Modeling And Dc-biased Magneticzation Research Of Single-phase Transformer Based On J-A Hysteresis Model

Currently, with the widely application of the DC power transmission, more andmore transformers work under the DC-biased magnetization. This kind of situationwould bring dangers to the transformer, so the research of the relationship between theexcitation current of transformer and the DC-biased magnetization is very necessary.The most important is transformer modeling and the research of the hysteresischaracteristics of core.The mathematical model of transformer is established based on J-A hysteresismodel in this thesis. Firstly, the development and formation mechanism of J-A modelis introduced. The error formula of model is improved in some domestic literature.Secondly, the impact of five parameters for J-A model on the hysteresis loop isresearched. The false position method is used to calculate the five parameter values ofJ-A model. These values are compared with the test data and the results proved thefeasibility of the method.A single-phase transformer model is established which is based on J-A model.Simulation model is built by MATLAB software, the paper uses the simulation data tocompare with the actual calculation value. It is proved that the results are very closelyand the transformer model is reasonable.Then, the paper introduces the formation principle of DC-biased magnetization,and simulates the change of transformer excitation current under DC-biasedmagnetization in different degrees. Finally, the paper introduces the dangers of DC-biased magnetization of transformer and power grid system and some methods ofinhibition of DC-biased magnetization.