A Consideration on AC Tree Growth at the Heat-Adhesive Interfaces of Diffrent Polymers

Abstract

Composite insulation systems consist of different insulators and their systems are widely used in high voltage equipment and in power cables. These interfaces are the weak part of the composite and play a decisive role in the electrical treeing and dielectric breakdown processes of the composite. Therefore, it is important to study the effects of their interfaces on the electrical treeing of polymer/polymer composite insulators.In this paper, we investigate the ac tree growth in the specimens having heat-adhesive interfaces between ethylene vinyl acetate copolymer (EVA) sheets and the other different polymer films. The polymer/polymer interfaces in our study are arranged as being parallel to the line of electric force. It is found that the characteristics of ac tree propagation in the vicinity of the polymer/polymer interfaces are considerably different at the combinations of different polymers.

Three-dimensional tree simulation of composite system considering an interface perpendicular or parallel to the electric force line

“…10. This tendency can also be observed in actual tree experiments with the heat-adhesive interface parallel to the electric force line in composite insulating materials [7] [8]. In this study, we carried out a three-dimensional tree simulation of a composite system with an interface perpendicular or parallel to the electric force line based on a dielectric breakdown model considering the growth probability.…”

Three‐dimensional tree simulation utilizing a three‐layer model

“…This simulation with the tree bypassing the barrier can be related to samples with weak adhesion between the base material and barrier film, as in the case of PET and FEP films [7]. In the experiments with a polymer/polymer interface, the data were measured only for 200 minutes of voltage application [16], and hence the phenomenon of bypassing the barrier was not observed.…”

“…This simulation of penetration through the barrier after creeping can be related to samples with strong adhesion between the base material and the barrier film, as in the case of a PP film barrier [7]. Therefore, one can assume that a simulation can be performed with a two-layer model ignoring the air layer when the barrier film can be easily penetrated after creeping on the interface, as in the case of the PP film.…”

“…One can relate such conditions to samples with weak adhesion between the base material and the barrier film, as in the case of PET and FEP films [7].…”