Study On The Ability Of Impedance On The Electrical Tree Of ZnO/Epoxy Composites

At present,epoxy resin with good electrical insulation performance is widely used in insulating materials.However,it can not meet the requirement of insulation reliability in power system.It is an important factor that aging procession result in insulation materials broken down.It has been attractive to improve resistance of the electrical tree in epoxy resin(EP)insulating materials by doping nano-particles.ZnO-particle in nanoscale not only has common properties among nano-particles,but make doped dielectric materials perform field-induced nonlinear conductivity and anti-ultraviolet characteristics.So ZnO-particle become the first choice of doped particles in this paper.In order to study the effect of nano Zinc Oxide on the electrical resistance of epoxy resin,the following researches were carried out in this paper.In this paper,epoxy resin was used as matrix doped zinc oxide nano-particles.ZnO/EP composite insulating material samples with different nano-doping amount were prepared in laboratory by blending method and assisted ultrasonic dispersion.The micromorphology of the prepared ZnO/EP samples were analyzed and the distribution of ZnO particles in epoxy resin was observed.It was found that there was no agglomeration of ZnO nanoparticles in 5wt%samples.The relative dielectric constant and thermal conductivity can be reach to the maximum4.79 and 0.196W/(m ℃)of nanometer ZnO with 5wt% doped in ZnO/EP material.Compared with the pure epoxy resin,the relative dielectric constant and thermal conductivity increased by39.4% and 29.8%,Choosing suitable experimental voltage to study the electrical property of the ZnO/EP composites materials based on the test results of the initial voltage and the average breakdown voltage of the experimental samples with different mass fraction nano-particles.It is the best content to resist the electrical branches with 3wt% doped.The breakdown voltage and localdischarge starting voltagemaximum value is 22 kv and 14.5kV,increasing by 40.1% and 52.6%compared with pure epoxy resin respectively.In this condition,the initiation probability of the electrical branch channel is up to 20%,the extension rate of the electrical tree channel becomes significantly slower,and the deteriorating area is minimal.It is found that the amount of traps increasing in organic compounds to enhance the ability of epoxy resin matrix to resist the aging of electric tree with nano-sized ZnO particles doped by the measurement of the internal traps of doped ZnO/EP materials.In conclusion,the thermal conductivity and dielectric property of epoxy resin with nanometer ZnO particles doped can be modified,the ability to resist aging of electric tree will be improved and the epoxy resin has good performance with the amounts of internal traps increasing.