What is Corona discharge in Power Transmission Lines?

The corona will occur on transmission lines when the strength(potential gradient) of the electric field around a conductor is high enough to form a conductive region, but not high enough to cause electrical breakdown or arcing to nearby objects. It is often seen as a bluish (or other color) glow in the air adjacent to pointed metal conductors carrying high voltages, and emits light by the same property as a gas discharge lamp.

 

The ionized gas of a corona is chemically active. In air, this generates gases such as ozone (O3) and nitrogen oxide (NO), and in turn nitric oxide (NO2), and thus nitric acid if water vapor is present. Ozone is unintentionally created this way

electrical discharge brought on by the ionization of a fluid surrounding a conductor that is electrically energized

A corona is an electrical discharge brought on by the ionization of a fluid such as air surrounding a conductor that is electrically charged.Corona discharge from high voltage electric power transmission lines constitutes an economically significant waste of energy for utilities.  

CORONA IS AN EFFECT IN OVERHEAD TRANSMISSION LINES.IT GENERALLY OCCURS ON THE ROUGH SURFACE OF CONDUCTOR DUE TO OVER VOLTAGE BY PRODUCING A BRIGHT LIGHT WITH HISSING SONG.THE OVERVOLTAGE CAUSES A LARGE CURRENT IN THE CONDUCTOR WHICH ACTUALLY IONIZED THE WHOLE AIR PARTICLES ARROUND IT BY PRODUCING OZONE GAS.

Corona mainly occurs due to air ionization and if the conductor is injured. Mostly the spark has been seen where there is an injured point at conductor ( even there also air get ionized ).....

Corona is a phenomenon associated with all transmission lines. Under certain conditions, the localized electric field near energized components and conductors can produce a tiny electric discharge or corona that causes the surrounding air molecules to ionize, or undergo a slight localized change of electric charge.

The ionization of air surrounding the conductor...............................

Producing sound.............................................

Producing spark.......................................

This is a major type of power loss during transmission..................................

More visual in stormy weather.

 

Current / electrons have the tendency to flow on the surface of the conductor, these free electrons Ionize the air surrounding it and energize its voltage level but does not results in breakdown.

Its ionisation discharge across conductor surface dissipate power, generally visible in rainy atmosphere.

The air around trnsmission line conductor is ionized and gives oftenly a spark this effect is known as "Corona effect". It usually happens in high voltage transmission lines.