What are the advantages of composite insulator?

In terms of structure and material, composite insulators are completely different from traditional porcelain or glass insulators. In terms of performance, composite insulators also have significant characteristics that are different from porcelain or glass insulators, which can be summarized as follows:

• The axial tensile strength of glass-steel mandrill used for composite insulators is very high, generally above 600MPa, which is 5 ~ 10 times that of porcelain, and is equivalent to the strength of high-quality carbon steel. In addition, the specific gravity of the mandrel material is only 2.0, much lighter than steel; The specific gravity of the umbrella skirt material is also less than 2.0, so it is relatively easy for composite insulators to produce a strength grade with a specified mechanical load of hundreds of kN, and the mass of composite insulators is only 10% ~ 15% of that of disc-type suspension insulators. In the construction and emergency repair of ultra-high voltage lines in mountainous areas, the synthetic insulation has the advantages of light weight and is not afraid of falling and is welcomed by operators and construction personnel.

• Composite insulators belong to the structure of rod insulators, and the distance between the inner and outer poles is almost equal. Generally, there is no breakdown of internal insulation, and no maintenance work to detect zero value is needed.

• The umbrella skirt sheath materials of composite insulators are all organic polymer materials with low surface energy and strong hydrophobicity. The moisture falling on the skirt surface condenses into many tiny water droplets separated from each other, but does not form a continuous water film conductive layer, so the leakage current is small, it is difficult to form a local arc, and it is not easy to occur along the surface pollution flashover. In addition, due to the high strength of the mandril, the rod diameter and umbrella diameter of the suspension insulator are much smaller than that of the porcelain insulator string and the shape coefficient is larger. Under the condition of the same dirty surface and the same surface conductivity, the surface resistance of the suspension insulator is higher than that of the porcelain insulator string with the small shape coefficient. There is a direct relationship between insulator pollution lightning voltage and surface resistance, the surface resistance is large, the leakage current is small, the corresponding pollution lightning voltage is high. The laboratory test results and operation experience have confirmed that the pollution flashover performance of composite insulators is high and pollution flashover accidents rarely occur.

• Easy operation and maintenance. With high pollution flashover performance, there is no need to clean up the dirt and no need to detect zero value. At present, the composite insulators under various voltage levels in China have not carried out traditional and heavy cleaning and zero detection maintenance work, which greatly reduces the maintenance workload.