What is what is corona ring and Why Do We Use Them?

Corona ring - Essential Knowledge

Corona discharge over insulator strings on high voltage transmission lines is a common phenomenon that needs to be controlled. Grading rings and corona caps were historically used in devices such as the 1.4 MV X-ray generator in 1947 at the US Bureau of Standards and the Cockcroft-Walton particle accelerator. These measures are still relevant today.

The company is the world’s best what is corona ring supplier. Our specialized staff will help you find the products tailored to your needs.

What is a Corona Ring?

A corona ring, also known as an anti-corona ring, is a metallic toroid attached to terminals or irregular high voltage equipment to distribute the electric field gradient and keep it below the corona threshold. This prevents corona discharge, commonly used in high voltage power transmission insulators, switchgear, and scientific apparatus.

Corona Discharge

Corona discharge occurs when electric current leaks into the air near high voltage conductors, often appearing as a blue glow. This phenomenon can cause significant power losses and hardware deterioration, releasing harmful ozone gas. Preventing corona discharge is crucial for maintaining efficiency and safety in electrical equipment.

In my years of working with high voltage equipment, I've seen how critical it is to manage corona discharge. For example, in electrostatic generators, excessive corona leakage can destabilize the voltage, leading to malfunctions.

How Corona Rings Work

Corona discharges only manifest when the electric field at a conductor's surface surpasses the air’s dielectric strength, roughly 30 kV/cm at sea level. Equipment terminals often feature rounded shapes like balls and toruses to suppress corona formation. Corona rings, electrically connected to high voltage conductors, lower the potential gradient at sharp points, preventing corona from forming.

Similar Devices: Grading Rings

Similar to corona rings, grading rings encircle insulators rather than conductors. They aim to reduce the potential gradient along insulators, preventing premature electrical breakdown. The improved voltage gradient helps use shorter, cost-efficient insulators while reducing aging and deterioration.

Practical Uses of Corona Rings

Corona rings are indispensable in very high voltage apparatus such as Van de Graaff generators, Cockcroft-Walton generators, and particle accelerators. Manufacturers usually recommend installing corona rings on insulator ends in transmission lines above 230 kV, with additional rings for lines above 500 kV to enhance insulator lifespan and performance. These rings also find application in high-power radio transmitter antennas, although they may increase insulator capacitance.

Additional Resources

For an in-depth understanding of related concepts, you can refer to:
Tips for Finding Glass Railroad Insulators? - Antique-Bottles.net
How do ceramic disk insulators support the weight of...
Isolator Selection Guide – dB Engineering

Want more information on Tension Clamp for ADSS? Feel free to contact us.

How Corona Rings Mitigate Corona Discharge

The function of a corona ring is to curb ionization and corona discharge, which can damage insulators. By reshaping the electric field intensity, corona rings reduce peak potential across surrounding air, diminishing the likelihood of air breakdown. They also ensure a more even voltage distribution across insulator stacks, lowering breakdown stresses on insulators.

Want more information on opgw hardware fittings? Feel free to contact us.