Measurement of high pressure dusty SF/sub 6/ plasma generated by arc extinction in GCB

Summary form only given. In advanced high voltage power systems, the compactness and high performance of a gas circuit breaker (GCB) is required. The compactness of a GCB is not only required for economic reasons but also following the environmental requirement, because SF/sub 6/ gas is known to be a greenhouse gas. In a GCB, the hot gas generated by the arc blast seriously reduces the dielectric strength of the GCB, and this effect becomes more significant when a GCB becomes compact. In a compact GCB, the exhaust gases are not merely dissociated into neutral particles, they can become ionized when the arcing current is large. Therefore, the exhaust chamber of a GCB can be expected to be an excellent device to generate high pressure SF/sub 6/ plasma. In the exhaust hot gas, large amounts of metal vapor and grains are mixed inside the hot gas. These metal vapors and grains will affect the electrical behavior of the plasma, such as the electrical conductivity. They will also affect the dielectric strength of the gas when SF/sub 6/ plasma is de-ionized. Furthermore, they may also change the dynamic property of the gas flow, because the mass of dust grains is much larger than the mass of the gas molecules. Therefore to study the high pressure dusty SF/sub 6/ plasma it is very important to determine the capability of arc extinction as well as dielectric strength of a GCB.