- The lines used for the transmission and distribution of electricity are called conductors. The conductor is mainly used to carry the electrical energy from the generating station to the distribution substation and from the distribution center to the consumer load centers.
- Conductors are the most expensive component in the overhead line transmission as the different parameters are taken into consideration for the material selection of the conductor.
- The size, shape, and type of material used are the main factors in selecting conductors.
Insulators:
- The material which holds the property of Insulation is called an Insulator. Insulation means property to oppose the flow of current which is the exact opposite to the conductor.
- The major application of using the insulators is to provide support for the conductor and maintain distance from one conductor to the other.
Cross-Arms & Clamps:
- Cross-arms and clamps are used mainly for supporting and holding the conductors and insulators
- Cross arms are of various types which are used to hold the conductors in different angles such as Line cross-arms, power cross-arms, etc.
- The cross-arms are mainly made up of wood or steel.
Guys & Stays:
- The Guys and Stays are used for the termination of the lateral forces by making the pole support in angle.
Lightning Arrestors:
- Lightning arrestors are used for the protection of the overhead lines from high-voltage surges
- The lightning arrestors are placed at the top of the overhead line as it collects the high voltage surges and gives them to the ground.
- Lightning arrestors play a vital role in bad weather conditions mainly during rainy climates.
Fuses & isolating Switches:
- The fuses are used to protect the appliances from high voltages and faults.
- The isolating switches are used for isolating the different appliances in transmission.
Earth Wire:
- Earth wire is used for collecting high voltage from lightning arrestors and supplying it to the earth.
- The earth wire will be running on the top of the tower
Vee-Guards:
- These guards are used for public safety, these are provided below the overhead line along the transmission lines
Guard Wires:
- These guard wires are used while crossing communication lines. They may be placed above or below the overhead lines and connected to the earth solidly.
Tower:
- Towers should be self-supporting and capable of resisting all forces due to conductor loads, unbalanced conductors, wind and ice in any direction.
- Such towers often have approximately square bases and usually four points of contact with the ground.
- A semi-flexible tower is designed so that it can use overhead grounding wires to transfer the mechanical load to adjacent structures if a phase conductor breaks and the structure is subject to unbalanced loads.
Dampers-
- Due to wind, overhead transmission lines will be excited to vibrations and oscillations that can lead to damage on the conductor.
- In order to reduce these vibrations and oscillations to an uncritical level, dampers are installed in the overhead transmission lines.
Spacers-
- It is used to establish the distance between the partial conductors of a bundle line in order to prevent conductors from knocking together and thus avoid damage done to conductors.
Barbed Wire.
- Barbed wire is wrapped on a pole at a height of about 2.5 m from the ground for at least 1 meter. This prevents climbing by unauthorized persons.
Danger plate.
- It is provided on each pole, as a warning measure indicating the working voltage of the line and the word "danger". It is provided at a height of 2.5 m from the ground.
Bird Guards.
- A stick of ebonite with rounded top is fixed near the insulator on the cross arm to prevent flashover due to birds pecking on the conductors (on lines with pin insulators).
Phase plates
- Phase Plates in order to distinguish the various phases