考虑累积效应的电力变压器绕组弹塑性形变分析  

Elastic-plastic deformation analysis of power transformer windings considering cumulative effect

作　　者：刘君 陈沛龙 吕黔苏 艾文灏 林晓青 李旭[2] 李堃 肖宁 LIU Jun;CHEN Peilong;LÜQiansu;AI Wenhao;LIN Xiaoqing;LI Xu;LI Kun;XIAO Ning(Electric Power Science Research Institute,Guizhou Power Grid Co.,Ltd.,Guiyang 550000,China;College of Electrical and Information Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]贵州电网有限责任公司电力科学研究院,贵州贵阳550000 [2]湖南大学电气与信息工程学院,湖南长沙410082

出　　处：《电力科学与技术学报》2024年第4期255-262,共8页Journal of Electric Power Science And Technology

基　　金：贵州电网有限责任公司重点项目(066600GS62200006);国家自然科学基金(51977063)。

摘　　要：短路导致的绕组形变是引发变压器故障的关键因素之一。为探究变压器绕组在多次短路冲击下的弹塑性形变规律,以一台型号为SFZ7-31500/110电力变压器作为研究对象,构建变压器三维有限元仿真模型。通过磁场—结构场耦合计算,获取短路过程中变压器的漏磁场分布及绕组所受电动力大小,系统分析绕组在多次短路冲击下的形变特性及其累积效应。结果表明,在短路冲击下,高、低压绕组的形变方向相反,且低压绕组的形变量明显大于高压绕组。此外,受到铁芯结构的影响,同一绕组位于铁芯窗内和窗外的受力和变形呈现出显著的不均匀性,窗内的绕组形变量较大。随着短路次数的增加,低压绕组上的塑性应变逐渐累积,初期增长迅速,但随后因材料硬化效应,形变累积速度逐渐减缓并趋于稳定;相反,高压绕组在整个过程中均保持弹性变形,未出现塑性形变。研究结果对变压器绕组动稳定性分析具有一定指导意义。The deformation of windings caused by short circuits is one of the key factors leading to transformer failures.To explore the elastic-plastic deformation law of transformer windings under multiple short-circuit impacts,a SFZ7-31500/110 power transformer is taken as the research object to construct a three-dimensional finite element simulation model of the transformer.Through magnetic field-structure field coupling calculation,the leakage magnetic field distribution of the transformer and the magnitude of the electromotive force on the windings during short circuits are obtained.The deformation characteristics and cumulative effects of windings under multiple short-circuit impacts are systematically analyzed.The results show that under short-circuit impacts,the deformation directions of high-and low-voltage windings are opposite,and the deformation of low-voltage windings is significantly greater than that of high-voltage windings.In addition,due to the influence of the iron core structure,the force and deformation of the same winding located inside and outside the iron core window show significant inhomogeneity,and the deformation of the winding inside the window is larger.As the number of short circuits increased,the plastic strain on the low-voltage windings gradually accumulate.It grows rapidly in the early stage,but the deformation accumulation speed gradually slows down and tends to stabilize due to the material hardening effect.On the contrary,the high-voltage windings maintain elastic deformation throughout the process and does not show plastic deformation.The research results have certain guiding significance for the analysis of the dynamic stability of transformer windings.

关 键 词：短路特性 累积效应 弹塑性形变 电力变压器 

分 类 号：TM863[电气工程—高电压与绝缘技术]