| Insulation equipment or components in power system are prone to partiat discharge phenomenon when their local bear targe electric field strength, even causing insulation breakdown if the situation serious, then affrcting the safe and stable operation of the system.In order to improve the electrical properties of epoxy resin insulation materiads, nano-ZnO modified bisphenol A epoxy resin material as the research object, and tested the insulation characteristic parameters such as the dc conductivity of polymer under different doping concentration and the partial discharge initial discharge voltage; The mechanism of nanometer ZnO to improve the insulati on propeties of epoxy resin also was been analyzed.Firstly, nano-ZnO particles with bisphenol A type epoxy resin E-51 as the matrix and wet-modified nano-ZnO particles were prepared. The contents of nanoparticles were 0wt%,2wt%, 5wt%, 10wt%, 15wt%, 20wt%, 30wt% nano-ZnO / epoxy resin composites. The microstructures of the samples were observed by scanning electron microscopy. The test samples were prepared according to the national standard under the prem i se of ensuring that the prepared nano-particles were in good contact with the matrix and no obvious agglomeration occurred. The electrical properties of the polymer with different doping concentration were compared. The effect of nano - ZnO panicles on the epoxy resin was analyzed.Secondly, in order to investigate the reason and meechanism of the nonlinear conductivity of epoxy resin composites after doping nano-ZnO particles, the nano-SiO2 modified epoxy resin composites with the same particle size as nano-ZnO were prepared. The non-linearity direct current conductance, dielectric constant, partial discharge discharge voltage and breakdown field strength of the two polymes under the same doping concentration were observed.The results of the analysis show that the composite material thas remarkable nonlinear conductivity when the nanometer ZnO doping is greater than 15%. When the nanometer ZnO doping increased, the dielectric properties showed no nonlinear properties; The dielectric loss of epoxy resin doped ZnO nano-particles increased with the increase of doping, with the maximum increase of 1.25 per thousand of pure epoxy resin to 3.34 per thousand. ZnO/EP composites under the needle plate electrode, the doping amount was 15% reach maximum discharge voltage starting, 33% higher than that of undoped resin, than nano - SiO2 doped resin increased by 22%; The strength of ZnO/EP was reduced to 23.8 kV by the unadulterated 31.5 kV.To sum up, the partial discharge inception voltage, dielectric constant and dielectric loss of the epoxy resin doped ZnO nanoparticles is obviously improve than the pure epoxy resin, and short communication breakdown voltage of pure epoxy resin decreases; Theoretical analysis shows that the introduction of ZnO nanoparticles significantly improve the performance of the insulation of the epoxy resin composite material, interface effect and nonlinear conductivity characteristics of ZnO nanoparticles has played a major role in improving the insulation properties of compound resin. In addition, when doping amount is more than 15% mass fraction,composite material has showed significant nonlinear conductivity characteristics, which could improve the non-uniform electric field on the needle plate electrode system, and improving the anti-aging ability of the material. |
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