Showing papers in "IEEE Transactions on Applied Superconductivity in 2005"
TL;DR: SupraTrans as discussed by the authors is an innovative transportation concept based on the principle of superconductive magnetic levitation, which uses the flux pinning in high temperature superconductors (HTS) to stabilize the lateral and vertical position of the vehicle on the magnetic track.
Abstract: SupraTrans is an innovative transportation concept based on the principle of superconductive magnetic levitation. The aim of the project is to create a fully working prototype, which proves its ability for passenger transport by explicit consideration of the compatibility between systems for propulsion, safety, positioning, power supply, transport logistics and the levitation system itself. The SupraTrans technology uses the flux pinning in high temperature superconductors (HTS) to stabilize the lateral and vertical position of the vehicle on the magnetic track. This self-stabilizing system is the main advantage of the superconductive levitation in comparison to all other levitation systems, which need electronic control and power to keep a constant distance between the train and the track.
308 citations
TL;DR: In this article, the authors presented fabrication and characterization procedures of devices for circuit quantum electrodynamics (cQED) with 3-GHz cavities with quality factors in the range 10/sup 4/-10/10/sup 6/, which allow access to the strong coupling regime of cQED.
Abstract: We present fabrication and characterization procedures of devices for circuit quantum electrodynamics (cQED). We have made 3-GHz cavities with quality factors in the range 10/sup 4/-10/sup 6/, which allow access to the strong coupling regime of cQED. The cavities are transmission line resonators made by photolithography. They are coupled to the input and output ports via gap capacitors. An Al-based Cooper pair box is made by e-beam lithography and Dolan bridge double-angle evaporation in superconducting resonators with high quality factor. An important issue is to characterize the quality factor of the resonators. We present an RF-characterization of superconducting resonators as a function of temperature and magnetic field. We have realized different versions of the system with different box-cavity couplings by using different dielectrics and by changing the box geometry. Moreover, the cQED approach can be used as a diagnostic tool of qubit internal losses.
209 citations
TL;DR: In this article, a hybrid energy storage system composed of a superconducting magnet and secondary battery was proposed for compensation of fluctuating loads such as railway substations and distributed generations such as wind turbines.
Abstract: An energy storage device with high energy density and high power density is desired for compensation of fluctuating loads such as railway substations and distributed generations such as wind turbines. Typically, a SMES (Superconducting Magnetic Energy Storage) has higher power density than other devices of the same purpose, and secondary batteries have higher energy density than SMES. In this study, the authors propose a hybrid energy storage system composed of a superconducting magnet and secondary battery for an energy storage system with high energy density and high power density. The sharing method of power for each storage device using a Fuzzy control and filters, simulation for the compensation of railway loads and the power of wind turbines are presented.
186 citations
TL;DR: A 5 MW, 230 RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor is presently under test at the Center for Advance Power Systems (CAPS) as mentioned in this paper.
Abstract: A 5 MW, 230 RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor is presently under test at the Center for Advance Power Systems (CAPS). This paper provides a summary of the key design features of the motor, predicted performance, factory test results and extended test results to date at CAPS. This motor was designed and built under the U.S. Navy's Office of Naval Research (ONR) funding (Contract #N00014-02-C-0190) to address the next generation of electric ship propulsion systems. HTS motors are characterized by high power density, quiet operation and high efficiency. HTS air-core motors have unique electrical characteristics and therefore require dynamic testing to validate all modes of operation. The test program at CAPS is designed to address dynamic performance and simulation of this class of propulsion motor. The motor has been operated at 5 MW load for over 3 hours at CAPS.
175 citations
TL;DR: In this article, the authors introduced the concept of wind farms linked by SMES systems and applied the SMES system to a wind farm that is interconnected with a grid through a back-to-back DC link for the variable speed operation of the wind turbines.
Abstract: The objective of this paper is to introduce the concept of wind farms linked by SMES systems. In this work, the SMES system is applied to a wind farm that is interconnected with a grid through a back-to-back DC link for the variable speed operation of the wind turbines. This system enables the output power leveling of the wind farm depending on the power demand and can reduce the capacity of the converter system by selecting an optimal discharge/charge rate of the SMES. By using the stored energy of the SMES, this system can also compensate the inertia of the blades so that the wind turbine speed can be rapidly controlled depending on the wind condition. This paper describes the design condition of the SMES for the output power leveling of the wind farm and discusses the SMES configuration for a 100-MW class wind farm.
