Much has been written about the massive winter storm that coated conductors and towers in eastern North America with up to 80 mm( 3 inches) of ice. The results were catastrophic, especially in Québec where hundreds of lattice transmission structures toppled. This image, taken only hours after the event, captures the macabre scene as tower after tower along a 735 kV line lie in a crumpled heap, the sub-conductors stretched out over the icy ground. But perhaps even more eerie is that standing right alongside is another such line of seemingly identical design yet virtually unscathed by the calamity.
It has long been known that wall bushings can be highly vulnerable to pollution flashovers from the phenomenon of uneven pollution deposition, especially if there is no roof overhang to limit wetting by rain. This is a photo of a massive porcelain bushing installed during the late 1990s at the ± 500 kV Nanqiao Converter Station near Shanghai and exposed to high ESDD levels from nearby chemical works( since relocated). One can quickly appreciate from this image just how uneven the pollution deposition can be along such a profile, tilted at an angle and partly shielded from wind by the building.