In high-voltage and ultra-high-voltage transmission lines, insulators are used as components to ensure the insulation of wires and towers, and their operating status will affect the safety and stability of the power grid. However, when the line voltage reaches a certain level, an easily overlooked but very destructive phenomenon may appear on the surface of the insulator, which is corona discharge. This kind of partial discharge caused by the ionization of air under the action of a strong electric field will not only cause power loss and electromagnetic interference, but also accelerate the aging of the surface of the insulator, and even cause flashover accidents. The corona ring coil on the insulator is an important protective component designed for this problem. It is not a simple metal ring, but a professional equipment that can optimize the distribution of electric fields and suppress corona discharge through special structures and installation methods. It is an indispensable insulating auxiliary component in high-voltage transmission lines.
The working principle of corona ring coil is to suppress the generation of corona discharge through electric field reconstruction. When corona ring coil is not installed, the connection between the metal fittings of the insulator and the wire, because of the sharp structure of the metal parts, will form a local strong electric field area. When the electric field strength exceeds the breakdown field strength of the air, the air molecules are ionized to form a corona discharge, which is manifested as a faint blue light visible at night, accompanied by a sizzling sound, and at the same time produces corrosive gases such as ozone and nitrogen oxides. After installing the corona ring coil, the ring body is connected to the insulator metal fittings through a bracket to form an extension electrode, which disperses the electric field originally concentrated in the sharp parts of the metal fittings to the rounded surface of the ring body, so that the electric field strength around the ring body is evenly reduced to below the air breakdown field strength, fundamentally preventing the occurrence of corona discharge. At the same time, corona ring coil can also optimize the electric field distribution on the surface of the insulator, reduce the electric field concentration at the edge of the insulator skirt, avoid the formation of local conductive channels when rain and dirt are attached, and reduce the risk of flashover of the insulator.
From the point of view of practical application value, the role of corona ring coil is reflected in many aspects. In terms of power loss control, corona discharge will cause continuous active power loss. For a 500kV transmission line, if corona ring coil is not installed, the annual power loss due to corona can reach hundreds of thousands of degrees, and the installation of corona ring coil can reduce corona loss by more than 80%, significantly improving transmission efficiency. In terms of equipment life protection, the corrosive gas generated by corona discharge will accelerate the aging of the silicone rubber or porcelain surface of the insulator, resulting in a decrease in the insulation performance of the insulator. After corona ring coil suppresses the corona, it can extend the service life of the insulator and reduce replacement costs. In terms of electromagnetic compatibility, corona discharge will produce wide-band electromagnetic interference, which affects the normal operation of peripheral communication equipment and radar systems. By eliminating corona, corona ring coil can effectively reduce the intensity of electromagnetic interference and comply with the relevant standards of the International Electrotechnical Commission on electromagnetic compatibility.
For B-terminal buyers, choosing a reliable corona ring coil is an investment to ensure the long-term safe operation of the transmission line. With many years of industry experience, we can provide you with corona ring coil selection support that meets international standards, and become your trusted partner in high-voltage transmission projects.
