High Tc superconducting (HTS) Cables are expected as a new technology to transmit large amount of electricity in a compact size with lower loss. There are many projects to demonstrate their performance and reliability in the grid around the world. Demonstrations of the cables include those with up to 275 kV in voltage and up to DC 10 kA in current. Maximum capacity is more than 1 GVA and length is in the km order. Therefore, their commercialization is expected to occur in the near future. This report shows the present development status of HTS cables outside Japan in the USA, Europe, Korea and China.
There are expectations for high-temperature superconducting (HTS) power cables as compact cables with large capacity and low-loss power transmission. Recently, the stable manufacture of many long REBCO (RE = rare-earth element) tapes has been achieved. REBCO tapes have a high critical-current density, and the AC loss resulting from the parallel magnetic field is extremely small because of the thin-film structure of the superconducting layer. The basis of the Materials & Power Applications of Coated Conductors (M-PACC) project is to develop a process technology for fabricating REBCO tapes and promote development aiming toward the commercialization of superconducting cables using REBCO tapes. Two types of HTS cables are being developing as part of this project. These cables have superior transmission efficiency, lower loss and larger capacity than existing power cables. One is a 66 kV/5 kArms three-core large-current cable and the other is a 275 kV/3 kArms single-core high-voltage cable. There are several development targets. We examined factors such as AC loss, thermal characteristics of the cables under overcurrent and the optimum cable design. The cable systems of the above mentioned two kinds of cables were developed by combining the above elemental technologies and verifying the performance. This paper provides an overview of the project and describes its results.