Determination of the Brittle Fracture Process of Field Failed HV Insulators

The brittle fracture of composite insulators is caused by the simultaneous action of an acid and a tensile mechanical stress on the FRP (Fiber Reinforced Plastic) core. Two diagnostic techniques are described that can be used to determine what type of acid is present on the fracture surface of field failed insulators. The analysis of 18 field failed insulators reveals, for most of them, the presence on the fracture surface of a type of acid that is produced by the hydrolysis of the resin of the FRP core.