Which material is used for overhead line insulators?


Which material is used for overhead line insulators?

Most commonly used material for overhead line insulators is porcelain. But glass, steatite and some other special composite material may also be used sometimes.

What are high-voltage lines made of?

Most of the hundreds of thousands of miles of high-voltage transmission lines in this country are made solely of metal—either aluminum or aluminum wrapped around a steel core. Adding a layer of insulation to every line would be pricey and has been deemed unnecessary given how high the lines are off the ground.

What is the preferred material for overhead conductors?

Conductor Materials Copper was the preferred material for overhead conductors in earlier days, but, aluminum has replaced copper because of the much lower cost and lighter weight of the aluminum conductor compared with a copper conductor of the same resistance. Following are some materials that are good conductors.

Which is the most common material used for overhead line insulators?

In spite of all these benefits, porcelain is the most commonly used material for manufacturing insulators for overhead transmission lines due to a number of reasons. Such insulators are made from clay, quartz or aluminium silicate and feldspar, and are covered with a smooth glaze to shed dust and moisture.

Why porcelain is used in line insulators?

Insulators made from porcelain rich in alumina are used where high mechanical strength is a criterion. Porcelain has a dielectric strength of about 4–10 kV/mm. Composite insulators are less costly, lighter in weight, and have excellent hydrophobic capability.

Which material is not used for overhead line insulators?

PVC have good insulation resistance but it does not have such mechanical strength so it is not suitable for overhead line insulators.

Why do transmission lines have high voltage?

What is a High Voltage Line? High voltage transmission lines deliver electricity over long distances. The high voltage is required to reduce the amount of energy lost during the distance. Unlike other energy sources such as natural gas, electricity can’t be stored when it is not used.

What is the most common cause of failure of overhead line insulators Mcq?

Explanation: Failure of overhead line insulators due to mechanical stress is rare because defective pieces are separated during routine factory test. Failure due to porosity and improper vitrification is also very low. The most common cause of failure of overhead line insulator is flashover.

How many classification of overhead line insulators are there?

There are 5 types of insulators used in transmission lines as overhead insulation: Pin Insulator. Suspension Insulator. Strain Insulator.

What does it mean to build an overhead power line?

Overhead Electric Line Construction. Generally an overhead electrical power line is a structure and it use for electric power transmission and distribution system and it transmit electrical energy or power for large distances from the generation center or plant.

How are electricity transmission lines different from overhead lines?

Firstly, power is generally transmitted over long distances to load centres. Obviously, the installation costs for underground transmission lines will be very heavy when compared to overhead lines. Secondly, electric power has to be transmitted at high voltages for economic reasons.

What kind of materials are used for overhead lines?

Therefore, while selecting a conductor material for a particular case, a compromise is made between the cost and the required electrical and mechanical properties. Commonly used conductor materials: The most commonly used conductor materials for overhead lines are copper, aluminium, steel-cored aluminium,…

What kind of wire is used for an overhead power line?

Overhead power lines are often equipped with a ground conductor (shield wire, static wire, or overhead earth wire). The ground conductor is usually grounded (earthed) at the top of the supporting structure, to minimize the likelihood of direct lightning strikes to the phase conductors.