Research On The Influence Of Oil Flow In Horizontal Oil Passage Of Oil-immersed Transformer Winding On Its Temperature Rise

Oil-immersed transformer is one of the important equipment in power supply and distribution system.In recent years,most of the transformers in China have been used for a long period of time,and the thermal problems caused by the temperature rise of the transformer are becoming more and more serious,which seriously affects the normal operation of the transformer.The oil flow of horizontal oil channel has direct influence on winding temperature rise.Study of oil-immersed transformer oil level of oil flow,and to optimize the structure of winding level oil duct,in order to improve the oil flow,to reduce the winding temperature rise,protect the winding insulation and other artifacts,has important academic value and practical significance.Based on this,this paper analyzes the thermal mechanism and heat dissipation mechanism of oil-immersed transformer,and USES computational fluid dynamics software to conduct modeling analysis of 35 kV oil-immersed transformer.Through the level of transformer winding oil flow and the calculation of the winding temperature rise,analysis of the oil level,oil temperature rise of winding,the influence of transformer winding for oil level of channel structure design and improvement to provide certain reference.The main research content of this paper is as follows:(1)Based on the related theories of heat transfer,this paper analyzes the heat source of the transformer and the internal heat transfer process.Taking the 35 k V oil-immersed power transformer as the research object,the finite element analysis software ANSYS Workbench was used to establish the transformer core and winding temperature calculation model under the condition of no-flow,and the winding temperature rise calculation result was obtained,which proved that the transformer had no oil flow when the winding The temperature rise has a great influence,so it is necessary to establish a fluid-structure coupled calculation model for the transformer.(2)Using the fluid dynamics calculation software ANSYS CFX to establish a physical model based on the actual size of the transformer components,establish a three-dimensional fluid-solid coupling numerical calculation model for the transformer oil flow area around the windings and windings,and use the finite volume method to calculate the transformer oil flow and temperature distribution.Analysis of the oil flow in the windings of the winding and its effect on the temperature rise of the windings.The fluid-structure coupled calculation model can achieve the desired simulation goals.Winding temperature rise experiments were performed to verify the validity of the calculation model.(3)To improve the oil flow in the oil passage and reduce the temperature rise of the winding,the horizontal oil passage structure of the winding is optimized.Considering the influence of horizontal oil passage height and oil flow guide baffle on the oil flow in the oil passage,a transformer model with different levels of oil passage is established to analyze the influence of oil flow at different levels on the temperature rise of the winding,which is the horizontal oil passage of the model of the transformer.The design and improvement provide reference.The research object of this article is an oil-immersed power transformer with a voltage rating of 35 k V and a capacity of 10000 kVA.By establishing a three-dimensional fluid-solid coupling calculation model for the transformer,the oil flow and temperature distribution of the horizontal oil passage are calculated,and the temperature rise test of the winding is performed to verify the simulation results,and the effectiveness of the coupled calculation model is proved.In order to reduce the temperature rise of winding hot spots,the horizontal oil passage structure of the winding is improved.The simulation results provide a reference for the optimal design of the oil passage structure of the transformer.