Streamers in long point-plane gaps in cyclohexane with and without additives under step voltage

This is a study of the effect of the additives dimethylaniline (DMA) and trichloroethylene (TCE) on the prebreakdown phenomena known as streamers, in a simple base liquid, cyclohexane. This has been done under a step-like impulse voltage in a long point-plane gap. The objective was mainly to find out which aspects of the chemistry of mineral transformer oils cause their good streamer-related dielectric properties, in particular the high voltage for the transition to a very fast mode of positive streamers, as pure cyclohexane does not have these good properties. It is found that DMA added indeed causes positive streamers to become very similar to positive streamers in mineral oil and has no effect on negative streamers. TCE causes the negative streamers to become more mineral-oil-like, and has only a little effect on positive streamers. © Copyright 2011 IEEE – All Rights Reserved