Failure analysis of a composite insulation system under impulse excitation

Breakdown occurred in an impulsively excited, composite insulation system in the region of the output spark gap and peaking capacitor of a Marx bank generator, The spark gap system contained 8 gaps in parallel operating in pressurized SFG. Systematic differences were observed in the damage morphology from module to module of the spark gap insulating system. These data were supplemented with voltage waveforms and a knowledge of the history of the system, The analysis yields a reconstruction of the sequence of events associated with growth of breakdown paths, an explanation of distinctive features of the damage configuration, and an estimate of average conduction properties of the gaseous breakdown plasma during two stages of channel development.