Electronic circuits for active control of acoustic noise generated by high voltage transformers

High voltage transformers in power distribution substations generate a mostly periodic acoustic noise with its fundamental component of nearly twice the system frequency. Conventional passive measures such as placing sound barriers or absorbers can be very expensive if used in the reduction of this noise. The low frequency and periodic nature of the transformer noise implies that it may be controlled by active means. This paper presents a design and implementation of electronic circuits for active control of acoustic noise. Experimental results show that there is a significant reduction (about 20 dB) in acoustic noise due to this proposed active noise control (ANC) system.