Composite insulator for its excellent characteristics has alternative ceramics

glass material insulator trends.Major manufacturers and power grid design construction unit did lots of for the selection of composite insulators

design

defects detection in many aspects such as the research and demands

and made great achievements.Aiming at a composite insulators fracture accident which was used for an overhead lines

this paper used the composite insulator’s commonly testing method（appearance testing）

and initially determined that the accident can’t be in the operation of the stress corrosion.Then we used the power grid infrastructure commonly used test method（metallographic detection

penetration testing and hardness testing） and grid equipment testing new technology（X-ray testing）.The result finally confirmed that the cause of the accident was due to the ice-shedding which take off the ice jump composite insulator by bending stress lead to fracture.It was recommended that the design unit design

selection of the composite insulator process to special consideration on the ice in serious tiny terrain and micro meteorological factors.