Comparison between Positive Corona and Negative Corona

Sr.
No.

Positive
Corona

Negative
Corona

1.

Nature of discharge : With positive electrode corona discharge is in
the form of uniform sheath all over the conductor surface.

With negative electrode, corona discharge is spotty or filamentary
all over the conductor surface.

2.

It appears smaller than negative corona.

It appears greater than positive corona.

3.

Current = With increase in
voltage, current increase steadily.

Current increases in the form of trichel charges with increase in
applied voltage.

4.

The total number of electrons and electron density is low.

The total number of electrons and electron density is more.

5.

Breakdown voltage : low

Breakdown voltage : high

6.

Corona discharge occurs at higher voltage.

Corona discharge occurs at lower voltage.

7.

The energy level is very high.

The energy level is relatively low.

8.

They are simpler in construction.

They are quite complex in construction.

9.

It generates much less ozone than negative corona.

It generates much more ozone than positive corona.

10.

The secondary electrons avalanches are generated by gas surrounding
the plasma region.

The secondary electrons avalanches are generated by the curved
electrode itself.

11.

The secondary electrons are generated by ionization caused by photons
emitted from the plasma.

The dominant process for secondary electron is photo electric effect
from the surface of electrodes itself.

12.

The electrons resulting from ionization are attracted towards the
curved electrode.

The general movement of electrons in negative corona is outward from
curved electrode.

13.

The colour of this corona is bluish white.

The colour of this corona is reddish.