不同热老化程度油纸绝缘介质在直流电场中的空间电荷特性  

Space Charge Properties Under DC Voltage of Oil-paper Insulation Materials During Thermal Aging

作　　者：廖瑞金[1] 李伟[1,2] 杨丽君[1] 唐超[1] 郝建[1] 周欣[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030 [2]重庆市电力公司璧山供电局,重庆402760

出　　处：《高电压技术》2011年第9期2197-2204,共8页High Voltage Engineering

基　　金：国家创新研究群体基金(51021005);中央高校基本科研业务费资助项目(CDJXS11150004);国家重点基础研究发展计划(973计划)(2009CB724505-1)~~

摘　　要：为理解油纸绝缘介质的热老化程度与其体内空间电荷特性间的关系,对由#25矿物变压器油和普通植物纤维素绝缘纸组合而成的油浸绝缘纸试样进行加速热老化试验,应用电声脉冲(PEA)法测量了不同热老化程度下试样在直流电场(20 kV/mm)作用时和作用后的空间电荷密度分布图像,讨论了热老化程度对试样内部空间电荷分布及电荷总量的影响。结果表明:随着油浸绝缘纸试样热老化程度的加深,外加直流电场时试样中部空间电荷注入量呈增大趋势,电荷密度到达极值所需时间延长;去压后试样内部积聚电荷消散所需时间明显延长,将致使材料内部场强畸变时间增加。研究得到去压后试样内空间电荷密度极值及电荷总量与消散时间呈现指数衰减关系,可用衰减时间常数τ来表征不同老化状态油纸绝缘的电荷消散能力。该研究成果为进一步评价油纸绝缘介质在不同热老化程度下的空间电荷特性提供了参考依据。In order to understand the relationship between thermal aging level of oil-paper insulation and its space charge properties,accelerated thermal aging tests were conducted on samples composed of #25 mineral oil and ordinary Kraft paper.The space charge properties of aged samples under DC voltage（20 kV/mm） were studied by using the pulsed electro-acoustic（PEA） method,and the impact of aging on the space charge evolution as well as the electric field distortion was discussed.The results show that during thermal aging,the deeper the trap emerges,the more space charge accumulates and the internal field distortion is enlarged as well under DC voltage,moreover,the duration of charge dissipation and internal field distortion become longer respectively.Furthermore,an exponential relationship between the total charge and decay time was obtained and the decay time constant τ was proposed,which could help realize the evaluation of charge dissipation ability in different samples.The results provide a basis for evaluation the electrical properties of oil-paper insulation system under different thermal aging conditions.

关 键 词：变压器 油纸绝缘 热老化 空间电荷 电声脉冲(PEA)法 陷阱 

分 类 号：TM215.6[一般工业技术—材料科学与工程]