Study on Microstructure of Composite Insulator Rod

Composite insulators have been widely used in EHV and UHV transmission lines due to their excellent anti-pollution flashover performance, high strength and easy installation. As an important part of composite insulator, glass fiber reinforced polymer rod needs to bear the main mechanical load and is also the key to insulation performance. In recent years, although the brittle fracture of rod has been effectively solved, the abnormal temperature rise and decay-like fracture caused by rod defects still affect the safe operation of transmission lines seriously. In this paper, the microstructure of the rod is studied by improved dye penetration test and three-dimensional scanning, and the influence of microstructure difference is studied by water absorption and loss power experiments. The results show that moisture penetration caused by large porosity and penetration channel is the key factor to increase the loss power of rod. By improving the performance requirements of rod, the heating and decay-like fracture of composite insulator could be avoided to some extent.