Abstract:

There are much higher technical requirements on composite insulators used in Qinghai-Tibet project, which is located in the plateau area with high altitude and strong UV radiation. According to the characteristics of high UV radiation in the region, the formulation optimization of silicone rubber for composite insulator was performed; furthermore, a 2 000 h UV aging test was carried out on silicone rubber before and after the improvement. The results show that the mechanical and electrical performance of silicone rubber, such as tensile strength, elongation ratio, volume resistivity and hydrophobicity, have been improved significantly after the formulation optimization, which can satisfy the use requirement of Qinghai-Tibet project. Then, this paper analyzed the UV aging mechanism and aging time trend of silicone rubber, whose results showed that the side chains of silicone rubber were cut by UV radiation and the crosslinking reaction happened to accelerate the aging process; however, UV radiation almost had no influence on the main chain of silicone rubber. Furthermore, there was a rapid decrease in the performance of silicone rubber during the initial aging period and the change tended to be stable after some time. 

Key words: Qinghai-Tibet project, composite insulator, silicone rubber, UV radiation, aging mechanism