Dry-type transformer vibration sound calculation method, system, equipment and medium

Abstract

The invention belongs to the technical field of transformer iron core vibration noise modeling calculation, and discloses a dry-type transformer vibration noise calculation method, system and device and a medium, and the method comprises the steps: obtaining the normal vibration speed time domain signals of a winding, a clamp and an iron core, and correcting the phase; determining a radiation sound pressure superposition formula taking conformal unit vibration as a model; a vibration-sound coupling frequency domain calculation model based on frequency decomposition is constructed by considering the difference of mechanical wave propagation characteristics under different frequencies; and establishing a mirror image source model considering the sound wave refraction and reflection effect, and superposing the indirect radiation sound pressure and the direct radiation sound pressure to obtain a total sound pressure value. According to the method, the difference of mechanical vibration propagation characteristics under different frequencies and the refraction and reflection effect of sound waves in the environment are introduced, the sound propagation process of the dry-type transformer is modeled, and the improved unit radiation superposition method is applied to vibration-sound coupling frequency domain modeling of the dry-type power transformer. And efficient and accurate calculation of the sound propagation process of the dry-type power transformer is realized.

Description

Technical Field

[0001] The present application relates to the technical field of transformer core vibration noise modeling and calculation, and in particular to a dry-type transformer vibration and noise calculation method, system, equipment and medium. Background Art

[0002] Dry-type transformers are power transformers whose cores and windings are not immersed in insulating oil and instead utilize natural or air cooling. As a relatively new type of power distribution equipment, they are widely used in power transmission and transformation systems in factories, high-rise buildings, commercial centers, airports, docks, subways, oil platforms, and other locations. Together with switchgear, they form compact substations. The mechanical vibrations generated by dry-type transformers during operation inevitably cause noise problems, which not only pollute the surrounding environment but also significantly impact the daily lives of nearby residents.

[0003] Currently, transformer vibration noise modeling and calculations mostly use finite element simulation methods, relying primarily on commercial boundary element software. While this method has some applicability for calculating near-field and far-field acoustics for a single transformer, its universality is significantly limited. Simulation models must be developed for different transformer types and models. Due to the complex modeling process and time-consuming computation, this method not only significantly increases the cost of vibration noise prediction but also fails to meet the practical needs of rapidly calculating transformer radiated noise. Summary of the Invention

[0004] In order to solve the above problems, the present application provides a dry-type transformer vibration and sound calculation method, system, device and medium to solve the problem of how to effectively improve the efficiency of dry-type transformer noise field modeling calculation.

[0005] According to the first technical solution of the present application, a method for calculating vibration and acoustics of a dry-type transformer is provided, the method comprising: Obtaining normal vibration velocity time domain signals of the winding, the clamp and the core, and correcting the phase of the normal vibration velocity time domain signals; Determine the superposition formula for the radiated sound pressure of rectangular elements used for the core and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal elements used for the windings; According to the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed; According to the calculation results of the vibration-acoustic coupling frequency domain calculation model, an image source model taking into account the sound wave refraction and reflection effect is established, and the indirect radiation sound pressure and the direct radiation sound pressure are superimposed to obtain the total sound pressure value.

[0006] Furthermore, the superposition formula of the radiated sound pressure of the rectangular unit is expressed as: ; Where, p rec is the total sound pressure radiated from the rectangular unit to the field point, j is an imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, i n For the n The elevation angle from the center of each radiation unit to the field point, For the n The azimuth from the center of each radiation unit to the field point, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium where the transformer is located, k is the sound wave number, N is the total number of divided radiation units, n is the index of the radiation unit, u n For the n Normal vibration velocity of a radiation unit, Δ w n and Δ h n are the length and width of the rectangular unit respectively, sinc is the Sinker function, and e is a natural constant.

[0007] Furthermore, the superposition formula of the radiated sound pressure of the cylindrical conformal unit is expressed as: ; Where, p cyl is the total sound pressure radiated from the cylindrical unit to the field point, R is the distance from the origin on the cylinder axis to the field point, i is the pitch angle from the origin on the cylinder axis to the field point, is the azimuth from the origin on the cylinder axis to the field point, j is the imaginary unit, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium where the transformer is located, k is the sound wave number, N is the total number of divided radiation units, n is the index of the radiation unit, u n For the n The normal vibration velocity of a radiation unit, α n and L n For then The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of the radiation unit to the origin, sinc is the Sinker function, and e is a natural constant Indicates the first category m The derivative of the Hankel function of order .

