What is the impact of UV aging on polymer insulators?

• A. UV exposure has no effect on polymer insulators
• B. UV exposure degrades the polymer, reducing hydrophobicity and increasing leakage/tracking potential
• C. UV exposure strengthens the polymer surface
• D. UV aging only changes color and has no electrical impact

Answer: (B)

Ultraviolet aging degrades the surface and chemical structure of outdoor polymer insulators. The hydrophobic surface is essential for shedding rain and preventing the formation of conductive water films on the contaminated surface. UV light causes photo-oxidation and chain scission, leading to rougher surfaces and the appearance of polar groups. This shifts the surface away from hydrophobic behavior, so water spreads more easily as a thin film rather than beading up. On a wetted, contaminated surface, that film lowers surface resistance and creates continuous leakage paths, increasing leakage current and the risk of tracking and eventual flashover. You may see visible signs like discoloration or chalking, but the critical impact is the loss of hydrophobicity and the resulting rise in leakage/tracking potential. So UV exposure degrades the polymer, reducing hydrophobicity and increasing leakage/tracking potential.