Vegetable oil based dielectric coolant

A transformer including a tank housing a core assembly / transformer windings, wherein the core assembly / windings is rodedado by a dielectric insulating fluid; and characterized in that the dielectric fluid comprises two or more vegetable oils and an antioxidant; vegetable oils have a viscosity between 2x10- 6 and 15x10-6 m2 / s at 100 ° C and less than 110x10-6 at 40 ° C, and in that vegetable oils have a flash point greater than 300 ° C open container.