【作者】 陈宇；

【导师】 高波；

【作者基本信息】 西南交通大学 ， 电气工程（专业学位）， 2017， 硕士

【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。更多还原

【Abstract】 The high magnetic induction grain-oriented silicon steel is the basic composition material of UHV transformer core,and its excitation performance directly affects the whole machine performance and operational reliability of UHV transformer operation.When high magnetic induction grain-oriented silicon steel used in UHV transformer are made into the transformer core through shearing,laminated and other processes,the excitation performance will produce a certain change,so the high magnetic induction grain-oriented silicon steel need to be studied further in the application of UHV transformer excitation conditions.The three kinds of silicon steel sheets which have been applied to UHV transformers are selected.By analyzing the principle of Epstein square ring,the excitation characteristics of three kinds of grades of silicon steel sheets under ideal conditions are contrastive studies.The result shows that the excitation performance of silicon steel sheet corresponds with nameplate and excitation performance of the same grade is fair.To the core structure of a typical UHV single-phase transformer,study the corresponding magnetic circuit and the magnetic flux distribution of each part,and analysis the correspondence between the excitation characteristics of the silicon steel sheet and the no-load characteristic of the transformer deeply,on this basis,give the calculation method of no-load current and no-load loss of transformer.The equivalent reduction model with same flux density and construction under different ratio rated voltages of UHV single-phase transformer core is developed,and the magnetic performance test system of silicon steel sheet is set up with the core model as the test transformer.According to the requirements of IEC and GB test to the transformer,the test scheme of excitation test of core model under frequency saturation excitation condition and DC bias condition is designed respectively.Aiming at the core model made of three grades,the test and analysis of the excitation characteristics under the conditions of frequency saturation excitation,DC bias and repeated over excitation are carried out respectively.The test results of the frequency saturation excitation are compared with those of the silicon steel sheet.The no-load loss and no-load current of the core model are compared and analyzed.The results show that there is a certain deviation between the no-load performance data obtained by the traditional calculation method and the measured value.Based on the deep analysis and research on the no-load characteristics of the three types of core models under different excitation conditions,a series of reference indexes for the evaluation of the excitation performance of the high magnetic induction silicon steel sheet based on the core model are proposed,and the three grades of silicon steel chip excitation performance by the index are evaluated.These indexes reflect the excitation performance of the high magnetic induction silicon steel sheet under the extreme application conditions,such as deep excitation saturation and DC bias,which can evaluate excitation performance of UHV transformer with oriented silicon steel chip more scientific and reasonable,which has important engineering application value in the UHV transformer core Material selection.更多还原