换流站交流滤波电容器振动与噪声辐射模型及其降噪措施研究

The AC filter capacitor installation is one of main noise sources in HVDC converter station. It has important significance to establish its vibration and noise radiation models and develop the research on its noise level prediction and noise control technology. In this project, the characteristics of electric stress applied on the capacitor element package and mechanical characteristics of each component in the capacitor will be studied, and then the vibration model of whole capacitor can be set up based on the generation model and propagation model of capacitor vibration. Furthermore, the surface vibration response when the impulse current flows through the capacitor, the variety of noise radiation ratio and its influence factors will also be explored. Therefore, the measurement method of vibration frequency response function based on electro-excitation can be presented, and the noise radiation model of capacitor will be founded.And then, the fundamental theory for the filter capacitor from vibration generation, propagation to noise radiation and the noise prediction method will be totally obtained. According to above research, the influence factors and laws of noise of single capacitor and capacitor installation will be further analyzed. Moreover, combined with the research results of vibration model and noise radiation model of capacitor, the efficient & effective noise reduction measures can be conclude and presented. The study results not only can enrich the fundamental theory of noise generation and radiation of AC filter capacitor in HVDC converter station, but also have important engineering application value for noise pollution treatment of our country's EHVDC and UHVDC converter station.

交流滤波电容器是高压直流换流站中噪声的主要来源之一，建立其振动及噪声辐射模型，并进行噪声水平估算及噪声控制技术的研究具有重要意义。本项目通过研究作用于电容器芯子上的电应力特征以及电容器各组件的机械特性，在分别得到电容器振动产生模型以及传递模型的基础上，建立起电容器整体的振动模型；进而探索电容器流过冲击电流时的外壳振动响应以及电容器噪声辐射比的变化及影响因素，从而提出基于电激励的振动频响函数获取方法，并建立起电容器噪声辐射模型，据此全面掌握滤波电容器从振动产生、传递到辐射出噪声的基础理论及噪声估算方法。在上述工作的基础上，深入分析单台电容器及电容器装置噪声的影响因素及影响规律，结合电容器振动模型、噪声辐射模型的研究结果，总结归纳出切实有效且可行的降噪措施。研究结果不仅可以丰富换流站中交流滤波电容器噪声产生及辐射的基础理论，而且对我国超特高压直流换流站噪声污染的治理具有重要的工程应用价值。

交流滤波电容器是高压直流换流站中噪声的主要来源之一，建立其振动及噪声辐射模型，并进行噪声水平估算及噪声控制技术的研究具有重要意义。本项目通过研究比较了作用于电容器心子上的电场力与磁场力，确定了电容器极板间电场力作用是其振动和噪声的直接激励源。通过激光测振仪测量了电容器外壳表面振动，并描绘出其振动形态。结果表明，滤波电容器的底面为整体振动形式，而侧面为弯曲波动形式的振动。由此可以确定出电容器的振动传递过程为，心子振动直接传递到电容器底面，底面振动通过弯矩作用导致侧面的振动。基于电激励的振动频响函数获取方法，并建立起电容器噪声辐射模型，据此可以预估出滤波电容器的噪声水平。在上述工作的基础上，深入分析单台电容器及电容器装置噪声的影响因素及影响规律，结合电容器振动模型、噪声辐射模型的研究结果，将新型泡沫铝材料应用于电容器降噪，降噪效果可达8dB。通过改变电容器装置布置形式，也可以实现电容器装置声场的优化。将三相电容器装置在横向错开一定距离布置，能取得优于水平排列的辐射声场。研究结果不仅丰富了换流站中交流滤波电容器噪声产生及辐射的基础理论，而且对我国超特高压直流换流站噪声污染的治理具有重要的工程应用价值。