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

Deterioration of an ADSS (all dielectric self-supporting) fiber optic cable jacket material has been reported near the tips of armor rod assemblies installed on high voltage transmission lines. Field observations and laboratory tests revealed that corona can exist on the tips of the armor rod. Electric field analyses reported herein reveal that the tip surface gradients are high enough to produce corona. Field conditions have been duplicated in a high voltage test chamber and jacket damage has been observed near generated corona. The deterioration mechanism is identified and jacket life expectancy is estimated. Different mitigation techniques are suggested.