Applying an active noise barrier on a 110 KV power transformer in Hunan

There are increasing needs to reduce the transformer noise recently in China because some residential buildings developed recently are located more and more close to the pre-existing substations. Passive barriers are often used around the outdoor transformers to block the noise. However, the noise reduction performance of the barriers is poor in low frequency range, especially when the noise wavelength is larger than the height of the barrier. Consequently, active noise control (ANC) system has been investigated to enhance the insertion loss of traditional barrier in low frequency. In this paper, a prototype active noise barrier (ANB) was developed and applied to a practical case. Physical system of the ANB was designed in first. Then a decentralized feedforward ANC system composed of the cascaded active units was developed, and the waterproof structures were developed to protect the elements of the system. Again, experiments were carried out on the rooftop of a five-floor building to verify the effectiveness of the system. Finally, the practical application in Hunan is investigated, in which the noise reduction of the 110kV power transformers was needed.