Temperature-induced attenuation in single-mode optical fibers for optical ground wire cables under fault current conditions

Power transmission networks use Optical Ground Wire (OPGW) cables, which worsen the performance when short-circuit fault currents raise the temperature. This study examines temperature-induced attenuation in two single-mode fibers, G652D and G657A, employing a comprehensive methodology that integrates thermal field analysis, finite element method (FEM) simulations, and experimental validation. The study makes three main contributions: first, it analyzes the post-fault thermal field distribution within the OPGW structure using FEM to analyze the delayed temperature rise in the optical fiber after fault clearance; second, it experimentally determines the refractive index profiles of both fibers, which are incorporated into a wave-optics FEM model to accurately simulate signal attenuation; and third, it compares the performance of G652D and G657A systematically under incremental thermal field distribution. Simulation and experimental results demonstrate that G657A exhibits superior thermal resilience, showing an attenuation of 0.0135 dB/km at 100 °C, compared to 0.0169 dB/km for G652D, a disparity attributed to its improved refractive index profile. The findings offer realistic guidance for OPGW cable design, advocating the utilization of G657A fibers to enhance signal integrity and reliability under fault-induced thermal stress.