3-Dimensional Tree Simulation Utilizing Three Layers Model

Abstract

Recently, polymer/polymer composite insulating systems have been widely used in high-voltage equipment and power cables. Such composite insulating systems always have an interface between two polymeric insulating materials. This interface may cause partial discharge and electrical treeing under high electric stresses. The electrical properties of this polymer/polymer interface have not yet been fully understood. It has been shown that the propagation characteristics of electrical trees in polymer/polymer composite insulating materials considerably vary depending on the combination of polymers. It has also been shown that a cavity or a thin gas layer generates near the polymer barrier molded in the base polymer, by the pressure of decomposing gas occurred in the tree channels during ac tree extension.
In this study, we will investigate the 3-dimensional simulated tree utilizing three layers model considering a thin gas layer on a barrier based on a DBM model with growth probability.
The results show that the critical fields of air layer are related to the easiness of tree propagation in the air layer. Moreover, it is suggested that the three layers model is more effective than the two layers model when the tree propagation is discussed in detail.