Research On The Core Vibration Characteristics And Noise Suppression Of Amorphous Alloy Transformers

As the core equipment of power transmission and conversion,amorphous alloy transformer is very important for the normal operation of power system.However,the high vibration of amorphous alloy transformers is mainly due to the high magnetostriction of their materials and their sensitivity to stress.If not limited,too high vibration will lead to structural parts damage and operating conditions change.The study of transformer vibration and noise reduction is a complicated scientific problem involving many physical fields such as electricity,magnetism,mechanics and heat.In this paper,vibration characteristics and noise suppression of amorphous alloy transformer under multiphysical field coupling are studied.The main contents are as follows:(1)A magnetostrictive constitutive model of ferromagnetic materials was established based on the macroscopic thermodynamic relationship and combined with the microphysical mechanism of magnetization of amorphous alloy transformer core.The calculated results can be used as the constitutive relationship of magnetostrictive strain calculation of stress field.(2)Based on the finite element analysis under the coupling of electromagnetic-magnetic-stressacoustic field,the main magnetic field of the iron core and the leakage magnetic field generated in the coil and structural parts were calculated,and the vibration of the iron core caused by the distribution of electromagnetic force and magnetic flux density at different times was analyzed.The stress field was sequentialized,and the deformation of the amorphous alloy iron core caused by Lorentz force and magnetostriction was compared.The effective acceleration and vibration energy distribution of the surface strain of the core at different times are obtained.The sound field is coupled sequentially,and the distribution of sound pressure in the core model without stable periodic motion and in the air around the core is calculated respectively.(3)By setting up a test platform for vibration and noise of iron core,the correctness of finite element calculation of multi-physical field is verified by comparing experimental and simulation values,including vibration acceleration,vibration amplitude and noise value of iron core.The vibration amplitudes of vibration signals at different positions of the core at different frequencies are analyzed.(4)Multilayer transformer vibration signals are decomposed by wavelet packet theory,feature vectors of the running state of the iron core are extracted,and mechanical faults of the iron core are identified by vibration energy.The mechanical faults of amorphous alloy such as structural loosening and abnormal force of iron core are identified by the numerical and sequential changes of vibration characteristic values.(5)The noise suppression method of amorphous alloy transformer must be designed in combination with its special structure when referring to the traditional silicon steel transformer.Based on the research results of the first five chapters,using vibration damping pad and applying appropriate binding force to the core interface to suppress the vibration of the core to reduce the noise of the amorphous alloy transformer can effectively suppress the vibration of the core at a specific frequency.The research results of this paper not only have important academic value for exploring the vibration mechanism and noise suppression mechanism of amorphous alloy transformer,but also have important significance for ensuring its green and efficient operation.