Small substation ventilation duct - with self closing shutters inhibiting excape of hot gases during fault

摘要

In an underground or semi underground switching or transformer substation an air duct is normally provided which enters the equipment below ground level. In the event of an internal fault causing arcing and the build up of pressure the hot gases are allowed to expand into the air duct. To protect passers by the duct is provided with self closing shutters which close when the pressure in the duct suddenly rises. These shutters are at the inlet to the duct, but an additional shutter may be provided at the inlet to the equipment. To achieve the required pressure relief the duct may have to be made larger than the cooling air requirements dictate.