Interruption capability and decomposed gas density of CF3I as a substitute for SF6 gas

• Published in: IEEE transactions on dielectrics and electrical insulation 2010-08, Vol.17 (4), p.1196-1203
• Main Authors: Kasuya, H, Kawamura, Y, Mizoguchi, H, Nakamura, Y, Yanabu, S, Nagasaki, N
• Format: Article
• Language: English
• Subjects: Circuit breakers; Circuit faults; Current measurement; Dielectric breakdown; Electric breakdown; Gas insulation; Geographic Information Systems; Global warming; Switches; Switchgear
• ISSN: 1070-9878; 1558-4135
• DOI: 10.1109/TDEI.2010.5539690

We investigated the fundamental characteristic of CF 3 I as a substitute gas for SF 6 . CF 3 I has lower global warming potential. The use of pure CF 3 I in gas-insulated switchgear and gas circuit breakers is difficult because liquid CF 3 I has a high boiling point. We therefore mixed CF 3 I with CO 2 or N 2 . In short line fault (SLF, 1 kA peak ) and breaker terminal fault (BTF, 3 kA peak ) interruption, the performance of CF 3 I-CO 2 approximated that of pure CF 3 I when the proportion of CF 3 I exceeded 30%. However, for BTF (20 kA peak ) interruption, the performance of CF 3 I-CO 2 remarkably decreased. In loop current interruption for disconnecting switches, CF 3 I-CO 2 (30%/70%) was successfully used 200 times for 4000 A. We also measured CF 3 I spectra. Investigation of the decomposed gas density after current interruption revealed that fluorine release from CF 3 I was less than that from SF 6 . Iodine density released from CF 3 I-CO 2 (30%/70%) was approximately one-third of that released from pure CF 3 I. In addition, iodine could be removed using an adsorbent.