An innovative 45 kV thin wall heater for ITER superconducting current lead terminal

Abstract

The thin wall heater plays an important role in heat compensating of ITER superconducting current lead terminal. Development of the 45 kV thin wall heater with limitarion of 3 mm thickness insulation makes a huge challenge, a composite insulation structure compose of epoxy resin, glass fiber and ceramics is proposed to meet requirements of high dielectric strength as well as good thermal conductivity. Electrical field and temperature distributions are calculated. In addition, the electric field distribution of the heater has been optimized with numerical analysis methods, the results indicate the maximum reduction of electric field intensity is 16.6 %. Furthermore, the high voltage − current leakage test under DC 45 kV are performed after heating test, the corresponding current leakage is less than 100 μA, which means the innovative structure of the developed heater can satisfy the working requirements of ITER superconducting current leads.