| Amorphous alloy core transformer has a good energy-saving effect,but the short circuit resistance ability is seriously inadequate,the short circuit resistance ability has become a bottleneck restricting the development of industry technology,so it is very important to analyze the short circuit characteristics of amorphous alloy core transformer and optimize its short circuit resistance ability.In view of the deficiency that the current simulation study on the short circuit characteristics of amorphous alloy transformer fails to fully consider the change of its dynamic characteristics,the electromagnetic model of the short circuit fault of amorphous alloy transformer is established.A SBH-M-400/10 amorphous alloy core transformer is taken as the research object by using the finite element numerical calculation method of electromagnetic coupling.Based on the field-circuit coupling principle,the transient physical characteristics of rectangular windings of amorphous alloy were simulated,the changes of electromagnetic and electrodynamic characteristics of amorphous alloy transformer windings after short circuit were studied,the dynamic vibration process of the transformer windings after short circuit was explored,and the change law was summarized.The calculation results show that the variation characteristics of magnetic field and electromagnetic force are basically consistent with the waveform of short-circuit current.The larger the amplitude of electromagnetic force at different positions of winding is,the higher the vibration acceleration is,that is,the more intense the vibration is.The main frequency of vibration occurs at the frequency of 100 Hz,twice the power supply.It is found that the dynamic process of short circuit of amorphous alloy transformer has a significant influence on the mechanical properties of winding,and the winding is easy to be unstable due to resonance,which can not be ignored in the anti-short circuit check in engineering.In the actual test study on china-africa crystal alloy series transformer winding short-circuit fault setting difficult,this article is based on electromagnetic field-structure field-the transient temperature field more physical field coupling theory,the transformer is established finite element three-dimensional model,the simulation under the condition of the low voltage side export three-phase short-circuit of amorphous alloy transformer short-circuit characteristics of rectangular winding,The effect of thermal stress on winding deformation caused by the temperature rise of amorphous alloy transformer during short circuit is studied.The stress and deformation of winding under single electromagnetic force and thermal stress coupling of electromagnetic force are compared.The results show that thermal effect has a great influence on transformer deformation,resulting in serious deformation and damage of several rectangular windings.Short-circuit temperature rise is a factor not to be ignored in transformer deformation and damage,but also a key problem to be considered in improving transformer short-circuit resistance.By electromagnetic dynamic characteristics analysis and physical field coupling simulation results was found that the long axis of rectangular winding Angle part stress after deformation is serious,the rectangle for amorphous alloy transformer winding,width size have strict requirements,but it’s on the corner of the rectangular winding arc on the craft that make different,this article put forward to increase the rectangular winding Angle radian to enhance its ability to resist short circuit optimization measures,The results show that the stability of the optimized winding is significantly enhanced.In engineering,the anti-short circuit performance of the amorphous alloy transformer winding can be improved by winding the winding Angle process.The most appropriate number of struts is selected by comprehensive analysis of the influence of struts and heat dissipation on the dynamic stability of the supporting winding. |
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