Different from large transformers,small and medium-sized transformers are devices that use electromagnetic induction to change AC voltage,which will produce various noises in operation.In order to determine the noise location, a high-speed synchronous noise location technology for small and medium-sized transformers considering noise radiation characteristics is proposed.Under the radiation condition,the Green's function of transformer noise is calculated,and the radiated sound pressure of transformer noise is calculated by establishing the integral equation of transformer noise boundary.The propagation process of transformer noise radiation in air is described by using hydrodynamic equation. According to the finite element equation of coupling between air and transformer noise,the process equation of transformer noise propagation is established and the propagation mechanism of transformer noise is analyzed.Through the decomposition of noise signal,the finite element function of noise signal in transformer is obtained by finite element analysis.According to the frequency domain component of noise signal,the fourth-order spectral cumulant of noise signal is calculated,and the noise of transformer is located by combining the spectral degree of noise signal.The experimental results show that the technology in this paper can locate the noise in the transformer and improve the positioning accuracy to more than 90%.