INSULATORINSULATOR

2

Insulator are required to support the line conductor and provide

clearance from ground and structure.

Insulator material-

High grade Electrical Porcelain

Toughened Glass

Fiber Glass

Choice of insulator material is govern by availability, price and ease of maintenance. Porcelain insulator are largely used in India.

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Type of Insulator-

Disc Type

Strut Type

Disc type Insulator

It consist of central suitable shaped porcelain/ glass body like a

disc with an metal clamp on one side and metal ball pin on other

side

Cap is made of malleable cost iron and the ball pins is of forged

steel.

Strut Type InsulatorStrut Type Insulator

4

It consist of several insulator disc cemented altogether

without any link.

It is rigid and can take both tension and compression load.

These are used for holding the conductor out of way of

structure.

Long Rod Insulator

Polymer Disc Insulator String

DISC INSULATORDISC INSULATOR

insulatorinsulator

protectionprotection

Lighting strokeLighting stroke

Condition of blasted discCondition of blasted disc

IR value of Insulators IR value of Insulators

0 – 50 M.Ohms - ‘A’ Grade

51 – 500 M.Ohms - ‘ B’ Grade

501 – 1000 M.Ohms - ‘ C’ Grade

1001 – 2000 M Ohms - ‘ D’ Grade

2000 & above - ‘ E’ Grade

Strings Strings

String efficiencyString efficiency

Cross armsCross arms

Guard ringGuard ring

Guard ringGuard ring

Grading ringGrading ring

Corona ringCorona ring

Vibration damperVibration damper

spacerspacer

PORCELAIN LONG ROD INSULATOR PORCELAIN LONG ROD INSULATOR STRINGSTRING

PORCELAIN LONG ROD INSULATOR STRINGPORCELAIN LONG ROD INSULATOR STRING

Tests on Line MaterialsTests on Line MaterialsType Tests

Acceptance Tests / Sample Tests

Routine Tests

Test During Manufacture

Type Test’sType Test’s

Mechanical & Electrical tests.It means those test which are to be carried

out to prove the process of manufacture and general confirmity of the material as per specification.

On sample prior to commencement of commercial production against the order.

Acceptance Tests/Sample Acceptance Tests/Sample TestsTests

It means those tests which are to be

carried out on samples taken from each lot offered for pre-dispatch inspection, for the purpose of acceptance of that lot.

Routine TestsRoutine Tests

Performed on each insulator before its dispatch

Eg. Power frequency voltage withstand test (dry- routine test, wet- type test)

Tests During ManufactureTests During Manufacture

Which are to be carried out during the process of manufacture and end inspection by the supplier to ensure the desired quality of the end product to be supplied by him to customer.

Tests on Insulator stringsTests on Insulator strings

Power frequency voltage withstand test under wet condition - 680Kv

Switching surge voltage under wet condition-1050Kv Impulse Voltage withstand under dry condition-

1600Kv Voltage distribution test – MAX 9KV Corona and Riv under dry condition Mechanical Strength Test IEC 60383/IEC 60575Cl 4.0