@article{LI2025, 
author = {Peng LI and Xiaochuan JING and Hao NING and Qingwei MENG and Mingxiao ZHU},
title = {Sag measurement system of overhead transmission lines based on laser point cloud},
year = {2025},
journal = {Experimental Technology and Management},
volume = {42},
number = {6},
pages = {55-61},
keywords = {point cloud completion, laser point cloud, nearest neighbor search, sag},
url = {https://www.sciopen.com/article/10.16791/j.cnki.sjg.2025.06.007},
doi = {10.16791/j.cnki.sjg.2025.06.007},
abstract = {[Objective]In recent years, with the rapid development of the economy, the demand for electricity and the scale of the global power grid have rapidly expanded. As an important channel for power transmission, the safe and stable operation of transmission lines is of vital importance. The sag of power conductors is a crucial parameter that can affect the working state of transmission lines. Therefore, achieving effective monitoring and adjustment of the sag of power conductors in transmission lines has become an important task in power line inspection. Effective monitoring of sag provides an important guarantee for the healthy operation of a transmission network.[Methods]This paper proposes an experimental platform for collecting the point cloud data of overhead transmission lines with an unmanned aerial vehicle (UAV) LiDAR as the main body. A software and hardware system applied to the sag measurement of power conductor point clouds is designed. A method for tracing the transmission conductors and completing the missing point clouds based on three-dimensional point clouds is proposed. By taking advantage of the high precision of laser point clouds, an accurate measurement of the conductor sag is realized. The specific process steps are as follows: 1) the UAV point cloud collection platform is used to collect the point cloud data of the overhead transmission line, and the point cloud data of the transmission line in the target section are obtained. 2) Kd-tree spatial reconstruction is carried out on the obtained point clouds of the overhead transmission line to accelerate the positioning speed of the target points and the searching speed of the neighboring points. 3) On this basis, conductor tracing is carried out on the reconstructed point clouds of the transmission line, and the target conductor is extracted from them. 4) The integrity of the collected point clouds of the power conductor is checked. If there are missing data, the cubic spline interpolation method is used to perform spatial shape fitting on the conductor point clouds. Then, according to the fitting results, data completion processing is carried out on the missing data part to obtain the complete conductor point clouds. 5) Finally, for the obtained complete conductor point cloud data, the sag of the target section of the conductor is calculated according to the sag calculation model and the final measurement result is obtained.[Results and Conclusions]This paper conducts measurement experiments on a typical section of the JL3/G1A-630/45 overhead transmission line of the Hanzhong–Zhengzhou line to verify the performance of the proposed sag measurement system. Verified by the measurement experiments, this measurement system can effectively and accurately measure the sag of power conductors and exhibits good robustness and high efficiency. It can accurately complete the task of measuring the conductor sag even when there are missing conductor data. In addition, this sag measurement system is a noncontact measurement, which has the advantages of convenience and safety. It provides a novel means for sag monitoring of high-voltage overhead transmission lines and can provide certain technical references for subsequent work, such as the inspection of the transmission network of the power system.}
}