[0008] Furthermore, according to the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal, a frequency-decomposition-based vibration-acoustic coupling frequency-domain calculation model is constructed, including: Converting the total sound pressure calculated by the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula into a frequency domain form to obtain a vibration radiation sound pressure frequency domain vector; Based on the vibration radiation sound pressure frequency domain vector, the expression of the vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is determined as follows: ; Where, G k is the vibroacoustic transfer matrix, P k and U k They correspond to the frequency domain vector of the vibration radiation sound pressure of the unit and the frequency domain vector of the surface normal vibration velocity; P k and U k The expressions are: ; ; Where, P ki and U ki The sound pressure and velocity time domain signals are transformed by Fourier transform at the frequency f i The corresponding sound pressure and velocity spectrum coefficients are i =1,2,……, I, I is the total number of frequency points analyzed, and T is the matrix transpose.

[0009] Furthermore, the total sound pressure calculated by the superposition formula of the rectangular unit radiation sound pressure and the superposition formula of the cylindrical conformal unit radiation sound pressure is converted into a frequency domain form by the following formula: ; ; Where, p cf is the frequency domain form of the total sound pressure radiated from the cylindrical unit to the field point, p rf is the frequency domain form of the total sound pressure radiated from the rectangular unit to the field point, j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, i n For the n The elevation angle from the center of each radiation unit to the field point, For the n The azimuth from the center of each radiation unit to the field point, R is the distance from the origin on the cylinder axis to the field point, i is the pitch angle from the origin on the cylinder axis to the field point, is the azimuth from the origin on the cylinder axis to the field point, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k i Frequency f i The corresponding wave number, N is the total number of divided radiation units, u n，i For the n The corresponding frequency of the radiation unit f i The normal vibration velocity under α n and L n is the first n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, Δ w n and Δ h n For the infinite plane baffle n The length and width of the radiation unit, sinc is the Singer function, Indicates the first category m The derivative of the Hankel function of order , where e is a natural constant.

[0010] Furthermore, the main diagonal elements in the vibro-acoustic transfer matrix are expressed as: ; Where, a ii and b ii The vibro-acoustic transfer matrices of rectangular and cylindrical elements are G k No. i main diagonal elements, j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, i n For the n The elevation angle from the center of each radiation unit to the field point, For the n The azimuth from the center of each radiation unit to the field point, R is the distance from the origin on the cylinder axis to the field point, i is the pitch angle from the origin on the cylinder axis to the field point, is the azimuth from the origin on the cylinder axis to the field point, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium where the transformer is located, k i Frequency f i The corresponding wave number, N is the total number of divided radiation units, α n and L n is the first n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, Δ w n and Δ h n For the infinite plane baffle n The length and width of the radiation unit, sinc is the Singer function, Indicates the first category m The derivative of the Hankel function of order .

[0011] Furthermore, the calculation formula for superimposing the indirect radiation sound pressure and the direct radiation sound pressure to obtain the total sound pressure value is: ; Where, P sum is the frequency domain vector of the total sound pressure at the field point, P d is the frequency domain vector of the total sound pressure directly radiated by the field point, P i is the frequency domain vector of the total sound pressure indirectly radiated from the field point, N is the total number of divided radiation units, O is the total number of mirror sources, K is the total number of harmonics, q o,n,k 、G o,n,k and U o,n,k Respectively o Mirror sources n The unit corresponds to k Reflection coefficient, vibroacoustic transfer matrix and surface normal vibration velocity frequency domain vector under subharmonics.

[0012] According to the second technical solution of the present application, a dry-type transformer vibration and acoustic calculation system is provided, the system comprising: a velocity phase correction module configured to obtain normal vibration velocity time domain signals of the winding, the clamp and the core, and correct the phase of the normal vibration velocity time domain signals; a sound pressure superposition calculation module configured to determine a radiation sound pressure superposition formula for a rectangular unit for the core and the clamp and a radiation sound pressure superposition formula for a cylindrical conformal unit for the winding; A coupled frequency domain calculation module is configured to construct a frequency-decomposition-based vibration-acoustic coupling frequency domain calculation model based on the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal; The total sound pressure calculation module is configured to establish a mirror source model taking into account the sound wave refraction and reflection effect based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, and superimpose the indirect radiation sound pressure and the direct radiation sound pressure to obtain the total sound pressure value.

[0013] According to a third technical solution of the present application, an electronic device is provided, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the method described above.

[0014] According to a fourth technical solution of the present application, a non-transitory computer-readable storage medium storing instructions is provided. When the instructions are executed by a processor, the method described above is executed.

