Nanosecond Breakdown Characteristics of C[sub.4]F[sub.7]N and Various Mixtures at Pressures Above 1 Atmosphere in Comparison with SF[sub.6]

This work measures the nanosecond pulsed breakdown performance of C4F7N and compares it to that of SF6. The results indicate that C4F7N and its various mixtures exhibit certain advantages in breakdown behavior over simply pure SF6 in pulsed spark gaps. This report evaluates the pulsed breakdown performance of C[sub.4]F[sub.7]N under a 6.8 kV/ns voltage excitation. The pulsed dielectric strength of C[sub.4]F[sub.7]N is compared to SF[sub.6] in the same experimental setup, and it is found that C[sub.4]F[sub.7]N concentrations of 50% or greater are required to achieve a dielectric strength greater than or equal to SF[sub.6]. Pure C[sub.4]F[sub.7]N demonstrated higher electric field hold-off for longer time periods and less statistical variance under pulsed conditions when compared to SF[sub.6]. Mixtures of 50%C[sub.4]F[sub.7]N with N[sub.2] or CO[sub.2] as buffer gases showed no appreciable difference in pulsed dielectric strength.