Evaluation of Strains in Dead-End Fittings of High-Temperature Low Sag Electrical Conductors Using FBG Sensors

A new approach is presented to use Fiber Bragg Grating (FBG) sensors to measure axial strains that are developed during crimping and loading of high-temperature low sag (HTLS) electrical transmission conductors. Crimping has been successfully used for dead-end fittings of ductile steel in traditional aluminum conductor steel reinforced conductors. However, strain limits of modern HTLS conductor rods can be lower and, unlike the steel cores, do not plastically deform. Therefore to ensure safety and longevity, it is important to quantify the strains experienced in the crimped sections of the rods. This work shows that strains from crimping and then loading in the crimped section of the rods can exceed those in the free section of the rod. Thus, rated loads should be reduced when utilizing crimped dead-end fittings. Alternatively, gripping techniques such as a collet and housing system could be considered as it is shown that strains do not exceed those of the free section of the rod for these dead-end fittings.