Small substation ventilation duct with self closing shutters - prevents the escape of hot gases following a fault by acting as an expansion chamber

摘要

In buried or partially buried small substations an air duct (4) is normally provided which connects with the equipment below ground level. In the event of a fault giving rise to arcing inside the equipment it is undesirable to let the hot gases escape from that part of the housing (2) above ground level as it presents a danger to passers by. The air duct (4) is therefore proportioned to fulfill the dual role of duct and gas expansion chamber, and is fitted, on the normal air inlet side, with hinged louvred shutters (24) which close when the pressure in the chamber suddenly rises. An additional shutter of the same type may also be provided between the housing and the duct.