146 citations
TL;DR: In this paper, the benefits of superconducting Fault Current Limiters (FCLs) which can be economically competitive with expensive conventional solutions are discussed, and the performance of a particular type of limiter, the Matrix Fault Current Limiter (MFCL), is presented and examples on how it could relieve fault current over-duty problems.
Abstract: The introduction of new generating facilities by independent power producers and increasing load demand can result in fault-current over-duty on existing transmission system protective equipment. Conventional solutions to fault current over-duty such as major substation upgrades, splitting existing substation busses or multiple circuit breaker upgrades could be very expensive and require undesirable extended outages and result in lower power system reliability. Less expensive solutions such as current limiting reactors may have unwanted side effects, such as increase in system losses, voltage regulation problems or possibly could compromise system stability. This paper discusses the benefits of superconducting Fault Current Limiters (FCLs) which can be economically competitive with expensive conventional solutions. Superconducting FCLs are invisible in normal operation and do not introduce unwanted side effects. The performance of a particular type of limiter, the Matrix Fault Current Limiter (MFCL) is presented and examples are provided on how it could relieve fault current over-duty problems. The use of this device in a particular application in the American Electric Power (AEP) 138 kV transmission grid is also discussed.
144 citations
TL;DR: In this paper, progress on the development of Bi-2212 round wires is reported, and the highest J/sub E/ of 266 A/mm/sup 2/ and J/ sub c/ was obtained in 0.81 mm wire.
Abstract: Bi-2212/Ag conductor is one of the most promising materials for expanding superconducting magnet applications to higher fields and/or temperatures than present LTS systems. From the view point of practical application, Bi-2212 round wires have significant advantages over more typical HTS tape conductors, such as no anisotropy, ease of handling and simpler coil winding, allowing considerable flexibility in the magnet design. Development efforts at OST have been aimed at enhancing transport properties in long length round wires for high field magnet applications. Recently, significant improvements in the J/sub E/ and J/sub c/ performance have been achieved by optimizing the starting powders, the filament size and fill factor, the deformation processes, and the melt-solidification parameters. The highest J/sub E/ of 266 A/mm/sup 2/ and J/sub c/ of 950 A/mm/sup 2/ at 4.2 K, 45 T with n-value of 17 was obtained in 0.81 mm wire. In this paper progress on the development of Bi-2212 round wires will be reported.
141 citations
TL;DR: In this paper, a 3D numerical modeling technique for solving problems involving superconducting materials is presented, implemented in finite-element method software and is based on a recently developed 3D formulation for general electromagnetic problems with solid conductors.
Abstract: A three-dimensional (3-D) numerical modeling technique for solving problems involving superconducting materials is presented. The model is implemented in finite-element method software and is based on a recently developed 3-D formulation for general electromagnetic problems with solid conductors. It has been adapted for modeling of superconductors with nonlinear resistivity in 3-D, characterized by a power-law E-J relation. It has first been compared with an existing and verified two-dimensional (2-D) model: Compared are the current density distribution inside the conductors and the self-field ac losses for different applied transport currents. Second, the model has been tested for computing the current distribution with typical 3-D geometries, such as corner-shaped and twisted superconductors. Finally, it has been used with two superconducting filaments in the presence of external magnetic field for verifying the existence of coupling currents. This effect deals with the finite length of the conductors and cannot be taken into account by 2-D models.
114 citations
TL;DR: In this paper, a high-temperature superconducting synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk field magnets was studied, and the magnetic field was varied from 0.5 T to 0.8 T on the surface of the bulk magnet poles.
Abstract: We studied a high-temperature superconducting synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk field magnets. The motor is an axial gap-type, brushless synchronous motor with eight rotating bulk field magnet poles. Liquid nitrogen is circulated to cool down the rotor components. Pulsed field magnetization was performed to excite the bulk field magnets by using a pair of the vortex-type armature copper windings under the zero-field cooling. The trapped peak field density on the surface of the bulk was varied from 0.5 T to 0.8 T. The trapped peak magnetic field 0.5 T on the surface of the bulk magnets provided the motor performance of 3.1 kW with 720 rpm. The field density distribution on the pole bulk magnet surface is anisotropic and different from the ideal conical shape. The optimized pulsed current waveform applied to the armature and the employing of a composite of bulk crystal magnets leading to a spatially homogeneous flux trapping are promising methods for reinforcement of the field flux from the rotor and the motor torque.
