Influence of Different Effects on Growth of Electrical Trees in Insulation Polymer

In order to study the relations between the electrical trees' growth stages and the partial discharge (PD) characteristics in the insulation polymer, we focus on the PD degradation characteristics on insulation polymer with void defects inside and the influence of partial discharge on growth of electrical trees. The methods analyze the discharge pulse waveforms and electrical degradation traces on insulation polymer surface or inside. For partial discharge form, the direct partial discharges which are independent of insulation polymer interface and the creeping discharge which is interrelated with insulation polymer interface are distinguished in the void defects through waveforms analysis and degradation traces on the polymer surface. The applied voltage and the duration in the test are also the variables which influence the degradation effects and traces. The three degradation effects induced by partial discharge processes are also recognized through degradation traces analysis. There are thermal and chemical processes as well as stress effects which play important roles in the electrical treeing degradation development process. The results of electrical trees' degradations test of samples which contain wedge shape voids defects inside show that partial discharge forms distinguished above can influence the electrical treeing degradation development, and there is a relation between the three degradation effect and the degradation state of insulation polymer. The major degradation effect in a certain electrical trees' development stage is always corresponding with some steady partial discharge behaviors, thereby, these conclusions imply that there are certain relations between electrical trees' development stages and partial discharge characteristics.