Study On Thermal Conductivity And Dielectric Properties Of Epoxy Adhesives For Large Motors Main Insulation Modified Based On H-BN

As an important equipment in the electric energy production link,the insulation state of large generators directly affects the safe of the generator set.As one of the key components of the generator,the stator winding will collect a large amount of heat when running,so that the main insulation will undergo thermal aging,so the insulation is required to have good heat dissipation performance.Epoxy resin adhesive is one of the main materials of motor main insulation,it has become the short board of high thermal conductivity insulation of the motor due to its poor thermal conductivity and heat resistance.so this thesis carries out high thermal conductivity epoxy resin adhesive research work,and tests the heat aging resistance of the material,laying a good foundation for the next step to manufacture high thermal conductivity insulation materials with superior performance.In this study,h-BN/Tungoil anhydride epoxy composites were created in the lab,and the impact of h-BN incorporation on the materials’ thermal conductivity,insulation capabilities,and dielectric capabilities was investigated through macroscopic parameter measurement and microstructure characterization.The findings demonstrate that by increasing the amount of h-BN filler,a thermal conductivity network can be established in epoxy resin adhesive,the thermal conductivity being greatly increased,and when h-BN filling reaches 30wt%,the sample’s thermal conductivity can exceed 0.424 W/(m K),which is 170.2% higher than pure epoxy.Due to the barrier effect of h-BN particles and the agglomeration phenomenon at high doping,an upward and downward trend was visible in the composite material’s breakdown electric field.and the breakdown field strength reached the maximum at 20wt% doping,and the 30wt% doped was equivalent to pure epoxy.Due to the introduction of traps during doping and the appearance of percolation phenomenon when filler increases,The material’s resistivity exhibits an increasing and then a decreasing trend,reaching its maximum when the doping concentration is 20wt%.Due to the effect of relaxation polarization on the material increases with the amount of h-BN filling,the relative permittivity and dielectric loss factor being increased.In order to investigate how heat aging affects the characteristics of modified materials,this research heat-ages the materials to 210°C while examining how heat aging affects their thermal conductivity,insulation,and dielectric properties.The findings demonstrate that thermal aging has no appreciable impact on a material’s thermal conductivity.As the duration of thermal aging lengthens,the destruction of the material’s microstructure,the expansion of flaws and the appearance of many low-level traps result in a declining trend in the breakdown field strength and resistivity of the material,and the downward trend is more obvious when the h-BN filler is high,and the increase of interface defects and polar groups makes the material ε’ and tand are on the rise,and the upward trend is more obvious when the h-BN content is high.