[0015] The dry-type transformer vibration and acoustic calculation method, system, device, and medium according to each solution of this application have at least the following technical effects: This application models the sound propagation process of dry-type transformers by introducing the differences in mechanical vibration propagation characteristics at different frequencies and the refraction and reflection effects of sound waves in the environment. At the same time, the improved unit radiation superposition method is applied to the vibration-acoustic coupling frequency domain modeling of dry-type power transformers, thereby achieving efficient and accurate calculation of the sound propagation process of dry-type power transformers, which can effectively improve the efficiency of sound field calculation and is applicable to a variety of different dry-type transformer models and environments.

[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a dry-type transformer vibration and acoustic calculation method provided in an embodiment of the present application; Figure 2 Schematic diagram of the principle of the dry-type transformer vibration measurement platform provided in the embodiment of the present application; Figure 3 A schematic diagram of the phase correction principle of the dry-type transformer vibration signal provided in an embodiment of the present application; Figure 4 A schematic diagram of a planar baffle and rectangular units on its surface provided in an embodiment of the present application; Figure 5 Schematic diagram of a cylindrical baffle and its surface conformal unit provided in an embodiment of the present application; Figure 6 Schematic diagram of the principle of noise catadioptric propagation in dry-type transformers provided in an embodiment of the present application; Figure 7 This is a structural diagram of a dry-type transformer vibration and acoustic calculation system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is described in detail below with reference to the accompanying drawings and specific implementation methods.

[0019] In one aspect of the present application, a method for calculating the vibration and acoustic properties of a dry-type transformer is provided. Figure 1 , is a flow chart of a dry-type transformer vibration and acoustic calculation method provided in an embodiment of the present application. The method includes the following steps S10 to S40.

[0020] S10: Obtain normal vibration velocity time domain signals of the winding, the clamp, and the core, and correct the phase of the normal vibration velocity time domain signals.

[0021] In this embodiment, according to the structural characteristics of the dry-type transformer, the time domain signals of the normal vibration velocity of the winding, the clamp and the core are collected and their phases are corrected.

[0022] In some embodiments, step S10 specifically includes: S11: Build a vibration test platform for dry-type power transformers to collect time domain signals of normal vibration velocity of the core, windings, and clamp surfaces; S12: Correct the phase of the measured vibration signal using a phase correction method commonly used in deformation mode measurement.

[0023] Specifically, the surface vibration of the dry-type transformer mainly comes from the exposed core and the external winding and clamp structure. Figure 2 The dry-type power transformer vibration test platform shown is used to measure the normal vibration signals of the dry-type transformer core, winding, and clamp surface under different external excitation power supplies. In order to more comprehensively obtain the vibration characteristics of each position, the measurement points are arranged as densely as possible.

[0024] When collecting transformer surface vibration signals, ideally, the normal vibration signals of all measuring points should be acquired synchronously. However, due to the limited number of sensors, it is difficult to achieve simultaneous measurement of all measuring points. To obtain synchronous vibration data at the equivalent vibration source, this paper uses the phase correction method commonly used in operating deformation shapes (ODS) measurement to process the normal vibration velocity signal, such as Figure 3 The specific approach is to select a certain measuring point as the reference signal and record the fixed phase difference between the remaining measuring points and the reference measuring point. After completing data acquisition at all measuring points, the phase of the reference measuring point is used as a reference to perform a unified phase correction on the signals of the other measuring points, thereby achieving phase consistency of the vibration signals of all measuring points.

[0025] S20: Determine the superposition formula of the radiation sound pressure of the rectangular unit used for the core and clamps and the superposition formula of the radiation sound pressure of the cylindrical conformal unit used for the winding.

[0026] In this embodiment, based on the improved unit radiation superposition method, the radiation sound pressure superposition formula based on the conformal unit vibration model can be derived, and the rectangular unit radiation sound pressure superposition formula for the iron core and the clamp and the cylindrical conformal unit radiation sound pressure superposition formula for the winding are obtained.

[0027] In some embodiments, the derivation process of the superposition formula of the radiation sound pressure of the rectangular unit used for the core and the clamp and the superposition formula of the radiation sound pressure of the cylindrical conformal unit used for the winding is as follows: Considering the ideal acoustic environment of a uniform, isotropic, and inviscid medium surrounding a dry-type transformer, and that the medium is sufficiently extended, boundary effects need not be considered. Under these assumptions, the wave equation satisfied by the sound pressure can be derived from the classical acoustic wave equation: (1); In the formula p Indicates sound pressure, c is the propagation speed of sound waves in the medium, t is time, ▽ is the gradient operator. Assuming that the dry-type transformer is usually in the air, its medium parameters are taken as the standard physical parameters of air, so r =1.29kg / m 3 , c =344m / s 2 .

