Research On Power Transformer DC Magnetic Bias Characteristics Based On ANSOFT And PSCAD Softwares

In recent years, with the development of modern electrical and electronics industry, electromagnetic field simulation is widely used in engineering practice, concluding the field of electrical equipment, machinery, automotive, aviation, shipbuilding, electronics and so on. In the electromagnetic field analysis, the finite element method is most widely used.there are many Electromagnetic field simulation softwares based on finite element method, such as ansoft, ansys, magnet, elecnet and so on.As the development of HVDC transmission projects, the issues related to the transformer are worth researching in AC and DC hybrid power system. Transformer DC magnetic bias is becoming a increasingly serious problem, which may affect the security and stability of the grid. In this paper, the500KV power transformer DC magnetic bias is studied with the following issues. Visibly, PSCAD and ANSOFT softwarse are the effective simulation and calculation softwares in the electrical engineering.The study of this paper focuses on the following aspects:First, on the basis of a brief analysis of the transformer DC magnetic bias mechanism, according to the technical parameters and magnetization characteristic of500KV power transformer, the DC magnetic bias pacad/emtdc no-load and load simulation models are established based on pscad/emtdc. Power transformer DC Bias is simulated with pacad/emtdc. Analysis is obtained under different DC bias conditions including the excitation current waveforms and harmonic properties,the transformer core magnetization curves, the equivalent core relative permeability, DC magnetic flux density variation, core flux density timing characteristics.Second, based on the theory of electromagnetic fields and finite element techniques,500KV power transformer three-dimensional finite element model is builded according to Ansoft maxwell software.The main and leakage magnetic field characteristics,the winding leakage flux and electromagnetic forcer; the leakage and eddy current properties of transformer tank,and transformer losses are studied.Finally, the experimental scheme of the500KV power transformer no-load and load DC Bias is gived.By the transformer DC magnetic bias test, transformer excitation current waveforms, harmonic characteristics, transformer noise changes and loss characteristics are obtained, the transformer function is tested before and after the expetiment. Through the test of actual power transformers DC bias, an important foundation for normal safe operation is provided, and the correctness of the simulation is verified because of consistent simulation and test data.