I've seen these stacked-disc structures on high voltage power lines everywhere. I could not find any information regarding this particular shape, though.
From what I've noticed, high voltage ceramic insulators only insulate conductors end-to-end (not inside to outside, like traditional plastic insulators). I can only assume the shape makes it difficult for an electric arc to travel along the ceramic material, as opposed to, say, along a solid cylindrical piece.
Why exactly are ceramic insulators shaped like that? Is it to reduce cost? Thermal concerns (from possible electric arcs)?