[0028] The surface of the dry-type transformer can be regarded as a radiation surface composed of infinite pulsating spherical sound sources. For a single pulsating spherical source, its wave equation is expressed in the spherical coordinate system as follows: (2); In the formula p is the sound pressure at a point in the coordinate system, r is the length of the straight line from this point to the center of the sphere source, c is the propagation speed of sound waves in the medium, t is the time. Solving this equation gives the sound pressure p The expression is: (3); Where j is the imaginary unit, p is the sound pressure at a point in the coordinate system, r is the length of the straight line from this point to the center of the sphere source, k = oh / c =2π / l is the number of sound waves, l is the wavelength of the sound wave, c is the propagation speed of sound waves in the medium, oh is the angular frequency, t For time. A and B are the amplitudes of the forward and reverse waves related to the intensity of the sound source. Inward radiation is not considered, so the second term on the right side of the equation can be ignored.

[0029] Furthermore, according to the vibration characteristics of the outer surface of the pulsating spherical source, corresponding boundary conditions can be set. By combining the relationship between sound pressure and the vibration velocity of the medium particle, the radial vibration velocity of the spherical source surface can be derived as: (4); Where j is the imaginary unit, r 0 is the radius of the pulsating spherical source, ( u r ) r=r0 is the radial velocity of the spherical source surface, u a is the radial velocity amplitude of the outer surface of the pulsating spherical source, k is the number of sound waves, oh is the angular frequency, t For time, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, r is the distance from the field point to the center of the ball source, A is the amplitude of the forward wave. For a point sound source, it is usually satisfied kr 0<<1, that is, the size of the spherical source is much smaller than the wavelength of the sound wave, from which the radiation sound pressure of the pulsating spherical source can be obtained as: (5); In the formula p is the radiation sound pressure at the field point, j is an imaginary unit, r 0 is the radius of the pulsating spherical source, u a is the radial velocity amplitude of the outer surface of the pulsating spherical source, k is the number of sound waves, oh is the angular frequency, t For time, r is the distance from the field point to the center of the ball source, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, and the intensity of the point sound source is defined as Q 0=4π r 0 2 u a It represents the ability of a small pulsating ball to radiate sound waves in free space. If the small pulsating ball is embedded in an infinite baffle and can only radiate into half space, then Q 0=2π r 0 2 u a .

[0030] Assume there is a surface sound source of arbitrary shape, and the surface of the sound source is S Divide into infinite small areas dS , in each bin dS The vibration of each point can be approximated to be uniformly distributed, so each surface element can be regarded as an equivalent point sound source. Therefore, the sound pressure generated by the entire surface sound source at any external point can be expressed as the integral superposition of the contributions of all point sound sources, that is, (6); Where j is the imaginary unit, p is the radiation sound pressure at the field point, r is the distance from the field point to the center of the ball source, u 0 is the amplitude of the surface vibration velocity of the panel element, oh is the angular frequency, t For time, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, l is the wavelength of the sound wave, dS is the unit cell area.

[0031] For approximately planar structures such as cores and clamps, their surfaces can be divided into multiple rectangular units, such as Figure 3 As shown, the total sound pressure at a point in space p 0 can be expressed as the coherent superposition of the sound pressures generated by all radiating elements at this point: (7); Where j is the imaginary unit, p 0 is the total sound pressure at the field point, t For time, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k is the sound wave number, N is the total number of divided radiation units, u n For the n Normal vibration velocity of a radiation unit, Δ w n and Δ h n are the length and width of the rectangular unit respectively. The distance from the unit center to the field point is expressed in rectangular coordinates. r n for: (8); Where ( x 0, y 0, z 0) is the coordinate of the field point, ( x n , y n ) No. n The coordinates of the center point of each radiation unit.

[0032] Since the main frequency of the transformer surface vibration signal is relatively low, usually concentrated in the range of 50-1000 Hz, and the size of the divided rectangular unit is small, the distance from each point on the unit to the field point can be approximately equal to the distance from the center of the unit to the field point. Therefore, formula (7) can be further simplified to: (9); Where j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, i n is the corresponding pitch angle, is the corresponding azimuth, p rec is the total sound pressure radiated from the rectangular unit to the field point, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k is the sound wave number, N is the total number of divided radiation units, u n For the n Normal vibration velocity of a radiation unit, Δ w n and Δ h n are the length and width of the rectangular unit respectively, and the sinc function sinc( x )=sin( x ) / x .

