Development of a DC −1 MV Insulating Transformer for Neutral Beam Injectors

A DC −1 MV insulating transformer has been developed for the power supply of the neutral beam injector (NBI) at ITER (International Thermonuclear Experimental Reactor) . A DC long-pulse −1 MV insulation structure between the primary and secondary windings, considering potential variation in the insulator for DC long pulse, has been designed. Simultaneous development of a compound bushing, which consists of an AC 500 kV condenser bushing inside a cylindrical fiber-reinforced plastic tube, has been carried out. The DC −1 MV insulation design has been verified by high-voltage insulation tests of AC 50 Hz 1300 kV peak for 1 min, DC −1200 kV for 1 h, and a long-duration test of DC −1060 kV for 5 h. The results showed that the insulating transformer satisfies the power supply requirements for the ITER NBI. Copyright © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.