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in subjects: "Superconducting Cables"

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Studies of helical conductor models for superconducting ac power transmission

In the BNL concept of a superconducting ac power transmission cable the conductors are made of Nb/sub 3/Sn tapes wound helically on cylinders. Recently, it was decided to make each conductor in the form of a double layer winding in which the layers are of opposite helicity. This reduces undesirable consequences of axial flux generation. After reviewing the considerations which lead to the double helix conductor, experiments with short models (0.8 m long) are described. Results are given for ac … more

Date: January 1, 1976

Creator: Garber, M; Barber, T & Morgan, G

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ultra high-current superconducting cables for a 2. 2-Tesla, 300-kilojoule energy storage magnet

These 2.2-T, 300-kJ magnets are to operate at 10 to 12 kA with a safety factor in critical current of about 50 percent at 10 kA. The conductor must exhibit low losses in addition to being stable. Magnetic Corporation of America (MCA) designed a flat conductor using 1224 copper-matrix, monofilament wires combined in two stages of cabling followed by two stages of flat braiding. Two of these conductors were constructed, one with wire already on hand and the second using wire made specifically for… more

Date: August 17, 1976

Creator: Miranda, G. A.; Rhodenizer, R.; Rackov, P.; Punchard, W. F. B. & de Winter, T. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Superconducting Power Transmission. Progress at Brookhaven and the Prospects for This Technology

The state of development of the technology at Brookhaven is described. This includes the 100 m outdoor test facility and the results of systems studies carried out in cooperation with electric utility companies. The status at other institutions throughout the world is given. It appears the first tests on an actual utility system will be carried out in Austria. Test stations for larger cables are under construction in the U.S.S.R. and the U.S.A.

Date: 1978

Creator: Forsyth, E. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electrical, cryogenic and systems design of a dc superconducting power transmission line

The electrical, cryogenic, and systems design concepts for a dc superconducting power transmission line are discussed. The line consists of a hollow-core flexible coaxial cable, using multifilamentary or tape Nb/sub 3/Sn superconductor and wrapped tape dielectric, within a rigid cryogenic envelope. Cryogen flows through the core, is expanded in a turbine and returns over the outer cable surface. The concept is applied to power levels of 1 to 10 GW and for a range of line voltages and maximum di… more

Date: January 1, 1976

Creator: Laquer, H. L.; Dean, J. W. & Chowdhuri, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Selection of a cryostabilized Nb/sub 3/Sn conductor cooling system for the large coil program

The Large Coil Project (LCP) is a program to design, fabricate and test relatively large superconducting toroidal field coils for tokamak fusion reactor applications. Some basic requirements that affect the conductor design are cryostabilization, 8 tesla peak magnetic field, and a specified maximum refrigeration load. The engineering considerations that led to the selection of a forced flow supercritical helium-cooled cable conductor are described. Comparisons of forced flow supercritical heliu… more

Date: January 1, 1977

Creator: Chi, J. W. H.; Murphy, J. H. & Jones, C. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Welding superalloy sheet for superconducting cable jackets

Autogenous gas tungsten arc welds produced in A-286 exhibit significantly lower yield and ultimate tensile strengths than comparably heat-treated base metal. Deformation in the aged weld metal is highly localized and delineates the dendritic microstructure. The observed mechanical properties are caused by the formation of precipitate-free regions located at the dendrite cores. These regions form as the result of titanium segregation during weld pool solidification which yields dendrite cores su… more

Date: August 1, 1983

Creator: Summers, L.T.; Strum, M.J. & Morris, J.W. Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effects of Formvar coating and copper-nickel outer sheath on the ac losses of multi-strand subsize cables

Ac losses of two subcables, one with Formvar coating on the strands of the BNL 12-ml NbTi/Cu/CuNi conductor and another without the coating, were measured using the ANL Subcable Test Facility. The results indicate that couplings among the strands with and without the Formvar coating were quite weak. Weak coupling of the bare strands is due to the high resistance of the copper-nickel outer sheath. In the regime of B(dot) = 0 approx. 1.2 T/s and B = 0 approx. 4 T, the magnetic diffusion time cons… more

Date: February 1, 1985

Creator: Kim, S. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Steady-state heat transfer to boiling liquid helium in simulated coil windings

The present data show that the worst case steady-state stability in the GE/LCT magnet windings is at a horizontal conductor orientation. The heat transfer improves with inclination of the conductor from horizontal. Calculations show that for these small regions normal zones will recover by cold-end conduction from the inclined conductor on either end.

