SF_6ガスプッシングの小形化に向けた絶縁技術開発: 小形800kVガスブッシングの開発

摘要

ガスブッシングの小形化に向けた絶縁技術について検討rnし，以下の事項が明らかになった。rn（1）リング-円筒電極を適用すると円筒電極時に比べ碍rn管表面電界における沿面方向成分の最大値を25%程度低減rn可能である。%As for gas insulated switchgear (GIS), small space requirement and economical efficiency have been demanded. Circuit breakers (CB), disconnecting switches (DS) and earthing switches (ES) have been designed toward compactness. Compact & light bushings have been also required. As for bushings of GIS, there are roughly three types; capacitor, gas-filled and molding bushings. Since gas-filled bushings have the feature which is both of the lightness and the economical efficiency, it is important to develop compact and light gas-filled bushings by improvement of insulation technology. The main subject for compact design is reduction of electric field strength on the outside hollow insulator around the inside grounded electrode tip. We devised a new inner grounded electrode structure which consists of some column electrodes. This paper describes the effect of reduction of maximum value of electric field strength on the outside hollow insulator by a new inner grounded electrode. Then, improvement of insulation performance for electrodes with insulation coating in SF_6 gas is described as composite insulation technology. Finally, the efficacy of these insulation technologies is described by fundamental insulation test results of prototype compact 800 kV SF_6 gas-filled bushing.