very good explain by dharmendra saran

1. Jodhpur Vidyut Vitran Nigam Ltd.
Presented by:
Dharmendra Kumar
(13EJIEE404)
(IV B.Tech., VII Sem.)
3/20/2017 17EETR: PT & IV
Power Insulator

2. 3/20/2017 7EETR: PT & IV 2
Jd.V.V.N.L Logo

3. Table of Contents
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 Introduction
 Types of Insulator
 Properties of Insulator
 Testing of Insulator
 Cause of Insulator failure
 Application of Insulator

4. Introduction
 Transmission line insulators are device
use to contain separate or support
electrical conductor on high voltage
electricity supply network.
 The insulator provide necessary
insulation between the line conductor or
support thus prevent any leakage
current from conductor to earth.
 Good insulator :- wood , Glass , Plastic.
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5. Types of Insulator
1. Pin type insulator
2. Suspension type insulator
3. Strain type insulator
4. Stay insulator
5. Shackle insulator
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6. Pin type insulator
 Pin type insulators are used for
transmission and distribution of electric
power at voltage up to 33kv.
 It is made of nonconducting materials
glass and porcelain.
 Beyond operating voltage of 33kv.
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7. Pin type insulator
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8. Suspension type Insulator
 These insulators consists of a number
of porcelain discs connected in series
by metal links in the form of a string.
 One disc is designed for a low voltage
, 11kv.
 66kv voltage line used six disc.
 It provide greater flexibility to the
line.
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9. Suspension type insulator
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10. Strain type Insulator
 When there is a dead end of the line
or corner or sharp curve.
 It is two or more strings are used in
parallel.
 It is mechanically strong.
 It is used for low voltage line (<11kv)
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11. Strain Insulator
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12. Stay insulator
 The stay insulators are to be insulated
from ground at a height(>3m).
 It is used for low voltage line nearly
about 33kv.
 It is usually made of porcelain and is so
designed that in case of breaks them
the stay wire will not fall on the ground.
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14. Shackle Insulator
 They can be directly fixed to the pole
with a bolt or to the cross arm.
 It can be used both in horizontal and
vertical position.
 The conductor in the groove is fixed
with a soft binding wire.
 Mostly used distribution purpose.
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15. Shackle insulator
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16. Properties of Insulator
1. Mechanically strong.
2. High insulation resistance.
3. High dielectric strength.
4. High relative permittivity.
5. Free from internal impurities.
6. It should not get affected change in
temperature.
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17. Testing of insulator
1. Mechanical strength test.
2. Electrical insulation test.
3. Environment test.
4. Corona test.
5. Temperature test.
6. Puncture voltage test.
7. Porosity test.
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18. Cause of Insulator failure
1. Flashover:-The most common cause of
the insulator failure is the flashover,
that causes unequal expansion of the
porcelain thereby shattering the
insulator with big cracks.
2. Cracking of insulator:-This cause
occurs due to unequal expansion of
steel , porcelain and cement during the
varying conditions of cold and heat.
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19. Cause of Insulator failure
3.Porosity of material:-This cause occur
usually absorb moisture from the
atmosphere or the cement, thereby
decreasing the insulation resistivity of the
material.
4.Short-Circuits:- Two or more conductor
are earth through the large birds.
5.Mechanical stresses.
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20. Application of insulator
1. It is used in transmission and
distribution of electricity supply.
2. It is provide necessary safety for
human and animals.
3. Many electronic components used
insulation materials like plastic.
4. Electricity supply board used insulation
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21. Conclusion
 Thus a brief idea about the types of
insulator used in overhead
transmission line has been obtained.
Each type of insulator is having it’s
own area of application. The system
was having a flaw that proper track
record of the insulator and poles
damaged or replacement was not
taken care of.
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22. References
 www.wikipedia.com
 www.electrical4u.com
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23. Thank you.......
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24. Conclusion
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Thank You……
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27. References
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