Correlation Study On The Dielectric Properties Of Nanocomposite Polyethylene In The Process Of Changing Temperature

Polyethylene is the main raw material for the insulation of cables and power equipment,but as the space charge inside the polymer continues to accumulate,it will cause the electric field inside the material to cause distortion,and under the influence of the external environment,it will further accelerate the aging of the insulation material Speed,will greatly shorten the service life of insulation equipment.In order to study the effect of temperature on the insulation properties of nano fumed silica composite polyethylene insulation material,two different types of nano fumed silica particles were used to dope polyethylene,and different types and different concentrations of nano-polyethylene were prepared.Vinyl composite material.The microstructure of the nano-polymer was characterized,the pores and surface area of the nano-particles were tested,and the scanning electron microscope test was also performed to observe the micro-morphology of the nano-particles and the degree of dispersion of different types of nanoparticles in the polymer,and found that it was hydrophobic The degree of dispersion of fumed silica is higher than that of hydrophilic silica.Differential scanning calorimeters have been used to test the crystallinity of different material samples.The crystallinity of the polymer after nano-doping is higher than that of pure polymer.For the crystallinity of ethylene,due to the difference in the molecular structure of the nanoparticle itself,the doping modification effect between the nanoparticle and the pure polyethylene is also different.In addition,the samples were tested for linear heating dielectric spectroscopy,variable temperature space charge test,and thermal stimulation current test to explore the relative dielectric properties of the polymer.In order to study the charge transport characteristics of silica-polyethylene composites under DC voltage,this paper measures and studies the accumulation of space charges inside the polyethylene composites and their dissipation characteristics at different temperatures.The influence law of the space charge transport characteristics inside the composite,the electroacoustic pulse method and the thermal stimulation current method were used to study the space charge suppression phenomenon and trap distribution of silica composite polyethylene.The electroacoustic pulse method was used to test the space charge distribution of the fumed silica nanocomposite under an electric field strength of 40 k V/mm,and the space charge short-circuit attenuation distribution under a linear heating rate.The test results show that fumed silica doping can significantly improve the space charge distribution.Experiments have found that nano-doping can increase the density and depth of traps in the polymer,and superimpose the amount of charge at different temperatures in time to obtain space The charge decay curve with time,the relevant trap parameters are calculated using formulas,and the curve is derived using relevant software to obtain the short-circuit current curve with time.The thermal stimulation current test was performed on the nano fumed silica polyethylene composite material,and then the correlation analysis was carried out with the space charge results.The current peak value,peak temperature and its trap distribution characteristics and the trap parameters and short-circuit current measured by the variable temperature space charge results were found The values are basically in agreement,and the accuracy of the space charge test is also verified.