Improving electric field distribution on corona ring by nano-coating.

Corona is a luminous, audible discharge that occurs when there is an excessive localized electrical field gradient upon an object that causes ionization and possible electrical breakdown of the fluid such as air adjacent to this object that is electrically charged. A corona ring also called an anti-corona ring or grading ring is a toroid of conductive material, usually a metal, attached to a terminal of high voltage equipment. The role of a corona ring is to distribute the electrical field gradient and lower its maximum values below the corona threshold, thus prevent corona discharge. Corona rings having larger diameter have a lower electric field gradient at the surface. Hence, corona rings having larger diameter produce lower corona discharge compared to corona rings with a smaller diameter. We know that coating Nanoparticles on the surface of the material increases the area to volume ratio, thus coating the corona ring using electrically conductive Nanoparticles increases the surface area of the ring and helps in improving electrical field distribution which results in reduced voltage stress per area on the ring and thereby reducing the corona discharge. [ABSTRACT FROM AUTHOR]