111 citations
TL;DR: A preliminary electromagnetic design of a 200 HP high temperature superconducting motor optimized in terms of power density targets the Cessna 172 propulsion requirements that are 200 HP at 2700 RPM.
Abstract: NASA conducts and funds research to advance the state of the art in aeronautics, including improvements in aircraft design leading to enhanced performance in areas such as noise, emissions, and safety. A particular initiative involves development of an all-electric aircraft requiring significant improvements in certain technologies. NASA has started a new project with one of the objectives being the development of enabling technologies for an all-electric aircraft. Electrical aeropropulsion requires the design of more compact and efficient electrical motors. In order to increase the power density, the weight/size must be minimized and the air gap flux density must increase significantly: the use of superconducting materials is an obvious choice. Existing HTS motors are proof-of-principle demonstrators and exhibit power densities lower than 1 HP/lb, which is too low to be considered in mobile systems. This paper deals with a preliminary electromagnetic design of a 200 HP high temperature superconducting motor optimized in terms of power density. The presented configuration is a synchronous motor with a nonconventional topology enhanced by HTS bulk material. The design targets the Cessna 172 propulsion requirements that are 200 HP at 2700 RPM.
110 citations
TL;DR: In this article, the performance of 2G high temperature superconducting wire manufactured by continuous reel-to-reel processes is nearing the 300 A/cm-width (77 K, self field) performance threshold for commercial power cable applications.
Abstract: The performance of Second Generation (2G) high temperature superconducting wire manufactured by continuous reel-to-reel processes is nearing the 300 A/cm-width (77 K, self field) performance threshold for commercial power cable applications. The 2G manufacturing approach under development at American Superconductor is based on the combination of the RABiTS substrate-buffer technology with metal organic deposition (MOD) of the YBCO layer. The capability of this process has been demonstrated in multiple 10 meter lengths with critical currents exceeding 250 A/cm-width with high uniformity and reproducibility. Critical currents of 380 A/cm-width have been achieved in short length samples prepared by the same basic process. The incorporation of nanoparticles ("nanodots") into the YBCO layer using the MOD process has resulted in a 2-fold improvement in the critical current at 65 K in a 3 T field. The research and development focus at ASMC is now directed toward the economical scale-up of the RABiTS/MOD process, optimization of the conductor properties for targeted applications and the use of 2G wire in initial demonstration applications.
TL;DR: In this article, a three-phase resistive current limiter was developed and successfully tested up to the nominal voltage and power (10 kV, 10 MVA) for the CURL 10 project.
Abstract: Within the German project CURL 10 a full scale three-phase resistive current limiter was developed and successfully tested up to the nominal voltage and power (10 kV, 10 MVA). This is up today the largest HTS current limiter world wide. The device is based on bifilar coils of MCP-BSCCO 2212 bulk material and operates at T=66 K. Per phase 30 components are connected in series in order to obtain the required resistance. The electrical stabilization is based on a metallic shunt contacted continuously to the superconductor and allows electrical fields up to 0.6 V/cm. We report on the development of the superconducting components and their large-scale manufacturing processes including material, contacts, mechanical stabilization, high voltage insulation and quality control. In a series of preliminary small scale tests at different temperatures as well as in the final tests with the full scale prototype reliable current limitation could be demonstrated in the full range of prospective fault currents, also in the particular dangerous small load regime. Since April 2004 the demonstrator has been installed within a field test in the grid of RWE.
TL;DR: In this article, the effects of localized, pulsed heat disturbance on a YBa/sub 2/Cu/sub 3/O/sub x/Ni-alloy conductor with Cu stabilizer was investigated.
Abstract: In the ongoing effort to investigate the normal zone behavior of coated conductors, the effects of a localized, pulsed heat disturbance on a YBa/sub 2/Cu/sub 3/O/sub x//Ni-alloy conductor with Cu stabilizer was investigated. The sample was conduction cooled by a GM cryocooler in a vacuum environment, establishing nearly adiabatic conditions. A NiCr wire heater mounted on the sample was used to provide the heat pulse that initiated the normal zone. Consecutive voltage taps along the length of both sides of the sample monitored the propagation of the normal zone. Several thermocouples were glued on both sides of the sample to measure the temperature profile of the conductor. The minimum quench energies and normal zone propagation velocities were measured at ambient temperatures from 58 K to 79 K and transport current ranging from 30% to 90% of I/sub c/. The voltage and temperature profiles are presented and discussed.