[0033] Similarly, for a cylindrical shell structure sound source such as a dry-type transformer winding, several conformal units can be divided on its surface, such as Figure 4 As shown, for this type of structure, the far-field radiation sound pressure model of the conformal unit in the infinitely long cylindrical baffle can be used to calculate: (10); Where j is the imaginary unit, R is the distance from the origin on the cylinder axis to the field point, i is the corresponding pitch angle, is the corresponding azimuth, p cyl is the total sound pressure radiated from the cylindrical unit to the field point, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k is the sound wave number, N is the total number of divided radiation units, u n For the nThe normal vibration velocity of a radiation unit, α n and L n For the n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, the Sinker function sinc( x )=sin( x ) / x , Indicates the first category m The derivative of the Hankel function of order .

[0034] S30: Based on the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed.

[0035] In this embodiment, considering the differences in mechanical wave propagation characteristics at different frequencies, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed according to the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal.

[0036] In some embodiments, the derivation or construction process of the frequency domain computational model of the vibro-acoustic coupling based on frequency decomposition is as follows: In actual operation, the excitation source of dry-type transformers is usually 50Hz AC voltage. The resulting transformer surface vibration is mainly caused by electromagnetic force and magnetostrictive effect. The vibration signal is mainly composed of the fundamental frequency of the power frequency (100Hz) and higher harmonics. When the transformer encounters non-ideal working conditions such as DC bias or harmonic current during operation, the vibration spectrum will further expand and include more frequency components. According to the wave number calculation formula k =2π f / c It can be seen that mechanical vibration waves of different frequencies correspond to different wavelengths. Therefore, in the process of calculating sound pressure, it is necessary to consider the influence of frequency on wave propagation characteristics and model and analyze each frequency component separately. Equations (9) and (10) can be further expanded into frequency domain form to achieve accurate calculation of vibration sound radiation at different frequencies: (11); (12); In the formula p cfis the frequency domain form of the total sound pressure radiated from the cylindrical unit to the field point, p rf is the frequency domain form of the total sound pressure radiated from the rectangular unit to the field point, j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, i n is the corresponding pitch angle, is the corresponding azimuth, R is the distance from the origin on the cylinder axis to the field point, i is the corresponding pitch angle, is the corresponding azimuth, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k i Frequency f i The corresponding wave number, N is the total number of divided radiation units, u n For the n The normal vibration velocity of a radiation unit, α n and L n is the first n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, Δ w n and Δ h n For the infinite plane baffle n The length and width of the radiation unit, the Single function sinc( x )=sin( x ) / x , Indicates the first category m The derivative of the Hankel function of order .

[0037] In order to facilitate subsequent calculations and analysis, the vibration-acoustic transfer relationship of a single unit is modeled in the frequency domain. The frequency domain calculation formula can be expressed as: (13); In the formula G k is the vibroacoustic transfer matrix, Pk and U k They correspond to the frequency domain vector of the vibration radiation sound pressure of the unit and the frequency domain vector of the surface normal vibration velocity, respectively. Their specific expressions are: (14); (15); In the formula P k and U k They correspond to the frequency domain vector of the vibration radiation sound pressure of the unit and the frequency domain vector of the surface normal vibration velocity, P ki and U ki The sound pressure and velocity time domain signals are transformed by Fourier transform at the frequency f i The corresponding sound pressure and velocity spectrum coefficients are i =1,2,……, I, I is the total number of frequency points analyzed. Vibration-acoustic transfer matrix G k is a diagonal matrix. According to equations (11) and (12), the vibration-acoustic transfer matrix corresponding to the rectangular unit and the cylindrical unit can be derived: G k Main diagonal elements G ii They are (16); In the formula a ii and b ii The vibro-acoustic transfer matrices of rectangular and cylindrical elements are G k No. i main diagonal elements, j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, i n is the corresponding pitch angle, is the corresponding azimuth, R is the distance from the origin on the cylinder axis to the field point, i is the corresponding pitch angle, is the corresponding azimuth, r is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k i Frequency f iThe corresponding wave number, N is the total number of divided radiation units, α n and L n is the first n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, Δ w n and Δ h n For the infinite plane baffle n The length and width of the radiation unit, the Single function sinc( x )=sin( x ) / x , Indicates the first category m The derivative of the Hankel function of order .

[0038] S40: Based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, an image source model is established that takes into account the refraction and reflection effect of the sound wave, and the indirect radiation sound pressure and the direct radiation sound pressure are superimposed to obtain the total sound pressure value.

