Creepage Discharge Characteristics Along the Interface Between Two Solid Insulation Materials in GN2

Glass-fiber-reinforced plastic (GFRP) and MC Nylon are widely used in superconducting apparatuses, such as in superconducting fault-current limiters, due to their excellent mechanical and dielectric performance. Many superconducting apparatuses are operated in a high-voltage condition. Thus, an unexpected dielectric accident can occur with damage to a superconducting magnet. Therefore, dielectric experiments on the creepage discharge characteristics of GFRP and MC Nylon were conducted for developing a high-voltage superconducting coil system. For this paper, the creepage discharges along the surfaces of solid insulators in gaseous nitrogen (GN2), and along the interface between two pieces of solid insulation in contact, were experimented on and analyzed, with respect to ac and dc voltages, at 300 K, under the absolute pressure of 0.1 MPa.