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PRODUCTS >> Corona ring / Shielding ring

Shielding / Corona Ring :

The purpose of the ring is to avoid corona discharges. It can be divided into arrester corona ring, lightning protection corona ring, insulator corona ring, transformer corona ring, corona ring of high voltage test equipment, power transmission line corona ring. Corona ring or shielding ring can be used in precision measurement of electrical equipment. Samgor offers designing, manufacturing and installation of corona/shielding ring. A corona ring, also called an anti-corona ring, is a toroid of conductive material, usually metal, which is attached to a terminal of high voltage equipment. The role of the corona ring is to distribute the electric field gradient and lower its maximum values below the corona threshold, preventing corona discharge. Corona rings are used on very high voltage power transmission insulators and switchgear, and on scientific research apparatus that generates high voltages. Corona rings are typically installed on very high voltage power line insulators. Corona rings prolong lifetime of insulator surfaces by suppressing the effects of corona discharge. Corona rings may also be installed on the insulators of antennas of high-power radio transmitters. However, they increase the capacitance of the insulators.

Corona discharges only occur when the electric field (potential gradient) at the surface of conductors exceeds a critical value. The electric field at a conductor is greatest where the curvature is sharpest, and therefore corona discharge occurs first at sharp points, corners and edges. However, some parts of high voltage circuits require hardware with exposed sharp edges or corners, such as the attachment points where wires or bus bars are connected to insulators. Corona rings are installed at these points to prevent corona formation. The corona ring is electrically connected to the high voltage conductor, encircling the points where corona would form. Since the ring is at the same potential as the conductor, the presence of the ring reduces the potential gradient at the surface of the conductor greatly, below the disruptive potential gradient, so corona does not form on the metal points.