OVERHEAD LINE INULATOR

Overhead line insulator

1. Insulators2.Insulator materials3.Properties of insulator 4.Types of insulator5.String efficiency

Insulator

Insulators are used between line conductors and supports.The main function of insulators is to provide perfect insulation between the line conductors and supports. And prevent any leakage current from the line conductors to earth through supports……..

Properties of insulatorHigh mechanical strengthHigh insulation resistanceHigh dielectric strengthFree from impuritiesHigh permittivity

Insulator materialsa..porcelain b..glass

Types of insulator

1-pin type insulator2-suspension type insulator3-string insulator4-shackle insulator5-stay insulator

1..Type of insulator

*pin type insulator

It is used for various voltage label.It becomes bulky for higher voltage lable.

*suspension type insulatorCemented cap type Hewlett or interlinking

type

Main drawback is fine crack and early failure.

*strain insulator

It is used at the dead end of line .It is used for higher voltage.

*shackle insulator

It is also called spool insulator.Used for low voltage distribution line.

*stay insulator

It is called egg insulator.Create insulation b\w pole and stay clamp.

String efficiencyThe nonuniformity in the voltage

distribution over a string of suspension insulators is expressed in term of a parameter called “string efficiency”.

Where ‘n’ is no of units or disks in string

String efficiency=voltage across the string /n*(voltage across the unit adjacent to the line conductor)

THANK YOU…..

PRESENTED BY--- ROHIT SINGH (LKO) PAWAN KUSHWAHA (BALLAN)