What is an insulator in transmission lines?
Electricity cannot be imagined without insulators and conductors. Here we will understand in detail about insulators. In which what is an insulator? What is the type of insulator? How does it work? We will understand it in detail here.
What is Insulator in electrical?
The importance of conductors in electricity is as much as that of insulators. The conductor carries the electricity and insulators are installed to block the electricity.
Electricity is excellent. But to maintain its beauty, it has to be stopped somewhere. To get a good output of electricity, it has to be used safely.
Metal is the standard for carrying current in a conductor. For example, copper conducts more current than aluminum. In the same way, different materials are used in insulators to keep electricity away.
Based on the value of voltage to the insulator, it is installed in the high tension line and HT Yard.
The insulator is necessary between the wire and the pole while carrying the electricity which supports the wire and keeps the pole away from electricity.
Definition of Insulator in electrical transmission line
To stop the electric current, the conducting device of different sizes, prepared from electrical conducting material, is called an insulator. It is used in electrical high tension lines and HT yards.
or
The material that separates the electric wire and the pole on a large electric pole is called an insulator.
Difference Between Insulator and Conductor
Insulator
- Electric current cannot pass through an insulator.
- Thermal conductivity is very low in insulators.
- It has very high resistance.
- Insulators do not have magnetic field storage.
- Its conductivity is very low.
- There is no movement of electrons in insulators.
- There is no free movement of electrons in the turret.
- Example – Rubber, Wood, Paper
- Used for insulation and support over electrical cables wire.
Conductor
- Electric current flows through the conductor.
- The thermal conductivity of the conductor is very high.
- It has very low resistance.
- Magnetic field storage occurs in the conductor.
- Conductivity is very high.
- Example – iron, Aluminum, Silver, Copper
- Used in making electric wire and wire.
Which material is used in the insulator?
The material of the insulator is to resist the electric current. The materials such as paper, wood, masonry, asbestos, PVC, and bakelite are electrical conductors.
Do not allow incoming electricity to pass through. Insulators of different compositions are prepared from this material. This insulator is used in high tension lines.
Best Insulator Property – What should be the material of a good insulator?
1) The mechanical strength of the insulator should be good.
2) Dielectric strength should be good. The higher it is, the higher the voltage can be used for it.
3)There should not be any adulteration in the material of insulation.
4) Temperature should not have much effect on the insulator.
5) Insulation resistance should be good.
6) There should be such a material that anyone can come and prepare it.
7) Fire should not be caught in insulator material and the water should not have any kind of effect.
Also Read - Why are colored balls used in Power Transmission Lines?
Types Of Insulator used for transmission lines
We can see the big pillars of the transmission line of electricity. The wires attached to these poles serve as the carrying of electricity. We put insulators to support this wire. These insulators are of different types depending on the material and its use. Which is explained in detail below.
Types of Insulator Material used for transmission lines poles and tower
- Glass Insulator
- Disc Insulator
- Suspension Insulator
- Porcelain Insulator
- Pin Insulator
- Post Insulator
- Polymer Insulator
- Shackle insulators
- Strain Insulator
- Reel Insulator
- Stay Insulator
Types of Insulator Basis on Material
There are three types of insulators depending on the material. All three types of insulators are used in high tension lines. The characteristics of all three types of insulating material are slightly different. Let us understand it in detail.
Porcelain Insulator in transmission line
Porcelain is a great insulation material. Porcelain insulator is visible in today's time. All types of voltage level insulators are made of porcelain.
1) We get to see porcelain insulators in different sizes. Which is not found in other insulators.
2) The insulator made of porcelain is very smooth. That is why there is less dust and moisture.
3) Due to good strength, the damage is less.
4) If you scrap this insulator, then it does not have any bad effect on the environment.
5) Dielectric strength of the porcelain insulator is 60KV/CM.
6) We can design it according to the requirement.
Glass insulator in transmission line
1) The dielectric strength of the glass insulator is very good. If we compare it with porcelain, the strength of glass is much better.
2) The dielectric strength of the glass insulator is 140KV/cm.
3) Glass insulator does not heat up quickly.
4) The price is also less compared to porcelain.
5) Mechanical compressive strength is 1.5 times higher than that of ceramic.
Disadvantages of Glass Insulators
The biggest disadvantage of glass insulators is the accumulation of moisture in them.
Dust gets accumulated there due to moisture. And at the time of leakage current, here the chances of Fleece over short circuit increase.
It is difficult to make this type of insulator in different sizes.
Polymer Insulator in transmission line
1) This type of insulator is very light in weight.
2) Fitting this type of insulator is very easy.
3) The polymer insulator is flexible. That's why there is no chance of it breaking.
4) Considered the best insulator in the dusty area. On which the effect of pollution is less.
5) Its tensile strength is more than porcelain.
The disadvantage of Polymer Insulators
- It is not used in the beach area. Moisture containing sea salt degrades the polymer.
