In high voltage and large capacity DC transmission system

the AC filter capacitor device becomes one of the main sources of audible noise in convertor stations. A set of capacitor shell vibration measurement test system based on laser Doppler vibrometer is set up. The vibration forms of the capacitor shell under the single-frequency and multi-frequency are measured.Then

the vibration and noise characteristics of AC filter capacitor is studied. Abtained the acoustic radiation efficiency at different frequencies and acoustic contribution of each surface. Noise control measures of capacitor device are studied at last. According to the coherence of acoustic source of capacitor

phased array technology the acoustic field focusing distance and capacitor spacing requirements

the formula for the longitudinal layout of the capacitor is presented. Based on the experimental data

different arrangement manner of capacitor device noise simulation model is established and sound levels are calculated using the boundary element method（BEM）. The results show that: the capacitor bottom surface vibration energy is much larger than the side

and the wide side vibration amplitude is slightly larger than the narrow side. Phased array arrangement could reduce the audible noise level of the whole device in a specific area.