TL;DR: The angular-dependent critical current density J/sub c/ in YBa/sub 2/Cu/sub 3/O/sub 7/ films grown by pulsed laser deposition exhibit a sharp peak for magnetic field orientations near the ab plane.
Abstract: The angular-dependent critical current density J/sub c/ in YBa/sub 2/Cu/sub 3/O/sub 7/ films grown by pulsed laser deposition exhibit a sharp peak for magnetic field orientations near the ab plane, which arises from the combined effects of intrinsic pinning and extended defects parallel to the planes. An analysis of the temperature and field dependence of the height and width of this peak allows us to distinguish both contributions. We find that, in a film on single crystal substrate, the peak at low fields is due primarily to the extended defects, but at high fields it is dominated by intrinsic pinning. We compare these results with those of coated conductors with a larger density of ab-oriented correlated defects. We show a novel effect consisting in an inverse correlation between J/sub c/ and the power law exponent (N) of the I-V curves that only occurs in the intrinsic-pinning dominated regime, and we present an interpretation of its origin.
TL;DR: In this article, the authors studied the strain dependence of the critical current for YBCO and DyBCO coated conductors with different buffer layers on Hastelloy substrates.
Abstract: The strain dependence of the critical current was studied for YBCO and DyBCO coated conductors with different buffer layers on Hastelloy substrates. A maximum of I/sub c/ was observed for both the YBCO and DyBCO tapes, however the sign of the strain at the I/sub c/ peak was opposite for the two superconductors. A reversible variation of I/sub c/ with applied strain was found and the reversible strain limit was observed to depend on the buffer layer. For the IBAD-CeO/sub 2//YSZ buffered YBCO tapes, I/sub c/ recovers reversibly when the applied strain is reduced starting from 0.30%. For those with an ISD-MgO buffer layer the irreversible degradation starts at a strain less than 0.22%. The reason for this difference is discussed based on microscopic observations. Quenching occurred during V-I measurements after the applied strain exceeded 0.30%, which is close to the yield strain of the composite tape.
TL;DR: In this paper, the main technical approaches and challenges in MRI superconducting electromagnetic design, trade-offs in the magnet parametric design space and their effect on the superconding design are discussed.
Abstract: Over the past two decades, magnetic resonance imaging (MRI) has developed into a mature technology, and is the leading commercial large-scale application of superconductivity. This is still a rapidly evolving field, characterized by constantly emerging configurations requiring innovative technical solutions, with trends toward increasing field strength B/sub 0/ and more advanced magnetic, cryogenic and integrated system design. This paper describes the main technical approaches and challenges in MRI superconducting electromagnetic design, trade-offs in the magnet parametric design space and their effect on the superconducting design. Recent trends, advanced novel configurations and different applications are discussed. The trend toward higher fields manifests itself in the ongoing shift of clinical applications to 3 T, as well as in recent developments of whole-body MRI with field strength up to 9.4 T. Illustrations are presented from commercial and developing MRI systems.
TL;DR: In this paper, a radial type superconducting magnetic bearings have been developed for a 10 kWh-class flywheel energy storage system, where the rotor is suspended without contact via the pinning forces of the bulk superconductors that are arranged such that the c-axis of each superconductor is aligned parallel to the radial direction of the cylinder.
Abstract: Radial type superconducting magnetic bearings have been developed for a 10 kWh-class flywheel energy storage system. The bearings consist of an inner-cylindrical stator of YBCO bulk superconductors and an outer-rotor of permanent magnets. The rotor is suspended without contact via the pinning forces of the bulk superconductors that are arranged such that the c-axis of each superconductor is aligned parallel to the radial direction of the cylinder. In this paper, we describe the implementation of the stator part and report the SMB test results, namely that the rotor was successfully rotated at up to 7,500 rpm. Thus we succeeded in energy storage of 2.24 kWh.
