【作者】 张智；

【导师】 舒立春；

【作者基本信息】 重庆大学 ， 工程硕士（电气工程）（专业学位）， 2017， 硕士

【摘要】 输电线路覆冰会对线路机械和电气性能造成巨大危害,严重覆冰会造成线路跳闸、断线和倒塔等恶性事故。为了避免输电线路冰灾事故的发生,做到提前预防,必须对导线覆冰情况特别是覆冰厚度进行快速、有效和精确的测量。针对传统输电线路覆冰厚度检测方法在浓雾中测量的不足,本文提出了基于激光测距的输电线路覆冰厚度检测方法。该方法使用准直激光对浓雾中的覆冰导线截面进行照射,通过测距模块和角位台分别得到测量距离和对应旋转角度,然后用几何迭代得到导线覆冰厚度。本文首先对检测装置测量原理进行介绍,推导了覆冰厚度计算方法和测量临界条件;其次确定检测装置的激光波长,选取532nm、635nm、808nm和980nm四种波长开展了激光在浓雾中传输特性研究和激光在不同输电线路覆冰类型表面的反射特性研究;然后对激光发散角进行准直压缩以提高测量精度,设计了激光准直系统;还确定了激光发射功率、接收装置、测距模块和角位台的参数,完成检测装置;在此情况下分析了检测装置在不同测量环境中的最大测量距离;最后在人工气候室内模拟导线覆冰,在浓雾中使用检测装置和游标卡尺分别进行了覆冰厚度测量,验证检测装置的测量性能。完成上述工作得出了以下结论:随着雾浓度的增加,透射率减小,减小趋势先快后缓,并且波长越大,透射率降低越多。在低雾浓度时,透射率随波长增大而增大;在高雾浓度时,透射率随波长增大而减小。相同雾浓度下,随着温度的降低,透射率增大;波长越小,透射率增量越大。随着覆冰类型从雨凇到雾凇的变化,BRDF均值增大,冰表面的反射能力增强;雨凇和混合凇反射规律接近于镜面反射,BRDF在接收角等于入射角时达到峰值,且随入射角的增大而增大。对同一冰表面,随着激光波长的增大,反射性能先增大后减小。随着透射率的增大,检测装置最大测量距离快速增大。测量目标为雾凇时最大测量距离较雨凇时大。当透射率小于0.78m-1或0.85m-1时,检测装置在浓雾中对雨凇或雾凇的最大测量距离大于能见度。透射率为0.71m-1时,测量距离为2.5m和5m,检测装置对雾凇的测量精准度很高,最大偏差量分别为0.28mm和-0.51mm;对混合凇的测量精度较高,最大偏差量分别为1.68mm和-1.06mm;而对雨凇的测量结果整体偏小,并随测量距离的增大有所增大,最大偏差量分别为-1.78mm和-2.29mm。更多还原

【Abstract】 Icing of transmission lines can cause great harm to the mechanical and electrical performance of transmission lines,which can lead to serious accidents such as trip,disconnection and tower collapse.In order to avoid the occurrence of ice disaster of transmission line,it is necessary to carry out a fast,effective and accurate measurement of icing condition,especially the icing thickness.In view of the shortcomings of traditional transmission line icing detection methods in dense fog,this thesis proposes a new method based on laser ranging to detect icing thickness of transmission lines.In this method,cross section of icing conductor in dense fog is illuminated by collimated laser.Measuring distance and corresponding rotation angle are obtained individually by distance measuring module and goniometer.And then wire icing thickness is obtained by geometric iteration.Firstly,thesis introduces measurement principle of detection device,deduces calculation method of icing thickness and critical condition of measurement.Secondly,to determine laser wavelength of detection device,532 nm,635nm,808 nm and 980 nm four kinds of laser wavelength are selected,and laser transmission characteristics in dense fog and reflection characteristics on different icing surfaces are discuss.Then,to improve the measurement accuracy,laser beam divergence angle is optimized by designing laser collimating system.Also,to complete detection device,the laser transmitting power,receiving device,ranging module and goniometer are determined.In this case,the maximum measurement distance of the detection device in different measurement environment is analyzed.Finally,glaze,mixed-phase and rime icing are simulated in artificial climate chamber,and ice thickness are measured in dense fog by using detection device and vernier caliper,respectively.And Measure performance of detection device is validated.Following conclusions can be drawn from the above work:With the increase of fog concentration,laser transmittance decreased,decreasing trend began very urgent then slow down,and the larger wavelength,the more laser transmittance decreases.When fog concentration is low,laser transmittance increases with the increase of wavelength.When fog concentration is high,laser transmittance decreases with the increase of wavelength.Under the same fog concentration,laser transmittance increases with the decrease of temperature,and the smaller wavelength,the larger laser transmittance increases.With the change of the ice type from glaze to rime,the average of BRDF increase,and reflection capacity of ice surface enhance.Because of glaze and mixed phase reflection law close to specular reflection,BRDF reach the peak at receiving angle equal to angle of incidence is.And with the increase of incident angle increases,the peak value of BRDF increases.For the same ice surface,with the increase of laser wavelength,reflection performance increases first and then decreases.With the increase of incidence angle,backward BRDF decreases.With the increase of the transmittance,the maximum measurement distance of detector increases rapidly.When measurement target is rime,maximum measurement distance is far than glaze’s.When transmittance are less than 0.78m-1 or 0.85m-1,maximum measurement distance of glaze or rime are greater than the visibility.in the fog.When transmittance is 0.71m-1 and measurement distance is 2.5m and 5m,less than the maximum measuring distance,detection device can accurately measure the rime,and the maximum deviation is 0.28 mm and-0.51 mm respectively.And maximum deviation of mixed phase was 1.68 mm and-1.06 mm,respectively.While measurement results of glaze is less than true value,and with the increase of measurement distance,deviation increases,and maximum deviation is-1.78 mm and-2.29 mm,respectively.更多还原