New Gaseous Insulation

Studies on gas mixtures are described over the past 15 years, Much work has been performed in universities, research institutes, and industries, to account for the synergistic effect of gas mixtures and to apply gas mixture insulation to electric power apparatus. From a basic point of view, various swarm parameters have been measured and are proposed for Boltzmann equation analysis to understand the synergistic effect experimentally and theoretically. The propagation characteristics of discharges and flash-over properties on the surface of a spacer in gas mixtures also have been investigated. In the application area, gas mixtures have been applied to two gas-insulated electric power apparatus: gas vapor-cooled transformers and cubicle-type GIS. Advantages such as excellent cooling ability, increased breakdown properties and compact apparatus which resulted from the application of gas mixture insulation, are described.