3D point cloud measurement method for space distance of hidden dangers from external damage to transmission lines

LIAO Ruchao; LIU Gao; WANG Hao; CHENG Guoxiong; ZHU Ling

doi:10.7688/j.issn.1000-1646.2025.01.02

Abstract：[Objective]Transmission lines are easily damaged by external forces,such as construction and vehicle impact.Accurately measuring the space distance of hidden dangers from their external damage helps give early warning,take timely measures to avoid faults,and thereby guarantee the safe and stable operation of transmission lines.However,in the case of long transmission lines,the density and unevenness of point clouds in the area are high,which brings difficulties to calculating the space distance of hidden dangers from external damage.At the same time,under the interference of noise points,measurement errors,inaccurate conversion parameters,and other reasons lead to coordinate conversion errors between the fault points and endpoints.To timely and intelligently measure the distance between the fault points of external damage and endpoints of transmission lines and quickly eliminate external faults,this paper proposed a 3D point cloud measurement method for the space distance of hidden dangers from external damage to transmission lines.[Methods]Based on the elevation filtering interval of point cloud density,this study traversed the entire image by using the kdtree spatial structure to obtain point cloud data.A series of preprocessing was performed such as color adjustment,rotation,resolution adjustment,and flipping on the target image of the transmission line extracted from the 3D point cloud.When an asymmetric short circuit fault was caused by an external damage to a transmission line,the space distance of the hidden danger from the external damage to the transmission line was calculated with the positive-sequence inductance,capacitance,and capacitive reactance information of the transmission line.The positive and negative-sequence components at both ends of the transmission line were analyzed,and the target pixel point was solved to eliminate the influence of asynchronous phase angles at the fault point.A space distance measurement function was constructed,and the search radius was determined according to the sum of the minimum and mean values of the subspace grid point cloud.The pixel points in the target image were solved to achieve accurate measurement of the space distance of the hidden dangers from the external damage to the transmission lines.[Results]The proposed method has a small absolute error in distance measurement under asynchronous phase angles and different transition resistances,with a maximum value of no more than 2 m,and there are no false roots.The measured space distance is closest to the fault distance,which can achieve accurate distance measurement of hidden dangers from external damage to the transmission line.When it is difficult for personnel to reach the site for inspection in adverse weather or complex terrain conditions,remote monitoring of point cloud data can be used to analyze the space distance of hidden dangers from external damage.If it is found that the space distance between an object(such as construction machinery approaching the transmission line)and the transmission line gradually decreases and reaches the set danger threshold,early warning should be issued,and measures should be taken in a timely manner to avoid external damage accidents.[Conclusion]By applying 3D point cloud measurement technology,the space distance of hidden dangers from external damage to transmission lines can be measured,which can monitor the environmental conditions around the transmission lines in real time and provide a more comprehensive and accurate understanding of the health status of the transmission lines.In this way,the inspection strategy can be optimized according to the actual situation,focusing on areas with high risks of hidden dangers from external damage,which can reduce unnecessary inspection workload and improves operation and maintenance efficiency.