[0039] In some embodiments, based on the calculation results of the vibro-acoustic coupling frequency domain calculation model, an image source model is established that takes into account the sound wave refraction and reflection effect, and the indirect radiation sound pressure is superimposed with the direct radiation sound pressure to obtain the total sound pressure value. The derivation process is as follows: Dry-type transformers are generally installed in indoor environments. The vibration noise they generate will encounter obstacles such as the ground and walls during the propagation process, resulting in refraction and reflection effects. Figure 6 As shown in the figure, the reflected sound waves and the directly radiated sound waves are superimposed in space, which will further enhance the noise pressure in the local area. For plane sound waves, the reflection coefficient at the interface can be expressed as: (17); In the formula r is the reflection coefficient of the plane wave, Z 1 and Z 2 are the characteristic impedances of the incident medium and the transmitted medium, i i and i t is the interface incident angle and refraction angle, according to Snell's law, the two satisfy the relationship k 1sin i i =k 2sin i t , k 1 and k 2 are the wave numbers in the two media respectively.

[0040] For the propagation of spherical waves on a single reflection plane, the complex acoustic wave reflection coefficient can be approximated by the corresponding plane wave reflection coefficient: (18); In the formula r is the reflection coefficient of the plane wave, q is the reflection coefficient of the spherical wave, F bl is the boundary loss coefficient of the plane, defined as: (19); In the formula F bl is the boundary loss coefficient of the plane, R is the distance from the center of the mirror unit to the field point, is the proportional auxiliary error function, and g is defined as: (20); Where j is the imaginary unit, R is the distance from the center of the mirror unit to the field point, is the proportional auxiliary error function, Z 1 and Z 2 are the characteristic impedances of the incident medium and the transmitted medium, i i and i t are the interface incident and refraction angles, k is the wave number of the sound source.

[0041] As mentioned above, the total sound pressure generated by a surface sound source at any point on the surface can be considered as the integral superposition of the contributions of all point sound sources on its surface. Therefore, the sound radiation process exhibits the characteristics of spherical wave propagation. To more accurately simulate the propagation behavior of sound waves near the boundary, the mirror method is used to construct a coherent virtual source acoustic model. That is, the reflection effect is equivalent to the sound field response generated by the interaction of the mirror source and the actual sound source. The total sound field is regarded as the superposition result of the interaction of all mirror sources and the original source: (twenty one); In the formula P sum is the frequency domain vector of the total sound pressure at the field point, P d is the frequency domain vector of the total sound pressure directly radiated by the field point, P iis the frequency domain vector of the total sound pressure indirectly radiated from the field point, N is the total number of divided radiation units, O is the total number of mirror sources, K is the total number of harmonics, q o,n,k 、G o,n,k and U o,n,k Respectively o Mirror sources n The unit corresponds to k Reflection coefficient, vibroacoustic transfer matrix and surface normal vibration velocity frequency domain vector under subharmonics.

[0042] Furthermore, the frequency domain vector of the total sound pressure at the field point is P sum Performing inverse Fourier transform can obtain the time domain vector of the total sound pressure at the field point: p sum ,Then the time domain signal is processed by A-weighted filtering and converted into sound pressure level form to achieve objective evaluation and analysis of the dry-type transformer radiated noise.

[0043] It should be noted that the components used in the model proposed in this application are all built-in components in the simulation software, and are equivalent through the connection between conventional components. The model is simple and convenient to build, providing a basis for analyzing the vibration and noise propagation of transformers under different working conditions and different environments.

[0044] Another aspect of the present application embodiment further provides a dry-type transformer vibration and sound calculation system, such as Figure 7 FIG. 1 is a structural diagram of a dry-type transformer vibration and acoustic calculation system provided in an embodiment of the present application. The dry-type transformer vibration and acoustic calculation system includes: The velocity phase correction module 701 is configured to obtain the normal vibration velocity time domain signal of the winding, the clamp and the core, and correct the phase of the normal vibration velocity time domain signal; The sound pressure superposition calculation module 702 is configured to determine the sound pressure superposition formula of the rectangular unit radiation for the core and the clamp and the sound pressure superposition formula of the cylindrical conformal unit radiation for the winding; The coupled frequency domain calculation module 703 is configured to construct a frequency-decomposition-based vibration-acoustic coupling frequency domain calculation model based on the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal; The total sound pressure calculation module 704 is configured to establish an image source model taking into account the sound wave refraction and reflection effect based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, and superimpose the indirect radiation sound pressure and the direct radiation sound pressure to obtain the total sound pressure value.

[0045] It should be noted that the dry-type transformer vibration and sound calculation device provided in the above embodiment and the dry-type transformer vibration and sound calculation method provided in the above embodiment belong to the same concept, and the specific manner in which each module and unit performs operations has been described in detail in the method embodiment and will not be repeated here.

