Introduction of 6 Kinds of Insulators Commonly Used in Power Systems

An important accessory in the power system is the insulator. The insulator is a kind of insulation product, which is generally made of electrical ceramics, also known as porcelain bottles. In addition, there are glass insulators made of tempered glass and synthetic insulators made of silicone rubber.

The purpose of the insulator is to insulate between the wires and between the wires and the ground, to ensure that the line has reliable electrical insulation strength, and to fix the wires to withstand the vertical and horizontal loads of the wires. In other words, the insulator should not only meet the requirements of electrical performance, but also meet the requirements of mechanical strength.

According to the requirements of mechanical strength, the insulator strings can be assembled into single strings, double strings and V-shaped strings. For ultra-high voltage lines or large spans, etc., due to the large tension of the wires and the high requirements for mechanical strength, sometimes three or four strings of insulators are used. There are basically two types of insulator strings, namely pendant insulator strings and tensile insulator strings. Suspended insulator strings are used on linear towers, and tensile insulator strings are used on tensile towers or corner and terminal towers.

(1) Ordinary porcelain suspension insulator

Ordinary porcelain suspension insulators can be divided into two types: ball type connection and slot type connection according to the connection method of metal accessories. Transmission lines mostly use spherical connections.

(2) Pin type insulator

Pin type insulators are mainly used for linear rods or small corner towers with line voltage not exceeding 35kV and wire tension is not large. The advantage is that it is simple and cheap to manufacture, and the disadvantage is that the level of lightning resistance is not high and it is easy to flash over.

(3) Pollution-resistant porcelain suspension insulator

Ordinary porcelain insulators are only suitable for normal areas, that is to say, relatively clean areas, such as use in dirty areas, because of its small insulation creepage distance, it is prone to pollution flashover accidents, so pollution-resistant ceramic suspensions should be used in dirty areas. Insulators can be used to achieve the creepage distance suitable for the level of the pollution area and prevent pollution flashover accidents.

(4) Suspension tempered glass insulator

Suspension glass insulators have light weight, high strength, good lightning resistance and high and low temperature resistance. When the insulator flashes over, its glass shed will burst by itself.

(5) Porcelain cross arm insulator

High insulation level, strong self-cleaning ability, can reduce manual cleaning; can replace steel cross arm, save steel; simple structure, convenient installation and low price.

(6) Synthetic insulators

Synthetic insulator is a new type of anti-pollution insulator, especially suitable for use in polluted areas, and can effectively prevent the occurrence of pollution flashover accidents of transmission lines. Compared with the pollution-resistant porcelain suspension insulator, it has the advantages of small size, light weight, long cleaning cycle, high pollution flashover voltage, not easy to damage, convenient installation and transportation, etc.