Power capacitor is one of main noise radiation sources in HVDC converter station and it is necessary to study test principle of audible noise of power capacitor

test condition and method etc.It is shown by the study that when test on the sound power of power capacitor unit through sound pressure method and for eliminating the un-free field error caused by the sound reflection of the testing environment

the correction value K of the indoor test environment shall be smaller or equal to 2 dB and background noise be lower than the noise of measured capacitor unit by 10 dB;In order to reduce the near-field error caused by model assumption

the distance from measured point to surface of the capacitor unit shall be over 1 m;In case of even distribution of measuring point on the measurement surface

average sound pressure level shall be calculated by the point average method and

in case of uneven

by area average method.