High Voltage Insulators Types

For high voltages 33 kv it is a usual practice to use suspension type insulators shown in fig.

High voltage insulators types.

Overhead conductors for high voltage electric power transmission are bare and are insulated by the surrounding air. Hence overhead power lines are always supported on insulators mounted on their support poles towers. For low voltage lines 11 kv shackle insulators are used as strain insulators. Tests on insulators are roughly divided into three groups.

The voltage capacity of this insulator is 11kv. Overhead line insulators it is obvious that if overhead power lines are not properly insulated from their support poles towers the current will flow towards the ground through the poles towers which also become hazardous. In all applications the insulation of the cable must not deteriorate due to the high voltage stress ozone produced by electric discharges in air or tracking. However for high voltage transmission lines strain insulator consists of an assembly of suspension insulators as shown in figure.

Insulating supports called insulators are required at the points where they are supported by utility poles or transmission towers insulators are also required where the wire enters. The suspension insulator is called as disc insulator. Conductors for lower voltages in distribution may have some insulation but are often bare as well. The pin insulator has a simple construction.

High voltage cables of differing types have a variety of applications in instruments ignition systems and alternating current ac and direct current dc power transmission. This kind of insulator is used in distribution systems. But what types of high voltage tests can you perform on insulators. Let s take a look at each of these in more detail.

This type of insulator is used in the high voltage overhead distribution line. In a 11 kv system we generally use one part type insulator where whole pin insulator is one piece of properly shaped porcelain or glass. The cost of pin type insulator increases rapidly as the working voltage is increased. Therefore in this types of insulators in transmission lines insulator is not economical beyond 33 kv.

Mostly suspension insulator is made of glass or porcelain insulating. The discs of strain insulators are used in the. Pin insulators are the earliest developed overhead insulator but are still commonly used in power networks up to 33 kv system. In order to relieve the line of excessive tension strain insulators are used.

The most important factor of strain insulator is a mechanical strength stay insulators and shackle insulators are part of strain insulators and these types of insulators widely use where high mechanical strength is necessary in low voltage applications. It requires less maintenance as compared to other insulator types. Type tests sample tests and routine tests. Strain insulator are widely used where the tension load of conductor is higher.