Field dependence of the initiation time of electrical trees in polymer insulation

Abstract

The article analyses the known expressions that describe the field dependence of the inception time of electrical trees in polymer insulation. It also highlights the need to modify these expressions to correctly determine the threshold parameters of tree initiation. We used the methods of catastrophe theory to develop the equation that describes the dependence of the tree inception time in polymer dielectrics on the value of the maximum local electric field strength. The parameters of this equation for epoxy and polyethylene insulation are determined. A good agreement has been established between the literature experimental data and the field dependencies of the inception time of trees constructed according to the proposed equation. The geometric properties of the fold catastrophe function, which characterizes the regularities of the change in the time of initiation of electrical trees in polyethylene insulation, are considered.

Keywords

• polymer insulation
• electrical trees
• inception time of trees
• maximum local electric field strength
• threshold parameters of trees initiation
• catastrophe theory