In High voltage power transmission, a very large power delivered through the conductor. When the power transfer through conductor the voltage impress between the conductor and air will create a capacitance for the line.The phenomena of violet glow, hissing noise, and creation of the ozone gas contained in the overhead transmission lines are normally preferred as the corona effect of the transmission line. The effect of corona provides bad effects for the transmission line system. In here we are also planning to discuss on some factors which affect on corona losses in transmission lines and how to minimize the corona effects.
When the voltage which applies for are getting exceed the critical disrupting voltage value, the conductor will get surrounded by a violet glow with hissing noise is known as corona effect. There are several factors which lead to form the corona.
- The appearance of violet glow surrounded by the conductor
- Hissing sound generated form the conductor
- Radio interference communication
- Production of ozone
- There is power loss in transmission line
How the corona gets form:
The ionized particles which available in our outer atmosphere when the high voltage is applied the free electron particle get good velocity and this produce more ions due to the result of this ionizations corona get the form and spark can also occur.
Why Corona formations are not good for Transmission Lines.
Corona formation in high voltage power lines are considered a disadvantage and by applying special designs the effect tries to get reduce for maximum level. Following are some of the main disadvantages which occur due to the corona formations of electrical power lines.
Formation of the corona is also created an energy loss so some part of valuable energy gets reduced due to this phenomena.
This effect also lead corrosion on the conductor of power lines and the conductor get weaken due to this.
When there are communication tower or any communication media this also interference the communication channels too.
The corona effect looks like this
Factors which effect on Corona Losses
when considering the corona losses there are several factors affect for the losses such as.
Atmospheric Condition: When the corona form due to the ionization of the air surrounded the conductor, Therefor this corona is affected by the physical state of the atmospheric conditions.
The Size of the Conductor: The effect of corona mainly depends on the shape of the conductor especially the cross-section area of the conductor and other parameters.
The Space between the conductors: The space between the conductor are also affected by this effect. When the distance between the conductor getting larger the effect of corona gets reduce.
The voltage of Power Line: The voltage of the powerline got a directly proportional relationship for the corona formation. When the voltage level is high the corona formation is getting high and when voltages are low the corona effects are also low.
Disadvantages of Corona:
- Formation of corona leads energy loss in the transmission line
- Due to the losses, this reduces the transmission efficiency of the system
- Generate Ozone which is harmful to outer atmosphere
- Due to the losses which occur due to the transmission line, the voltage drop can happen and this also can lead to low voltage regulation.
How to minimize the corona effect.
Due to mention disadvantages the transmission tower and power line systems are designed to reduce the effect. So following design steps are taken into action while construction and design stage of transmission lines.
The diameter of the Conductor Increase: to reduce the corona losses the diameter of the conductor increases. since the increase of conductor diameter occurs serious cost, the diameter is getting increase by the hollow conductors.
The Voltage of The Lines are also Increase: To reduce the effect the voltage levels are can increase. But the increase of the of voltage can only perform up to certain limitation.
Increase the spacing between the conductors: The spacing between the conductors is increased to reduce the effect of the corona. but like the increasing of the voltage levels space can also increase up to certain limitation. Because the when the spacing of conductor increases the voltage drop between them also increase.
