Studies of dielectric breakdown under pulsed power conditions

Summary form only given. In an effort to develop transmission lines with higher energy storage capabilities for compact pulsed power applications we have been developing and studying ceramic dielectrics and their electrical breakdown strength (BDS). Results of research to-date show that dense titania ceramics with nanocrystalline grain size (/spl sim/200 nm) exhibit significantly higher BDS as compared to ceramics made using coarse grain materials when tested under DC conditions. We have performed pulsed testing under similar electric field stresses and found comparable behavior. However, we also found that these ceramics tend to breakdown at lower electric fields under pulsed conditions compared to DC conditions (approximately 25% lower). This is opposite from the behavior of liquid dielectrics, but has also been shown in our studies to be the case with ordinary dielectrics such as Mylar. This presentation will describe our test results, review the statistics that are used to analyze the data, and relate our understanding to what has been accumulated in the literature to-date in the context of dielectric breakdown. Our progress in developing a pulser to test large ceramics under higher energy conditions will also be discussed.