Study On Vibration Generation And Transmission Mechanism Of Power Transformer And Adaptive Active Noise Control

The mechanical vibration and noise pollution of transformers in the operation of modern power grid have become an important problem that can not be ignored in the power industry because of the coupling effect of electromagnetic and mechanical.In this paper,starting from the mechanism and propagation process of mechanical vibration during the operation of power transformer,the optimization control technology of secondary sound source in the sound field of power transformer and the intelligent algorithm of adaptive active noise reduction of power transformer,theoretical exploration and application research are carried out.The three aspects are interrelated and form an organic whole for the detection,fault diagnosis and intelligent grid equipment.The multi-physical field simulation model of dry-type transformer is established.Comprehensive treatment of environmental noise provides theoretical and technical support.The specific research contents of this paper are as follows:(1)In Chapter 2,starting from the mechanism of vibration and noise of transformer body,the generation process of vibration and noise of transformer core and winding is studied.Considering the process of its propagation in the surrounding space,using COMSOL Multiphysics multi-physical field simulation software,a complete acoustic field calculation model is established to analyze the spectrum distribution of vibration and noise of power transformer.The electrodynamic force changes with time.In addition,the core displacement caused by magnetostriction and the sound field distribution in the air around the transformer are analyzed,and the noise spectrum characteristics at the designated points in the space are analyzed,which provides a simulation basis for the subsequent noise reduction work of the transformer.By coupling the electromagnetic field,structure field and pressure sound field in turn,the electromagnetic vibration noise of transformer body and the distribution of air sound field in the specific space distance around transformer body are finally obtained.(2)In Chapter 3,based on Huygens principle and acoustic superposition interference cancellation principle,the transformer is equivalent to a spherical primary sound source.Aiming at the sound field distribution in the surrounding space,the secondary sound source array is used for acoustic interference,so as to achieve the purpose of active noise reduction.In order to determine the optimal matching parameters of secondary sound sources and the optimal location of secondary sound sources in the acoustic field,the objective function of acoustic field optimization is established according to the principle of acoustic control.The key parameters such as number,location,source strength and initial phase angle are optimized by genetic algorithm.The location and number are coupled,which reduces the computational load and the difficulty of arranging secondary sound sources in actual operation.Thus,the optimal layout strategy of secondary sound sources is obtained when the noise reduction effect is optimal.COMSOL Multiphysics software is used to build the sound field interference model,and the secondary sound source placement strategies with different numbers and spatial locations are simulated to verify the correctness of the secondary sound source optimization.(3)In Chapter 4,this paper studies the active noise reduction algorithm of adaptive transformer.The algorithm is divided into three parts.The first part and the second part offline model the secondary channel and the primary channel respectively.The third part online model the secondary channel,which effectively reduces the noise of transformer.Then genetic algorithm is used to optimize the convergence coefficient of the noise reduction filter and improve it.The convergence performance and stability of the algorithm are compared with the random white noise FXLMS algorithm in the simulation analysis,which verifies that the proposed algorithm has better performance in secondary channel online modeling and transformer noise reduction.On the basis of secondary sound source optimization and active noise reduction adaptive algorithm as the core,an intelligent control strategy of transformer active noise reduction system is proposed to improve the stability and noise reduction of the noise reduction system.it provides a theoretical basis and engineering basis for the subsequent research and development of active noise reduction equipment.