Date: January 1, 1981

Creator: Walstrom, P.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Evaluation of a cryostable low-loss conductor for pulsed field applications

A cryostable, low loss conductor as the basic strand in a 50 kA cable for a 20 MJ prototype, tokamak induction heating coil has been developed, fabricated, and evaluated. The conductor has a copper matrix multifilamentary NbTi core surrounded by a CuNi ring and stabilizing copper segmented by radial CuNi fins. Pulsed loss measurements have been made up to 2.2 T and for decay times from 0.7 to 278 ms. Measurements made on samples with various twists and portions etched away have allowed accurate… more

Date: January 1, 1980

Creator: Wollan, J. J.; Walker, M. S.; Zeitlin, B. A.; Pollack, D. A. & Shen, S. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Development of Nb/sub 3/Ge conductors for superconducting power transmission

Superconductors based upon Nb/sub 3/Ge have been fabricated by the chemical vapor deposition (CVD) process in long lengths in a configuration suitable for an ac power transmission line. This material exhibits a transition temperature T/sub c/ greater than or equal to 21.0/sup 0/K and a critical current density J/sub c/ = 2.5 x 10/sup 6/ A/cm/sup 2/ at 14.0/sup 0/K and offers the possibility of high current operation at temperatures approx. 14.0/sup 0/K. AC-power losses which are acceptably low … more

Date: January 1, 1978

Creator: Newkirk, L. R.; Maley, M. P.; Thompson, J. D. & Valencia, F. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effects of strain on the superconducting properties of niobium-tin conductors

Investigations were performed to ascertain additional information on the connection between the cubic to tetragonal martensitic phase transformation and the phenomenon of superconductivity in Nb/sub 3/Sn. Of particular interest is the degradation of the critical parameters, such as T/sub c/, H/sub c2/, and J/sub c/, with mechanical straining of the superconductor. These studies yielded information that assisted in the derivation of the critical current-strain scaling laws mentioned above.

Date: November 1, 1980

Creator: Hoard, R.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Measurements on insulating materials at cryogenic temperatures. Annual report

Progress made to date on developing instrumentation and measurement methodology for studying high-voltage dielectric losses at cryogenic temperatures is detailed. The work described has been done in support of ERDA-funded ac superconducting transmission line projects at Brookhaven National Laboratory (BNL) and the Linde Division of the Union Carbide Corporation (UCC-Linde). Dissipation factor measurements have been made at a temperature of 4.2/sup 0/K and at stresses up to 40 kV/mm. Care has be… more

Date: January 1, 1976

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Ac losses in YBa sub 2 Cu sub 3 O sub 7 and Bi sub 2 Sr sub 2 Ca sub 2 Ci sub 3 O sub 10 superconductors at power frequencies

Ac losses of sintered and melt-textured YBa{sub 2}Cu{sub 3}O{sub 7} bars and powder-in-a-tube processed Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} tapes were measured at 4.2, 65, 70 and 77 K and at 15--180 Hz. In general, the results are well described by the critical state model for the ac losses. However, the losses for the Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} tapes at 4.2 K exhibited significant contributions from the eddy currents in the Ag sheath.

Date: January 1, 1991

Creator: Orehotsky, J.; Reilly, K.M.; Suenaga, M. (Brookhaven National Lab., Upton, NY (United States)); Hikata, T.; Ueyama, M. & Sato, K. (Sumitomo Electric Industries Ltd., Osaka (Japan). Osaka Research Lab.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Application of high temperature ceramic superconductors (CSC) to commercial tokamak reactors

Ceramic superconductors operating near liquid nitrogen temperature may experience higher heating rates without losing stability, compared to conventional superconductors. This will permit cable design with less stabilizer, reducing fabrication costs for large fusion magnets. Magnet performance is studied for different operating current densities in the superconductor, and cost benefits to commercial tokamak reactors are estimated. It appears that 10 kA . cm/sup -2/ (at 77 K and approx.10 T) is … more

Date: October 1, 1987

Creator: Ehst, D. A.; Kim, S.; Gohar, Y.; Turner, L.; Smith, D. L. & Mattas, R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Heating-induced flows in cable-in-conduit conductors

Hoenig et al and Miller et al have both reported high stability margins for cable-in-conduit conductors cooled by stationary supercritical helium. Miller et al proposed that strong flows induced in the helium in the early stages of recovery enhanced heat transfer and greatly increased the stability margin over what had been expected for stationary helium. In this memorandum, the flow and pressure transients induced in initially stationary helium by energy transfers typical of those associated w… more

Date: January 1, 1979

Creator: Dresner, L

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Helium research in support of superconducting power transmission. Annual report, July 1975--September 1976

This is the second annual report of research on helium related problems in support of superconducting power transmission development. Results are presented from experimental and computer modeling of the performance of current leads cooled with supercritical helium gas. Performance characteristics studied are burn-out conditions and existence of oscillation in the helium gas. Some conclusions on the feasibility of data transmission from high-voltage regions to grounded read-out instrumentation, … more

Date: February 1, 1977

Creator: Jones, M. C.; Arp, V. D.; Parrish, W. R.; Daney, D. E.; Ludke, P. R.; Frederick, N. V. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Fabrication of superconductors. [NbTi in Cu, CuNi matrix]

