基于特高压变压器铁心模型的高磁感取向硅钢片磁性能研究

发布时间：2018-08-20 09:30

【摘要】：高磁感取向硅钢片作为特高压变压器铁心的基本组成材料,其励磁性能直接影响到特高压变压器运行的整机性能和运行可靠性。特高压变压器用高磁感取向硅钢片经过剪片、叠片等工序加工成变压器铁心时,其励磁性能会产生一定程度的改变,因此高磁感取向硅钢片在特高压变压器应用条件下的励磁性能有待深入研究。选取目前已应用于特高压变压器的三种牌号硅钢片,通过分析爱泼斯坦方圈的原理,对比研究了三种牌号硅钢片在理想条件下的励磁特性,结果表明:硅钢片的励磁性能基本与牌号对应,同类型的励磁性能相当。针对一种典型特高压单相变压器的铁心结构,研究了对应的磁路和每部分的磁通分布,深入分析了硅钢片励磁特性与变压器空载特性之间的对应关系,在此基础上,给出变压器空载电流和空载损耗的常规计算方法。研制了与特高压单相变压器铁心在不同比例额定电压下等磁密、结构相同的等比缩小模型,以铁心模型为试验变压器搭建了硅钢片应用磁性能测试系统。根据IEC和国标中对变压器整机试验的要求,分别设计了工频饱和励磁条件下和直流偏磁条件下铁心模型励磁性能测试的试验方案。针对所选取三种牌号制成的铁心模型分别进行了工频饱和励磁、直流偏磁和反复过励磁条件下励磁特性的测试和分析,并对工频饱和励磁下的测试结果与由硅钢片单片磁性能计算得到的铁心模型空载损耗和空载电流进行了对比分析。结果表明:常规计算方法求得的变压器空载性能数据与实测值有一定偏差,其中空载损耗的偏差较小有一定的参考价值,而空载电流的偏差较大,参考价值有限,从侧面反映传统计算方法的局限性。通过对三种类型铁心模型在不同励磁条件下空载特性的深入分析和研究,提出一系列基于铁心模型的高磁感取向硅钢片励磁性能评估参考指标,并利用该指标评估了本文研究所选取的三种牌号硅钢片的励磁性能。这些指标反映了高磁感取向硅钢片在深度励磁饱和及直流偏磁等极端应用条件下的励磁性能,从而能更科学合理评估特高压变压器用取向硅钢片的励磁性能,对特高压变压器的铁心材料选型具有重要的工程应用价值。
[Abstract]:High magnetic inductive oriented silicon steel sheet is the basic component material of UHV transformer core. Its excitation performance directly affects the whole machine performance and operation reliability of UHV transformer. When the high magnetic inductive oriented silicon steel sheet used in UHV transformer is processed into transformer core through shearing and lamination, its excitation performance will change to a certain extent. Therefore, the excitation performance of high magnetic inductive oriented silicon steel sheet in UHV transformer needs further study. By analyzing the principle of Epstein square ring, the excitation characteristics of three kinds of silicon steel sheets have been studied under ideal conditions, which have been applied to UHV transformers. The results show that the excitation performance of the silicon steel sheet is basically corresponding to the grade, and the excitation performance of the same type is equivalent. In view of the core structure of a typical UHV single-phase transformer, the corresponding magnetic circuit and magnetic flux distribution of each part are studied, and the corresponding relationship between the excitation characteristics of silicon steel sheet and the no-load characteristic of transformer is deeply analyzed. The conventional calculation method of transformer no-load current and no-load loss is given. An equal ratio reduction model with the same magnetic density and structure as the core of UHV single-phase transformer under different proportion rated voltage is developed. A magnetic performance test system for silicon steel sheet is built with the core model as the test transformer. According to the requirements of IEC and GB, the test scheme of core model excitation performance under the condition of power frequency saturation excitation and DC bias magnetic field is designed respectively. According to the core model made by the three grades selected, the excitation characteristics under the condition of power frequency saturation excitation, DC bias excitation and repeated overexcitation are tested and analyzed, respectively. The results of the measurement under the power frequency saturation excitation are compared with the no-load loss and the no-load current of the core model calculated from the magnetic properties of the silicon steel sheet. The results show that there is a certain deviation between the normal calculation method and the measured value, in which the deviation of no-load loss is small and the deviation of no-load current is large, and the reference value is limited. The limitation of the traditional calculation method is reflected from the side. Based on the analysis and study of the no-load characteristics of three types of core models under different excitation conditions, a series of parameters for evaluating the excitation performance of silicon steel sheets with high magnetic induction orientation based on the core model are proposed. The excitation performance of three kinds of silicon steel sheets selected in this paper is evaluated by using this index. These indexes reflect the excitation performance of high magnetic inductive oriented silicon steel sheet under extreme application conditions such as deep excitation saturation and DC bias magnetic field, so that the excitation performance of oriented silicon steel sheet for UHV transformer can be more scientifically and reasonably evaluated. It has important engineering application value for core material selection of UHV transformer.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM275;TM41

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