One of the main noise-generated equipments in the UHVDC（ultra high voltage direct current）converter station is valve outside cooling equipment. To obtain the noise characteristics of the equipment

this paper systematically measured and analyzed the audible noise of four water cooling towers outside valve in an UHVDC converter station using sound level meter and PULSE audio analyzer. The sound pressure level and noise spectrum of the cooling towers are obtained. According to the test and analysis results the following conclusions can be drawn: the sound pressure level with A weighting of measuring points distributed about 75 d B to 85 d B

the sound pressure level distribution of different cooling tower groups are very similar and the side where the fan installed is significantly greater than the other ones. The audible noise is a broadband noise which frequency component is rich. The maximum amplitude of the sound pressure appear at a frequency from 20 Hz to 50 Hz in noise frequency narrowband spectrum with Z-weighted and the maximum amplitude in 1/3 octave spectrum with A-weighted is reached at the frequency band with a center frequency of 1 600 Hz. The paper provides basis and guidance for converter station noise control technology.