TL;DR: In this article, the quantum efficiency and the noise equivalent power (NEP) of the latest generation, nanostructured, superconducting, single-photon detectors (SSPDs) in the wavelength range from 0.5 to 5.6 /spl mu/m, operated at temperatures in the 2.0-to 4.2-K range were studied.
Abstract: We present our studies on the quantum efficiency (QE) and the noise equivalent power (NEP) of the latest-generation, nanostructured, superconducting, single-photon detectors (SSPDs) in the wavelength range from 0.5 to 5.6 /spl mu/m, operated at temperatures in the 2.0- to 4.2-K range. Our detectors are designed as 4-nm-thick and 100-nm-wide NbN meander-shaped stripes, patterned by electron-beam lithography and cover a 10/spl times/10-/spl mu/m/sup 2/ active area. The best-achieved QE at 2.0 K for 1.55-/spl mu/m photons is 17%, and QE for 1.3-/spl mu/m infrared photons reaches its saturation value of /spl sim/30%. The SSPD NEP at 2.0 K is as low as 5/spl times/10/sup -21/ W/Hz/sup -1/2/. Our nanostructured SSPDs, operated at 2.0 K, significantly outperform their semiconducting counterparts, and, together with their GHz counting rate and picosecond timing jitter, they are devices-of-choice for practical quantum key distribution systems and free-space (even interplanetary) quantum optical communications.
TL;DR: In this paper, a 70 kA current lead for the ITER TF Coils using High Temperature Superconductors (HTS) was installed and tested in the TOSKA facility of the Forschungszentrum Karlsruhe.
Abstract: In the frame of the European Fusion Technology Programme, the Forschungszentrum Karlsruhe and the CRPP Villigen have designed and built a 70 kA current lead for the ITER TF Coils using High Temperature Superconductors (HTS). At the beginning of 2004 the HTS current lead was installed and tested in the TOSKA facility of the Forschungszentrum Karlsruhe. The scope of the experiment was to characterize the current lead in steady state conditions and to explore the operation limits as well. For this, the temperature profile, the contact resistances, the heat load at 4.5 K, the required 50 K He mass flow rate, and the temperature margin were evaluated. The safety margin in case of a loss of He mass flow was studied, too. The paper describes the experimental results as well as the thermal and electrical models developed.
TL;DR: In this article, a three-phase resistive high-Tc superconducting fault current limiter (SCFCL) for 10 kV, 10 MVA has been developed, manufactured, and tested within a publicly funded German project called CURL 10.
Abstract: A full scale three-phase resistive high-Tc superconducting fault current limiter (SCFCL) designed for 10 kV, 10 MVA, has been developed, manufactured, and tested within a publicly funded German project called CURL 10. The device is based on 90 bifilar coils of MCP BSCCO-2212 bulk material. The operating temperature of 66 K is achieved by cooling of liquid nitrogen using two Stirling cryocoolers. Until today, this is the largest HTS fault current limiter world wide. We report on the design features, the composition, and the operation parameters of the SCFCL system. From April 2004 on CURL 10 is installed and tested within the network of the utility RWE at Netphen near the city of Siegen, Germany. The results of the laboratory test and the field test of CURL 10 are given.
TL;DR: In this paper, the authors measured AC losses in RABiTS nonstriated as well as striated coated conductors provided by the US Air Force Research Laboratory and found that AC losses of striated samples with multiple bridges are higher than those of the samples with no bridges due to significant filament coupling.
Abstract: We measured AC losses in RABiTS nonstriated as well as striated coated conductors provided by the US Air Force Research Laboratory. In addition, samples with different kinds of well defined inter-filament bridging have been measured and their losses compared with those of samples with unbridged filaments and with mono-layer samples. This bridging is designed to aid current sharing between filaments, which is advantageous, but it is necessary to determine if the effect on AC losses is detrimental. It was found that AC losses of striated samples with multiple bridges are higher than those of the samples with no bridges due to significant filament coupling but even so the losses are still substantially lower than those of a monolayer sample.
TL;DR: In this article, a set of new processing tools have been employed, including a high density (ICP) plasma etching of niobium and aluminum, and low temperature plasma-enhanced chemical vapor deposition of interlayer dielectric (SiO/sub 2/) from a TEOS source.
