Active Noise Control for Ventilation Soundproof Doors of Substations

With an increasing number of substations located in urban areas, noise pollution has become more and more serious. The soundproof doors, with slits or louvers for ventilation, are used to block the transformer noise in lots of substations. However, the noise reduction performance of the soundproof doors deteriorates with these ventilation and sound transmission path, especially for transformer noise which is characterized by low-frequency components. Active noise control (ANC) system is investigated to enhance sound insulation of the soundproof doors in this paper, and a natural ventilation soundproof door with the combination of active and passive noise control is proposed. The performance of the system with different system configurations is analyzed. Experiment results show that the noise reduction are of 12.4 dB, 19.4 dB, 13.8 dB at discrete frequency of 200 Hz, 300 Hz, 400 Hz, respectively, and of 13.8 dB with multiple frequencies noise.