Study of the Use of Current Limiting Resistors for Protecting High Energy Superconducting Magnets

Due to their pulsed and fast discharge operation, the superconducting systems of ITER will experience high voltage variations and, as a result, the instrumentation for quench detection will also experience those high voltage levels. Therefore the risk of an electrical breakdown between instrumentation wires and ground cannot be discarded. Current Limiting Resistors (CLRs) inside the cryostat, connected in series with magnet instrumentation wires, and embedded in the ground insulation, were included in the instrumentation base line to prevent consequential damage following an electrical breakdown. A CLR can mitigate the effects of the surge currents through instrumentation wires in case of unexpected incidents. This paper describes the study of the potential installation of the CLRs and the rationale of why finally it was concluded that their use was not suitable for a superconducting magnet with the high voltage and energy that ITER needs.