Plenary talk — HTS superconducting wire development and applications in Korea

Summary form only given. High-temperature superconducting wire is a vital component of superconducting power devices along with cryo-cooling system and low temperature insulating materials. With much efforts devoted by many research groups, performance of superconducting wires was drastically improved, leading to many meaningful and impressive demonstrations of electric power devices. In Korea DAPAS (Development of Advanced Power system by Applied Superconductivity technologies) program began in 2001 to develop HTS wire and electric power devices such as cable, fault current limiter, motor and transformer. For wire, we tried various processes and materials for substrate, buffer layers, superconducting layer, and protection layers. During 10 years of research in three phases, we chose what we thought is the best process and material for each layer in terms of performance and long term cost effectiveness. Especially we elaborated EDDC (Evaporation using Drum in Dual Chambers) for superconducting layer deposition with advantages such as low source cost and high deposition rate. One drawback of EDDC is that it is a batch type process, i.e. there is a limit in maximum piece length of the wire, which in our case is about 100 meters. To overcome such limitation, we developed a co-evaporation process with reel to reel process capability which we termed as RCE-DR (Reactive Co-Evaporation - Deposition and Reaction). This is somewhat similar to EDDC but superconducting layer growth mechanism is quite different in that RCE-DR has fast growth speed of forming 1.5 μm thick film in less than 30 seconds. We can routinely fabricate HTS wire with Ic of 700 A (12 mm width) and length of 600 meter on stainless steel substrate as well as on Hastelloy. To accelerate the progress, a new government funded HTS wire project has begun on June with objectives such as achieving 1 kA/cm critical current in 1 km long wire and enhancement of in-field characteristic to suit for 10 MW class- superconducting wind turbine generators. With the successful completion of the DAPAS program in 2011, Korea became a major player in the field of HTS wire and devices. Now distribution level cable (22.9 kV, 50 MVA) and fault current limiter have been operating successfully in live grid more than one year and transmission cable (154 kV) demonstration projects are ongoing. Also many institutions are working on HTS coils/magnets and rotating machines.