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

Deterioration of ADSS (All Dielectric Se& Supporting) fiber optic cable jacket material has heen rcported near the tips of armor rod assemblies installed on high voltage transmission lincs. Field observations and laboratory tests revealed that corona can exist on the tips or the armor rod. Electric field analysis reported herein reveals that the tip surface gradients are high enough to prodnce corona. Ficld conditions have been dnplicatcd in a high voltage test chaiuber and jackct damage has been obscrved near generated corona. The detcrioration mechanism is identified and jackct life cxpectancy is cslimated. Diffcrcnt mitigation tcchuiques are suggcsted.