Increasing Lightning Strength of Optical Ground Conductors

Karabay S.

TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS, vol.67, no.1, pp.105-114, 2014 (SCI-Expanded) identifier identifier


In this article, testing and improvement stages of AA6101 and 6201 materials used in manufacturing of new generation optical ground conductors (OPGW) installed against lightning strike have been presented. The designed and manufactured prototype composite conductor OPGW for Turkey's transmission lines is composed of six galvanized steel wires, one stainless steel tube with multi glass fibers and 12 aluminium alloy wires. Test samples prepared from prototype failed in first trial of lightning strike due to spot melting of conductor outer surface. The amplitude of the arc current was adjusted to 200A. The duration of the arc was 500 ms with 100C total charge. It caused breaking of excessive aluminium alloy wires at outer layer. Thus material improvement by inoculation with AlB2 compound into molten metal was applied at continuous casting line. Its aim is to obviate destroying effects of lightning strike by the increasing conductivity of the base conductive part composed of alloy AA6101 and 6201 wires. Conductivity increases were made by transforming detrimental transition impurities Ti, V, Cr and Zr into diborides as TiB2, ZrB2, CrB2, and VB2. After all OPGW composite conductor manufactured with improved aluminium alloy wires passed lightning strike tests perfectly.