ITER Coil Power Supply and Distribution System

The ITER Coil Power Supply and Distribution System (CPSDS) will be installed to receive power from the French 400 kV transmission grid and to provide controlled DC power to the superconducting tokamak magnets for plasma operation. The Coil Power Supply System (CPSS) consists of AC/DC converter units connected in series with Switching Network Units (SNU) and Fast Discharge Units (FDU) to provide the controlled DC for plasma initiation, current, shape and position control, error field correction, as well as superconductive magnet quench protection. The installed power of the ITER CPSS is nearly 2 GVA. Thyristor based technology is used for the AC/DC converters, with four-quadrant operation and circulating current capability introduced as a basic design feature due to the high current rating and DC voltage and current characteristics. The SNU and FDU comprise of large resistor banks inserted into the magnet coil circuits by means of opening appropriate circuit breakers. A complex DC busbar system will be integrated through various ITER buildings to connect all the components into the circuit. The CPSS will draw large power pulses from the grid, with short rise times and steps in active and reactive power. Rapid reactive power control is necessary for voltage stabilisation and compensation together with filters to eliminate harmonics generated by the power converters. Thus a Reactive Power Compensation and Harmonic Filtering (RPC&HF) system will be installed with an installed total power of 750 Mvar. As an integral system, the ITER CPSDS poses significant technical challenges due to the large scale, special requirements and complicated interfaces. The conceptual design of the ITER CPSDS has been successfully completed. Further engineering design work and fabrication will be performed under the responsibility of the ITER Domestic Agencies in China, Korea and Russia as part of the ITER procurement arrangements.