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Two 3-rn long, single-phase cables have been fabricated by Ultera from second generation (2G) superconductor wire supplied by American Superconductor. The first cable was made with two layers of 2G tape conductor and had a critical current of 5,750 A while the second cable had four layers and a critical current of 8,500 A. AC loss was measured for both cables at ac currents of up to 4 kArms. Ultera performed initial fault current studies of both cables in Denmark with limited currents in the range from 9.1 to 44 kA. Results from these tests will provide a basis for a 25-m long, three-phase, prototype cable to be tested at ORNL early next year and a 300-rn long, fault current limiting, superconducting cable to be installed in a Consolidated Edison substation in New York City. [ABSTRACT FROM AUTHOR]

Ultera has installed a single 200-meter long high temperature superconducting (HTS) 3-phase triaxial design cable at the American Electric Power (AEP) Bixby substation in Columbus, Ohio. The cable connects a 138/13.2 kV transformer to the distribution switchgear serving seven outgoing circuits. It was designed to carry 3000 Arms. Testing of 3- to 5-meter length prototype cables, including a 5-meter prototype with full scale terminations tested at ORNL was conducted prior to the manufacture and installation of the AEP triaxial cable. These prototypes were used to demonstrate the crucial operating conditions including steady state operation at the 3000 Arms design current, high voltage operation, high voltage withstand and 110 kV impulse, and overcurrent fault capability. A summary of the results from the thermal analysis and testing conducted by Ultera and ORNL will be presented. Some analysis of the cable thermal-hydraulic response based on the testing that were used to determine some of the cable Cryogenic system requirements are also presented. [ABSTRACT FROM AUTHOR]

Oak Ridge National Laboratory (ORNL) has designed, built, and tested a 1.25-m-long, prototype high temperature superconducting (HTS) power cable made from second-generation YBa2Cu3Ox (YBCO)-coated conductor tapes. Electrical tests of this cable were performed in liquid nitrogen at 77 K. DC testing of the HTS cable included determination of the V-I curve with a critical current of about 2100 A, which was consistent with the critical currents of the two layers of 4.4-mm wide YBCO tapes. AC testing of the cable was conducted at currents up to about 1500 Arms. The ac losses were determined electrically by use of a Rogowski coil with a lock-in amplifier. Over-current testing was conducted at peak current values up to 4.9 kA for pulse lengths of 0.3–0.5 s. Test results are compared to earlier data from a 1.25-m-long power cable made from 1-cm-wide YBCO tapes and also comparable BSCCO cables. This commercial-grade HTS cable demonstrated the feasibility of second-generation YBCO tapes in an ac cable application. [ABSTRACT FROM AUTHOR]

The use of high temperature superconducting (HTS) materials for power transmission cable applications is being realized in several utility demonstration projects. Tape testing on short-sample cables is conducted to determine the suitability of HTS tapes for use in different cable designs. Testing includes deter- mining the DC critical current, ac loss and overcurrent behavior in a wound cable configuration. The short-sample cable configuration is similar in physical respects, such as winding diameter, winding pitch, application of dielectric, to a practical length cable. With more attention being paid to the short-circuit fault protection, the over-current pulse behavior of the cable will be tested thoroughly. The temperature history of the cable in the radial direction and the re-cooling of the cable will be monitored and compared with a model calculation. This paper describes the testing and results from one such series of tests of a short-sample cable made with copper laminated HTS tapes for use in future projects. [ABSTRACT FROM AUTHOR]

The Ultera/ORNL team have built and tested 3-m and 5-m triaxial cables rated at 3 and 1.3 kA-rms, respectively. The three concentric superconducting phases are made of BSCCO-2223 HTS tapes, separated by layers of cold-dielectric tapes. A copper braid is added as the grounding shield on the outside of the three active phases. Tests of these cables were performed at temperatures ranging from 70 to 84 K. AC loss data reconfirmed the previous result on a 1.5-m prototype cable that the total 3-phase ac loss is about the sum of the calculated ac losses of the three concentric phases. These and other test results of the 1,3 and 3 kA cables will be used to construct a second S-m triaxial cable rated at 3 kA-rms, 15 kV. Preliminary test results supporting this new cable and the associated termination are summarized. [ABSTRACT FROM AUTHOR]