Design Of Magnetic Structure And Research On Short-Circuit Impedance Of Industrial Frequency Transformer

Short-circuit impedance of transformer refers to the rated frequency and the reference temperature,the equivalent impedance looking from the other side while one side circuit was short.Short circuit impedance is a significant parameter in transformer performance indicators,it is important for safe operation of the transformer cost,efficiency and economic indicators.Accurate calculation of the transformer short-circuit impedance is an essential work for research and design of the transformer.The traditional calculation methods of transformer short-circuit impedance including analysis method,energy method and magnetic circuit method,etc.When we use different transformer distribution and permeability structure,the distribution of transformer leakage magnetic field will change,and the traditional design method is difficult to satisfy the requirement of the calculation precision.Therefore,this article uses the field-circuit coupling method,which is based on the finite element analysis software FLUX 3D,by using the simulation analysis of leakage magnetic field distribution of different winding distributions and magnetic structure,then calculates the short-circuit impedance and finds the relationship between winding distribution and magnetic flux guide.In this paper,the research work mainly includes the following three aspects:(1)First,we use the experimental platform to measure the geometrical and physical parameters of power frequency transformer,do the experiment under various working conditions;Secondly,we set up the simulation model of the transformer according to the parameters by using finite element analysis software FLUX 3D;Finally,we do the transformer simulation experiment on steady state and transient state,then compare the simulation values and measured values to verify the accuracy of the model.(2)Short-circuit impedance of transformer is related to leakage magnetic field distribution.For different winding distribution will produce different leakage magnetic field,we change the distribution of transformer winding which will makethe change of leakage magnetic field of transformer winding,and then get a different short circuit impedance.Therefore,based on accurate model,using FLUX 3D software change the distribution of winding of transformer model,Through the analysis of the magnetic field distribution and get the transformer short-circuit impedance,studying the relation between the distribution of the winding and short circuit impedance.(3)Increase the magnetic flux guide between high and low voltage windingwill also affect the leakage magnetic field of transformer,and then change the short circuit impedance of transformer.Therefore,we increase the magnetic flux guide between the high and low voltagewinding,analysis the distribution of leakage magnetic field by changing the thickness of the magnetic flux guide,get the short circuit impedance and analysis its relationship with the thickness of magnetic flux guide.In this paper,the proposes method to design new type of magnetic structure and to improve the leakage magnetic flux,which is based on the finite element analysis software FLUX 3D to study the relationship between short-circuit of power frequency transformer with winding distribution and thickness of magnetic flux guide.It can reduce the design period,improve the efficiency and reduce the production cost of transformer by improving all kinds of transformer,which has a good practical significance and use value.