变压器油纸绝缘频域介电响应非线性特性研究  

Research on Nonlinear Characteristics for Frequency Domain Dielectric Response of Transformer Oil-paper Insulation

作　　者：张明泽 孟繁昊 刘骥 刘贺千 贾海峰 李璐[1] ZHANG Mingze;MENG Fanhao;LIU Ji;LIU Heqian;JIA Haifeng;LI Lu(Key Laboratory of Engineering Dielectrics and Its Application of Ministry of Education(Harbin University of Science and Technology),Harbin 150080,Heilongjiang Province,China;Electric Power Research Institute of State Grid Heilongjiang Electric Power Co.,Ltd.,Harbin 150030,Heilongjiang Province,China)

机构地区：[1]工程电介质及其应用教育部重点实验室(哈尔滨理工大学),黑龙江省哈尔滨市150080 [2]国网黑龙江省电力有限公司电力科学研究院,黑龙江省哈尔滨市150030

出　　处：《中国电机工程学报》2023年第2期831-842,共12页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51977051)。

摘　　要：频域介电响应(frequency domain dielectric response,FDS)技术作为变压器油纸绝缘无损评估的重要手段,而油纸绝缘介电性能非线性变化将影响评估的准确性,因此需要开展油纸绝缘FDS非线性变化规律的研究。该文在实验室条件下制备了多组不同老化程度、不同含水率的油纸绝缘试样,开展不同温度下油纸绝缘非线性FDS测试。研究发现,测试温度较低、油纸绝缘水分含量较小时,油纸绝缘低频介电响应与电压呈负相关,且随着测试温度的升高,非线性变化区域向高频且损耗因数增大的方向移动,FDS变化规律与测试激励幅值的关系减弱;当测试温度较高、油纸绝缘水分含量较大时,油纸绝缘低频介电响应出现与电压呈正相关的非线性变化规律;同时,根据频温平移计算发现,油纸绝缘的弛豫活化能与交流电导活化能均与其内部水分含量存在线性变化关系,而测试激励幅值对交流电导活化能的影响更为显著。为了消除测试温度对交流电导率的影响,该文建立电导率修正函数,实现了高温、高含水率下油纸绝缘低频交流电导率曲线的平移修正;最后,结合所构建的水分基团迁移率计算模型,定量计算水分含量对老化油纸绝缘频域介电响应非线性变化的影响,其规律与实验结果一致。Frequency domain dielectric response(FDS)technology is an important method for nondestructive evaluation of transformer oil-paper insulation.The nonlinear change of dielectric properties of oil-paper insulation will affect the accuracy of evaluation,thus it is necessary to study the nonlinear FDS properties of oil-paper insulation.In this paper,several groups of oil-paper insulation samples with different aging and moisture content are prepared in the laboratory conditions.The nonlinear FDS test of oil-paper insulation under different test temperature is carried out.According to the test,when the moisture content of oil paper insulation is lower,the low-frequency dielectric response of oil-paper insulation is negatively correlated with voltage at low test temperature.With the increase of test temperature,the nonlinear changing region moves towards high frequency.The relationship between FDS variation and test excitation amplitude decreases.When the test temperature is high and the moisture content of oil-paper insulation is large,the low-frequency dielectric response of oil-paper insulation shows a new nonlinear law,which is positively correlated with voltage.Both relaxation activation energy and AC conductivity activation energy have a linear relationship with the moisture content in oil-impregnated pressboard.The test excitation amplitude affects the AC conductance activation energy more significantly.To eliminate the influence of test temperature on AC conductivity,the correction function is established to correct the low-frequency AC conductivity of oil-paper insulation at high temperature and high moisture content.Finally,combined with the calculation model of water molecular group mobility established in this paper,the influence of moisture content on the nonlinear change for frequency dielectric response of aging oil-paper insulation is quantitatively calculated,and the law is consistent with the experimental results.

关 键 词：油纸绝缘 频域介电响应 非线性 电导率 

分 类 号：TM855[电气工程—高电压与绝缘技术]