Design and analysis of Switching Network Units for the ITER coil power supply system

In ITER, high voltage required for the central solenoid modules and the PF1 and PF6 poloidal field coils at the beginning of the plasma pulse to ensure gas breakdown and initial plasma current ramp-up will be obtained by inserting resistors in series with the preliminary energized coils. It will be provided by switching networks capable to interrupt current up to 45 kA in few ms and to transfer it to discharge resistors at a voltage up to 8.5 kV. description of the switching network configuration and operational sequence the paper focuses on the design of the main components, the specific features of which reflect high demands resulting from ITER coil operation parameters.