换流站滤波电容器可听噪声的测试与特性研究

Test and Characteristic Study on Audible Noise of Filter Capacitor at Converter Station

滤波电容器是直流换流站中主要噪声源之一,从复杂的换流站相干声场中分离识别出滤波电容器正常工作时噪声的量值及其频率成分,对于电容器单元噪声测试的模拟加载和换流站滤波场噪声预测与控制具有十分重要的意义。研究表明,采用声—振相干分离法可以排除其他噪声源对电容器噪声成分的干扰,从而分离出电容器的现场工作噪声;测试和分离的结果显示,某换流站现电容器的噪声具有明显的指向性,距电容器单元套管侧面1 m处的噪声声压级约为55.6 dB(A);电容器的工作噪声主要分布在100 Hz到2 400 Hz频率范围内,且都是以100 Hz为基频的高次谐波成分,在600 Hz左右的高次谐波噪声成份较大。研究还发现,当多个频率的电流同时注入电容器时,电容器辐射噪声会突然增大,即呈现出"多频噪声跳变"现象。

Filter capacitor is one of the main noise sources at DC converter substation. To separate and identify noise magnitude and its frequency component from coherent acoustic field of complicated converter station at normal operation of filter capacitor is of great importance to the simulation and loading of noise testing of capacitor unit and noise prediction and control of filter field of converter station. It is shown by that the study that adoption of noise-vibration coherent separation method can eliminate the interference of other noise resources on the noise component of capacitor, thus separate site opera- tion noise from capacitor. It is shown by the tested and separated result that the noise generated by capacitor from site of certain converter station has clear directivity and the noise level 1 meter away from the side of bush of capacitor unit is 55.6dB （A）. Operation noise of capacitor is distributed mainly within the frequency range from 100Hz to 2400 Hz, and is the high harmonic component with 100 Hz as the fundamental frequency and the high harmonic noise is bigger around 600 Hz. It is also found by the study that when current of multiple frequency is input into capacitor, the radiation noise increases suddenly, thus occurring so-called multifrequency noise jump phenomena.