Effect of additives and pre-stressing on tree inhibition

Author

Rasikawan, S. ; Ishihara, K. ; Shimizu, N.

Author_Institution

Dept. of Electr. Eng., Nagoya Univ., Japan

fYear

1991

fDate

8-12 Jul 1991

Firstpage

113

Abstract

The effect of additives on treeing initiation was studied in LDPE (low-density polyethylene) and XLPE (cross-linked polyethylene) under various oxygen concentrations. The additive effect on AC tree suppression was found to be a function of oxygen concentration absorbed in PE and remarkable in the range from 1 p.p.m. to 10%. This suggests that the additive works as a radical stabilizer to suppress the tree. In contrast with the case of an AC tree, the additives had little effect on positive impulse tree initiation. But they decrease the negative impulse tree initiation voltage. On the other hand, AC prestressing suppresses tree initiation by AC ramp voltage. After prestressing, it was observed that additive molecules migrate to concentrate around the tip of the needle electrode. This probably causes the field relaxation effect

Keywords

electric breakdown of solids; high-voltage techniques; organic insulating materials; polymers; AC prestressing; AC ramp voltage; AC trees; LDPE; XLPE; additive molecules migration; additives effect; cross-linked polyethylene; field relaxation effect; low-density polyethylene; negative impulse tree initiation; oxygen concentrations; positive impulse tree initiation; radical stabilizer; tree inhibition; tree initiation; tree suppression; treeing initiation; Additives; Dielectrics and electrical insulation; Electrodes; Joining processes; Microscopy; Needles; Polymers; Steel; Trees - insulation; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Properties and Applications of Dielectric Materials, 1991., Proceedings of the 3rd International Conference on

Conference_Location

Tokyo

Print_ISBN

0-87942-568-7

Type

conf

DOI

10.1109/ICPADM.1991.172027

Filename

172027