Electrical Tests of Superconducting Busbar Insulation of ITER FEEDER PF4 CFT

The busbar of PF4 CFT (Cryostat Feedthrough of No. 4 Poloidal Field Coil) have insulation which consists of several half-overlapped pre-preg and glass kapton. In this paper, three kinds of electrical tests for PF4 CFT busbar insulation acceptance were introduced, include Direct Current (DC) High Voltage (HV) test, Alternating Current (AC) Partial Discharge (PD) high voltage test, and Paschen test. The site environment control, electrodes connection configuration, and test processes of busbar insulation electrical tests are introduced. All the test electrical results can meet the production requirements greatly and gave a strong quality guarantee for insulation of PF4 CFT superconducting busbar.