What Is a Corona Discharge?

Corona discharge refers to the local self-sustained discharge of a gas medium in an uneven electric field. It is the most common form of gas discharge. Near the tip electrode with a small radius of curvature, the corona discharge occurs because the local electric field strength exceeds the ionization field strength of the gas, which ionizes and excites the gas. When a corona occurs, light is seen around the electrodes with a snoring sound. Corona discharge can be a relatively stable discharge form, or it can be an early stage of development in the process of non-uniform electric field gap breakdown.

The formation mechanism of corona discharge differs depending on the polarity of the tip electrode, which is mainly due to the different accumulation and distribution of space charge during corona discharge. in

Corona discharge is characterized by a "hissing" sound, sometimes with a faint glow; when the conductor has

(1) Corona on the wires of high-voltage and ultra-high-voltage transmission lines in the power system will cause corona power loss, radio interference, television interference, and noise interference. When designing the circuit, select a sufficient cross-sectional area of the wire or use a method of splitting the wire to reduce the electric field on the surface of the wire to avoid corona. For high-voltage electrical equipment, the occurrence of corona discharge will gradually destroy the insulation performance of the equipment. Under certain conditions, the space charge of corona discharge can increase the gap breakdown strength. When lightning or operating overvoltage occurs on the line, the overvoltage amplitude can be weakened due to corona loss.

(2) Corona discharge can be used for electrostatic dedusting, sewage treatment, air purification, etc.

(3) The corona discharge of trees and other pointed objects on the ground under the action of the earth's electric field is an important part of participating in the electrical balance of the atmosphere.

(4) Corona discharges on sputtered water droplets on the ocean surface can promote the formation of organic matter in the ocean, and may also be one of the effective discharge forms of pre-synthesized amino acids in the ancient atmosphere of the earth.

(5) The energy of the corona discharge can act on the surface of the material through light radiation, neutral molecular flow and ion flow. The effect of these energy is the fundamental reason for the surface modification of the material. The process of corona discharge and its effect on the surface of polymer materials are shown in the figure. ^[2]

Corona discharge process and its effect on the surface of polymer materials ^[2]