基于分布式动态应变传感的光纤复合相线脱冰跳跃监测技术OA

De-icing jump in overhead transmission lines may lead to serious consequences such as inter-phase short circuits,conductor damage,and even severe accidents involving conductor breakage and tower collapse.Therefore,real-time monitoring of de-icing jumps is crucial.However,traditional monitoring methods predominantly focus on early-stage predictive alarms and post-event fault analysis,lacking real-time online monitoring capabilities with high sampling rates,thus making it difficult to promptly evaluate the severity of damage to transmission lines.To address this issue,this paper integrates the structural mechanics characteristics of transmission lines with phase-sensitive optical time-domain reflectometry(Φ-OTDR)technology and proposes a monitoring model specifically tailored for optical fiber composite phase conductors.The proposed model can accurately localize de-icing spans and points,and effectively monitor the de-icing rate and maximum height of de-icing jumps in real-time. Initially,based on the capability of phase-sensitive optical time-domain reflectometry to achieve distributed sensing of dynamic strain along optical fiber composite phase conductors,a mathematical relationship between the internal optical fiber phase variations and strain distributions along the conductor is established.Using this foundational relationship,a methodology for precisely localizing spans affected by de-icing jumps and identifying specific de-icing points within these spans is proposed.Subsequently,by analyzing the variations in vibration characteristics under different ice-loading conditions before and after de-icing events,a correlation between the de-icing rate and the changes in natural frequencies of various vibration modes is developed.Finally,employing the conductor deflection curve equation and integrating Φ-OTDR technology,the paper establishes a model connecting the displacement at any point along the transmission line at any given moment with the spatial differential phase variations within the optical fiber embedded in the de-icing span,thereby introducing a method to monitor the maximum height of de-icing jumps. Experimental tests conducted on a simulated de-icing jump platform demonstrate that significant differences exist in the phase-change patterns of Rayleigh backscattering light within optical fibers embedded in spans undergoing de-icing compared to spans without such events.This distinctive difference enables effective localization of de-icing spans.Furthermore,through detailed analysis of spatial phase variations along sensing regions,precise identification of de-icing points within spans is achievable,with localization errors less than 5 meters.Experimental findings also indicate that as the ice load increases,the natural frequencies of various vibration modes of the conductor decrease correspondingly.The average relative error in measuring the de-icing rate is approximately 7.86%,with errors diminishing progressively as the severity of the de-icing increases.Additionally,the strain variations caused by de-icing jumps within the conductor are attenuated by excess optical fiber length and fiber grease.Introducing correction coefficients can mitigate these influences to a significant degree,ultimately yielding an average relative error of 14.13%in measuring the maximum height of de-icing jumps.This confirms the capability of the proposed model for real-time monitoring of de-icing jump height in overhead transmission lines. The experimental results support several conclusions:(1)The model enables precise localization of spans affected by de-icing jumps and accurately identifies specific de-icing points by analyzing spatial differential phase variations along the conductor.(2)The model reliably monitors the de-icing rate,with measurement accuracy improving as the severity of de-icing events increases.(3)Based on Φ-OTDR technology and considering the structural characteristics of optical fiber composite phase conductors,this model can achieve online monitoring of the maximum height of de-icing jumps in transmission lines under simultaneous de-icing conditions caused by different de-icing excitations.