The paper discusses the development of a process for making high performance, fine-filament superconducting wires, utilizing dual matrix stabilization and Nb/sub 46/Ti superconducting filaments. Minimum filament size-achieved was 8 ..mu..m using OFHC copper and Cu/sub 30/Ni matrix materials. Ductility of the NbTi starting material was found to exert a major influence on the properties of the finished wire, and specifications for acceptable NbTi were developed. When specific impurity levels are … more

Date: January 1, 1976

Creator: Turner, W. C.; Lundberg, L. B.; Zeitlin, B.; deWinter, T. A. & McDonald, W. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Stability-optimized, force-cooled, multifilamentary superconductors

A numerical program has been written to calculate the temperature-time history of a uniformly pulse-heated composite superconductor cooled by supercritical helium in forced convection. The program determines the maximum sudden temperature rise from which the conductor can still recover the superconducting state. The program includes the effects of (1) current sharing, (2) the temperature variation of the specific heat of both the matrix and the superconductor, and (3) the temperature variation … more

Date: January 1, 1976

Creator: Dresner, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Cryogenic recovery analysis of forced flow supercritical helium cooled superconductors

A coupled heat conduction and fluid flow method of solution was presented for cryogenic stability analysis of cabled composite superconductors of large scale magnetic coils. The coils are cooled by forced flow supercritical helium in parallel flow channels. The coolant flow reduction in one of the channels during the spontaneous recovery transient, after the conductor undergoes a transition from superconducting to resistive, necessitates a parallel channel analysis. A way to simulate the parall… more

Date: August 1, 1977

Creator: Lee, A. Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Superconductor design study. Final report. [Composite conductor research for carrying 10,000 A at 12T]

The objective of this program was to continue the developmental effort aimed toward production of a composite conductor capable of carrying 10,000 A at 12 T and suitable for use in large fusion magnets. This program pertains specifically to the development of Nb/sub 3/Sn multifilamentary conductors containing tubular Nb filaments with Cu-Sn alloy cores in a high conductivity copper matrix. The specific tasks include: (1) Fabricate 1000 ft of 1000 A, 12 T conductor for coil evaluation. (2) Fabri… more

Date: April 1, 1976

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Energy analysis of the basic materials utilized in electric power transmission systems

The energy content per mile of installed underground and overhead power transmission systems has been calculated for the following types of systems: self-contained oil-filled cables; HPOF pipe-type cables; extruded dielectric cables; compressed-gas-insulated systems; overhead lines (ac and dc) and two proposed superconducting systems (ac and dc). The system operating voltages analyzed included 138, 230, 345, 500, 765 and 1,200 kV for ac systems, but all systems were not analyzed at the higher v… more

Date: April 30, 1979

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Fusion-neutron damage in superconductors and magnet stabilizers

Two NbTi and two Cu wires were irradiated with 14.8 MeV neutrons at 4.2 K to fluences of 6 to 8 x 10/sup 20/ n/m/sup 2/, using RTNS-II. Electrical resistances of Cu were monitored during irradiation. Magnetoresistances were measured in fields up to 12.4 T before and after irradiation and after isochronal annealing up to 273 K. Critical currents of NbTi were measured after irradiation, in feilds up to 10 T. The initial rate of increase of resistivity of the Cu was found to be 2.23 x 10/sup -31/ … more

Date: August 7, 1981

Creator: Van Konynenburg, R.A.; Guinan, M.W. & Kinney, J.H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A Device for Precision Dimensional Measurement of Superconducting Cable

A need for continuous sampling of the dimensions of superconducting cable has lead to the development of a machine for that purpose. This device measures average thickness, width, and keystone angle for a wide variety of cable sizes while under the mechanical loading anticipated in the final coil structure. Linear dimensions can be measured to {plus minus}0.0001 in. and angle to {plus minus}0. 01{degree}. Cable can be measured with and without insulation. Loading is variable up to 25 ksi. This … more

Date: May 19, 1986

Creator: Carson, J. A.; Barczak, E.; Bossert, R.; Fisk, E.; Mantsch, P.; Riley, R. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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dc breakdown strength of dielectric materials at cryogenic temperatures

The HVDC superconducting cable, under development at the Los Alamos Scientific Laboratory will operate at a temperature of 12/sup 0/K and a helium pressure of 1.38 MPa. Because dc breakdown data of dielectric materials at these operating conditions were not previously available, extensive tests were performed on 11 dielectric materials in sheet form. Three of these materials were impregnated with mineral oil, which increased their dc withstand strength significantly. Four of these 11 materials … more

Date: January 1, 1979

Creator: Chowdhuri, P.; Bement, T.R.; Espinoza, C.N. & Weeks, G.

Item Type: Article

Partner: UNT Libraries Government Documents Department