Nanosecond Breakdown Characteristics of C4F7N and Various Mixtures at Pressures Above 1 Atmosphere in Comparison with SF6

This report evaluates the pulsed breakdown performance of C4F7N under a 6.8 kV/ns voltage excitation. The pulsed dielectric strength of C4F7N is compared to SF6 in the same experimental setup, and it is found that C4F7N concentrations of 50% or greater are required to achieve a dielectric strength greater than or equal to SF6. Pure C4F7N demonstrated higher electric field hold-off for longer time periods and less statistical variance under pulsed conditions when compared to SF6. Mixtures of 50%C4F7N with N2 or CO2 as buffer gases showed no appreciable difference in pulsed dielectric strength.