Effect of Additives and Pre-Stressing on Electrical Tree Initiation

Abstract

The effect of additives and AC voltage pre-stressing on electrical tree initiation was studied in LDPE using needle to plane electrode system. The tree suppression effect of additive is increased by pre-stressing. It was frequently observed after pre-stressing that tree starts from side portion of the needle electrode instead of the tip. By doping of Methyleneblue as an additive, the migration of additive under high field was proved. The additive migration may be caused by dielectro-phoresis. The voltage hardening effect in additive doped sample was well explained by the term of the concentration of additive at the needle tip.