Dielectric properties in high pressure CO2 and N2 gas using coaxial cylindrical electrode and on the surface of spacer

CT-SF₆ gas is widely used in electric power apparatus such as gas insulated switchgears (GIS) and gas circuit breakers (GCB) due to its excellent dielectric and arc-quenching performance. However, SF₆ gas has been recognized as a greenhouse gas and it was decided to reduce its emissions at COP3 at Kyoto in 1997. Thus, surveys on the amount of emissions and efforts to reduce emissions have been continued all over the world. Simultaneously, studies on alternative gases to SF₆ gas have increased. In fact, studies on alternative gases, the purpose of which was to find a gas that had better performance than SF₆ gas, had been carried out previously. However, the purpose of the latest studies is to reduce environmental impact.