Failure characteristics and nondestructive testing of insulators

Structure and failure characteristics of porcelain insulator

There are two main types of hanging insulator used in substation, such as vertical vertical and transverse load. Because of the high degree of installation, there is more research on the insulator.

Composite insulator internal mandrel by tens of thousands of root of glass fiber resin impregnated structure, to ensure that the mandrel has sufficient mechanical strength is high, but the core ageing resistance function is relatively weak; the mandrel external sheath and umbrella skirt is generally composed of silicone rubber material. The outer surface of the outer surface of the core rod is sheathed on the one hand, and the utility model provides a good external insulation function.

The brittle failure of the composite insulator is also a great harm when the composite insulator is running on the internet. The sealing performance of the interface between the sheath and the core rod is decreased, and the air gap is generated between layers. Therefore, it is the key to detect the tightness (air gap) between the umbrella skirt and the sheath, the sheath and the mandrel.

The insulation characteristics of insulators determine that it is not suitable for eddy current and magnetic particle testing of these two kinds of electromagnetic methods. Can detect the surface crack of porcelain glaze on liquid penetration method, but the porcelain insulator iron flange mouth often can not remove the sand, so the detection effect of permeability method is very poor. It is known that the method is not suitable for the detection of the failure of the composite insulator. The ultrasonic method is used for the detection of insulators in service, which has the advantages of low cost, high efficiency and no harm to human body and environment.