SF6 GIS Of Three-Phase Enclosure Concept For The Voltage Range Of 69 To 145 kV

Until recently application of the three-phase enclosure concept for SF6-GIS designs was limited to simple busbar sections. Advancement in the design of solid dielectric insulators, excellent operational experience with three-phase busbar systems up to 245-kV, a greater understanding of field stress and its control in SF6 gas together with the development of a more advanced single-pressure circuit breaker made the breakthrough to a total three-phase concept of SF6-GIS possible. A 50% saving in space over single-phase enclosures, economy in cost and simplification of design accompanied by improved operational reliability are the features of the new Type ELK-0 SF6-GIS, subject of this paper.