Effects of Magnetic Field on Partial Discharge in Epoxy Resin for Superconducting Coil Insulation

Superconducting coil is the core component of Tokamak device, and epoxy resin plays the role of mechanical support and electrical isolation. Inevitably, various defects introduced in the casting process of epoxy resin will cause partial discharge. The insulation failure in superconducting coil is mainly caused by continuous partial discharge. In this paper, the electrical conductivity of epoxy resin and the partial discharge characteristics in high magnetic field were investigated. The results show that the conductivity of epoxy resin increases with the increase of magnetic field strength. At the same magnetic field strength, the conductivity of epoxy resin decreases slightly with the increase of magnetic field angle. The partial discharge initiation voltage decreases with the increase of magnetic field, and decreases with the increase of magnetic field angle at the same magnetic field strength.