This document discusses different types of tests performed on insulators. It describes three main categories of insulator tests: type tests, sample tests, and routine tests. Type tests are designed to determine if a particular insulator design is suitable for its intended purpose. Sample tests are conducted on a few insulator samples and include tests like puncture voltage, porosity, mechanical loading, and electro-mechanical stress. Routine tests are shorter tests done on all manufactured insulators to check for defects. Examples given are mechanical load and corrosion resistance tests.

1. Tests on
Insulators
Name : Hasmukh Vaza
Sagar Gohil
Anand mandora

2. Index
 What is insulator.?
 Types of insulators.
 Tests on insulators.

3. What is insulator.?
 A material or an object that does not easily
allow heat, electricity, light, or sound to pass
through it. Air, cloth and rubber are good
electrical insulators.

4. Types of insulators.
 1 Pin type Insulators.
 2 Suspension Type.
 3 Strain Insulators.
 4 Shackle Insulators.

5. Tests on insulators.
 The tests on insulators can be divided into three
groups
1) Type Test.
2) Sample Test.
3) Routine Test.

6. 1. Type Test.
 These tests are done to determine whether the particular design is suitable
for the purpose.
 (a) Withstand Test:
 Specified voltage is applied.
 Flashover or puncture should not occur. [otherwisepermanently
damaged].
 The test is repeated five times for eachpolarity.
 (b) Dry One-minuteTest
 The insulator (dry) at prescribed voltage should be gradually brought up
and maintained for onemin.
 There shall not be puncture or flash-over during the test.
 (c) Dry flash-overtest:
 The voltage shall then be increased gradually until flash-overoccurs.
 This is repeated ten times. There shall be no damageto theinsulator.

7. 1. Type Test.
 (d) One-minute Rain test:
 The insulator is made wet at temp 10’c.
 The prescribed voltage is maintained for one min.
 Wet flash-over test:
 The voltage shall then be increased gradually until
flash-overoccurs.
 This is repeated ten times. There shall be no damage
to theinsulator.

8.  Impulse FrequencyFlashover Voltage TestofInsulator
 Theoverhead outdoor insulator must be capable ofsustaining
 high voltage surgescaused by lightning etc. Sothis must be
tested againstthe high voltage surges.
1. Theinsulator is kept asit would be usedpractically.
2. Thenseveral hundred thousands Hzvery high impulse voltage
generator
 is connected to theinsulator.
3. Suchavoltage is applied to the insulator and the spark
over voltageis noted.

9. 2.SampleTests
 (d) PunctureVoltage Testof Insulator
 Theinsulator is first suspendedin an insulatingoil.
 Then voltage of 1.3 times of flash over voltage, isapplied to the insulator.
 Agood insulator should not puncture under thiscondition.
 (e) Porosity test:
 Theinsulator is first broken intopieces.
 ThenThesebroken piecesof insulator are immersed in a0.5 %alcohol solution
of fuchsine dye under pressureof about 2000 PSIfor 24hours.
 After that the sample are removed andexamine.
 Thepresenceof aslight porosity in the material is indicated by adeep
penetration of thedye into it.

10. 2.SampleTests
 Thesampleis tested fully, up to and including the point of
breakdown. Thisis done only on afew samplesof the
insulator.
 a) Mechanical loadingtest:
 Insulator , mechanically loaded up to the point of failure.
 When failure occurs,the load should not be lessthan2000
lbf.
 (b) Electro-mechanicaltest:
 Theinsulator is simultaneously subjected to electrical and
mechanical
 stress.
 Thereshould be no damagecaused.

11. 3.RoutineTests
 Mechanical RoutineTest:
 Mechanical load of 20%more than working load, applied after
suspending the insulator for one minute.
 There should be no mechanical failure of theinsulator.
 Corrosion Testof Insulator
In corrosion test of insulator,
1. Insulator is suspended into acopper sulfate solution for 1min.
2. Then the insulator is removed from the solutionand wiped,
cleaned.
3. Again it is suspended into the copper sulfate solution for one
minute. 4.The process is repeated for four times.
Then it should be examined and there should not be any
corrosion onit.