Instability criteria at interface regions of spherical cavities in solid dielectric cable

Document Type

Conference Proceeding

Publication Date

10-1-1990

Abstract

Charge formation and the associated electric field distribution is described for a spherical cavity embedded in solid dielectric cable are treated analytically. This model is useful for understanding the high-voltage breakdown process in dielectric materials. Emphasis is placed on understanding the role of various phenomena at the cavity interface. The effects of space charge, discharge, polarization, and charge relaxation are considered. The analysis is based electrically on Poisson's equation and kinematically on the diffusion transport mechanism. The interaction between the gaseous plasma in the cavity and the dielectric surface is critical. The prebreakdown mechanism at the gaseous/dielectric interface is linked to the argument (Kv × r2). Kv is a degrading factor related to the dynamic interaction between partial discharge and the dielectric surface, and r2 is the cavity size. Dielectric instability at the interface increases with r2 and decreases inversely with Kv. Instability implies degradation at the interface due to local field enhancement.

Identifier

0025496790 (Scopus)

Publication Title

Conference on Electrical Insulation and Dielectric Phenomena CEIDP Annual Report

ISSN

00849162

First Page

307

Last Page

312

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