Support insulators for metal encapsulated conductors - are designed so that field lines do not penetrate insulator surface

摘要

To eliminate travelling discharges from the surface of conductor ducts filled with an insulating gas, for example SF6, or with a liquid dielectric such as oil, the insulator surface between the two electrodes (1, 2) is shaped so that the lines of the electric field (17, 18) do not travel for part of their length through the insulator body. An optimum contour is achieved in the integral of the normal field strength along the insulator length approximates to zero. Field lines (16) which are external to the insulator, leaving and entering between points (VII, VIII) near to the electrodes, are permissable, and are not likely to cause discharges.