Overhead power transmission

All of us have a sound knowledge regarding overhead transmission system.Simply we can tell “Its a structure used for energy transmission and distribution along a large distance.”This system mainly consists of poles or towers and conductors.This poles or tower will give a mechanical supports for conductors and it will helps to avoid short circuits in conductors.Conductors are using for transmitting power from producing area to consumer point. Metalic conductors like aluminium is using for this system sometimes copper.Aluminium conductor steal reinforced(ACSR) is using normally in all area because of its low resistance and its price.

Overhead power transmission

Overhead power transmission

Operating voltage used in overhead transmission system
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Operating voltage used in overhead transmission system are mainly divided into five types based on range of voltages.
1. Low voltage distribution system(LV) : Less than 1000OV(1KV) .Its used for domestic purpose like sonnection between residential areas and small commercial customers.

2. Medium voltage distribution system(MV) : Its range between 1 KV to 69KV .Its used for distribution in urban and rural areas.

3. High voltage distribution system (HV): Its range between less than 100 KV.subtransmission or transmission at voltage such as 115 kV and 138 kV), used for sub-transmission and transmission of bulk quantities of electric power and connection to very large consumers.

4. Extra high voltage transmission(EHV) : over 230 kV, up to about 800 kV, used for long distance, very high power transmission.

5. Ultra high voltage (UHV) : higher than 800 kV.

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Insulators

Insulators are the support material for conductors with poles/tower.Insulators are usually made of wet-process porcelain or tightened glass. Insulators are broadly classified as either pin-type and suspension type.Pin type we used as support structure for the conductor(here condutors are up of the structure).suspension types conductors are used where the conductors hangs below the structure. Suspension insulators are made of multiple units, with the number of unit insulator disks increasing at higher voltages. The number of disks is chosen based on line voltage, lightning withstand requirement, altitude, and environmental factors such as fog, pollution, or salt spray.
suspension-string

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