Fuel tank: the oil tank is the shell of the oil-immersed high frequency transformer. The winding and core of the transformer generate heat during operation. In order to quickly release heat into the surrounding air, the method of increasing heat dissipation area can be adopted. The structural types of transformer oil tank mainly include plate type, tube type, etc. For large capacity of transformer, use outside of the tank wall is equipped with discharge pipe tube tanks to increase the cooling area, when the oil is heated expansion, the hot oil rises to the top of the tank in the cabinet, the oil radiator pipe after cooling down to the bottom of the tank, form the natural cycle, the heat to the surrounding air. For large capacity transformer, the method of forced cooling, such as fan cooling high frequency transformer, can be used to improve the cooling effect. high frequency transformer oil consists of high and low voltage winding set on the core of the iron is always called the body, the body is placed in the tank, the tank is filled with transformer oil.