Masayuki Sato

Dielectric properties in high pressure CO/sub 2/ and N/sub 2/ gas using coaxial cylindrical electrode and on the surface of spacer

CT-SF/sub 6/ 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, SF/sub 6/ 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 SF/sub 6/ gas have increased. In fact, studies on alternative gases, the purpose of which was to find a gas that had better performance than SF/sub 6/ gas, had been carried out previously. However, the purpose of the latest studies is to reduce environmental impact.

Dielectric Performance of CO2 Gas Compared with N2 Gas

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 recently 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 started 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 recent studies is to reduce environmental impact.

Forces affecting metallic particle motion in GIS

The bounce height of a metallic particle in Gas Insulated Switchgear (GIS) is one of the key factors which affect GIS reliability. Simulation of particle motion can evaluate bounce height if the relevant forces acting on the particle are taken into account. This paper presents an approach to simulating particle trajectories including dipolar force and drag force from SF6 viscosity. The influence of various forces is evaluated through the comparison between the simulation results and particle trajectories determined from high speed camera observation of particle motion.

Approximate formula of electrostatic force on spheroidal particle between coaxial electrodes

An existence of an electrostatic force which draws the particle in the direction of increasing field was indicated by FEM analysis. An approximate formula of the electrostatic force was derived analytically and compared with the results of FEM analysis. This force is sufficiently large to be relevant to particle motion in gas insulated switchgear.