In this paper

the influence of different filtering branch filtering current on capacitor noise is analyzed by way of summarizing and analyzing the characteristic harmonic current parameters of typical filter branches of AC capacitors in HVDC projects in recent years.Through the analysis of the proportion of harmonic currents in the frequency bands of 100～500 Hz

550～1 200 Hz and 1 250～2 500 Hz of each typical branch

it is found that the proportion of harmonic currents in the medium high frequency band of550～1 200 Hz

1 250～2 500 Hz and the number of accumulated harmonic currents are the main factors affecting the noise of capacitors.In the premise of the same harmonic current

the higher the capacitance of the capacitor unit

the lower the noise level.The theoretical analysis is fully confirmed by the actual measurement of noise of tested sample.This conclusion is of great significance for noise assessment of branch capacitors in the bidding stage and the early stage of product development.At the same time

different noise reduction measures can be adopted for different frequency bands of harmonic current to achieve the best noise reduction effect and reasonable economic benefits.