Overview of the toroidal power supply system of RFX-mod after ten years of operation

The Reverse Field eXperiment (RFX) explores the physics of Reverse Field Pinch (RFP) plasmas as an alternative confinement option with respect to Tokamak and Stellarator concepts. The toroidal field power supply of RFX, modified and upgraded during a long shut-down in 1999, is based on IGCTs (Integrated Gate Commutated Thyristors) and combines an extremely complex circuit topology and a fast, reliable and flexible control system. It includes, among other devices, 12 dc/ac converters rated for 3kV, 6kA, pulse duty operation (0.5s/10') and 14 static breakers rated for 4kV, 16kA, 128 MA2s. This paper will describe in detail the system, from the power to the control and protection sections. Experimental waveforms will also be reported and interesting indication about the system reliability and availability will be given, derived from more than ten years of operation.