Abstract: HYPRES has developed new fabrication processes for higher critical current density Josephson junctions (JJs). These processes incorporate an additional anodization step for junction insulation, which enables fabrication of junctions down to submicron sizes. A set of new processing tools has been employed, including a high density (ICP) plasma etching of niobium and aluminum, and low temperature plasma-enhanced chemical vapor deposition of interlayer dielectric (SiO/sub 2/) from a TEOS source. A set of new parametric control monitor (PCM) test chips has been designed and implemented. Results of electric and SEM characterization of JJ's, wiring, and contact-hole etching are presented. The critical current spreads and shunt resistance uniformity along with the effects of junction shape are discussed. The critical current 1/spl sigma/ spreads of 1.2% have been achieved for the 4.5 kA/cm/sup 2/ process.
TL;DR: The first HTS power cable project was started in the second half of 2002 and on site system installation was finished at Puji Substation of China Southern Power Grid in March, 2004 as mentioned in this paper.
Abstract: China's first HTS power cable project was started in the second half of 2002 and on site system installation was finished at Puji Substation of China Southern Power Grid in March, 2004. This cable system consists of three 33.5 m, 35 kV/2 kA/sub rms/ cables, six terminations, and a closed cycle liquid nitrogen cooling station. The conductors of the cables were made of 4 layers of BSCCO 2223 HTS tapes. Off grid field testing and live grid trial operation has been carried out since the completion of the installation. In this paper, we will report the key technical parameters of the system. Descriptions of the installation site, demonstration of the system installation, and results of testing and trial operation will also be presented and discussed.
TL;DR: The first long length, transmission level voltage, cold dielectric, high temperature underground superconductor power cable was designed for permanent installation in the Long Island Power Authority (LIPA) grid and is being designed to carry 574 MVA at a voltage of 138 kV.
Abstract: The US Department of Energy is currently funding the design, development and demonstration of the first long length, transmission level voltage, cold dielectric, high temperature underground superconductor power cable. The cable is designed for permanent installation in the Long Island Power Authority (LIPA) grid and is being designed to carry 574 MVA at a voltage of 138 kV. The project is led by American Superconductor and the team is comprised of Nexans, Air Liquide and LIPA. This paper describes the goals of the project, and an overview of the cable design, refrigeration system and site system requirements. It also includes a discussion of the influence of transmission network requirements, such as fault currents, on the design of the cable.
TL;DR: In this paper, the characteristics of the transition to the normal state and normal-zone propagation in YBCO sample tapes were examined experimentally and numerically, and the experimental results were compared with a newly developed computer program based on the finite element method (FEM).
Abstract: YBCO tape is expected to be used in future HTS applications, because it has better J/sub c/ characteristic in high temperatures and in high applied magnetic fields. It is important to consider the stability in superconducting applications. To establish the stability criterion for coated conductors, the characteristics of the transition to the normal state and normal-zone propagation in YBCO sample tapes were examined experimentally and numerically. The YBCO sample tapes were produced by IBAD/PLD method. Measurements were performed as a function of both heat input and operating current for operating temperatures of 55 K, 60 K, and 65 K in a background magnetic field of 5 T. The experimental results were compared with a simulation using a newly developed computer program based on the finite element method (FEM). In the computer program, the I-V characteristics of the YBCO sample tapes were taken into account. The computer program could simulate the normal transition and propagation phenomena and its validity was confirmed. The influence of the thickness of a Ag-stabilizer on the transient thermal behavior of YBCO tapes was examined experimentally and numerically and the results were presented here.
TL;DR: A team consisting of SuperPower, Inc. (HTS systems manufacturer), The BOC Group (global industrial gases company), Sumitomo Electric Industries (cable manufacturer), and Niagara Mohawk (electric utility) is developing a 34.5 kV HTS cable for installation in the distribution network in downtown Albany, NY as mentioned in this paper.
Abstract: A team consisting of SuperPower, Inc. (HTS systems manufacturer), The BOC Group (global industrial gases company), Sumitomo Electric Industries (cable manufacturer), and Niagara Mohawk (electric utility) is developing a 34.5 kV HTS cable for installation in the distribution network in downtown Albany, NY. Energization is projected for the winter of 2005. The cable will be rated for 800 Arms, with all three electrical phases in one cryostat. The 350 m long cable will be pulled through a duct that includes a 90/spl deg/ bend. A field installed underground cable joint will allow for the replacement of a 30 m section of the original first generation HTS cable with a section manufactured utilizing second generation superconductor, in 2006. This paper will summarize the progress made to date and outline future development work.
