Beautiful corona discharge, but harmful phenomenon in the energy sector

Have you ever seen around the high-voltage wires beautiful glow, and in wet weather, passing by power lines, heard not very pleasant crackle? All this is a manifestation of a corona discharge. In this article I will discuss the mechanism of its formation, as well as why it is so not like all energy. So, let's begin.

What is the corona discharge

First, let's define this effect, so Corona discharge - is a self-discharge in the gaseous mediumThat appears in a strongly inhomogeneous fields at the electrodes with a large surface curvature (sharp edge).

The main condition for the beginning of the formation of discharge is that necessarily should be near the edge of the raised electric field intensity than the rest of the path between the electrodes that create precisely the difference potentials.

This in itself is an insulator airspace at standard pressure and maximum electric intensity is equal to 30 kV / cm. It is in these terms at the tip of the electrode begins to form a barely discernible glow that looks like a crown. Because of this, this type of discharge, and became known as corona.

Remarkably this ionization process typically occurs only around the discharge electrode and the second electrode thus looks generally (crown offline).

Note. Do not think that this phenomenon is purely man-made. This phenomenon occurs in the natural environment. Thus, for example, tall trees before severe storm or snowstorm.

As corona discharge is generated

So now let's look at step by step process of the formation of the discharge (generally accepted theory will be considered).

Arbitrary random air molecule is ionized, the resulting separated electron which is accelerated under the influence of the electromagnetic field near the sharp edge. And the electron acquires an amount of energy that the collision with the next molecule is ionized new molecule (thus as separated electron).

This means that the total number of charged particles that are actively moving in a magnetic field around the tip of a growing avalanche manner.

In the case, if the discharge electrode became the negative electrode (cathode), then this is called crown negative, and the avalanche of electrons in such a case would move from the tip towards the positive electrode.

Once electrons are moving into the region where the electric field is no longer keeps avalanche ionization, electrons begin to recombine with air molecules, wherein the negative ions are generated, these should become carriers of the current in the external crown area. Crown with a negative charge differs uniform glow.

If the corona source is a positive electrode (anode), the electron avalanche is moved to the tip, and vice versa ions tend outwardly from the tip.

As a result of this process a certain distance from the tip, wherein the electromagnetic field is weakened, charge carriers are only positively charged ions toward the negative rushing electrode.

And it turns out that the distinguishing feature of the positive corona are tape drives that can take on the form of spark channels.

The corona discharge damage than

The formation of a corona discharge to the HV results in an increase of energy losses. To avoid this phenomenon, depending on the class of voltage, phase separated into a number of individual conductors. This helps reduce local tensions around the wires and prevent the formation of a corona discharge in principle.

Besides it can be applied anti-corona rings that are externally represent a toroids made of conductive metal. At the same time, these products are usually attached to the terminals or other high voltage equipment parts.

Where to use this effect

This process learned how to use and benefit. Thus, for example, corona discharge is applied to the electrostatic gas purifier for finding defects (cracks) in the finished product. In copiers for charging, discharging and carrying photoconductor toner to the paper.

conclusion

That's all I wanted to tell you about this no doubt a beautiful phenomenon as corona charge. If the article was interesting to you, you will appreciate her huskies and thank you for your valuable attention!