Short Answer

Corona effect is a phenomenon in transmission lines where the air around the conductor gets ionized due to high voltage, producing a faint glow, hissing sound, and energy loss. It usually occurs in high voltage transmission lines when the electric field becomes strong enough to break down the surrounding air.

This effect leads to power loss, noise, and interference in communication lines. It can be reduced by using larger conductors, proper spacing, and smooth conductor surfaces.

Detailed Explanation:

Corona effect in transmission lines

Corona effect is an important phenomenon observed in high voltage transmission lines. When the voltage across a conductor becomes very high, the electric field around the conductor also becomes strong. If this electric field exceeds a certain limit, it ionizes the surrounding air.

Ionization means that air molecules break into charged particles such as electrons and ions. These charged particles start moving around the conductor, producing a faint violet glow. This visible glow around the conductor is called corona.

Corona is usually accompanied by a hissing or buzzing sound and sometimes produces a smell of ozone. It mainly occurs in high voltage lines, especially during bad weather conditions such as rain, fog, or high humidity.

Causes and effects of corona

Corona effect depends on several factors related to the transmission line and surrounding environment.

One main cause is high voltage. When voltage increases, the electric field strength around the conductor also increases, leading to ionization of air.

Another factor is the size and shape of the conductor. Thin and rough conductors have higher electric field intensity, which increases corona formation. Smooth and thick conductors reduce this effect.

Spacing between conductors also affects corona. If conductors are placed too close, the electric field becomes stronger, increasing the chances of corona.

Weather conditions play a significant role. Rain, dust, fog, and humidity increase the conductivity of air, making ionization easier and increasing corona effect.

Corona effect has both disadvantages and advantages.

Disadvantages

The most important disadvantage is power loss. Energy is wasted in the ionization process, reducing transmission efficiency.

Corona also produces noise, which can be disturbing in nearby areas. It creates electromagnetic interference that can affect communication lines such as radio and telephone.

Another disadvantage is deterioration of insulation. Continuous corona discharge can damage insulators and reduce their life.

Advantages

In some cases, corona has small advantages. It can reduce voltage surges by dissipating excess energy. It also makes the electric field distribution more uniform around the conductor.

However, these advantages are limited compared to its disadvantages.

Methods to reduce corona

Corona effect can be reduced by taking certain measures in transmission line design.

Using conductors with larger diameter reduces electric field intensity. Bundled conductors are also used in high voltage lines to minimize corona.

Increasing the spacing between conductors helps reduce the electric field strength.

Using smooth and polished conductors reduces irregularities where corona can start.

Corona rings are sometimes used in high voltage equipment to control electric field distribution.

Conclusion

Corona effect is a phenomenon caused by ionization of air around high voltage conductors. It leads to power loss, noise, and interference in transmission lines. By proper design and selection of conductors, the corona effect can be minimized, improving the efficiency and reliability of the power system.