Basics of Electrical Power Transmission Components

The overhead transmission lines transmit the electricity from the power station to consumers.

The components of transmission lines are:


The current carrying wires which carry power from the station to our homes. Our electricity transmission system is a three phase AC power system which uses three conductors for carrying the power. Copper, Aluminum, and steel can be used in the manufacturing of conductors. Copper is an excellent conductor of electricity, It has high tensile strength. However, it’s heavy and costly.
Aluminum is light and cheap; however, its tensile strength is very small. Steel is a poor conductor of electricity. However, its price is lowest of three.
In the light of economic considerations and technical facts the present trend is to reinforce the Aluminum conductor with steel, technically named as ACSR (Aluminum conductor steel reinforced)


The poles which support the transmission lines and carry the conductors above the earth. Different sizes of poles are manufactured and used. The size of pole depends on the level of voltages. Poles are either made up of steel or RCC (Reinforced concrete).


A transmission line contains three live conductors. The pylons itself is a conductor of electricity. Connecting conductors to the pylon will introduce a short circuit between all of them. Therefore, conductors are not directly joined to the pylon. Instead, the Insulators are attached to cross arms of pylons and conductors are connected to them.

Cross arms

The arms of a pole which extends through and carry the insulators.

Ground wire

The electrical thunders and lightning introduce heavy faults in transmission lines. A ground wire connects over the lines and provides a low resistance path which moves fault towards the ground.


A transmission line carrying the small voltage level contains single conductors for each phase. However, a line with large voltage levels is composed of multiple conductors. In such conditions, a spacer is used in between the conductors.

Lightning arresters

These are used to divert electrical lightning from line to ground.

Danger plates

These are used to indicate the voltage levels of a line.


These are used at different points for stepping of voltages.

Guy wire

The wire which supports the line and balances it.

Let’s take a visual overview of these components.
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