The audible noise of the filter capacitors is one of the main noise sources in the convertorstation.For reducing the noise level of the capacitor further

in this paper

a kind of noise reduction structure of perforated plate which is mounted at the bottom of the capacitor is proposed on the basis of analysis of the noise frequency feature of the capacitor.The resonance frequency of the perforated plate is controlled by way of adjusting acoustic impedance of the perforated plate with purpose of eliminating the noise of certain section of frequency. It is proved by the experiment that in case of particularly high ultra-harmonic current at certain frequency loaded by capacitor

the result of suppressing the noise generated by the excitation to be suppressed by the perforated plate is remarkable.The best result is the noise level at bottom can be reduced by14 dB and the average noise level of the capacitor can be reduced by 5 dB.