Composite Insulator

I. Definition

Composite insulators are a special type of insulation control that can play an important role in overhead transmission lines.
Composite insulators are also known as synthetic insulators, non-porcelain insulators, polymer insulators, rubber insulators, etc. The main structure is generally composed of a shed skirt, a FRP core rod and an end fitting. The shed skirt is generally made of organic synthetic materials, such as ethylene propylene rubber, high temperature vulcanized silicone rubber, etc.; FRP mandrels are generally made of glass fiber as a reinforcing material, and a oxidizing resin as a base material; The end fittings are generally carbon steel or carbon structural steel coated with hot zinc-aluminum.

II. Classification

Composite insulator can be divided into: line composite insulators and power stations, electrical composite insulators. It can also be divided into rod-shaped suspension composite insulators, pin-type composite insulators, cross-arm composite insulators, pillar composite insulators, wind-proof partial composite insulators, and so on.

III. Advantages
Small size, easy to maintain; Light weight, easy to install; High mechanical strength, not easy to break; Excellent seismic performance and good stain resistance; Fast production cycle and high quality stability. IV. End Fitting Structure
Composite insulators vary in their structure depending on the characteristics of use. In addition to meeting the tensile strength, meeting the requirements, and reliably connecting with the mandrel, the design of the metal tip also needs to meet the special requirements for application under high voltage. Composite insulators are generally made in the shape of a rod with a small capacitance. Therefore, the voltage distribution on the surface of the insulator is very uneven. Thus, in normal operation, the generated corona will be harmful, so it is necessary to use a pressure equalization measure. In addition, the synthetic insulating material cannot withstand an electric arc of several tens of kiloamperes. In the event of a short circuit fault, it will burn the umbrella near the wire and the tower, so arcing is required. At home and abroad, the method of adding a pressure equalizing ring is generally adopted to uniform the end electric field, weaken the corona, and lead to the fault arc.

The voltage equalizing ring of the composite insulator is a component of the composite insulator. Its function is to control the electric field strength inside the insulator, avoid internal partial discharge, reduce the local electric field strength of the external surface, especially the surface of the metal connecting part, and reduce the radio interference. Leading the power frequency arc to avoid burning the surface of the insulator and minimizing the local electric field strength near the end surface to improve its anti-smudge performance.