Influence of Corrosion on Electrical and Mechanical Properties of Porcelain Suspension Insulators: An Overview

Corrosion of porcelain insulators has become a consequential threat to the secure and steady performance of power utilities. The losses due to corrosion have been calculated to be approximately 2–5% of the gross national product of any country. Under the influence of various contaminated environment, space between lower surface of iron cap and porcelain surface bridged by water which supports corrosion in iron cap and pin because of electrolytic process. Investigations validate corrosion found within metal part of insulators can worsen the bond between metal part and other accessories surrounding it and degrade its electrical and mechanical characteristics. These issues can be suppressed partially by utilizing various approaches such as washing and greasing of insulators, utilizing corrosion resistant metals and nonmetallic pins, zinc sleeve concept and U-shaped zinc ring etc. This paper highlights principle of corrosion mechanism especially focusing on corrosion occurs in metal part of insulators, causes of corrosion, dominance of pin and iron cap corrosion on mechanical and electrical characteristics of insulators. Furthermore, various approaches for suppression of corrosion in metal part of suspension insulators have been reviewed.