A transformer system for containing energy resulting from a sudden generation of gases which increases the pressure inside a transformer tank. The system comprises a) a transformer tank for housing a transformer coil and core assembly therein, and containing a dielectric fluid that is capable of electrically insulating components of the transformer coil and core assembly; and b) at least one heat exchanger connected to the transformer tank, wherein the at least one heat exchanger comprises at least one hollow panel or radiator. As the dielectric fluid increases in temperature and expands within the tank, the dielectric fluid is cooled by circulating the dielectric fluid through the at least one hollow panel or radiator in the at least one heat exchanger. The transformer tank and the at least one heat exchanger are capable of expanding in volume to contain energy resulting from the sudden generation of gases which increases the pressure inside the transformer tank.