There are several materials of insulators used in overhead lines
Commonly used insulators for overhead distribution lines are pin insulators, column porcelain insulators, suspension insulators, butterfly insulators (also known as tea table porcelain bottles), rod porcelain insulators, pull-wire porcelain insulators, ceramic crossarm insulators, and discharge clamp porcelain Insulators, etc. There are two types of low-pressure porcelain bottles for low-voltage circuits: needle type and butterfly type.
Pin insulators. Pin-type insulators are mainly used for linear rods and corner rods with smaller angles to support wires, and are divided into two types: high voltage and low voltage. As shown below:
2. Post-type porcelain insulators. The purpose of the post-type porcelain insulator is basically the same as that of the pin-type insulator. The insulating porcelain pieces of the pillar-type porcelain insulators are poured into the iron shoe of the base to form an "iron-clad porcelain" outer casting structure, as shown in the figure below. However, when using column-type porcelain insulators, the angle of the wires for erecting the straight corner rods cannot be too large, and the lateral force cannot exceed the allowable bending strength of the column-type porcelain insulators.
3. Suspended porcelain insulators. Suspended porcelain insulators are shown in the figure below. It is mainly used for tension poles of overhead distribution lines. Generally, low-voltage lines use one piece of suspension insulator to suspend the wire, and 10kV lines use two pieces of insulator string to suspend the wire. Suspended porcelain insulators are connected in two ways: ball and socket type and groove type.
4. Butterfly insulator. Butterfly-type insulators are commonly known as tea-table porcelain bottles. There are two types: high pressure and low pressure, as shown in the figure below. Butterfly-type porcelain insulators and suspension insulators form "tea hangers" on 10kV lines, which are used for small cross-section wire tension rods, terminal rods or branch rods, or on low-voltage lines as straight or tension insulators.
5. Porcelain cross arm insulators. Porcelain cross arm insulators are solid porcelain pieces with metal accessories cast on one end. They are generally used for 10kV line linear poles, as shown in the figure below.
6. Rod-type porcelain insulators. Rod-type porcelain insulators, also called porcelain pull rods, are solid porcelain bodies with steel caps cast on one or both ends, or pure porcelain pull rods, as shown in the figure below.
7. Pull-line porcelain insulators. Tension porcelain insulators, also known as cable round porcelain, are generally used for the terminals, corners, and tension rods of overhead distribution lines to pass through the cables to insulate the lower cable from the upper cable.
8. Discharge clamp insulator. The bottom of the discharge clamp insulator is basically the same as the column insulator. The insulating porcelain is installed in the iron shoe of the base to form an "iron-clad porcelain" outer casting structure. The top insulating porcelain is poured in the iron cap and installed on the iron cap. With aluminum pressure plate