【作者】 王昊；

【导师】 张黎；

【作者基本信息】 山东大学 ， 电气工程， 2025， 博士

【摘要】 本文从高压换流变压器的组件结构模态、激励组合形式、声场分布形态等方面,系统地开展了高压换流变压器的振动噪声特性及机理研究,为高压换流变压器振动噪声抑制方法提供了理论参考。(1)搭建了适用于高压换流变压器的振动噪声测量平台,测试了多种型号高压换流变压器在不同工况下的振动特性,提出了振动传感器测点布置方案。基于在运高压换流变压器(型号ZZDFPZ-415000/500-800)的运行及结构参数,设计搭建了高压换流变压器电-磁-力(声)多场耦合仿真模型。通过对比两台不同型号在运高压换流变压器的实测振动参数,验证了仿真模型的准确性。(2)提出了基于相似原理及基于注意力机制的卷积神经网络(Convolutional Neural Network Based on Attention Mechanism,CNN-AM)的两种高压换流变压器振动缩比方法。基于CNN-AM振动缩比方案制备了适用于实验化研究的系列缩比样机,配备了可更换的不同结构铁心3种、不同结构绕组4种、不同结构油箱2种、不同结构垫脚绝缘2种及不同结构定位部件4种,为高压换流变压器振动噪声机理研究提供了实验平台。(3)研究了直流(Direct Current,DC)偏磁过程中高压换流变压器振动特性,阐明了不同直流含量下高压换流变压器内部组件在电磁场、损耗和振动特性方面的演化机理,分析了电磁、应力、损耗等参量在偏磁过程中的耦合作用;直流偏置系数为1.0时达到转折点,铁心接近饱和点,此时直流偏置系数继续增加,主磁感应强度的增加速度减慢,铁心损耗急剧增加,而漏磁通继续快速增加,加剧了绕组损耗,直流偏磁下振动加速度的时域振幅最大可增加10%;当直流含量达到1.0和1.5时,高压换流变压器的主频分别右移至250 Hz和350 Hz。(4)考虑谐波激励共振特性,设计开展了不同铁心、绕组、油箱结构、内部组件定位方式对高压换流变压器振动分布特性的影响研究,量化对比了它们在不同运行工况下的振动噪声特性,得出了最佳降噪组件拓扑结构为:9 mm六步进-135叠片铁心、内屏纠结式绕组、“十字”加强筋油箱、无垫脚绝缘及偏心圆定位结构组合;其中,9mm六步进-135叠片铁心结构下的振动幅值相较于25 mm二步进叠片结构可降低6.52%;内屏纠结式绕组结构下的振动加速度幅值相较于纠结式绕组降低了 17.1%;不同定位结构对换流变压器振动特性改善效果排序为:上偏心圆定位-下浇注定位>上下浇注定位≈上偏心圆定位-下无定位>上梁定位-下无定位。(5)基于高压换流变压器多场耦合模型,对比分析了不同工况及谐波成分下高压换流变压器的声场分布形态,工频激励下高压换流变压器的声场分布呈现偶极分布形态,而多频工况下的声场分布形态表现为多极分布形态。通过对基频叠加不同数量和频次谐波下的声场分布仿真和实验分析,证明了偶极与多极声场分布之间存在边界效应,确定了声场分布类型改变的决定性谐波频次为5、7、11、13、27及29之间的两两以上组合。工频与两种频次谐波叠加下的声压最大差别可达0.01 Pa,将一类多极最小单元转变为偶极声源,噪声最大可降低5 dB。更多还原

【Abstract】 This dissertation systematically studies the vibration and noise characteristics and mechanisms of high voltage converter transformers from the aspects of component structure mode,excitation combination form,and sound field distribution form,providing theoretical reference for vibration and noise suppression methods of high voltage converter transformers.(1)A vibration and noise measurement platform suitable for high-voltage converter transformers has been built,and the vibration characteristics of various models of high-voltage converter transformers under different working conditions have been tested.A vibration sensor measurement point layout scheme has been proposed.Based on the operation and structural parameters of the operating high-voltage converter transformer(model ZZDFPZ-415000/500-800),a multi field coupling simulation model of the high-voltage converter transformer’s electric magnetic force(sound)was designed and constructed.The accuracy of the simulation model was verified by comparing the measured vibration parameters of two different models of high-voltage converter transformers in operation.(2)Two vibration scaling methods for high-voltage converter transformers based on similarity principle and attention mechanism using Convolutional Neural Network Based on Attention Mechanism(CNN-AM)were proposed.A series of scaled down prototypes suitable for experimental research were prepared based on the CNN-AM vibration scaling scheme,equipped with three types of replaceable iron cores with different structures,four types of windings with different structures,two types of oil tanks with different structures,two types of insulation pads with different structures,and four types of positioning components with different structures,providing an experimental platform for the study of vibration noise mechanism of high-voltage converter transformers.(3)We studied the vibration characteristics of high-voltage converter transformers during direct current(DC)demagnetization process,elucidated the evolution mechanism of internal components of high-voltage converter transformers in terms of electromagnetic field,loss,and vibration characteristics under different DC contents,and analyzed the coupling effects of parameters such as electromagnetic,stress,and loss in the demagnetization process;When the DC bias coefficient is 1.0,it reaches a turning point and the iron core approaches saturation.At this point,the DC bias coefficient continues to increase,and the rate of increase in the main magnetic induction intensity slows down.The iron core loss increases sharply,while the leakage flux continues to increase rapidly,exacerbating winding losses.The time-domain amplitude of vibration acceleration under DC bias can increase by up to 10%;When the DC content reaches 1.0 and 1.5,the main frequency of the high-voltage converter transformer shifts to 250 Hz and 350 Hz respectively.(4)Considering the resonance characteristics of harmonic excitation,a study was conducted on the influence of different iron core,winding,oil tank structures,and internal component positioning methods on the vibration distribution characteristics of high-voltage converter transformers.The vibration and noise characteristics of these components were quantitatively compared under different operating conditions,and the optimal noise reduction component topology was obtained as follows:a 9mm six step-135 laminated iron core,an inner screen tangled winding,a "cross" reinforced rib oil tank,a combination of footless insulation,and an eccentric circular positioning structure;Among them,the vibration amplitude under the 9mm six step-135 laminated iron core structure can be reduced by 6.52%compared to the 25mm two-step laminated structure;The vibration acceleration amplitude under the internal screen tangled winding structure is reduced by 17.1%compared to the tangled winding structure;The order of the improvement effect of different positioning structures on the vibration characteristics of converter transformers is:upper eccentric circle positioning lower pouring positioning>upper and lower pouring positioning≈upper eccentric circle positioning lower no positioning>upper beam positioning lower no positioning.(5)Based on the multi field coupling model of high-voltage converter transformers,the sound field distribution of high-voltage converter transformers under different operating conditions and harmonic components was compared and analyzed.The sound field distribution of high-voltage converter transformers under power frequency excitation showed a dipole distribution,while the sound field distribution under multi frequency operating conditions showed a multipole distribution.Through simulation and experimental analysis of the sound field distribution under the superposition of different numbers and frequencies of harmonics at the fundamental frequency,it was proved that there is a boundary effect between the dipole and multipole sound field distributions.The decisive harmonic frequencies for changing the sound field distribution type were determined to be pairwise or more combinations between 5,7,11,13,27,and 29.The maximum difference in sound pressure under the superposition of power frequency and two types of frequency harmonics can reach 0.01 Pa.By converting a type of multipole minimum unit into a dipole sound source,the maximum noise reduction can be 5 dB.更多还原