滤波电容器心子中介质薄膜表面残余电荷对其振动影响的分析

高压直流输电换流站滤波电容器噪声问题日益凸显，亟须深入探索其内部振动规律，为提出更有效的减振降噪措施奠定基础。本文为了研究电容器心子内部介质薄膜表面残余电荷密度的大小，及其对电容器心子振动带来的影响，以静电探头和电荷反演为手段实测了电容器心子内部介质薄膜表面残余电荷量，计算分析了电荷随机分布下极板受力的概率统计规律。然后通过电场-机械力-振动耦合仿真了电容器心子表面振动加速度，并与实验结果对比验证了仿真结果的有效性。研究发现：电容器心子内部介质薄膜表面残余电荷密度主要分布在?10^?4~10^?4C/m²，当施加单频激励时，电容器心子受力以及振动频谱不仅包含了传统分析中认为存在的二倍频成分，也存在由残余电荷引起的与外施激励同频的分量，该分量加剧了电容器内部极板受力的不平衡。

Analysis About the Effect of Dielectric Film Surface Residual Charge on Vibration of Filter Capacitor Core

The noise of filter power capacitor in high voltage direct current (HVDC) converters is becoming increasingly prominent. Thus, the vibration mechanism of capacitor should be further investigated to provide theoretical reference for noise reduction measures. In this regard, two main goals are to study the residual charge density on the surface of dielectric film inside the capacitor and its effect on the vibration of the capacitor core. Therefore, the residual charge density is measured by means of electrostatic probe and charge inversion, and the probability statistical law of the electric force of electrode plate with the residual charge distributing randomly is calculated and analyzed. Finally, the vibration acceleration of capacitor is obtained through Electric Field-Mechanical Force-Vibration coupling simulation and the results are validated by experiment. The results indicate that the residual charge density of films mainly distributes between ?10^?4 and 10^?4C/m². When a single-frequency excitation is applied, the force and vibration spectrum contains not only the double-frequency component but also the base-frequency component, which aggravates the imbalance of force on internal electrode plate.