Review of the research and development for insulation of superconducting fault-current limiters

The effect on residual stresses of porosity and surface roughness in high temperature insulation coatings on Ag tape for magnet technologies

“…Electrical insulation systems of HTS power apparatus are generally placed in a pool of cryogenic liquid coolant, and when transition from superconducting state into normal conducting state called quench occurs on superconductors, it is possible that its electrical insulation strength is significantly reduced by the vaporization of the liquid coolant due to the Joule heat at the quenched part of the superconductors. These cryogenic environments and the quench phenomena are not experienced in normal conducting power apparatus, and so must be taken into account in the electrical insulation design, and of course in high voltage tests of HTS power apparatus (Hara et al, 2005;Olding et al, 2001;Mitsuii, 1998 A basic idea of the equivalent insulation testing method at room temperature for HTS power apparatus with coil structure at the stages of its development, manufacturing and shipment due to technological and economical reasons is proposed, and reported the determination method of the equivalent insulation test voltage at room temperature. The determination method is based on the idea that no partial discharge is allowed in the HTS apparatus inasmuch as organic insulation materials are used in its insulation systems and they are easily degraded by partial discharges.…”

“…Most failures in sol-gel coatings also depend on processing parameters, i.e. solution properties (precursors, solvents, chelating agent, pH value, gelation, viscosity, chelation and complexation rate), withdrawal rate, drying, heat treatment and annealing conditions (Mitsuii, 1998;Paterson et al, 1997;Islamoglu et al, 2002). Besides, it is necessary to build up several layers to achieve the required film thickness in the production of sol-gel films.…”

Insulation coating of silver tapes using an organometallic solution of Zr and Ca for application to Bi-based superconductors

“…Electrical insulation of superconducting elements is required in diverse applications of superconductivity [7][8][9][10]. It is most likely that the solution to the insulation problem for superconductors will differ for each specific application depending on many factors such as the processing route, operating conditions and conductor type, size and shape [11][12][13]. An insulating coating layer on silver clad Bibased superconductors will have to comply with certain mechanical, chemical and physical requirements.…”

Insulation Materials and Systems for Superconducting Powertrain Devices in Future Cryo-Electrified Aircraft: Part I—Material Challenges and Specifications, and Device-Level Application

“…In addition, there are AC magnetic fields everywhere inside the cryostat. Therefore, a cryostat made of GRE as a non-magnetic, non-conductive electrical insulating material is commonly used in many superconducting applications 29 . Better GRE and GFRP composites have been developed recently to replace G10.…”