纳米改性变压器油的击穿及油纸复合绝缘频率响应特性

Transformer Oil Breakdown and Dielectric Frequency Response Characteristic of Oil-paper Insulation Modified by Nanoparticles

添加纳米粒子改性是提高变压器油纸复合绝缘的可能途径,为此,采用电介质频率响应法,分别测试了纯净油纸复合绝缘与TiO2及SiO2纳米粒子改性油纸复合绝缘的频率响应,对比分析了微水质量分数与温度对3种不同油纸复合绝缘介质损耗的影响;测试了2种不同密度下的纳米粒子改性变压器油的工频击穿特性,分析了纳米粒子提升变压器油击穿电压的机制。结果表明:添加SiO2纳米粒子能够提高油纸复合绝缘的介电性能;纳米粒子改性变压器油提高了工频击穿电压,TiO2与SiO2纳米的体积质量为0.06g/mL时的工频击穿电压分别提高了61%和149%;纳米粒子的添加降低了改性变压器油的势阱,但是增加了浅陷阱的数量,增强了电荷的迁移能力。

Modifying insulation by nanoparticles is a promising way to improve insulation of oil-paper insulation, so we experimentally studied the frequency response of two kinds of nanoparticle-modified oil paper insulator （OPI） using the dielectric frequency response method. Three kinds of samples, namely, pure oil, and two kinds of oil modified by TiO2 and SiO2, were adopted in the experiments, respectively. Dielectric loss of the three kinds of samples was tested with different moisture contents and different temperatures. Moreover, the breakdown voltage characteristics under power frequency of two kinds of nanoparticle modified transformer oil with different densities were compared, in order to analyze how the nanopartieles influenced the breakdown voltage. The results show that dielectric property of OPI is improved by adding SiO2 nanoparticles. Adding nanoparticles can enhance the breakdown voltage of oil under power frequency： when the concentrations of TiO2 and SiO2 nanoparticles are 0.06 g/mL, respectively, the breakdown voltages are increased by 61% and 149%. It is concluded that adding nanoparticle additive can lower the trap energy of transformer oil, but increase the number of shallow traps, and eventually enhance the charge-transport ability of the oil.