The development and testing of a 66 kA by-pass switch with arc commutation capability for the ITER coil power supply system

Mechanical by-pass switches rated for a continuous current of 60 kA and provided with some arc commutation capability are required in the ITER discharging networks to be connected in parallel to the main vacuum circuit breakers. The development work was carried out on a suitable industrial switch and was aimed at increasing substantially its voltage rating and at improving its speed of operation. A fully rated commutating unit was built and subjected to an extensive test program aimed at its full characterisation.