基于图像处理的输电线路导线表面损伤特征研究

On the Surface Damage Features of Transmission Line Conductors Based on Image Processing

导线表面损伤是影响架空输电导线力学性能和电气性能的重要因素,研究导线表面损伤特征对输电导线耐久性设计和安全性评估具有重要意义。为此选取不同地区实际输电线路中截取的不同电压等级的典型导线(钢芯铝绞线)作为研究对象,利用图像处理技术提取了不同导线损伤表面图像信息。针对传统像素点覆盖法的不足提出一种改进的像素点覆盖算法,给出了导线表面损伤特征与分形维数间的关系。研究结果表明,导线表面形貌具有明显的分形规律,分形维数能够度量架空输电导线表面的损伤特征。导线表面损伤程度越低,二维分形维数越小;导线表面不平整度的增加将使得三维分形维数增加。导线表面损伤特征为伤痕时,二维分形维数介于1.5~1.7之间;损伤特征为磨损时,二维分形维数介于1.2~1.4之间;损伤特征为锈蚀时,二维分形维数介于1.4~1.5。

The surface damage of conductors is an important factor in affecting the mechanical and electrical performances of overhead transmission lines.Thus,it is important to study the surface damage features of conductors for the durability design and safety assessment of transmission conductors.Firstly,several typical conductors(aluminium conductor steel reinforced,ACSR)in different regions and voltage levels are selected as the objects of study in this paper.Then the image information of the damaged surface of conductors is extracted by image processing technology.An improved pixel covering algorithm is proposed to make up for the shortcomings of the traditional pixel covering method,and thus the relations between surface damage features and fractal dimensions of conductors can be established.Research results show that there is obvious fractal rule in the conductor surface topography.The fractal dimensions can measure the surface damage characteristics of conductors.The two-dimensional(2D)fractal dimension tends to become smaller with the decrease in the conductor surface damage.The increase in the unevenness of conductor surface will improve the 3D fractal dimensions.When the damage of the conductor surface is a scar,the 2D fractal dimension is between 1.5 and 1.7.If the damage is characterized with wear,the fractal dimension spans from 1.2 to 1.4;whereas the damage is characterized with corrosion,the fractal dimension ranges from 1.4 to 1.5.