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Effect of defects and moisture on insulation characteristics of XLPE insulated cable
Author(s) -
Katsuta Ginzo,
Toya Atsushi,
Kanaoka Mamoru,
Katakai Shoshi,
Maruyama Yoshio,
Muto Hideji
Publication year - 1994
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.4391140409
Subject(s) - moisture , materials science , impulse (physics) , composite material , electric field , void (composites) , partial discharge , voltage , dielectric , high voltage , breakdown voltage , forensic engineering , environmental science , electrical engineering , optoelectronics , engineering , physics , quantum mechanics
Sample cables having a few types of defects (such as voids, contaminants, and protrusions) with more volume than usual, were prepared intentionally to clarify how these defects affect separately insulation characteristics under the presence/nonpresence of moisture. In the case of void inclusion, insulation characteristics are even more susceptible to ac voltage than impulse voltage, and the distribution of lifetimes is classified into a wornout failure type due to discharge deterioration. While protrusions and some other contaminants can greatly deteriorate original dielectric strength, these defects have a relatively slight effect on long‐term endurance in the atmosphere. Therefore, the distribution of lifetimes is classified into an early‐failure type. With reference to the influence of moisture, in a strong electric field (exceeding 15 kV/mm) and in a short‐term region, there is an increase in harmfulness around defects with water absorbed, thereby inducing electrical trees and resulting in a breakdown. In the light electric field (no more than 15 kV/mm) and in a long‐term region, harmfulness of defects will not deepen to a considerable extent, and the growth of water trees very possibly is influential.