TL;DR: It is expected that the new real-time SCFCL model will provide a valuable tool not only for further protection system studies but for a wide range of RT-HIL experiments of power systems.
Abstract: A model for the SCFCL suitable for use in real time computer simulation is presented. The model accounts for the highly nonlinear quench behavior of BSCCO and includes the thermal aspects of the transient phenomena when the SCFCL is activated. Implemented in the RTDS real-time simulation tool the model has been validated against published BSCCO characteristics. As an example for an application in protection system studies, the effect of an SCFCL on a utility type impedance relay has been investigated using a real time hardware-in-the-loop (RT-HIL) experiment. The test setup is described and initial results are presented. They illustrate the effect of how the relay misinterprets the dynamically changing SCFCL impedance as an apparently more distant fault location. It is expected that the new real-time SCFCL model will provide a valuable tool not only for further protection system studies but for a wide range of RT-HIL experiments of power systems.
TL;DR: An 8-bit microprocessor using passive transmission lines based on single-flux-quantum LSI technology and the design flexibility of the floor plan was enhanced and the performance of the microprocessor was improved by 20% compared with the previous design.
Abstract: We have successfully demonstrated an 8-bit microprocessor using passive transmission lines based on single-flux-quantum LSI technology. In the microprocessor designed here, called CORE1/spl alpha/6, a simple bit-serial architecture with seven instructions was employed. In the CORE1/spl alpha/6, the floor plan was designed with consideration toward integration of a memory, and superconductive passive transmission lines (PTLs) were used to connect circuit blocks. Utilization of PTLs helped us reduce the propagation delay in long interconnections. The design flexibility of the floor plan was enhanced and the performance of the microprocessor was improved by 20% compared with our previous design. The CORE1/spl alpha/6 was composed of 6319 Josephson junctions and 15 PTLs with power consumption of 2.1 mW. We have confirmed the complete operations of the CORE1/spl alpha/6 by on-chip high-speed tests. The maximum clock frequencies for bit operation and instruction execution have been found to be 18 GHz and 1.2 GHz, respectively, where the performance corresponds to 240 million instructions per second (MIPS).
TL;DR: In this article, the authors have developed a fabrication process for GHz-counting-rate, single-photon, high-detection-efficiency, NbN, nanowire detectors.
Abstract: We have developed a fabrication process for GHz-counting-rate, single-photon, high-detection-efficiency, NbN, nanowire detectors. We have demonstrated two processes for the device patterning, one based on the standard polymethylmethacrylate (PMMA) organic positive-tone electron-beam resist, and the other based on the newer hydrogen silsesquioxane (HSQ) negative-tone spin-on-glass resist. The HSQ-based process is simple and robust, providing high resolution and the prospect of high fill-factors. Initial testing results show superconductivity in the films, and suggest that the devices exhibit photosensitivity.
TL;DR: The Albany Project plans to install a 350 m High Temperature Superconducting (HTS) cable in the power grid of the Niagara Mohawk Power Company to carry 800 arms at 34.5 kV as discussed by the authors.
Abstract: The Albany Project plans to install a 350 m High Temperature Superconducting (HTS) cable in the power grid of the Niagara Mohawk Power Company to carry 800 Arms at 34.5 kV. The type of the cable has 3 HTS cores in one cryostat with Bi-2223 used for HTS conductor and shield layers. The three cores are housed within double SUS corrugated pipes which provides thermal insulation. The tapes are manufactured with a new innovative sintering method with controlled over pressure (CT-OP) technology. Polypropylene laminated paper (PPLP) is used as electrical insulation. The cable will be installed in long underground conduit. A cable joint will be made in an underground vault to connect a 30 m length of the cable with the remaining 320 m. The original Bi-2223 30 m cable will be replaced with a 30 m YBCO cable after long-term operation. The terminations at both ends of the cable will have three bushings in a cryogenic vessel. Typical performance evaluation experiments, such as cable bending tests, voltage tests, and fault current tests, have been conducted with sample cables to check the design. Voltage tests for 69 kV AC and 200 kV impulse were successfully applied to a 5 m cable in accordance with the Association of Edison Illuminating Companies (AEIC) code of 35 kV class cable. The cable will be manufactured and installed in 2004 and 2005, then, long-term operation will be started.