- Life is too short.
- Mostly used in 11KV only.
Types of insulator on Basis of Use in transmission lines
Depending on the use of the insulator, different names are given based on its composition. Here we will discuss all types of Insulator.
Pin insulator – Pin type insulator in transmission line
Pin insulators are made from ceramic, rubber, silicone, polymer, and porcelain. Pin insulators are used from 415 volts to 33 KV.
We can use a pin insulator according to the voltage value. For low voltage, if one pin is used insulator. So as the voltage increases so do the number of insulators.
Usually, it is used in 11KV line and 11KV switchyard. If the overhead line is straight, it is better to use a pin insulator.
The high tension wire pin extends past the support of the top of the insulator.
If the overhead line is not straight, the chances of the wire coming down increase. By the way, the overhead wire is wrapped with wire. Even if the line is not straight, the insulator remains in tension.
Shackle insulator in transmission line
Porcelain is commonly used in shackle insulators. Apart from this, it is also made from fiberglass and ceramic.
The shackle insulator can be applied both horizontally and vertically. This type of insulator is used in low voltage.
The shackle insulator has a D' type clamp. In the middle of this clamp is the insulator. The D' Clamp is fastened to the pole with a nut bolt.
There is a V-shaped groove in the middle of the insulator. The wire is passed through it and the wire of this overhead line is tied with soft wire.
The mechanical strength of this type of insulator is good. This insulator is very effective in such a situation where the angle is formed.
Disc Insulator in transmission line
Disk insulator is the most commonly used insulator. Disc insulators are made for 11 KV voltage. But the biggest advantage is that it can be used up to such a high voltage level as many discs are connected.
Disc insulators are made out of glass and porcelain. Disc insulator 11KV, 22KV, 33KV, 66KV, 110KV, 220KV, used up to 400KV.
The number of discs in a disc insulator varies depending on the voltage level. There is a formula for how many discs are at what voltage, which we can see below.
How to select the number of disc insulators on transmission line based on voltage level?
Disc Insulator Formula
N =P KV /(√3 *11 KV )
N = number of Discs insulators
P KV = Value of voltage level
11KV = Capacity of a disc insulator
Here we understand with an example.
The voltage of High Transmission over the headline is considered to be 220KV.
N = 220 KV/(√3 *11 KV) = 11. 54
If we hold one step ahead, we can put 12. But voltage in electricity varies slightly with the load. That is why a disc of 13 insulators will have to be installed here.
Suspension Insulator in transmission line
Suspension Insulator is similar to Disc Insulator. This insulator is prepared by adding a disc of glass or porcelain insulator. This insulator isolates and supports the line conductor.
Like we have seen in the disc insulator, a disc is of 11KV voltage level. This disc is connected according to the voltage. This type of insulator is used in the overhead transmission line of high voltage.
The wire remains under this type of insulator. That is, the spreading wire connects with the last disc of the insulator. In this type of insulator, if the disc gets damaged, it is replaced.
Suspension Insulator Disc as per voltage level
How many discs are installed at what voltage in a suspension insulator? Its calculation is given below.
Number of Disc for Suspension insulator based on Voltage Level in Transmission line.
- 33KV - 3
- 66KV-4
- 110KV -6
- 132KV - 8
- 155KV - 11
- 220KV - 14
- 280KV - 15
- 340KV - 18
- 360KV - 23
- 400KV - 24
- 500KV - 34
- 600KV - 44
- 750KV - 59
- 765KV - 60
Advantage of Suspension Insulator
1) Each unit of suspension insulator is 11KV. It is applied based on voltage level.
2) If anyone unit of suspension insulator is damaged, then it can be replaced. There is no need to replace the entire insulator.
3) The suspension insulator has very good flexibility.
4) Due to the conductor being connected below, there is no fear of lightning.
Post insulator in transmission line
Clamps are used on both sides in post insulators. This insulator is used for voltage levels above 33KV. Most post insulators are made of ceramic.
If the voltage level is high, then more insulators can be added to it. This insulator looks beautiful and its reliability is also very good.
In this type of insulator, the wire is attached to the top with a clamp.
Post insulators are available in different models. We can use it as per our requirements.
We can use a Post insulator up to 1100KV voltage level.
Stay insulator in transmission line
A wire connects to the ground near the electric pole in the village. The stay insulator is used more in the same wire.
If the wire has to be twisted or bent in the overhead line, then a letter stay type insulator is installed at such a place.
There are holes in the stay insulator. There are two groups facing each other. It is connected in different ways. But everyone's job is to keep the live wire away.
Stay insulator is made from porcelain.
One feature of stay insulators is that even if the wire breaks or falls to the ground, the live wire does not touch the ground.
Reel Insulator in transmission line
In this article related to insulators, all types of insulators have been discussed. Still, if you have any questions related to the insulator, then you can write me on my social media accounts.
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