Composite insulator surface state diagnosis based on clustering analysis

With the development of the power system, composite insulators are widely used in China. However, the contamination flashover caused by the loss of the hydrophobicity of silicone rubber remains a threat to the insulation, especially in EHV and UHV transmission lines. The statue variations of the composite insulator surface were studied in this paper. Based on the cluster analysis method, the leakage current was also investigated. And 16 parameters were extracted to characterize the surface state. It was showed that these parameters could be used to recognize the degree of hydrophobicity loss over the composite insulator surface. The discharge model spectrum diagram of composite insulator surface was also established, which could be used for the diagnosis of the degree of hydrophobicity loss and salt deposit density over the insulator surface. This work can enrich the recognition methods of surface statue of composite insulators and may provide useful reference for performance evaluation of composite insulators in service.