This presentation provides an overview of insulators from Bharat Heavy Electricals Limited (BHEL). It discusses the different types of insulators including pin, suspension, and strain insulators. It also covers the need for insulators, dielectric strength, and electrical breakdown in insulators. Key applications of insulators mentioned are in power transformers, generators, circuit breakers, and cables. The conclusion emphasizes the importance for engineers to develop knowledge about insulator manufacturing, design, and applications.

1. A SUMMER TRAINING
PRESENTATION ON INSULATORS
FROM BHEL
JAGDISHPUR(SULTANPUR)
Presented
ANU GUPT
B.TECH AE
1218748004

2. BHARAT HEAVY ELECTRICALS LTD.
1st unit set up in Bhopal in August 1956.
B.H.E.L. is the largest engineering and
manufacturing enterprise in India in the
energy/infrastructure sector with strong man
force of 82000 people.
B.H.E.L. manufacture over 180 products under
thirty major product groups and caters to core
sectors of the Indian Economy viz., Power
Generation and Transmission, Industry,
Transportation, Telecommunication, Renewable
Energy, etc.

3. MANUFACTURING UNITS OF BHEL
First Generation Units
BHOPAL Heavy Electrical Plant
HARDWAR Heavy Electrical Equipment Plant
HYDERABAD Heavy Electrical Power Equipment
Plant
TIRUCHY High Pressure Boiler Plant
Second Generation Units
JHANSI Transformer and Locomotive Plant
HARDWAR Central Foundry and Forge Plant
TIRUCHY Seamless Steel Tube Plant
Unit Through Acquisition and Merger
BANGALORE Electronic Division
Electro Porcelain Division
New Manufacturing Units
RANIPAT Boiler Auxiliaries Plant
JAGDISHPUR Insulator and Csu-Plant
RUDRAPUR Component and Fabrication Plant
BANGALORE Industrial System Group

4. INSULATORS

5. CONTENTS
1.Introduction
5.Need of insulators
3.Types of insulators
3.Dielectric strength
4.Breakdown in insulator
6.Applications

6. INSULATOR
 A perfect insulator is a material that does not
respond to electric field and resist the flow of
electric charge through it.
 Perfect insulator do not exist.
 Dielectric material with high dielectric constant
are considered as insulator.

7. NEED OF INSULATORS
Insulators are required for following purposes:-
 Between coils and earth.
 Phase to phase insulation
 Inter turn insulation

8. TYPES OF INSULATOR
 Gas or vacuum
 Liquid dielectric
 Solid dielectric
The solid dielectric insulators are further classified as follows:-
1. Pin type Insulators
2. Suspension or string type
3. Strain insulators

9. DIELECTRIC STRENGTH
 The dielectric strength of an insulating material is
defined as maximum dielectric stress which the
material can withstand without any conduction.
 The electric stress to which an insulating material is
subjected is numerically equal to voltage gradient
and which is equal to electric field intensity.
 Voltage at which current starts flowing through the
dielectric is known as breakdown voltage.

10. GAS INSULATOR
 Air at atmospheric pressure is the most
common gaseous insulation.
 Breakdown strength of air is 3okv/cm.
 other gases such as nitrogen (N2), carbon
dioxide (CO2), Freon (CCl2F2) and sulphur
hexafluoride (SF6) are also .
 Breakdown strength can be increased by
operating gases at higher pressure.

11. LIQUID INSULATOR
 Liquids are usually 103 times denser than gases.
 So, they possess much higher dielectric strength of
the order of 107 V/cm.
 Petroleum oils are the commonest insulating liquids
 Fluorocarbons ,silicones, esters are also used as
insulating oil.

12. SOLID INSULATOR
 Solid dielectrics have higher breakdown
strength compared to liquids and gases.
 Many inorganic and organic materials are used
as insulator.
 Inorganic insulators used are ceramic and
glasses
 Organic insulator commonly used are PVC,
polythene,cross linked polythene etc.
 Dielectric strength can be up to 10MV/cm

13. .
 There are several types of solid insulators but the most
commonly used are pin type, suspension type, strain insulator and
shackle insulator.

14. 1. PIN TYPE INSULATORS

15. • As the name suggests, the pin type insulator is secured to the cross-arm on
the pole. There is a groove on the upper end of the insulator for housing the
conductor.
• Pin type insulators are used for
transmission and distribution of
electric power at voltages upto 33
kV.
• Beyond operating voltage of 33 kV,
the pin type insulators become too
bulky and hence uneconomical.

16. 2 . Suspension Type
• For high voltages (>33 kV), it is a usual practice to use suspension type
insulators shown in Figure. consist of a number of porcelain discs connected
in series by metal links in the form of a string.
• The conductor is suspended at the bottom end of this string while the
other end of the string is secured to the cross-arm of the tower. Each unit
or disc is designed for low voltage, say 11 kV. The number of discs in
series would obviously depend upon the working voltage. For instance, if
the working voltage is 66 kV, then six discs in series will be provided on
the string.

17. 3 . Strain Insulators
• When there is a dead end of the line or there is corner or sharp curve, the line is
subjected to greater tension. In order to relieve the line of excessive tension, strain
insulators are used. For low voltage lines (< 11 kV), shackle insulators are used as
strain insulators.
• However, for high voltage transmission lines, strain insulator consists of an
assembly of suspension insulators as shown in Figure. The discs of strain
insulators are used in the vertical plane. When the tension in lines is
exceedingly high, at long river spans, two or more strings are used in parallel.

18. ELECTRICAL BREAKDOWN
Gaseous dielectric
 ionization leads to breakdown of gases.
 Ionization may occur due to….
 A) collision
 B)photo ionization
 C)thermal ionization
Liquids dielectrics
 Presence of any solid impurity lead to breakdown
 Formation of gaseous product

19. Solid dielectrics
 Electronic breakdown
 Structural imperfection also leads to breakdown.
 Chemical reaction such as oxidation , hydrolysis also
leads to breakdown.

20. APPLICATION
 Insulators are employed in:-
 Power transformer
 Generators
 Circuit breaker
 Cables

21. CONCLUSION
 Engineers need to develop knowledge and skills
necessary to evaluate and compare suppliers and
products from many different countries
 An understanding of the basics of insulator
manufacturing, design and application is more essential
than ever before

22. REFERENCES
 High voltage engineering by M S Naidu
 Wikipedia
 Power system by Asfaque Husain

23. .
THANK YOU!!