-Step Power Transfer (TSPT) model based on PV analysis and DC-optimal power flow. The proposed TSPT model will be applied to 2022 KEPCO systems with offshore wind farms.

Stiffness of radial high-temperature superconducting (HTS) bearings is widely researched by experiments (measurement method). These researches include radial stiffness and axial stiffness at different temperatures and rotational speeds, cross stiffness, and so on. The measurement method can obtain the precise value of stiffness, while it takes so much time and cost. Simulation calculation method is suitable to model radial HTS bearings which have different structures, and it is easier to obtain stiffness than the measurement method. The problem is that the calculation precision is sensitive to the parameters in the simulation calculation. The measurement and calculation method of the radial stiffness of radial HTS bearings has the strong points of saving time and cost, and high precision. In this paper, this method is improved. Radial stiffness between HTS bulk and permanent magnet (PM) rotor is analyzed basing on a new mechanical model, and equation for the radial stiffness of radial HTS bearings is deduced. The error of calculation is reduced to 2.86 % according to the measured values. Application of this method for calculating the radial stiffness of radial HTS bearings with different number of HTS stator layers is introduced.

We have been studying the compact magnet for NMR device that consists of a stacked high temperature superconducting (HTS) GdBCO bulk annuli. We can generate the trapped magnetic field over 1.5 T at 77.4 K and 150 ppm/cm 3 on inner diameter of 20 mm HTS bulks using field compensation methods. However, it is necessary to enlarge the inner diameter of the HTS bulk magnet because the diameter of commercial NMR probe is larger than 20 mm. In this paper, we studied an optimal shape of the stacked HTS bulk magnet to obtain the enlarged inner diameter using 3-D FEM based analysis. We was able to enlarge the inner diameter of the HTS bulk magnet from 20 mm to 34 mm remaining magnetic field strength of 1.5 T and magnetic field homogeneity of 666 ppm/cm3 by proposed passive field compensation method.

As the world progresses towards green and cost-effective energy applications, it is imperative to discover and introduce viable electrocatalysts to replace platinum, which is expensive and scarce. High-temperature superconductors have been intensively studied at the end of the 20th century owing to their unique electrical behaviour; nonetheless, we wish to show their interesting electrocatalytic properties as well. This work seeks to investigate the feasibility of two high-temperature superconductors, YBa2Cu3O7 (YBCO) and Bi2Sr2CaCu2O8 (BSCCO) in catalysing the hydrogen evolution and oxygen reduction reactions electrochemically. These materials can be easily synthesized by solid state reactions and this in combination with the fairly impressive electrocatalytic properties displayed in our study, mean that they definitely possess the potential to replace platinum as prospective electrocatalysts.

In the case of motors and generators, the benefits of using high temperature superconducting (HTS) coils can be represented by the reduction of 50% in both losses and sizes compared to conventional machines. However, it is hard to establish quench detection and protection devices for the HTS coils applied to the rotors of motors and generators. So, the stability of the coils is lower than for the quiescent coils applied to NMR, MRI and so on. Therefore, it is important to improve the self-protection ability of HTS coils. We have studied the methods to improve the self-protection ability of HTS coils by removing the layer-to-layer insulation and inserting metal tape instead of the electrical insulation. The operating current in the non-insulated HTS coil was bypassed into the transverse direction by the generated normal region because of their electrical contact among the winding. In this study, we examined the method to control the current bypassing on layer-to-layer for controlling the inductance of the non-insulated HTS coil. The current bypassing properties on non-insulated HTS coil wound with 2G wires will be discussed.

The results from investigations into the formation, structure, and physicochemical properties of new high-temperature superconducting (HTSC) phases in Ln–Ba–Cu–O systems are summarized. The effect of the composition of the superconducting phase, features of the crystal structure of the HTSC REE cuprates, their morphology, and crystal defects on the temperature of the transition to the superconducting state is analyzed. The advantages and disadvantages of existing approaches to the production of superconducting ceramics are discussed.

The temperature and magnetic field data acquisition system is developed for HTS Magnet of ITER. According to its working environment, the type of probes used for detection and the corresponding supporting equipment are chosen. Based on the requirements of data acquisition precision, the selection of the data acquisition instruments is completed. Optimize the number and configuration of probes and keep key monitoring on its Conduction-cooled structure. A complete set of complete data collection and human-computer interaction system is designed by using LabVIEW.

High temperature superconducting tapes of 2nd generation (HTS 2G) are being manufactured by several companies worldwide, which use different methods of fabrication of superconducting layers that affect the behaviour of HTS 2G tapes in actual practice. This paper presents the results of the study of HTS 2G tapes delamination process, the influence of alternating temperature impacts on critical current and the behaviour of current carrying capacity of HTS 2G tapes in external magnetic fields. The abovementioned problems can arise in almost any case of designing devices based on HTS 2G tapes. Furthermore, the developed measuring techniques are very important for controlling of output parameters of HTS 2G tapes that are to be manufactured in NRC “Kurchatov institute”.

The heat capacity for anisotropy of high temperature superconducting material is hard to calculate. This paper analyze the structure characteristics of Bi superconducting material , build polymolecular Bi-2223 system, simulate the specific heat of the Bi system high temperature superconducting material based on the molecular dynamics method. And then obtain the material parameters of the specific heat of the Bi - 2223 range of 20~40K.

A 35kV high temperature superconducting controllable reactor (HTS-CR) is under development and the electromagnetic design has been completed. Due to the AC conditions, the thermal stress caused by AC losses can be so strong that the stress analysis should be carried out to verify that the maximum stress under different operating conditions is in appropriate range. In addition, Lorentz force of HTS windings will impact the bobbin structure of the HTS windings which will endanger the 35 kV HTS-CR. Stress analysis is important for the design of a mechanically stable structure. This paper provides the analysis of the bobbin structure and its result of optimization design considering the requirements of safety and cooling.