[0046] Another aspect of the embodiments of the present application further provides an electronic device, including: a controller; and a memory for storing one or more programs, which, when executed by the controller, execute the methods in the above-mentioned embodiments.

[0047] Another aspect of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned method. The computer-readable storage medium may be included in the electronic device described in the aforementioned embodiment, or may exist independently and not be incorporated into the electronic device.

[0048] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable computer program. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. A computer program embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0049] Another aspect of the present invention further provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the methods provided in each of the above embodiments.

[0050] According to one aspect of an embodiment of the present application, a computer system is further provided, including a central processing unit (CPU), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) or a program loaded from a storage portion into a random access memory (RAM), such as executing the method in the above embodiment. Various programs and data required for system operation are also stored in the RAM. The CPU, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0051] For example, a computer system includes a central processing unit (CPU), which can perform various appropriate actions and processes, such as executing the methods described in the above embodiments, based on programs stored in read-only memory (ROM) or programs loaded from a storage unit into random access memory (RAM). RAM also stores various programs and data required for system operation. The CPU, ROM, and RAM are connected to each other via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0052] The following components are connected to the I / O interface: an input section including a keyboard, mouse, etc.; an output section including a cathode ray tube (CRT), liquid crystal display (LCD), and speakers; a storage section including a hard disk; and a communication section including a network interface card such as a LAN (Local Area Network) card and a modem. The communication section performs communication processing via a network such as the Internet. A drive is also connected to the I / O interface as needed. Removable media such as magnetic disks, optical disks, magneto-optical disks, semiconductor memories, etc. are installed in the drive as needed so that computer programs read from them can be installed into the storage section as needed.

[0053] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication portion, and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), various functions defined in the system of the present application are executed.

[0054] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Among them, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0055] The module units involved in the embodiments described in this application can be implemented by software or hardware, and the units described can also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0056] The above implementation modes are only used to illustrate the present application and are not intended to limit the present application. Ordinary technicians in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions also fall within the scope of the present application, and the scope of patent protection of the present application shall be defined by the claims.

Claims

1. A method for calculating vibration and acoustics of a dry-type transformer, characterized in that: The method comprises: Obtaining normal vibration velocity time domain signals of the winding, the clamp and the core, and correcting the phase of the normal vibration velocity time domain signals; Determine the superposition formula for the radiated sound pressure of rectangular elements used for the core and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal elements used for the windings; According to the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed; According to the calculation results of the vibration-acoustic coupling frequency domain calculation model, an image source model taking into account the sound wave refraction and reflection effect is established, and the indirect radiation sound pressure and the direct radiation sound pressure are superimposed to obtain the total sound pressure value.

2. The method according to claim 1, characterized in that The superposition formula of the rectangular unit radiation sound pressure is expressed as: ； Where, p rec is the total sound pressure radiated from the rectangular unit to the field point, j is an imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, θ n For the n The elevation angle from the center of each radiation unit to the field point, For the n The azimuth from the center of each radiation unit to the field point, ρ is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium where the transformer is located, k is the sound wave number, N is the total number of divided radiation units, n is the index of the radiation unit, u n For the n Normal vibration velocity of a radiation unit, Δ w n and Δ h n are the length and width of the rectangular unit respectively, sinc is the Sinker function, and e is a natural constant.

3. The method according to claim 1, characterized in that The superposition formula of the radiated sound pressure of the cylindrical conformal unit is expressed as: ； Where, p cyl is the total sound pressure radiated from the cylindrical unit to the field point, R is the distance from the origin on the cylinder axis to the field point, θ is the pitch angle from the origin on the cylinder axis to the field point, is the azimuth from the origin on the cylinder axis to the field point, j is the imaginary unit, ρ is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium where the transformer is located, k is the sound wave number, N is the total number of divided radiation units, n is the index of the radiation unit, u n For the n The normal vibration velocity of a radiation unit, α n and L n For the n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of the radiation unit to the origin, sinc is the Sinker function, and e is a natural constant Indicates the first category m The derivative of the Hankel function of order .

4. The method according to any one of claims 1 to 3, characterized in that According to the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal, a frequency decomposition-based vibration-acoustic coupling frequency domain calculation model is constructed, including: Converting the total sound pressure calculated by the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula into a frequency domain form to obtain a vibration radiation sound pressure frequency domain vector; Based on the vibration radiation sound pressure frequency domain vector, the expression of the vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is determined as follows: ； Where, G k is the vibroacoustic transfer matrix, P k and U k They correspond to the frequency domain vector of the vibration radiation sound pressure of the unit and the frequency domain vector of the surface normal vibration velocity; P k and U k The expressions are: ； ； Where, P ki and U ki The sound pressure and velocity time domain signals are transformed by Fourier transform at the frequency f i The corresponding sound pressure and velocity spectrum coefficients are i =1,2,……, I, I is the total number of frequency points analyzed, and T is the matrix transpose.

