Preparation And Thermal Analysis Of Magnetic Fluids Based On Transformer Oil

With the constant improvement of the voltage level in the process of transmission, the developing direction of the power transformer is higher insulation, larger capacity and miniaturization. Those directions require insulating medium to have better heat dissipation and insulation performance. In order to adapt to the new directions and improve the insulation characteristics of traditional transformer oil, researching some kind of more excellent insulating medium is imminent. Under the action of the magnetic field, the magnetic fluid can obviously reduce internal temperature of the oil-immersed transformer and improve its dielectric performance. Owing to its excellent potential, the magnetic fluid is considered as the next generation insulation which has become a hot spot in the field of international power technologies.In this paper, the preparation of magnetic fluids using transformer oil as a base fluid was studied. The properties examination and the characteristic of Tem, XRD and Zeta were carried out to the prepared magnetic fluids. And the experiment process were analyzed and discussed. Some of notable issues in preparing processes were researched. The results show that the major component of the magnetic particles is anti-spinel Fe3O4. The property of the nanometer magnetic fluid is stable and no flocculation was found over6to8months. The concentration of FeCl2and FeCl3is0.4mol/L and the dosage of surfactant was2.24ml, the coating temperature is70℃and the coating time is60min and20min microwave, the dispersing temperature is100℃to105℃and the time is40min and15min microwaveThen, some main components of transformer were introduced. According to the service life of the insulation materials, the principles of transformer thermal numerical analysis and the concept of temperature rise limit were introduced, too. Then, this paper analyzes the heat resources and the cooling process in detail which provides the basis calculation conditions for the numerical simulation;Finally, the three-dimensional temperature field and oil flow field of natural oil circulation transformer are analyzed by large finite element software Fluent based on different insulating mediums. The3D model of the numerical simulation results show that the average oil temperature and the hotpot using the magnetic fluid as the coolant is lower than the pure oil14k and11k respectively; The2D model of the numerical simulation results show that the average oil temperature and the hotpot using the magnetic fluid as the coolant is lower than the pure oil15k and7k respectively; The thermal numerical analysis results show that the magnetic fluid has better heat dissipation performance.