Sunk underground transformer with enclosing tank - has continuous layer of bitumen between tank and transformer housing

摘要

The transformer is sunk completely or partly into the ground and the transformer housing is accommodated in a tank sunk into the ground. Corrosion of the transformer is prevented by bitumen poured in the gap between the tank walls and transformer housing. The transformer housing and the tank are separated by a continuous bitumen layer on the sides and at the bottom. Insulating supports can be placed between the transformer housing base and bottom of the tank which can be made from thin sheet metal or plastics. The tank walls project above the ground level. The transformer housing is filled with cooling oil which is cooled in the heat exchanger housing at the top of the transformer.