5. The method according to claim 4, characterized in that The total sound pressure calculated by the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula is converted into a frequency domain form by the following formula: ； ； Where, p cf is the frequency domain form of the total sound pressure radiated from the cylindrical unit to the field point, p rf is the frequency domain form of the total sound pressure radiated from the rectangular unit to the field point, j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, θ n For the n The elevation angle from the center of each radiation unit to the field point, For the n The azimuth from the center of each radiation unit to the field point, R is the distance from the origin on the cylinder axis to the field point, θ is the pitch angle from the origin on the cylinder axis to the field point, is the azimuth from the origin on the cylinder axis to the field point, ρ is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium, k i Frequency f i The corresponding wave number, N is the total number of divided radiation units, u n,i For the n The corresponding frequency of the radiation unit f i The normal vibration velocity under α n and L n is the first n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, Δ w n and Δ h n is the infinite plane baffle n The length and width of the radiation unit, sinc is the Singer function, Indicates the first category m The derivative of the Hankel function of order , where e is a natural constant.

6. The method according to claim 4, characterized in that The main diagonal elements in the vibro-acoustic transfer matrix are expressed as: ； Where, a ii and b ii The vibro-acoustic transfer matrices of rectangular and cylindrical elements are G k No. i main diagonal elements, j is the imaginary unit, R n For the n The distance from the center of each radiation unit to the field point, θ n For the n The elevation angle from the center of each radiation unit to the field point, For the n The azimuth from the center of each radiation unit to the field point, R is the distance from the origin on the cylinder axis to the field point, θ is the pitch angle from the origin on the cylinder axis to the field point, is the azimuth from the origin on the cylinder axis to the field point, ρ is the static density of the medium where the transformer is located, c is the propagation speed of sound waves in the medium where the transformer is located, k i Frequency f i The corresponding wave number, N is the total number of divided radiation units, α n and L n is the first n The circumferential angle and axial length of each radiation unit, β n and D n Respectively n The horizontal azimuth of the center of the first radiation unit and the n The axial distance from the center of each radiation unit to the origin, Δ w n and Δ h n is the infinite plane baffle n The length and width of the radiation unit, sinc is the Singer function, Indicates the first category m The derivative of the Hankel function of order .

7. The method according to claim 1, characterized in that The calculation formula for superimposing the indirect radiation sound pressure and the direct radiation sound pressure to obtain the total sound pressure value is: ； Where, P sum is the frequency domain vector of the total sound pressure at the field point, P d is the frequency domain vector of the total sound pressure directly radiated by the field point, P i is the frequency domain vector of the total sound pressure indirectly radiated from the field point, N is the total number of divided radiation units, O is the total number of mirror sources, K is the total number of harmonics, q o,n,k 、 G o,n,k and U o,n,k Respectively m Mirror sources n The unit corresponds to k Reflection coefficient, vibroacoustic transfer matrix and surface normal vibration velocity frequency domain vector under subharmonics.

8. A dry-type transformer vibration and acoustic calculation system, characterized in that: The system comprises: A velocity phase correction module is configured to obtain normal vibration velocity time domain signals of the winding, the clamp and the core, and correct the phase of the normal vibration velocity time domain signals; a sound pressure superposition calculation module configured to determine a radiation sound pressure superposition formula for a rectangular unit for the core and the clamp and a radiation sound pressure superposition formula for a cylindrical conformal unit for the winding; A coupled frequency domain calculation module is configured to construct a frequency-decomposition-based vibration-acoustic coupling frequency domain calculation model based on the calculation results of the rectangular unit radiation sound pressure superposition formula and the cylindrical conformal unit radiation sound pressure superposition formula and the corrected normal vibration velocity time domain signal; The total sound pressure calculation module is configured to establish an image source model taking into account the sound wave refraction and reflection effect based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, and superimpose the indirect radiation sound pressure and the direct radiation sound pressure to obtain the total sound pressure value.

9. An electronic device, characterized in that: The electronic device comprises: Memory for storing computer programs; A processor, configured to execute the computer program to implement the method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium storing instructions, characterized in that: When the instructions are executed by a processor, the method according to any one of claims 1 to 7 is performed.

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