Types of insulators and their uses in electricity transmission

Insulators are used in electricity to prevent the flow of current to the earth from its supporting points. No current can flow from these insulators. In overhead electricity transmission the conductors are supported by poles and towers. These towers and poles are properly grounded. The insulator is kept between the towers and poles and the current carry conductor to prevent flow of current to the ground.

Generally three types of insulators are used as overhead insulators and two other types are used for low voltage applications. Pin insulator in used in networks up to 33 KV systems. These insulators are used in one part, two part or three part types according to the demand of the current used in transmissions lines. Up to 11 KV systems the one part pin insulator is used, which is one whole piece of insulator. For high voltages like 33 to 66 KV the one part pin insulator is not manufactured as it becomes difficult to do so. In higher voltages the thickness of insulator is more, that is why the one thick piece insulator cannot be made. So, in this case multiple insulators are fixed by Portland cement to make one complete insulator.

Post insulators are similar to pin insulators but are used for high as well as low voltages. This type of insulator has greater height and can be mounted vertically and horizontally. Only one piece of porcelain is used to make it and fix clamp is arranged on both top and bottom side. Unlike pin insulator, in post insulators one of more insulators can be placed one above other for in high application of voltages.

Suspension insulators are used in application beyond 33 KV voltages. They are a series of insulators joined to make a string and the bottom insulator is used to carry the line conductor. The individual insulators in suspension insulator are called disc insulator because of their disc like shape.

String   insulator is actually a suspension insulator. When an extraordinary tensile load of conductor is sustained by the suspension string, it is called string insulator. This happens when there is an end or the transmission line has to make a sharp turn, then line has to sustain a great load of conductor line. 

Stay insulators are used in low voltages lines .There function is to keep the transmission line insulated above ground.  The insulator is designed Porcelain insulators manufacturers in Delhi   in such a way that in case of breakage of the insulator will not led the wire coming on the ground.

Shackles insulator or spool insulators find used in low voltage distributions. They can be used both in horizontal or vertical positions. But recently their use has come down because of use of underground cables. The material Drop out Fuse Manufacturers in Delhi which is mostly used for the making of insulators is porcelain, which is aluminum silicate. It’s mixing with plastic kaolin, quartz and feldspar to get hard porcelain insulator.