ABSTRACT
It is well known that heavy gases belonging to the seventh group of the periodic table (fluorine, chlorine, etc.) have a considerably higher dielectric strength compared to air under similar experimental conditions. The high breakdown strength depends mainly on their capability of taking up free electrons, thereby forming heavy negative ions. Gases having these properties are called electronegative. Of the many available electronegative gases, sulfur hexafluride, SF6, has especially gained importance because of its chemical stability as well as its high breakdown strength. It is therefore the dielectric gas of choice. Furthermore, due to its effectiveness in the extinction of arcs, it is used extensively in circuit breakers as well. This chapter provides a comprehensive review about the basic properties, dielectric characteristics and applications of SF6 insulation.
