Through a grant program that encourages private industry to partner with university scientists, a research team from Florida State University’s Center for Advanced Power Systems and the Colorado-based Advanced Conductor Technologies LLC has demonstrated the first high-temperature superconducting direct current power transmission cable using ACT’s Conductor on Round Core (CORC) cable technology. The cables enable transmission of vast amounts of power at high currents that could be used to fuel power grids or help operate an all-electric ship for the US Navy, according to the team.
“The demonstration is an exciting development and a significant leap forward in achieving the required high-power densities in shipboard power transmission,” says CSA member Sastry Pamidi, associate director of CAPS and professor at FAMU-FSU College of Engineering. “CAPS has been developing the cryogenic helium gas circulation technology and superconducting power applications and established the state-of-the-art research facilities that support ACT and other businesses to move the technology forward.”
Engineers at ACT formed the two-pole direct current power transmission cable by twisting two 10-meter-long monopole CORC cables together and then cooled it with pressurized cryogenic helium gas before testing at currents exceeding 4,000 amperes.
The cables are a major improvement over current technology, according to ACT, because they are much thinner, and thus smaller and lighter than other high temperature superconducting cables. “It’s been extremely exciting to develop CORC power transmission cables into a working prototype,” says Danko van der Laan, ACT’s founder and 2014 CSA Roger W. Boom Award winner. “We had to overcome some technical challenges related to pressurized helium gas operation at high currents, but—in the end—the cable system worked the first time.”
ACT engineers developed the CORC power transmission cable and sent it to CAPS as part of an ongoing collaborative program funded through a Small Business Innovative Research (SBIR) grant from the US Navy. SBIR grants encourage businesses to find university partners to conduct advanced research. CAPS conducts research on advanced modeling and simulation of electric power systems, advanced controls, power conversion equipment and high temperature superconducting devices. CAPS has also long partnered with the Navy to develop technology for all-electric ships.
“This successful test is a major step forward in the development of power cables that will permit integration of high power/high energy systems on future ships,” says Roger McGinnis, CAPS director. “The size and weight reduction the CORC cables bring to the system will permit installation of the new sensors and systems onto many more classes of ships than current cable technology would permit.”
The Navy has significantly ramped up its efforts to develop superconducting cables over the past decade, according to CAPS, as efforts to meet increased electric power needs on Navy ships demand more efficient means of transmitting the power equivalent to that used by a small city with almost no loss in a compact and lightweight system that can’t be achieved using conventional technology.
“The recent demonstration of the CORC cable is the result of the Navy’s continued development of superconducting cable technology,” says Jacob Kephart, who is the applied superconductivity team lead at the US Navy’s Naval Surface Warfare Center, Philadelphia Division. “The primary benefit superconductivity brings to naval applications is the extremely high current density and lossless current transport compared to copper conductors. These superconductivity cables offer new design options and flexibility to move large amounts of power around a ship to meet the mission requirements.” ■