Simulation Analysis Of Electromagnetic Field Of Balance Transformer Based On ANSYS Maxwell

In recent years,with the rapid development of electrified railways,balance transformers have been widely used.With the gradual increase of transformer capacity and voltage level,the analysis of the insulation electric field strength and leakage magnetic field of the transformer becomes very important.Traditional formulas and assumed calculation methods have always laid particular stress on theoretical analysis and have their limitations in practical engineering applications.However,finite element method is famous for its flexibility,versatility and strong problem-solving ability.Taking the actual balance transformer as an example,based on the actual structure and main functional parameters of the transformer,two-dimensional and three-dimensional models of the transformer are established after appropriate simplification by ANSYS Maxwell.In this paper,the two-dimensional electrostatic field simulation of the balancing transformer is carried out when the balancing transformer works at the rated condition.Firstly,through the simulation observation of the electric field strength distribution of the oil gap between the windings and the calculation of the insulation margin,it can be judged whether the insulation requirements are met under the rated condition.On this basis,it can be judged that the insulation breakdown of the oil between the windings under different dielectric constants,It can provide some reference for the selection of materials with different dielectric constants by judging the influence of different dielectric constants on the field strength distribution of the winding oil and the insulation margin,Secondly,the influence of the angle ring on the field strength at the corner of the end of the high voltage winding is simulated.According to the different breakdown field strength of different thickness of insulating paperboard,the paperboard thickness is set to reduce the consumption of paperboard materials as much as possible.Judging the rationality of insulation design through these measures not only plays a decisive role in the safe and reliable operation of the transformer,but also has an extremely important impact on the economic indicators of the transformer.By observing the law of symmetrical distribution of magnetic lines of flux in single-phase transformer windings with respect to the middle of windings through simulation by ANSYS Maxwell,a method(magnetic flux leakage method)for calculating leakage inductance in three-dimensional transient magnetic field is proposed.The leakage inductance of primary and secondary windings is obtained by magnetic flux leakage method in the single-phase transformer model,and the correctness of magnetic flux leakage method is verified by comparison with traditional energy method and test method.The magnetic leakage flux method is used to calculate the changing rule of the leakage inductance when the distance between the transformer winding and the iron core changes.The influence of winding deformation and winding layout on the leakage inductance value of the transformer is studied,which provides certain theoretical basis for reasonably arranging the positional relationship between the winding and the iron core in the transformer design.On this basis,using the magnetic flux leakage method proposed in this paper,the simulation analysis and calculation of the balance transformer are carried out as follow:The leakage inductance values of each winding are calculated Separately;The influence of current on the leakage inductance of winding is analyzed;The influence of winding layout and connection mode on the leakage inductance of balancing transformer is analyzed,and the conclusion is that cross layout winding can balance the impedance of balancing transformer;The influence of winding deformation of balancing transformer on the leakage inductance of balancing transformer winding is analyzed;The above analysis and calculation provide a theoretical basis for the design of balance transformer.