Oil storing tank

The utility model relates to an oil storing tank applied to power systems, which mainly comprises tank body composed of a bottom disc, an outer cover and an upper cap, wherein, an inner and an outer two corrugated pipes are arranged in the tank body, the bottom ends of the inner and the outer two corrugated pipes are fixedly connected with the bottom disc, the upper ends of the inner and the outer corrugated pipes are connected with an annular sealing cap, an air inlet and outlet passage is formed between the inner and the outer two corrugated pipes, and the bottom end of the air inlet and outer passage is communicated with an air inlet and outlet port arranged on the bottom disc. The inner and the outer two corrugated pipes can be compressed or expanded by the rise or reduction of the temperature of insulating liquid so that the size of the volume in the oil storing tank is changed. The insulating liquid in the oil storing tank always keeps a filling state, negative pressure is not generated in the oil storing tank, environmental gas and water can not enter the oil storing tank, and therefore, the utility model has the advantages of long service life, safe operation, maintenance free and manpower and material saving.