A fusing switch for fault suppression in the SNS High Voltage Converter Modulators

The High Voltage Converter Modulators (HVCMs) at the Spallation Neutron Source (SNS) have operated in excess of a combined 250,000 hours. Performance and reliability improvements to the HVCM are ongoing to increase modulator availability as accelerator system demands increase. There is a relatively large amount of energy storage in the HVCMs, ~180 kJ. This energy can be released into unsuppressed faults, cause damage, and increase the time to repair. The ¿fusing switch¿ would provide a means to isolate this stored energy from the location of the most common faults. This paper introduces this concept and its application to the HVCMs.