Dielectric assessment of composite core conductors: impact and return of experience from a field deployment

HTLS (High Temperature Low Sag) type 4 composite core conductors are a modern technology used in refurbishment of old overhead lines. Reconductoring the old conductors with theses higher performance solutions allow drastic ampacity increase, in a record time, and for a relatively low financial investment. As these solutions become more and more deployed on a global scale, several issues at installation also appear on a more regular basis. Higher strength and stiffness of carbon composite indeed brings newer requirements in terms of handling, bendability and care, which the industry is still learning and adapting to. Because of these specificities and the question of liability in case of defective product (in between manufacturers, contractors or user), several network operators have pushed for the development of novel monitoring technologies able to successfully ensure the integrity of the composite material at different stage of the conductor lifecycle. One of these solutions relies on dielectric assessment of the interface material in between aluminium (conductive layer) and carbon composite (load bearing layer), with the ability to trace back a current leak to a conductor mechanical flaw.