During the late 1980s, mass pollution flashovers occurred in the eastern province of KwaZulu Natal and it was at this stage that Eskom became among the first utilities in the world to consider widespread application of composite insulators. Actually, several hundred silicone insulators had already been installed on lines located in heavily-polluted areas and, except for a handful of mechanical failures, these performed well electrically – even with a specific creepage distance of only 23 mm / kV.
A decision was therefore made in 1990 to specify silicone insulators with 30 mm / kV to progressively reinsulate all 275 kV and 400 kV
Mass pollution flashovers during the late 1980s made Eskom among the first utilities in the world to consider widespread application of composite insulators.
Photos: INMR © lines located in areas exposed to severe pollution. As a result, by 1995 Eskom had over 15,000 composite insulators in service on its transmission network and overall performance was judged very good.
I Examples of pollution deposition on glass insulators in South Africa. Shattered glass stub shows onset of corrosion.
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