Of Transformer Winding Deformation Detection Technology Applied Research

Electric Power Transformer is the important electric equipment of power network,its safe operation premise the safety service of electrical power system. The study of winding deformation is significative because of the transformer winding deformation is the most common trouble .As one of the methods of diagnosing the winding deformation,the frequency response analysis method is being widely used at present. It's mainly depended on the comparison of frequency response curves and have no uniform criteria to diagnose winding deformation. This dissertation discussed a type of testing system that is capable of discovering the deformation of large power transformation windings according to the theory of Frequency Response Analysis. At the same time,writing arithmetic to identify analytical expression of transformer winding's transfer function from frequency response were discussed.Through the method based on orthogonal polynomials. Also,obtaining the zeros and poles by means of orthogonal companion matrix.At last,the application of the distribution of zeros and poles to diagnosis the transformer winding deformation was studied.It reflects the essences of winding's characteristic and makes a great progess from that of only depending on the frequency response curves.This dissertation consists of six chapters.Chapter 1 and 2 introducts the structure of transformer and discusses the cause and effect of such deformation.At the same time,it discusses the domestic and international researches at present on deformation of power transformer windings.Pointing out the primary problems and introduces the contents of this dissertation.Chapter 3 discusses the theories and structures of the testing system who is used to test winding deformation,elaborates the realization of hardware and software module.In chapter 4,the theory of using orthogonal polynomials to estimate the transfer function based on the least square methodology is introduced,then the zeros and poles are obtained from the transfer function.In the fifth chapter,the equivalent model of winding is simulated using ORCAD.And the frequency response data of practical transformer winding is also given in this chapter.The simulated and practical data all demonstrated the validity of the arithmetic,and the method by using the poles distribution is better than the method only depending on frequency response curves.In the last chapter,the whole text is summarized and some questions to be perfected are brought forward.