Development of composite insulators in China

The development of composite insulators in China dates back to the early 1970´s. In the 1990´s they have become widely used in China. At present, up to 600000 composite insulators are operating on 35 to 500 kV ac overhead transmission lines. They are to be introduced into the ±500 kV HVDC transmission schemes. In China all composite insulators in service are silicone rubber and are operating in various contamination conditions. They have successfully and efficiently avoided serious pollution flashover, which occurred frequently when conventional ceramic insulators were used, and radically reduced the maintenance cost of transmission lines in pollution areas. Study of composite insulators is very active in China. The main aspects include properties of materials such as silicone rubber and fiberglass reinforced polymer (FRP) rods, electrical and mechanical performance, aging as well as evaluation and inspection of composite insulators. These fruitful works greatly promote the development of composite insulators in China