虚拟声屏障在变压器低频降噪中的实验研究

Experimental study of applying a virtual sound barrier to reduce low-frequency noise of transformers

在开口处布放若干扬声器和误差传声器构成虚拟声屏障,可有效抑制室内变压器通过开口向外辐射的低频噪声。本文采用内部合成参考信号的自适应算法,搭建了15通道全耦合虚拟声屏障系统。实验室实验表明在1.6 m×3.2 m的开口处搭建系统,距虚拟声屏障10 m范围内100 Hz和200 Hz的降噪量分别为16.6 d B和7.7 d B。变电站现场测试表明,在2.0 m×2.7 m的开口处搭建系统,100 Hz、200 Hz和300 Hz的误差点平均降噪量分别为12.7 d B、19.9 d B和22.2 d B,在开口辐射声压贡献较大的范围内,虚拟声屏障的降噪效果与单层封闭窗户相当。相比于传统被动降噪措施,采用虚拟声屏障有助于室内的自然通风、采光和变压器的散热。

Implementing a virtual sound barrier composed of loudspeakers and error microphones at the opening of a building works as an effective way to reduce the low-frequency transformer noise radiated outside. A 15-channel fully-coupled virtual sound barrier system is implemented which applies the algorithm with an internally synthesized reference signal. The experiments in the laboratory show that such a virtual sound barrier at the opening of 1.6 m × 3.2 m achieved a noise reduction of 16.6 dB and 7.7 dB for tonal noise of 100 Hz and 200 Hz, respectively, within the area 10 m away from the virtual sound barrier. Measurements in a substation show that the average noise reduction at error points is 12.7 dB for 100 Hz, 19.9 dB for 200 Hz and 22.2 dB for 300 Hz when the system is implemented at a 2.0 m × 2.7 m opening, and the performance of the virtual sound barrier and the windows are almost the same within the area where sound radiated from the opening dominates the sound field. Compared with traditional passive noise control methods, the advantage of applying such a virtual sound barrier system is that it helps the ventilation and lighting of the building as well as the heat dissipation of the transformers.