Outdoor SF6 Gas-insulated switchgear (GIS)

Description：

GIS is a type of switchgear that combines multiple high-voltage electrical appliances and is completely enclosed in a grounded metal casing. The casing is filled with SF6 gas at a certain pressure as an insulation and arc extinguishing medium.

1 Compact design

It is one of the most compact designs of single-phase enclosure GIS in the world. The width of a typical bay is 1200mm or 1500mm. The inner conductors and enclosures are made of corrosion-resistant aluminum. A bay with double busbar weights approx. 2,500 kg.

2 Superior interrupting capability

The circuit breaker is equipped with self-energized interrupter that is characterized by a self-adapting ability breaking of both small and large currents.

These breakers can cope with all known switching phenomena. Their efficiently designed interrupter clears both the severe rate of rise of the recovery voltage of short-line faults and the high recovery voltage peak of out-of-phase interruption. In magnetizing current switching, the overvoltage is less than twice the applied voltage. No restrike or reignition occurs in charging current switching.

Since the spring operating mechanism requires neither compressed air nor hydraulic fluid, inspection and maintenance work is minimized. Also, these breakers seldom require inspection since SF6 gas deterioration and arcing contact wear, owing to arc breaking, are negligible.

4 Perfect assembling and testing conditions and minimum work at site The GIS is assembled and tested against similar conditions of assembling site, packed in transport unit after tested, for easy and convenient transport and minimizing work at site.

5.The mode of separated monitoring is used in the SF6 gas system of GIS, doing away with SF6 valves and SF6 piping system. New self-sealed adapters and SF6 gas densimeters are used to get rid of the possibility of SF6 leakage outside the GIS, lowering the SF6 gas leakage.

In the GIS all elements are single phase enclosure except the main bus which is three phase enclosure. The enclosure is coaxial with the inner conductor supported by the insulators or spacers. Tulip contactors are used to adjoin the inner conductors together. Cable sealing end or SF6 outdoor bushing can be used to connect GIS with overhead lines or transformers.

The auxiliary electrical units required for command input, warning, locking, SF6 density monitoring etc are accommodated in local control panel of each bay.

Parameters