This document discusses the key considerations for selecting conductors for transmission lines. It outlines that conductors should have high conductivity to reduce resistance and power losses, and sufficient mechanical strength to withstand weather conditions like wind and ice. Two common conductor types are discussed - aluminum conductors with steel reinforcement (ACSR), which have high strength but also high conductivity and current capacity, and aluminum conductor alloy reinforced (ACAR), which provide an alternative to ACSR.

1. CONDUCTORS OF
TRANSMISSION LINE

2. General Considerations
Electrical Considerations for T.L. Design:
• Low voltage drop
• Minimum power loss for high efficiency of
power transmission.
• The line should have sufficient current
carrying capacity so that the power can be
transmitted without excessive voltage drop
or overheating.

3. • Conductivity of Conductor:
R = p.L/A , or
R = L/6. A
Where:
L: Conductor length.
A: Conductor cross sectional area.
p: resistivity
6: Conductivity 1/p)

4. • The conductor conductivity must be very high
to reduce Conductor resistance R and hence
reduce losses
I2 .R

5. Mechanical Considerations for T.L. Design:
• The conductors and line supports should
have sufficient mechanical strength:
- to withstand conductor weight, Conductor
Tension and weather conditions (wind, ice).
- The Spans between the towers can be long.
- Sag will be small.
- Reducing the number and height of towers
and the number of insulators.

6. • Heat expansion coefficient must be very small.
Rd' Ro•(! o•’)
a t is the heat expansion coefficient at t.

7. Aluminum Conductors (AAC)
lowest cost - low mechanical strength
Used for small span

10. Aluminum Conductor Steel
Reinforced (ACSR)
1 Steel strands
2 Aluminum strands
ACSR (26/7)

14. Advantages of ACSR
• High mechanical strength can be utilized by
using spans of larger lengths.
• 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.

15. 4-Aluminum Conductor Alloy
Reinforced (ACAR)