It is about 20 years for composite insulators application of large scale in electric system in China.Because of its excellent antifilthy spark overability,composite insulators which were the inevitable choice to solve external insulation problem of UHVDC transmission project were used more and more in the transmission lines.The paper firstly introduces the manufacture, development and application of composite insulators in China, then analyzes and discusses the key technical study of the insulator, such as the environment and theory of break and brittle failure happened, test method of artificial pollution that about how to choose insert material,ambient temperature and transfer time, shed parameters of overhang and distance influence the DC flashover voltage of insulator, infra-red and ultraviolet technical for in-line monitoring etc.The test results showed that insert material, ambient temperature and transfer time have a signficant influence on the result;appropriate shed distance and overhang can greatly in-creased the DC flashover voltage of insulators; infra-red and ultravioled technique have a remarkable effectiveness on on-line monitoring for composite insulator.

From:High Voltage Engineering, Vol. 37, No. 3, March 31, 2011