Corona caused deterioration of ADSS fiber-optic cables on high voltage lines

Deterioration of ADSS (All Dielectric Self-Supporting) fiber optic cable ja cket material has been reported near the tips of armor rod assemblies insta lled on high voltage transmission lines. Field observations and laboratory tests revealed that corona can exist on the tips of the armor rod. Electric field analysis reported herein reveals that the tip surface gradients are high enough to produce corona. Field conditions have been duplicated in a h igh voltage test chamber and jacket damage has been observed near generated corona, The deterioration mechanism is identified and jacket life expectan cy is estimated. Different mitigation techniques are suggested.