Electromagnetic Property Modeling Of Laminated Core And Components In Power Transformers Uneder Working Conditions

It is very important to make a systematic research of electromagnetic performance of laminated core and components of large power transformer,including iron loss coefficient and process, vibration and noise as well as the excitation power and so on.The modeling and simulation of electromagnetic fields and loss within multi-scale core is very complex as to high voltage and large capacity transformer,.The date of electromagnetic performance supplied by the manufacture is usually obtained in the standard laboratory which has a wide gap between the actual data.It is necessary to study the material simulation under different working condition.Furthermore,the loss generated by the rotation magnetic flux in the conner and the additional iron loss inside the laminated core produced by alternating magnetic flux leakage perpendicular to silicon steel sheet is a very challenging problem.Making a research of the simulation and numerical of the laminated core and components of power transform,the main points of this paper are:1 The classical implementations of the eddy current based on T-Ψ-Ψ is derived,taking the nonlinear and anisotropic properties of electrical materials into account in the finite element analysis of 3-D electromagnetic fields.It is beneficial to guild on building a reasonable mathematical model of electromagnetic materials.2 The weighted method based on different regions of the frame is used to determine the mean path of the Epsteinframe in this paper.The distribution uniformity of the conner is verified through the experimental measurement and numerical simulation.The specific power loss of the silicon steel is measured under different working conditions(different rolling direction, frequency and temperature) based on the Epsteinframe.The result and conclusions obtained are beneficial to the structure design of transform core and evaluation of the building factor.3 Based on two core models,which have same material and structure but different length of the yoke,the specific power loss of the core models can be obtained through the weighted method considering the the effects of the conner.Furthermore, the building factor of the model can be obtained according to the measured results by the Epestein frame and the two transformer-based core models.4 The paper carry out the test based on mirror coil measurement device to separate the eddy-loss of the coil and the shielding under different working conditions.The reasonable3 D finite element model is established to verify the reasonableness of the mirror measuring method.