Research On Demagnetizing Winding To Reduce Excessive Flux Of Yoke Of EHV And UHV Transformer

Demagnetizing winding technology is an important part of UHV transformer research and developmentThe application of this technology accompanies with the entire UHV transformers'development process. Because demagnetizing winding is the technical structure which must be used during the design and development, it's important to carry out the demagnetizing winding research for UHV transformers research. By the research of the UHV transformers'demagnetizing windings,we can learn more about UHV electromagnetic field distribution inside the transformers, which can significantly improve the transformers'load and unload performance parameters.The research takes an important role in continuously pushing forward the study of the internal structure of UHV equipments.Existing UHV AC transformer is presented in this paper, on the basis of original technology, the actual demand of demagnetizing winding is analyzed and the design process, and combining the law of electromagnetic induction and electromagnetic field theory, the calculation and design of the demagnetizing winding model, and the software validation and electrical test, will eventually study demagnetizing winding used in real production, it has certain operability is regulated production and technological process.First, this paper discusses the present situation of UHV AC transformer and the problems facing in a half circle line, introduces the new situation of UHV AC transformer facing the challenges and opportunities. On the basis of the analysis of the UHV AC transformer in the half circle line problems brought about by the difficulties, puts forward the demagnetizing winding is an effective method to solve this problem. The basic principle of demagnetizing winding are discussed. From the magnetization curve of silicon steel sheet is put forward in current window has a harmful effect on UHV AC transformer. At the same time, which is based on specific physical case, is an object with specific data, formula and draw graphics, window system in this paper, the half circle line, wear the concept and principle of current, demagnetizing winding.Secondly, put forward the UHV AC transformer demagnetizing winding design target and principle, and the concrete structure design can be divided into three box four-post type structure and four box five pillar type structure are discussed respectively. In two kinds of discussion, we first analyzed the demagnetizing winding with the main magnetic flux and half a circle line flux interaction relations. Then in the concrete structure of the discussion, analyzed four box five pillars of the demagnetizing winding in the structure of the location and two demagnetizing winding connection mode and three boxes of the demagnetizing winding in the four pillar type construction of the location and two demagnetizing winding connection mode. And the direction of the magnetic circuit of the structure are analyzed. In this model analysis, system elaborated the demagnetizing winding is used to wear a window offset half a circle line current generated by the flux of the impact of the design purpose. And detailed tells the story of two kinds of model, demagnetizing winding, the mode of arrangement and connection, as well as with specific data illustrates the degaussing current, voltage and the relationship between the transformer parameters.Thirdly, on the basis of the model is established, the parameters are calculated based on the actual product, and two ways of verification measures to ensure the reliability of the scheme and conclusion. Is a kind of software validation; Is a kind of test.Finally, this thesis topic is reviewed, the key technology project of specific research questions. Wear the transformer window current problems in single-phase auto-transformer 334 MVA/500 kV transformer, single-phase auto-transformer 250 MVA /500 kV transformer, single-phase 500 kV generator transformer, the column structure of single-phase voltage regulator since the coupling transformer of 500 kV transformer and UHV AC has carried on the concrete analysis, research and summary.