The composite insulator consists of a core rod, a shed skirt and a connecting fitting. The mandrel is made of FRP, which is used to provide the mechanical properties of the insulator. The sheath is connected to the surface of the mandrel by an adhesive to protect the mandrel. The connecting fitting is located at both ends of the composite insulator to serve as a composite insulator and tower. The role of gold fittings.

The composite insulator end connection can be divided into wedge type and crimp type. The wedge type can be divided into an outer wedge type and an inner wedge type.

The production process of the insulator umbrella skirt and the mandrel can be divided into an extrusion umbrella and an integral injection type. The squeezing umbrella is used to bond the shed to the mandrel, so there are two interfaces of the core rod-sheath, the sheath-the umbrella sleeve, and the integral injection type umbrella skirt and the core rod sheath are integrally formed, only the core rod – Sheath interface.

Composite insulator failures include flashover, mechanical strength reduction, core rod breakdown, brittle fracture, core rod rupture, external force damage, and the like. Among them, external force damage is related to external environmental control, while others depend mainly on the insulator’s own state and are closely related to aging.
At present, the composite insulator mainly adopts a crimp connection structure, and the composite insulator of the structure almost no longer causes an event that the mechanical properties are degraded and the insulator is broken. In the case of an acid-resistant core rod, the composite insulator is almost no longer brittle.
Therefore, the failure of composite insulators currently associated with aging mainly includes mandrel breakdown and rupture. The decrease in water repellency may also cause discharge and damage to the mandrel, so the decrease in water repellency is also considered to be a form of failure associated with aging.