HTS Roebel cable

We develop and manufacture high temperature superconductor Roebel cable for use in high field and accelerator magnets, transformers, generators and motors.

High Temperature Superconductors (HTS) are ceramic materials capable of conducting large direct currents with virtually zero resistance. Winding a set of flat strands of HTS into Roebel cables allows the cable to carry a greater current and makes the material suitable for large scale applications such as transformers, generators, and high field magnets.

Advances in Roebel cable manufacturing at RRI

In 2007 Robinson engineers developed the first Roebel cable winding machine for use with HTS wire. This eliminated the need for time consuming hand winding and has enabled us to supply long lengths of cable for use in generators and transformers. In 2013 Lachland Clelland, a student at Robinson, was awarded The Ray Meyer Medal for excellence in Student Design for his improved HTS winding machine.

In addition to the advances in cable winding technology, Robinson has developed new  techniques for manufacturing HTS strands. HTS tape is cut by a reel-to-reel punching machine into serpentine shaped strands. The process preserves the current carrying properties of the tape, and delivers a highly consistent pitch length. Our production methods allow us to work successfully with wire from any high-quality manufacturer.

In 2007 we began producing HTS Roebel cable commercially under GCS Ltd, a partnership between Robinson and General Cable Corporation. GCS Ltd supplies our HTS Roebel cable to leading institutions and corporations around the world including Siemans, C-EPRI, and Cern.

Roebel cable and our research: transformers, accelerator magnets, and ultra-high field magnets

Roebel cable has played an important role in several of our internal projects. In 2014 we built a 1 MVA distribution level transformer using HTS Roebel cable for the secondary winding. The solenoid winding used a 20 m 15/5 cable with an operating current up to approximately 2000 A at –203°C. Measurements showed that the Roebel cable reduced AC losses in the winding cable to a level less than, or comparable to, losses in other parts of the system such as the current lead and cryostat. The project confirmed that Roebel cable is stable in operation and a suitable conductor for HTS transformers.

Roebel cables are a good candidate conductor for the next generation of accelerator magnets and our cables have already been used for testing at the Large Hadron Collider at CERN. Roebel cable based on YBCO type material has the ability to operate at higher fields than the low temperature NbTi and Nb3Sn superconductors that are currently used. Our latest research has been to test the mechanical integrity of Roebel cable under the large mechanical forces involved in accelerator magnet applications.

Roebel cable – Flat strands of cable bound together forming a cylinder. The end has been disassembled to show the geometry of the strands (photo courtesy of Siemens Corporate Technologies).
Roebel cable. The end has been disassembled to show the geometry of the strands (photo courtesy of Siemens Corporate Technologies).