Search

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 impact of Ni-5at%W substrates on ac loss and inductance of HTS cables was examined. Two 1.2-m prototype cables were made with stainless steel laminated BSCCO tapes and were wound on a 25.4 mm diameter former. Each cable consisted of two layers of 15 BSCCO tapes wound at opposite lay angles and has an estimated critical current of 3000 A at 77 K. One cable had four additional layers of 4.8 mm wide Ni-Sat % W tape co-wound with the BSCCO tapes to simulate a commercial second generation IITS cable. The Ni-5at%W tapes had the same width as the BSCCO and a thickness of 50 microns. Through the use of a coaxial copper ground, the cable inductance was measured at room temperature and liquid nitrogen (77 K) using high frequency rf measurement techniques. Experimental results for the cable inductance and ac loss were compared against numerical calculations to determine the significance of the Ni-5at%W substrate contribution. Results indicate that inductance and ac loss changes from these substrates in commercial cables should be small. [ABSTRACT FROM AUTHOR]