Photo: INMR ©
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The catastrophic failure of any porcelain-housed component( such as the transformer bushing shown in this image) can lead to ejection of lethal shards at velocities that make them a threat not only to people but also to other assets across a large radius. Explosive failures have occurred in many countries, such as this one at a substation in Crete a few years ago that caused over million Euros of collateral damage and was reported on in INMR. Fortunately, no one was nearby at the time since sharp pieces of porcelain were later found embedded in structures many meters away.
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If pecking silicone insulators was not enough to make power engineers want to hurl stones in the direction of large birds, an even more widespread ornithological threat is demonstrated by this image. Bird excretions( better known by the euphemism‘ streamers’) sometimes launch massive volumes of conductive material directly onto insulator surfaces or across air gaps, often triggering flashover in an instant. Indeed, most outages with no apparent cause are usually attributed to birds.
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Photo: Courtesy of Cemig
It may seem strange these days, but in the early 1990s few power engineers had ever heard of or cared much about that tongue twister term,‘ hydrophobicity’. However, this has changed dramatically as silicone vaulted from relative obscurity in the T & D field to becoming a mainstay of HV line and substation insulation, comparable to porcelain or glass. An insulator with the excellent hydrophobic behavior shown in this image( Class 1) should provide peace of mind to engineers, with its implied assurance that no matter what the pollution and wetting situation, it will resist formation of conductive paths and excessive leakage current.
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Photo: Courtesy of Wacker Chemie