.40.5 Cabinet Kv Gas Insulated Metal-enclosed Switchgear Research And Development

Cubicle type gas insulated metal-enclosed switchgear (abbreviated to C-GIS) is a product developed from gas insulated switchgear. Its main elements, including circuit breaker, disconnector, earthing switch etc, are mounted in a sealed metal enclosure, which is filled with low pressure SF₆ gas for insulation. The cable terminations are connected to the incoming or outgoing lines. C-GIS is one of the developing trends of high voltage electric apparatus. The paper describes the selection principle of primary schemes for C-GIS and determines the general structure arrangement by comparing different elements and box structure, analyzes the insulating characteristics of SF₆ gas and calculates the SF₆ gas clearance and along surface insulation. It puts forward the factors that should be considered and strength analysis methods when designing gas chamber structure and analyzes the reasons of influencing the temperature rise of gas chamber and offers the ways of radiating. The vacuum circuit breaker and three-position disconnector are designed for C-GIS and special micro-computer controller for the three-position disconnector is developed. On the basis of new type sensors, suitable control and protection system for C-GIS is suggested. The type test items for C-GIS and its internal elements are introduced to prove that the development is successful.