Experimental and numerical analysis of damage characteristics to opgw strands under first lightning strike and continuous current

Abstract

Optical fiber ground wires (OPGWs) are used to protect power transmission lines from lightning strikes. A lightning test system with a tension device was established to study the properties and influence factors of lightning damage for OPGWs under multiple consecutive lightning strikes composed of current impulse and continuous current. The lightning damage can be divided into arc sweeping damage, melting damage and ablation damage. The lightning energy injected through a W-Cu electrode was the most concentrated, leading to the most serious ablation damage and the smallest sweeping damage area. As the action integral and external tensile force increased, the lightning damage became more severe. The broken strands and ablation damage volume decreased as the discharge gap increased from 20 to 40 mm. In addition, a 3D finite element simulation of lightning melting damage was conducted considering the lightning test conditions. When 1850 K, which is close to the melting point of steel, was selected as the criterion temperature for melting damage, the deviations between the simulation and experimental results were less than 10%.