For electrical students

1. 
power TrANSMISSIoN
Presented By,
M.RAJESHWARAN
P.SAI RAM
R.SATHYA PRAKASH
VIGNESH
M.S.VINOTH KUMAR
Guided by,
B.RAJESH KUMAR
(Asst. professor)
M.KUMARASAMY COLLEGE OF ENGINEERING
(Autonomous)
Thalavapalayam,karur-639113.
DEPARTMENT: DATE:22.07.2015

2.  Introduction
 Conductors
 Types of conductors
 Poles
 Towers
 Insulators
 Types of insulators
 Cables
 Types of cables
 Conclusion
Contents

3. 
 Commonly used conductor materials:-
 a)Copper
 b) Aluminium
 c)Steel-cored aluminium
 d) Galvanized steel
 e)Cadmium copper
 Conductors are preferably stranded to increase flexibility.
Conductors

4. 

5. 
 High electrical conductivity
 Greater tensile strength
 Hard drawn copper used
 High current density
 Smaller cross-sectional area required
High cost & non availability
Copper

6. 
 Cheaper & light in weight, for small span
 Small conductivity & tensile strength (60% of copper)
 Cross-sectional area of conductor larger than
copper(Aluminium diameter= 1.26 times of copper)
 Higher tower with greater sag
 Specific gravity lower than copper
 Larger cross-arms required
 Not suitable for long distance transmission
Aluminium

7. 
• High mechanical strength can be utilized by using spans
of larger lengths.
• Tower of smaller height can be used
• A reduction in the number of supports also include
reduction in insulators and the risk of lines outage due
to flash over or faults is reduced.
• losses are reduced due to larger diameter of conductor.
• High current carrying capacity.
Advantages

8. 
 Wooden poles
 Steel poles
 RCC poles
 Lattice steel towers
Types of line supports

9. 
 Shorter span up to 50 m
 Less cost & used for distribution purpose in rural areas
 Pesticides required e.g. creosote oil
 Used for voltage up to 20 kv
 Smaller life(20-25 years)
 Less mechanical strength
 Made of Sal or Chir
 Moderate cross-sectional area
Wooden poles

10. 
Wooden Poles

11. 
• Greater mechanical strength
• Longer life
• Larger spans
• Used for distribution purpose in cities
• Three types:
Rail poles
Tubular poles
Rolled steel joints
Steel poles

12. 
Steel Poles

13. 
1- Suspension Tower
2- Tension Tower
3- Angle Tower
Types of tower

14. 
 Conductors are simply suspended from the tower
 Mechanical strength
 Tower carry a downward force and a lateral force
 But not an longitudinal force
Suspension tower

15. 
Tension tower

16. 
Angle tower

17. Types:
 Pin type :- For transmission and distribution upto 33
KV
 Suspension type :- For voltage greater than 33 KV
 Strain type:- For dead ends,corner or sharp curve
 Shackle type:- For low voltage distribution lines &
canbe used either in a horizontal or vertical position
Insulators

18. 

19. 
 High mechanical strength
 High electrical resistance to avoid leakage currents to
earth
 Insulator material should be porous,free from
impurities & cracks
Properties

20. 

21. 
1. Single core Cable
2. 2 core Cable
3. 3 Core Cable
4. 3.5 core Cable
5. 4 Core Cable
6. Armoured Cable
7. Unarmoured Cable
Types of Cable

22. 
 A cable is most often two or more wires running side
by side and bonded, twisted, or braided together to
form a single assembly.
What is Cable ?

23. 
A single core cable consists of stranded conductors
twisted together and housed in a PVC covering. It
comes as a 6 mm sq. single core, colour coded green
and yellow, and is used for supplementary earth
bonding.
Single Core Cables

24. 
 In 2 Core cable, one conductor acts as a face and
another acts as natural conductors, both the
conductors have equal cross sectional area.
– It is used in telephone service and to connect
computer devices
2 Core Cable

25. 
 In 3 Core cable all the conductors have equal cross
sectional area. 3 strands carry R,Y & B phase
respectively
 It is used as a Neutral wire.
3 Core Cable

26. 
 3conductors are having the same cross sectional area
& are used for 3 different phase. Therefore this
conductor is treated as half conductor and hence the
name is 3.5 core cable.
 It is used to carry the Neutral Current.
3.5 Core Cable

27. 
 In case of unbalanced load some neutral current
exists. Therefore in some cases 4 core cable is
proffered.
 It is used for lighting, load distribution &
applications where unbalanced loading conditions
occur frequently.
4 Core Cable

28. 
 It consists of one or two layers of galvanized steel
wire or steel tap.
 It is used protection against mechanical injury.
Armoured Cables

29. 
 Constructions of unarmoured cables are same as that
armoured cables expect that Unarmoured cables are
not provided with armouring.
 Unarmoured cables also consists of all parts such as
insulation metallic sheath, bedding & serving.
Unarmoured Cables

30. 
 High electrical conductivity.
 High tensile strength in order to withstand
mechanical stresses.
 Low cost so that it can be used for long distances
 Low specific gravity so that weight t volume is
small.
Properties