There are main three categories of insulator that is used as an overhead insulator:
- Pin Insulator
- Suspension Insulator
- Strain Insulator
Pin Insulator is one the youngest overhead insulator, that has a capacity up to 33 KV system. It has one part, two parts, and three parts type, which totally depends upon voltage that has been supplied. In 11 KV system, we used one part type insulator where the shape of Pin Insulator is like properly shaped porcelain
In 33 kV beyond voltage, suspension insulator is used. Using pin insulator and handling the bigger size of insulator unit is one of the tough tasks.,so that’s why we used suspension insulator, In this type, no of the insulator are connected in series to form a string and a line conductor is carried by the bottom-most insulator. Each insulator I the suspension string is called disc insulator.
When the suspension string is used to sustain the extraordinary tensile load of the conductor it is referred as string insulator. A strain insulator must have considerable mechanical power as well as the necessary electrical insulating properties.
Note: Additionally there are two more types of the electrical insulator for low voltage application, e.i. Stay Insulator and Shackle Insulator.