Solid Insulated Switchgear and Investigation of its Mechanical and Electrical Reliability

摘要

SF_6 gas is widely employed in medium-voltage switchgear because of its high insulation reliability and down-sizing ability. However, SF_6 gas was placed on the list of greenhouse gases under the Kyoto Protocol in 1997. Since then, research on low-SF_6 or SF_6-free insulation has been carried out actively. Therefore, we focused on solid materials with higher dielectric strength than SF_6, and we have now developed solid insulated switchgear (SIS) that uses molding of all main circuits. A new epoxy casting material is used which contains a large amount of spherical silica and a small amount of rubber particles. This new material has high mechanical strength, high thermal resistance, high toughness, and also high dielectric strength because of direct molding of the vacuum bottle, as well as reduced size and high reliability. This paper describes the technology of the new epoxy casting material which makes possible SIS. In addition, mechanical and electrical reliability tests of SIS using a new epoxy resin were performed, and the effectiveness of the developed material and the mechanical and electrical reliability of the SIS were verified.