Power Fittings Suspension Insulator

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According to the definition of GB/T5075-2001 standard "Terms and Terms of Power Hardware": Power hardware is a metal accessory that connects and combines various devices in the power system and plays a role in transmitting mechanical loads, electrical loads and certain protective functions.
Insulator, generally made of insulating parts (such as porcelain parts, glass parts) and metal accessories (such as steel feet, iron caps, flanges, etc.) glued or mechanically clamped with adhesive. Insulators are widely used in power systems. They are generally external insulation and work under atmospheric conditions. The busbars of overhead transmission lines, power plants and substations, and the external live conductors of various electrical equipment must be supported by insulators and insulated from the earth (or grounding objects) or other conductors with potential differences.
Insulator classification
Ordinary type
The umbrella-shaped insulator is a type of suspension insulator with a long history of use. Its characteristics are simple structure and shape, low cost, and suitable for use in clean areas. They are usually used on AC transmission lines.
Disc type
Disc type suspension insulator is a common and important line insulator. As shown in Figure 2.1, this insulator is made of iron cap, insulating porcelain and feet bonded with cement adhesive. The surface of the steel foot and iron cap in contact with the adhesive is coated with a thin layer of buffer layer, generally asphalt, and there is an elastic pad between the porcelain parts on the top of the steel foot. The surface of the porcelain part is generally white glazed, and the surface of the iron cap and steel foot is all hot-dip galvanized. There is an appropriate gap between the lower edge of the cap and the insulating part to avoid stress damage to the insulating part when the material expands.
Disc type suspension porcelain insulators are mainly ball-and-socket connection and slot-type connection. The ball-and-socket connection structure is non-directional and has the advantages of easy installation and disassembly, especially easy to replace insulators under power. Therefore, the ball-and-socket connection structure is generally used on high-voltage, ultra-high-voltage and ultra-high-voltage lines. The slot-type connection structure has simpler connection hardware, but it is not convenient for live operation. It is generally used in lower voltage level lines in my country. In order to ensure that the insulator does not fall off the string during operation, each insulator is equipped with a locking device, in which a locking pin is used for locking in the ball-and-socket connection structure, and a cylindrical pin is used in the slot connection structure, and a cotter pin or a camelback pin is used for locking.

The umbrella-shaped insulator has a long under-umbrella edge, and the product can achieve a larger creepage distance. The inner cavity under the umbrella is not easily affected by moisture, and has a higher pollution withstand voltage. It is more suitable for use in AC and DC transmission lines in coastal, foggy, humid and saline-alkali areas.
Double and triple umbrella type
These two types of products have good wind and rain self-cleaning performance and low natural pollution accumulation rate because the under-umbrella is smooth and has no edges and is open. In addition, the larger creepage distance makes the product have a good pollution withstand voltage level, and the use of the umbrella structure can better play the advantages of the umbrella structure in a dusty environment. This type of umbrella-shaped insulator is called "aerodynamic type". They are suitable for various operating conditions, especially AC and DC transmission lines in heavy pollution, high altitude and desert dry areas.
Straw Hat Type
The diameter of the umbrella disc of this product is particularly large, the bottom of the umbrella is smooth and has no edges, the streamlined structure, good self-cleaning performance, and small amount of dirt accumulation. The use feature is that it is inserted into the upper and middle parts of the suspended string of AC and DC line insulators. The extra-large disc diameter structure can inhibit the occurrence of line pollution flashover caused by ice and bird droppings.

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