Research On Transformer Noise Dual-channel Active Noise Reduction System

Because the magnetostrictive phenomenon of the power transformer radiates high-decibel noise to the outside,the noise is mainly dominated by low frequencies,and the noise penetrating ability is strong and the propagation distance is far away.The low-frequency noise can reach directly to the bones of the ears,stimulating the nerves of human beings easily,resulting in rapid heartbeat and blood pressure.The increase in symptoms,more serious than mid-and high-frequency noise damage,seriously affect the work and life of the station staff and nearby residents,so the transformer noise reduction is of great significance.This article relies on the major scientific and technological projects of the State Grid Corporation of China(study on noise characteristics and noise reduction technology of transformers under various measurement methods),aiming at the active noise reduction of power transformers.Through the actual measurement of transformer noise,the noise components are analyzed by frequency spectrum.An active noise reduction model with three dipole sound sources is established,and the three-dipole sound field cancellation characteristics are studied.Find out the optimal angle of the secondary sound source in the model to optimize the placement of the secondary sound source.At the same time,in order to improve the stability of the system,an adaptive filter algorithm is used to study the effect of different filter parameters on the noise reduction effect.The feasibility analysis of active noise reduction of power transformer noise was simulated.Finally,a DSP dual-channel active noise reduction system based on LMS algorithm was built.The experimental results show that when the two-stage sound source ? is located in the model at an angle of 180°,The noise is best,which can reach 10-14 dB.At the same time,compared with the single-channel noise reduction system,the noise reduction effect is better than the single-channel active noise reduction system.On the basis of confirming the effectiveness of the dual-channel active noise reduction system,the phononic crystal material is attempted to be added,and the active noise reduction technology is combined with the passive noise reduction technology to achieve a better noise reduction effect.