Effects of Impregnating Materials on Thermal and Electrical Stabilities of the HTS Racetrack Pancake Coils Without Turn-to-Turn Insulation

• Published in: IEEE transactions on applied superconductivity Vol. 23; no. 3; p. 7700404
• Main Authors: Hyun-Jin Shin, Kwang Lok Kim, Yoon Hyuck Choi, Oh Jun Kwon, Seungyong Hahn, Iwasa, Y., Lee, H. G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Coil impregnation; Coiling; Coils; Cooling; CTD-521; Design. Technologies. Operation analysis. Testing; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electromagnets; Electronics; Exact sciences and technology; Field coils; GdBCO racetrack coil; High temperature superconductors; Insulation; Integrated circuits; Miscellaneous; Pancake coils; paraffin; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Stability; Stycast 2850 FT; Superconducting magnets; Superconductivity; Thermal conductivity; Thermal stability; Various equipment and components; Wind turbines; Cooling; Thermal management (packaging); GdBCO racetrack coil; paraffin; Wind generator; Torsional vibration; Time variation; Superconducting coils; Thermal stability; Degradation; Impregnation; Impregnated material; CTD-521; Cooling system; Coil impregnation; Magnetic field; Stycast 2850 FT; High temperature superconductor; Damaging
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2012.2234179

A high temperature superconducting (HTS) coil without turn-to-turn insulation is proposed for the field coil of a wind turbine. In the case of the field coil, epoxy impregnation is generally necessary to protect the coil from mechanical disturbances by time-varying magnetic fields and rotational vibrations to provide high mechanical integrity. This study examined the thermal and electrical stabilities of non-insulated GdBCO racetrack pancake coils impregnated with CTD-521, Stycast 2850 FT, and paraffin through cool down, over-current, and repetitive cooling tests. Among the three epoxy impregnated coils, the Stycast 2850 FT-impregnated coil exhibited the best thermal and electrical stabilities during over-current testing. In repetitive cooling conditions, the CTD-521-impregnated coil exhibited less degradation of its superconducting property due to the well-matching of the thermal contraction between the GdBCO racetrack pancake coil and the epoxy.