Flashover mechanism of silicone rubber insulators used for outdoor insulation - I

George G. Karady, Minesh Shah, R. L. Brown

Research output: Contribution to journalArticlepeer-review

106 Scopus citations


Experimental results show that the contamination performance of silicone rubber composite insulators is better than porcelain insulators. This is attributed to the hydrophobicity of the silicone rubber. This suggests that the flashover mechanism of these insulators is different. This paper experimentally investigates contamination build-up, diffusion of low molecular weight (LMW) polymer chains, surface wetting, electrical field caused interaction between droplets, generation of conductive regions and filaments, field intensification caused spot discharge and the ultimate flashover of silicone rubber along wetted filaments. The studies resulted in a new flashover mechanism, which provides a better understanding of the superior performance of silicone rubber outdoor insulators. The results will be useful for development of improved laboratory test procedures and to evaluate composite insulators' performance in contaminated conditions. The paper is divided into two parts: Part I describes the overview of flashover mechanism and the diffusion of LMW polymer chains and wetting of the silicone rubber surface in detail.

Original languageEnglish (US)
Pages (from-to)1965-1971
Number of pages7
JournalIEEE Transactions on Power Delivery
Issue number4
StatePublished - 1995

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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