Birds build nests on the overhead line towers (pylons, poles). Rats feed on the outer sheath of cable lines. Fungus settles on polymer insulators (Photo). What’s next?

The photo shows the 110 kV disconnector support insulators installed in Karelia (a region on the southern border of Finland). During operation, it was noticed that over time, the installed insulators are covered with impurities consisting of individual black spots with a diameter of up to 20 mm. Only the lower surfaces of the ribs are visible in the photo, but the contamination equally covers the upper surface, concentrating to the outer periphery of the ribs. Vertical cylindrical surfaces are slightly less polluted.

Gradually increasing in size, on some insulators over five years of operation, contamination spots covered the surface of the polymer protective shell with a solid layer, which necessitated special cleaning of these insulators.

Despite the presence of contamination, the surface of the insulators fully retains its hydrophobicity: water concentrates on it in the form of isolated droplets, while it forms an even film on porcelain insulators. The research of my colleagues allowed us to draw the following conclusions:

1️⃣Microphotographic and mycological analysis of contamination on the surface of polymer insulators indicates that the cause of increased contamination of insulators in the Karelia is the growth of colonies of microscopic fungi Exophiala, Aureobasidium, Torula.
2️⃣To stop the growth of contamination, chemical disinfection of the surface with known antiseptic drugs and subsequent mechanical cleaning should be used.
3️⃣In the future, to prevent the growth of microscopic fungi on the surface of polymer insulators, a protective coating material containing biologically active additives that hinder the development of fungi should be developed.
4️⃣Fungus resistance tests and microscopic quality control of the surface of the protective coating should be introduced into the practice of manufacturing insulators.

As far as I know, there are similar stories from England, Canada, China…