电力变压器在受到极端短路电流冲击、接地系统故障等因素影响时，不仅机械性能及内部绝缘等级下降，还会发生铁芯松动，产生振动和噪声，严重影响电网设备的稳定运行。电力变压器减振降噪是设备开发的一个重要方向。随着电网基建设备运行的年限增加，早期投入使用的电力变压器存在不同程度的振动噪声问题，对于已投入运行的设备，如何在不改变原有基本结构的情况下实现减振降噪，是目前研究的热点和难点之一。本文研究的SSZ11-63000(110kV)级电力变压器，在为期2年的运行期间内，受到接地故障等影响，导致其运行噪声超标。本文采用理论分析、模拟仿真、噪声试验、工程降噪等方式，在不改变原有基本结构的基础上，成功实现国内首台SSZ11-63000(110kV)级电力变压器的减振降噪，具有较高的行业推广价值。本文首先以振动理论为基础，分析并验证了铁芯硅钢片磁致伸缩产生的位移形变远大于纯电磁力产生的效果，从而确定了铁芯硅钢片的磁致伸缩效应是诱发变压器振动噪声主要贡献源。第二，建立了铁芯结构的电磁场-结构场耦合分析模型，利用有限元分析软件ANSYS建模计算出铁芯模型的表面振动位移和法向振动加速度；在此基础上，结合声学分析软件SYSNOISE，实现了对硅钢片及铁芯结构振动的噪声分析，通过仿真模拟计算了铁芯振动过程中任意点的声压及噪声集中分布区域，从而建立起铁芯振动源与噪声声场之间的对应关系，并以此为依据设计和搭建噪声试验平台。第三，针对变压器振动噪声的主要成因，建立金属橡胶的悬臂梁模型、铁芯叠片的多自由度弹簧系统模型，分析了系统的阻尼特性，提出了基于弹性单元的综合阻尼减振降噪技术。构思并验证了硅钢片叠片增设丁腈橡胶夹层、铁芯与油箱底部定位销增加减振金属橡胶及加强筋灌沙在内的综合减振降噪方案。噪声测试试验验证了减振措施的正确性与可行性，成功实现SSZ11-63000(110kV)级电力变压器的减振降噪目标，并满足行业Q/GDW 13007.11-2018标准噪声声压级低于60dB(A)的要求。
Power transformers under the impact of extreme short-circuit current, grounding system failure and other factors, not only the mechanical performance and internal insulation grade decline, but also the loosening of iron core, vibration and noise, seriously affect the stable operation of power grid equipment. Vibration and noise reduction of power transformer is an important direction of equipment development. For the transformer that has been put into operation, how to achieve vibration and noise reduction without changing the original basic structure is one of the hot spots and difficulties in current research. The SSZ11-63000(110kV) class power transformer studied in this paper is affected by grounding fault during the 2-year operation period, resulting in its operating noise exceeds the standard. In this paper, the first ssZ11-63000 (110kV) power transformer in China has been successfully achieved by means of theoretical analysis, simulation, noise test and engineering noise reduction without changing the original basic structure.Based on the vibration theory, this paper first analyzes and verifies that the displacement deformation caused by magnetostriction of ferro-core silicon steel sheet is much larger than that caused by pure electromagnetic force, thus confirming that the magnetostriction effect of ferro-core silicon steel sheet is the main contribution source of induced transformer vibration noise. Secondly, the electromagnetic field and structure field coupling analysis model of the iron core structure was established, and the surface vibration displacement and normal vibration acceleration of the iron core model were calculated by using the finite element analysis software ANSYS. On this basis, combining with the acoustic software SYSNOISE, implements of silicon steel sheet and core structure vibration noise analysis, through the simulation calculation of the arbitrary point in the process of iron core vibration sound pressure and noise on regional distribution, so as to establish the core corresponding relations between the vibration source and noise sound field, and on this basis to design and build the noise test platform. Third, aiming at the main cause of transformer vibration and noise, the metal rubber cantilever beam model and the multi-degree-of freedom spring system model of iron core laminates are established, the damping characteristics of the system are analyzed, and the integrated damping and noise reduction technology based on elastic element is proposed. The comprehensive vibration and noise reduction scheme including silicon steel sheet laminated NBR interlayer, metal rubber locating pin at the bottom of iron core and fuel tank, reinforcing bar sand filling was conceived and verified. The noise test proves that the effect of the vibration reduction measures is significant, and the ssZ11-63000 (110kV) power transformer is successfully achieved, and the noise sound pressure level is lower than 60dB(A), which meets the industry standard Q/GDW 13007.11-2018.
