Virtual sound barrier for indoor transformers

Power transformers sometimes locate in an enclosed room with an opening surface for the ventilation purpose. Under these situations, most noise radiates out from the opening, so a virtual sound barrier can be built to suppress the sound radiation outside by employing a multiple-channel active noise control system. Based on the sound radiation model of indoor monopoles, the noise reduction performances of both centralized and decentralized control systems are investigated and compared. Considering the channel number requirement, a virtual sound barrier is built for an actual indoor transformer, where both the centralized and the decentralized strategies are investigated. Simulation results show that the fully independent virtual sound barrier is effective for the indoor transformer noise control