Electrical Corona Effect | Causes, Effects & Ways to minimise | TheElectricalGuy

have you ever noticed the humming noise while passing by a substation or high an extra high voltage transmission line have you ever noticed the violet glow that occurs on high and extra high voltage transmission lines what is all of this well an electrical engineering this is called as Corona effect or Corona discharge in this video we'll learn about the Corona discharge or Corona effect in detail and to know about it I'll recommend you to watch the video hello everyone my name is Gaurav J I post videos related to electrical engineering with easiest explanation on this channel so if you are new here consider subscribing the channel in this video we'll learn about these things what is Corona effect and how it is produced what are the effects or disadvantage of Corona how can we minimize the Corona let's say we have two conducting electrodes in parallel with each other separated in air by distance D as we know air is not a perfect dielectric or in simple language air is not the perfect insulator even in the normal condition air has lot of three ions and electrons now let's say these electrodes are carrying 25 kilo volts as these are carrying electricity each electrode will generate its own electric field as shown here now the free electrons in the air will acquire motion and they start maintaining very small current this current is almost negligible if the electric field intensity is less than 30 kV per centimeter this 30 kV per centimeter I am saying based on the studies made and different calculations the value depends upon many other factors which we will see in this video so if the electric field intensity is less than 30 kV per centimeter then the value of current flowing between these two is negligible and you can ignore it there is no problem about that but what will happen if we increase the voltage from 25 kV to 45 kV well of course you guessed it correctly electric field intensity between the electrodes will increase let's say it is now 40 kV per centimeter now this is enough to break the insulation properties of air the air will lose its insulation property complete electrical breakdown occurs and an arc will stuck between these two electrodes same thing happens with the transmission lines carrying high and extra high voltage the only difference is the distance between two conductors is more when the conductor is carrying high or extra high voltage air surrounding the conductor becomes ionized due to the electric field around it intensity of the electric field is maximum at the surface of conductor and as we move away from the conductor it decreases it is same like magnet and a metal clip as you bring the clip near to the magnet you will feel more force and as you take it away from the magnet the force will decrease here also the same case intensity is maximum at the surface and as you move away from the conductor it keep on decreasing as the intensity at the surface of conductor is maximum the air near to the surface will become ionized if the electric intensity is high enough and because of the breakdown of air a faint violet glow will appear and at the same time humming noise will be heard and this is nothing but the corona in electrical engineering if the electric field intensity increases the glow and the noise will also increase until a spark over take place further if the surface of conductor is not smooth and it has some rough points there the glow will be brighter as compared to the smooth areas the voltage value at which the breakdown of air happens all the corona starts is called as critical voltage in our case of two electrodes critical value was 40 kV per centimeter the value depends upon many things like temperature humidity pollution level in air condition of the conductor surface and etc please remember that Corona effect is generally seen in the lines carrying 245 kV or higher so if you are passing by a 11 kV or 36 kV line you may not see the violet glow and the humming noise will not be there so this is how the corona happens now you may ask let the corona happen what is bad in that anyways it is happening at heights of what wrong it will do well there are few things which Corona causes and for which an electrical engineer should be concerned those things are power loss over the entire length of line because of the Corona discharge power loss takes place over the entire length of line even in the fair weather conditions this loss increases when the weather becomes humid so let's say if the line length is 100 kilometer and even if we consider power loss of 0.5 kilo watt per kilometer just for our reference and calculation purpose I am saying so our entire length we will lose approximate of power if we consider 0.5 kilo watt loss per kilometer and if this loss is not controlled power available at the receiving end will be lower than the sending end the next is interference with radio and tell you as we have seen Corona emits a humming noise and this noise is of a very high frequency which can interact with the nearby radio receivers or TV sets the next is ozone gasps yes corona also produces the ozone gas which can reduce the life of insulator and the conductor and hence ignoring the corona is not at all a good idea so what to do of course we cannot 100% avoid Corona but we can definitely minimize it let's see what are the ways to minimize the corona so first of all what is causing Karuna the electric field around the conductor's and hence to reduce the corona we should try to reduce the electric field around the conductor surface either by increasing the diameter of the conductor or arranging the conductors in sets of two three or maybe four per phase this arrangement helps in reducing the electric field around the conductor and hence the corona effect and this is the reason why you will see bundling of the conductors not only transmission lines but also the high and extra high voltage equipment like bushing of transformer or circuit breaker disconnectors etc are likely to face the corona effect in case of such equipment that Corona discharge can happen where there is a sharp edge or the points which has small curvature this is because electric field intensity is more at such points this can be avoided by using the Corona rings Corona rings are nothing but the ring made up of thick conducting material here you can see in the photo it's a circuit breaker and the round thing highlighted is Corona ring so what Corona ring does is that it reduces the electric field intensity by giving a nice curvature shape at the sharp points in this way the current does not ionize the air but it flows through the round Corona ring again this effect is generally seen in equipment which are used above 245 kV voltage levels so these are the ways by using which you can minimize the Corona effect so let's summarize this video Corona is an effect in which due to ionization of air around the conductor a violet glue and humming noise along with the ozone gas produces Corona is generally seen in transmission line and equipment of 245 kV and above Corona can cause lot of power loss it produces high frequency noise which can interfere with the nearby radio receivers and TV sets production of ozone gas can reduce the life of insulator and conductor Corona can be minimized by increasing the diameter of the conductor by bundling the conductor in sets of two three or four per phase in case of high and extra high voltage equipment Corona can be reduced by using Corona rings you can take screenshot of this summary slide store it in your phone share it with your friends and read it whenever you want this will give you a nice brief idea about de Corona I hope you now have clear idea about what is Corona effect and electrical engineering if you like the video do hit the like button and share it with your friends also do check out the description of this video as I have mentioned some of the other videos which you may like that's all for this video guys I'll see you in my next one but till then keep watching keep learning [Music]

Channel: Gaurav J - TheElectricalGuy

Views: 107,728

Keywords: theelectricalguy, gaurav j, electrical, electrical engineering, corona, corona effect, corona discharge, electrical corona, causes of corona, effects, electrical engineering corona, corona in power system, power system, corona in transmission line, corona power transmission

Id: m-jeQgXAqJA

Length: 8min 52sec (532 seconds)

Published: Sun Mar 29 2020