Corona ring
A corona ring , also control ring and English corona ring is a ring-shaped component made of electrically conductive material, usually metal, which for controlling the electric field strength at certain points of an electrical line is used. The corona ring is usually used as a fitting on long rod insulators on overhead lines that are operated with high voltage . The name of the fitting is derived from the corona discharge , which occurs at high electrical field strengths .
principle
The corona ring is a two-dimensional simplification of the Faraday cage . According to the laws of electrostatics , the inside of such a ring is almost free of electrical fields , so no corona discharges can occur there. In the outer area of the ring, corona and partial discharges can occur due to unevenness and locally high field strengths , as shown in the adjacent figure. These discharges can be made visible with corona cameras .
application
The corona ring on an insulator has the effect that the sometimes sharp edges of the fastening elements on the live end of the insulator are of little importance for the electrical field, since these components are located in an almost field-free area within the corona ring. This means that almost no peak discharges occur at their edges .
Corona rings can be found for example
- on the insulators of high-voltage lines with operating voltages above 100 kV.
- on the tensioning insulators of self-radiating transmission masts where high voltages occur.
- with marker lamps for air traffic control on high-voltage lines.
literature
- Andreas Küchler: High voltage technology . 2nd Edition. Springer, 2005, ISBN 3-540-21411-9 .
Individual evidence
- ↑ Horst Klengel: Insulators and fittings for insulator chains in overhead power lines . andersseiten.de, 2017, ISBN 978-3-95501-126-0 , p. 173-174 .
- ^ J. Wilhelm Hofmann: 100 years of JWH electrical fittings. (PDF) RIBE-Elektroarmaturen, company publication, pp. 49 - 51 , accessed on November 6, 2017 .