Characterization and Statistical Analysis of Breakdown Data for a Corona-Stabilized Switch in Environmentally Friendly Gas Mixtures

Characterization of a corona-stabilized switch in the single-shot regime, including triggering range, delay times, and jitter, is reported over the pressure range 0-3 bar gauge, as a continuation of work from similar characterization with this switch filled with SF6 with different gap spacings. When filled with mixtures of 1,3,3,3-tetrafluoropropene (HFO-1234ze) and N-2, the breakdown voltage can be increased by up to similar to 306% and similar to 191% under negative and positive polarities, respectively, of that using 100% N-2. These results were achieved with gas mixtures consisting of 80% N-2 and 20% HFO-1234ze, by pressure. The maximum negative polarity triggering range was 13.6 kV, comparable to that achieved previously using SF6. The measured delay time and calculated jitter were generally found to increase with increasing pressure, and with increasing percentage (from 5% to 20%) of HFO-1234ze in the gas mixtures. von Laue statistical analysis of time-to-breakdown data showed that both the formative time and statistical time increased with increasing pressure, and with increasing percentage of HFO-1234ze in the gas mixtures. The formative time under negative polarity was significantly longer than that for positive polarity. The results indicate that HFO-1234ze may be considered as a suitable candidate to replace SF6 for switching applications, although there are some operational observations that require further investigation.