Effective monitoring and early warning of overhead power lines are critical for ensuring power supply stability and personnel safety.However,existing methods that rely solely on single vision or light detection and ra...Effective monitoring and early warning of overhead power lines are critical for ensuring power supply stability and personnel safety.However,existing methods that rely solely on single vision or light detection and ranging(LiDAR)have limitations such as numerous invalid alarms,hardware equipment constraints,and lack of real-time monitoring capabilities.This article proposes an intelligent monitoring method for safety distance of the powerline corridor based on heterogeneous sensor information.Firstly,an optimised single-stage detector is designed to detect safety hazard objects.In the detector,the backbone network and the sample matching strategy are improved;in addition,the learning strategy is adjusted.Next,the pose transformation relationship is obtained through the visual matching of prior LiDAR information and images.The back projection transformation of 2D–3D is achieved according to the relationship.Finally,a monocular camera-based end-to-end distance measurement scheme is proposed by combining 2D object information with coordinate transformation relationships.The scheme is applied to the distance measurements from hazard objects to powerlines.The experimental results show that the optimisation method improves the detection accuracy and reduces the computational complexity of the model.Also,case experiments with continuous frame data verify the effectiveness of the safety distance monitoring scheme.展开更多
In order to explore the pyrolysis mechanism of palm oil as the natural ester insulating liquid from the molecular aspect,the ReaxFF reactive force field was used to simulate the pyrolysis process of palm oil.Firstly,t...In order to explore the pyrolysis mechanism of palm oil as the natural ester insulating liquid from the molecular aspect,the ReaxFF reactive force field was used to simulate the pyrolysis process of palm oil.Firstly,the molecular models of the four main molecules of palm oil-tripalmitin,trilinolein,triolein,and tristearin-are constructed via density functional theory(DFT).Secondly,the vibrational frequencies of the four molecules are calculated,so as to calculate the infrared(IR)spectra.Thirdly,molecular dynamics(MD)simulations employing the ReaxFF method are performed to simulate the pyrolysis reaction of the palm oil system under different temperatures,so as to observe the generation pathways of major products used in the dissolved gas analysis(DGA)in the transformer thermal fault analysis.Finally,hydrogen bonds in the pyrolysis process are counted.It is found that the number of hydrogen bonds gradually increased with the increase of pyrolysis time and pyrolysis temperature.It reveals why the life of the insulating paper immersed with natural esters is prolonged,and why the breakdown voltage is reduced slowly in the actual experiment from another perspective.This study can provide theoretical guidance and effective reference for the thermal fault analysis of an insulating liquid using palm oil as raw material.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:52277139,52367014Guangxi Science Fund for Distinguished Young Scholars,Grant/Award Number:2024GXNSFFA999017。
文摘Effective monitoring and early warning of overhead power lines are critical for ensuring power supply stability and personnel safety.However,existing methods that rely solely on single vision or light detection and ranging(LiDAR)have limitations such as numerous invalid alarms,hardware equipment constraints,and lack of real-time monitoring capabilities.This article proposes an intelligent monitoring method for safety distance of the powerline corridor based on heterogeneous sensor information.Firstly,an optimised single-stage detector is designed to detect safety hazard objects.In the detector,the backbone network and the sample matching strategy are improved;in addition,the learning strategy is adjusted.Next,the pose transformation relationship is obtained through the visual matching of prior LiDAR information and images.The back projection transformation of 2D–3D is achieved according to the relationship.Finally,a monocular camera-based end-to-end distance measurement scheme is proposed by combining 2D object information with coordinate transformation relationships.The scheme is applied to the distance measurements from hazard objects to powerlines.The experimental results show that the optimisation method improves the detection accuracy and reduces the computational complexity of the model.Also,case experiments with continuous frame data verify the effectiveness of the safety distance monitoring scheme.
基金National Natural Science Foundation of China,Grant/Award Number:51907034Specific Research Project of Guangxi for Research Bases and Talents,Grant/Award Number:2020AC19010。
文摘In order to explore the pyrolysis mechanism of palm oil as the natural ester insulating liquid from the molecular aspect,the ReaxFF reactive force field was used to simulate the pyrolysis process of palm oil.Firstly,the molecular models of the four main molecules of palm oil-tripalmitin,trilinolein,triolein,and tristearin-are constructed via density functional theory(DFT).Secondly,the vibrational frequencies of the four molecules are calculated,so as to calculate the infrared(IR)spectra.Thirdly,molecular dynamics(MD)simulations employing the ReaxFF method are performed to simulate the pyrolysis reaction of the palm oil system under different temperatures,so as to observe the generation pathways of major products used in the dissolved gas analysis(DGA)in the transformer thermal fault analysis.Finally,hydrogen bonds in the pyrolysis process are counted.It is found that the number of hydrogen bonds gradually increased with the increase of pyrolysis time and pyrolysis temperature.It reveals why the life of the insulating paper immersed with natural esters is prolonged,and why the breakdown voltage is reduced slowly in the actual experiment from another perspective.This study can provide theoretical guidance and effective reference for the thermal fault analysis of an insulating liquid using palm oil as raw material.
