Overhead Transmission Line Ice Density Measurement System Design

Overhead transmission lines are prone to severe icing in winter weather,which can lead to large areas of inverted towers,broken lines and other power safety accidents,for which a large number of studies on transmission line icing have been carried out at home and abroad.However,there is a lack of technical research related to online monitoring of ice density,and the hazards caused by different densities of ice on transmission lines are obviously different.At the same time,most of the ice density used in calculations related to ice cover is estimated,which can bring unavoidable errors to the calculation results.In this paper,by studying the principles of load cell measurement of mass and binocular camera measurement of volume,we design a measurement system that can monitor the ice density of simulated conductors online,which will be mounted on an ice-watching robot,which is hung on the overhead transmission line,and the ice cover of the simulated conductors is close to the ice cover state of the transmission line,by measuring the ice density of the simulated conductors so as to achieve the purpose of observing the ice density of overhead transmission lines.The system has high measurement accuracy and effectiveness,and the main research results are as follows:First,a system for measuring ice cover quality based on analogue conductors is designed.Based on a load cell,a weighing structure based on the analogue conductor and a Lab VIEW-based sensor data acquisition software,the system can measure the ice cover mass of the analogue conductor.To analyse the effect of irregular circular motion on the system,the mass of the simulated conductor is used as the object of study and the mass and inclination of the simulated conductor are used as variables to design the mass measurement experiment.Based on the 45 sets of data collected,the influence of mass and inclination angle on the measurement accuracy was analysed and it was found that an increase in both mass and inclination angle triggered an increase in measurement error.Finally,in order to improve the measurement accuracy of the system,the truncated mean algorithm is introduced to process the mass data output from the sensor.The experimental results show that the measurement accuracy of the experimental data processed by the truncated mean algorithm is significantly improved,and the mass measurement error of the system is less than 2g.Second,an ice cover volume measurement system based on the simulated conductor is designed.Based on binocular vision,an ice volume measurement model of the simulated conductor is developed and a volume measurement system is built based on this model,which can measure the ice volume of the simulated conductor.The binocular camera is calibrated,and the resulting left and right image pairs are stereo-corrected according to the calibration parameters.Three algorithms based on SGM,AD＿Census and ZED are used to obtain the global point cloud.To improve the accuracy of point cloud segmentation,a determination basis is introduced,based on an improved threshold segmentation algorithm,to achieve high accuracy segmentation of the point cloud.The principles of point cloud-based volume calculation are elaborated.Finally,for the measurement target white cone,a simulated volume measurement experiment is designed to obtain the point cloud data through ZED,calculate the equivalent height and equivalent base area of the cone,and finally realise the measurement of the cone volume.The experimental results show that for the measurement target white cone used in this paper,a complete and clear contour point cloud can be obtained,and the volume measurement error is 4.11%,which basically meets the needs of engineering measurement.Then,an ice cover density measurement system based on a simulated conductor is designed.Based on the mass and volume measured by the above system,the system can calculate the ice density of the simulated conductor.Based on the weighing structure and modules such as binocular cameras,the overall hardware of the system is designed and mounted on the body of the ice viewing robot.Based on the application environment of the robot and the transmission mode of the signal,the wireless communication software as well as the upper computer interface are designed to enable the wireless transmission of mass,volume and pictures to be displayed on the upper computer,and the calculation process of the ice cover density of the simulated conductor is presented.In addition,based on the designed density measurement system,experiments are designed to measure the volume of the simulated conductor,which is finally calculated to be 100056mm~3.Finally,density measurement experiments were designed to further validate the effectiveness of the system and apply it to a practical environment.Firstly,based on the designed measurement system,density measurement experiments were designed for water-filled white cones suspended from simulated wires in a laboratory laid overhead wire environment.The experimental results show that for the two white cones in this paper,the density measurement error is 10.9%.The system was then used to measure the mass of the standard weights and the thickness of the ice cover of the conductor in the actual environment of the Guiyang Key Laboratory of Disaster Prevention and Mitigation,and the real ice cover thickness was measured with a ruler to compare the two,and the results showed that the system still has a more accurate measurement accuracy in the real environment.After validation of the system,on-line monitoring experiments were carried out on the experimental lines at the Guiyang Disaster Prevention and Mitigation Key Laboratory to measure simulated conductor ice density online,combined with pictures of ice cover to determine the type of ice cover,and applied to actual overhead transmission lines.