Study of electrohydrodynamic properties in insulating liquids and research of an alternative mixture to mineral oil for energy transformers

Abstract

The article discusses, the electro-hydrodynamic phenomenon of three types of insulating oil, one mineral and two vegetable (olive oil and corn oil) and their mixtures in terms of aging time. The experimental results, allowing us the determination of the initiation and the development of electro-convection voltage of different insulating oils.A very important results was obtained, concerning the relaxation time of the insulating liquid after the appearance of its movement under the effect of the electric field. The analyzed physicochemical properties of different insulating liquids were: viscosity, resistivity, conductivity, breakdown voltage and dissipation factor, all carried out and compared by means of measurements. A close correlation between the flexibility of liquid dielectrics in movement in an electric field and their susceptibility to static electrification is approved. It appears from the various tests carried out that the optimal mixture obtained consists of 60% naphthenic mineral oil and 40% olive oil. The respect of these percentages of mixtures has made it possible to improve some characteristics of this insulating liquid and to keep the good properties possessed by naphthenic mineral oil. From the recorded observations, We have found that this mixing percentage also leads to the reduction of turbulent movements which can participate in the fight against the breakdown of energy transformers.