【摘要】：當局部承受的電場強度較大時,電力系統(tǒng)中的絕緣設備或部件容易發(fā)生局部放電現(xiàn)象,嚴重時甚至造成絕緣擊穿,影響系統(tǒng)的安全穩(wěn)定運行。為了改善環(huán)氧樹脂絕緣材料的電氣性能,本文以納米ZnO改性雙酚A型環(huán)氧樹脂材料為研究對象,測試不同摻雜濃度下聚合物的直流電導、局部放電起始放電電壓等絕緣特征參數(shù)的變化趨勢:對比分析了納米ZnO改善環(huán)氧樹脂絕緣特性的作用機理。首先,實驗制備了以雙酚A型環(huán)氧樹脂E-51為基體,濕法改性處理過的納米ZnO粒子為填料,納米粒子含量分別為Owt%、2wt%、5wt%、10wt%。、15wt%、20wt%、30wt%的納米ZnO/環(huán)氧樹脂復合材料試樣。利用掃描電子顯微鏡觀測試樣內部微觀結構,在確保所制備的試樣內部納米粒子與基體之間接觸良好、并且沒有發(fā)生明顯團聚的前提下,按照國家標準制備測試樣品,搭建電導特性、介電特性等電氣性能測試平臺,對比純環(huán)氧樹脂與不同摻雜濃度的聚合物電氣性能參數(shù),分析納米ZnO粒子對環(huán)氧樹脂的作用效果。其次,為了更好地探討摻雜納米ZnO粒子之后,環(huán)氧樹脂復合材料出現(xiàn)|非線性電導特性的原因以及作用機理,制備與納米ZnO相同粒徑的納米SiO2改性環(huán)氧樹脂復合材料,實驗對比了相同摻雜濃度下兩種聚合物的直流電導、介電常數(shù)、局部放電起始放電電壓、擊穿場強等絕緣特征參數(shù)的變化趨勢。分析實驗結果可知,當納米ZnO摻雜量大于15%質量分數(shù)時,復合材料具有顯著的非線性電導特性:納米ZnO摻雜量增大時,介電特性沒有表現(xiàn)出非線性特性:摻雜ZnO納米粒子的環(huán)氧樹脂介質損耗隨摻雜量的增加而增大,由純環(huán)氧樹脂的1.25‰最大升高至3.34‰; ZnO/EP復合材料在針板電極下,摻雜量為15%時起始局放電壓達到最大值,比無摻雜樹脂提高了 33%,比納米SiO2摻雜樹脂提高了 22%; ZnO/EP試樣的擊穿強度由未摻雜的31.5kV下降至23.8kV。綜上所述,摻雜納米ZnO粒子的環(huán)氧樹脂的局部放電起始電壓、介電常數(shù)、介質損耗較純環(huán)氧樹脂明顯提高,而交流短時擊穿場強純環(huán)氧樹脂有所降低;理論分析表明,納米ZnO粒子的引入顯著提高了環(huán)氧樹脂復合材料的絕緣性能,納米ZnO粒子的界面效應和非線性電導特性在改善復合樹脂絕緣特性方面發(fā)揮了主要作用。另外,ZnO/EP復合材料當摻雜量大于15%質量分數(shù)時,復合材料具有顯著的非線性電導特性,對針板電極系統(tǒng)下的不均勻電場有改善作用,有利于提高材料的抗老化能力。
[Abstract]:When the local electric field is strong enough, partial discharge is easy to occur in the insulation equipment or components of the power system, and even insulation breakdown occurs in serious cases, which affects the safe and stable operation of the system. In order to improve the electrical properties of epoxy resin insulating materials, the direct current conductance of polymers with different doping concentration was measured by using nanometer ZnO modified bisphenol A epoxy resin as the research object. The variation trend of insulation characteristic parameters such as partial discharge initial discharge voltage: the mechanism of nanometer ZnO to improve the insulation characteristics of epoxy resin was compared and analyzed. Firstly, ZnO nanoparticles modified by wet method were prepared with bisphenol A epoxy resin E-51 as matrix and nano-particles content as Owt%,2wt%,5wt%,10wt%.,15wt%,20wt%,. 30 wt% nanosized ZnO/ epoxy resin composites. Scanning electron microscope (SEM) was used to observe the microstructure of the samples. The test samples were prepared in accordance with the national standards without obvious agglomeration and good contact between the nanoparticles and the matrix. The electrical properties of pure epoxy resin and polymer with different doping concentration were compared, and the effect of nano-sized ZnO particles on epoxy resin was analyzed. Secondly, in order to better investigate the reason and mechanism of nonlinear conductivity of epoxy resin composites after doping nano ZnO particles, nano SiO2 modified epoxy resin composites with the same size as nano ZnO were prepared. The variation trends of dielectric parameters, such as DC conductance, dielectric constant, initial discharge voltage of partial discharge and breakdown field strength of the two polymers with the same doping concentration were compared experimentally. The experimental results show that when the content of nanometer ZnO is more than 15%, the composite has remarkable nonlinear conductance: when the doping amount of nanometer ZnO increases, The dielectric properties of epoxy resin doped with ZnO nanoparticles increased with the increase of doping content, from 1.25 鈥，

本文編號：2407145