Control And Simulation On Water Clusters In Transformer Oil Modified By TiO₂ Nanoparticles

As an important liquid insulating medium,the performance of transformer oil is closely related to the safe operation of electric power system.It has been proved that water is the main factor of insulation performance in transformer oil,and TiO2 nanoparticles can improve the water resistance of transformer oil into deterioration.However,the relationship between micro characteristics of transformer oil and the distribution and existing state of water is lack of research.Therefore,the titanium dioxide nano transformer oil was taken as the research object,and explored the influence of morphology,particle size and concentration of nanoparticles in transformer oil on the distribution and existing state of water molecular in transformer oil;analyzed of the dielectric properties of TiO2 under different water conditions of transformer oil;simulated the form and distribution of moisture in transformer oil by nano molecular dynamics simulation analysis.In this paper,we got four type TiO2 nanoparticles-nanospheres with diameter 5nm and 10nm,nanorods with 4:1 and 10:1 ratio of length to diameter with solvent-thermal method,and we got nanoparticle modified transformer oil with great stability using ultrasonic.Through adjusting,testing and analyzing the 10ppm-60ppnm moisture content of nanoparticle modified transformer oil,we found that water molecules can be adsorbed by nanoparticles in oil,and the amount of adsorption increases with the decrease of particle size,while the ratio of length to diameter has little effect on the amount of water adsorption,which making the form of water molecules from main monomer to dimer and timer.In addition,we tested the power frequency breakdown voltage of nanofuilds and pure oil,and found TiO2 nanoparticles can improve the water resistance degradation of transformer oil.The power frequency breakdown voltage of the 5nm TiO2 sphere modified transformer oil was up to nearly 2 times that of the pure oil.Finally,we built geometric models of TiO2 nanoparticle modified transformer oil with different water content,and the simulation parameters were adjusted according to the experimental environment,and we have carried out molecular dynamics simulation experiments.It’s found that water molecules are firmly adsorbed on surface of the nanoparticle by hydrogen bonds,and the main existing state is dimer/timer water molecules in models.In the meantime,the proportion of water cluster decreased as the size of nanoparticles become larger.