摘要
研究直流电压下油纸绝缘局部放电发展过程对于准确判断换流变压器的绝缘缺陷十分重要。为此搭建了油纸绝缘直流局部放电试验系统,采用球-板电极模型、阶梯式加压方法试验研究了直流局放发展过程,得到了发展过程存在潜伏期的结论,同时采用光学显微镜、原子力显微镜及宽频介电谱仪对直流局放发展过程中的油纸绝缘材料特性进行了测试,试验结果表明:潜伏期内油纸绝缘表面变得光滑,类似"山峰"状的纤维结构基本消失;油纸绝缘粗糙度呈现先降低后上升的趋势;油纸绝缘相对介电常数呈下降趋势而电导率呈上升趋势。研究结论可用于进一步分析油纸绝缘直流局部放电的机理。
It is significant to estimate insulation defect of converter transformer exactly by studying partial discharge developing process of oil-paper insulationunder direct voltage. So a test system was established which can detect partial discharge of oil-paper insulationunder direct voltage. Based on this system, the partial discharge developing process under direct voltage wasanalyzedwith the sphere-plate electrode model by step-up voltage test method. The conclusion that there existed a latent period during developing process was obtained. Meanwhile, the material characteristics of oil-paper insulation were tested by optical microscope, AFM and broadband dielectric spectrometer respectively. The test results show that the surface of oil-paper insulation turns smoother and the peak-shaped fiber structures disappear during latent period. The roughness tendency of oil-paper insulation declines at first and then increases during the developing process. The dielectric constant of oil-paper insulation declines while conductivity increases at the same time. The results can be used to explore the mechanism of partial discharge under direct voltage of oil-paper insulation further.
出处
《电网技术》
EI
CSCD
北大核心
2016年第2期614-619,共6页
Power System Technology
基金
国家电网公司科技项目(GY71-13-035)~~
关键词
油纸绝缘
直流电压
局部放电
潜伏期
表面粗糙度
介电常数
电导率
oil-paper insulation
direct voltage
partial discharge
latent period
roughness
dielectric constant
conductivity
