What Is Corona Effect In Transmission Lines, Advantages

Hello Guys, welcome back to our blog. In this article, we will discuss what is corona effect on transmission lines, the factors that are affecting corona, and how to reduce corona effects, advantages, and disadvantages.

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Nowadays, if you are studying the transmission and distribution subject, then you will hear a word called the corona effect in transmission lines. Corona effect will occur in overhead lines due to many reasons.

Corona Effect On Transmission Lines

If the voltage applied in line is increased to the breakdown value i.e., 30Kv/cm, the velocity acquired by the free electrons is sufficient to strike a neutral molecule with the force to dislodge some electrons from it. This produces another ion. The result of this ionization is that Corona is formed or a spark takes place between the conductors.

What is ionization?

Ionization means the atom which becomes a positive or negative charge, by gaining and losing electrons to form an ion is called ionization.

When a corona occurs in a line of ozone gas, violates color glow and hissing noise is produced, it is called the corona effect. If the lines are smooth and polished then the corona occurs uniformly and if the line is rough corona will be brighter.

If you want to see the corona, then you can go to a place where transmission lines are erected and you can watch the corona if some conditions are satisfied. i.e.,

01. Critical Disruptive Voltage – The minimum voltage required to make air ionization, if the voltage is more than critical disruptive voltage then ionization takes place.

02. Visual Critical Voltage – The minimum voltage required to form a corona, if the voltage is more than visual critical voltage then a corona takes place. The visual critical voltage varies based on climate if the climate is rainy then the visual voltage will reduce and in the non-rainy season, it will be more.

Suppose the critical disruptive voltage is 30 KV then the visual voltage will be 50 KV if the voltage is more than 50 KV corona takes place.

Factors Affecting Corona

01. Conductor Size
02. Line Voltage
03. Spacing Between Conductors
04. Atmosphere
05. Frequency

01. Conductor Size – It will decrease the value of breakdown voltage if the conductor is rough and have an irregular surface then the corona effect will be more, so the conductor size will also matter.

02. Line Voltage – If the line voltage is high, then the electrostatic stress at the conductor surface makes the air around the conductor act like a conductor and a corona is formed. If the line voltage is less then there will be no corona effect.

03. Spacing Between Conductors – If the spacing between the conductor is less then electrostatic stress will be increased at the conductor surface and a corona will occur. If the spacing is more then we can reduce corona effecting between the conductor is more than the electrostatic stress will be reduced at the conductor surface.

04. Atmosphere – We all know that Corona is formed due to the ionization of surrounding air, it depends upon weather i.e., cold or hot.

05. Frequency – The frequency of the line is directly proportional to the corona if frequency increases then the corona effect will also increase.

How To Reduce Corona Effect

When a corona occurs in a line then the efficiency of the line will decrease.

01. By increasing the size of the conductor
02. Spacing between conductors
03. By using bundle conductors

01. By Increasing Conductor Size – If the voltage at which the corona effect takes place is raised then the corona will not appear. Use A C SR conductor.

02. Spacing Between Conductors – If the spacing between conductors is more then it will reduce the electrostatic stress at the conductor surface, hence corona will not occur.

03. Use Bundle conductors – If the line voltage is more than 220 kilovolts then bundle conductors are used. I will write a different article for bundle conductors. A bundle conductor means one or more conductors used as a single conductor the pass electricity then it is called bundle conductor

Advantages of the Corona Effect

01. It reduces the transient effect produced in the line, the transient effect is produced due to surge which increases the line voltage but this increase in voltage corona will reduce it by dissipating heat or light.

02. Due to the corona the air surrounding the conductor acts like a conductor, suppose suddenly current increases in the line then that current will go through the air and thus protect the conductor from damage.

Disadvantages of the Corona Effect

01. Power losses will occur and efficiency will be reduced.

02. Corona produces the ozone gas, ozone gas produces some acid in the line and due to this acid corrosion is formed in a conductor.

This was about the “Corona Effect On Transmission Lines“. I hope this article may help you all a lot. Thanks for reading.

Tags: what is the corona, how to reduce corona, advantages, and disadvantages of the corona.

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Chetan Shidling

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