Experiment on Temperature Monitoring of In-Service Optical Fiber Composite Overhead Ground Wire under Icing Conditions Based on Distributed Fiber Optic Sensing Technology

Icing poses a severe threat to the safe and stable operation of Optical Fiber Composite Overhead Ground Wires (OPGW), potentially leading to tower collapse and line breakage accidents. Temperature variations serve as a key characteristic of OPGW icing, reflecting the icing conditions to a certain extent. Distributed fiber optic sensing technology, with advantages such as long sensing range and simple operation, demonstrates significant potential in temperature monitoring. This study utilized temperature as a characteristic parameter of OPGW icing, combined with distributed fiber optic sensing technology, to conduct a 168-hour online temperature monitoring experiment on an in-service, long-distance OPGW line spanning moderate and heavy icing zones in southwestern China. The results were compared with data from micro-meteorological monitoring terminals installed on transmission towers. Key findings include: multi-segmentation in the Brillouin scattering spectrum due to variations in fiber manufacturing processes and production batches; a temperature coefficient C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf> = 1.2971 for the OPGW’s Brillouin frequency shift, with a coefficient of determination R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.98, demonstrating high reliability; and strong consistency in temperature trends between distributed fiber optic sensing technology and micro-meteorological terminal data, with deviations remaining within acceptable engineering tolerances. These results indicate that distributed fiber optic sensing technology effectively monitors temperature variations in OPGW, offering practical advantages such as resistance to electromagnetic interference and real-time full-line coverage. This study lays the foundation for future research on ice thickness monitoring using distributed fiber optic sensing technology.