Theory of arc resistance of solid dielectrics

Three criteria determined solely by the properties of arc plasma and solid dielectric are deduced from the analysis of interaction between a strip-type arc and the dielectric walls of a flat narrow channel. Each of these criteria represents quantitatively the concept of arc resistance at a certain material state. Depending on the appropriate temperature threshold, these criteria may be considered as characteristic of nondamaging arcing, or as characteristic of the material phase transition interval, or as characteristic of the ablation rate. The material ranking according to the criteria of arc resistance is independent of the current, time and size of the model in a wide range of these parameters. Each of the arc-resistance criteria can, in principle, be estimated in a simple test as a ratio of the appropriate threshold electricity change to the square root of the channel´s width. Numerical values of the criteria for some solid dielectrics are presented.