Power capacitor is one of the noise at high voltage DC converter station

which

if not being controlled effectively

will cause danger to the social environment.Therefore

the experimental measurement of capacitor radiation ratio can be studied by directly calculating the capacitor noise through the radiation ratio

to provide evidence of noise estimation of the capacitor.In the laboratory

the normal measurement method of radiation ratio is surface vibration velocity method.In this paper

the system testing noise radiation ratio of the capacitor is established firstly at a semi-anechoic room.Then

the exponent curve of noise radiation of capacitor is

under excitation of sine scan frequency

measured by surface vibration velocity and frequency response function（FRF） respectively.And

under sine excitation of several single frequencies

the surface noise value of capacitor is calculated according to the noise radiation exponent curve of different surfaces in the measured capacitor

the calculated noise value and actually measued one are compared and the correctness of FRF methods is verified.