Expansion vessel for electrical transformer protection against foreign gas

摘要

Foreign gases are prevented to enter the transformer by an expansion vessel. There is a buffer liq. (2) separated by an impermeable diaphragm (5), while an inner expansion vessel (1) is of vol. changing type and communicates with the insulating, or heat carrier medium. The buffer liq. is in contact with ambient air, or can be pressurised or set under vacuum. Between the transformer tank and expansion vessel is a riser (4), and an N2 cushion is provided over the buffer liq. An appropriate insulating liq. vol. and a riser level safeguard absence of underpressure at the lowest expected temp. of the insulating liq.