电力变压器结构件漏磁场和温度场的分析与研究-电气工程专业论文.docxVIP

电力变压器结构件漏磁场和温度场的分析与研究 电力变压器结构件漏磁场和温度场的分析与研究 河北工业大学硕士毕业论文 河北工业大学硕士毕业论文 ANALYSIS AND RESEARCH OF TRANSFORMER’S STRUCTURAL ELEMENTS LEAKAGE FIELD AND TEMPERATURE FIELD ABSTRACT The transformer is one of important devices in Power System , it play a important role in power transmission、flexible distribution、safe use. When power transformer is running, especially its capability larger, great leakage fluxes in end of the winding will go through clamps and other structure parts of transformer, besides some leakage fluxes go through transformer oil and oil tank. These leakage fluxes will add loss of transformer, which may make some parts over heat. The paper analyzes a transformer of 250000kVA/500kV and builds simulation model by calculation software of MAXWELL3D. The paper makes a simulation of static magnetic field for transformer, and gets non-saturation work area of core by comparison with BH curve. Then the paper research loss distribution of core which works in non-saturation area when transformer is excited by sinusoidal current. Building simulation model based on product data of factory by MAXWELL3D, the paper make the simulation and analysis of transformer model which is excited by non-sinusoidal current. Firstly, the paper do a simulation for transformer model without magnetic shield, the paper get a conclusion that the loss of clamping parts and middle oil tank is larger, the reason of which may be greater leakage fluxes in them. So we add magnetic shielding for transformer model, and make the simulation again. After compared with model without magnetic shields, the loss of yoke clamping and middle oil tank is heavily reduced, which prove that reason of greater loss is leakage fluxes. In order to reduce the loss of magnetic shielding, magnetic shielding is made of lamination, people usually analyze it as whole one. To solve this problem, the paper applies Bertotti time-domain models which break the total core loss into static hysteresis loss, classical eddy curre