The characteristics of DC treeing breakdown associated with short-circuit resistance in low density polyethylene blended with organic compounds

The effects of organic additives and short-circuit tree resistances on the characteristics of DC treeing in low-density polyethylene were investigated. The inception voltage and growth characteristics of DC trees for several different short-circuit resistances were studied on samples blended with additives such as aniline, m-cresol, and p-dichlorobenzene. The observed characteristics for zero short-circuit resistance are mainly related to the short-circuit tree formed at the step of the short-circuit procedure due to the strong Poisson field resulting from space charges in the vicinity of the needle electrode. This kind of tree shows a distinct polarity effect, so that the inception voltage in the case of positive polarity on the needle electrode is larger than in the case of negative polarity. The observed characteristics for high short-circuit resistances are related to the impressed tree, defined as the tree formed when the pressure is impressed at the electrodes. This kind of tree shows a clear inverse polarity effect compared to the case of zero short-circuit resistance