Methods, systems, equipment, and media for calculating vibration and noise in dry-type transformers

Abstract

This application belongs to the field of transformer core vibration noise modeling and calculation technology, and discloses a method, system, equipment, and medium for calculating the vibration and sound of dry-type transformers. The method includes: acquiring the time-domain signals of the normal vibration velocities of the windings, clamps, and core and correcting the phase; determining the superposition formula of radiated sound pressure based on conformal element vibration; considering the differences in the propagation characteristics of mechanical waves at different frequencies, constructing a vibration-sound coupling frequency domain calculation model based on frequency decomposition; establishing a mirror source model that considers the sound wave refraction and reflection effects, and superimposing the indirect radiated sound pressure and the direct radiated sound pressure to obtain the total sound pressure value. This application models the sound propagation process of dry-type transformers by introducing the differences in the propagation characteristics of mechanical vibration at different frequencies and the refraction and reflection effects of sound waves in the environment, and applies the improved element radiation superposition method to the vibration-sound 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.

Description

Technical Field

[0001] This application relates to the field of transformer core vibration and noise modeling and calculation technology, and in particular to a method, system, equipment and medium for calculating vibration and noise of dry-type transformers. Background Technology

[0002] Dry-type transformers are power transformers whose cores and windings are not immersed in insulating oil and are cooled naturally or by air. 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. They can also be combined with switchgear to form compact substations. The mechanical vibrations generated by dry-type transformers during operation inevitably cause noise problems, which not only cause noise pollution to the surrounding environment but also significantly impact the daily lives of nearby residents.

[0003] Currently, most modeling and calculations of transformer vibration and noise employ the finite element method (FEM), with noise simulation calculations primarily relying on commercial boundary element software. While this method has some applicability in near-field and far-field acoustic calculations of a single transformer, its versatility is significantly limited. For different types and models of transformers, corresponding simulation models must be established. Due to the complexity and time-consuming modeling process, this method not only significantly increases the cost of vibration and noise prediction but also fails to meet the practical need for rapid calculation of transformer radiated noise. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a method, system, device, and medium for calculating the vibration and acoustics of dry-type transformers, thereby resolving the problem of how to effectively improve the efficiency of noise field modeling and calculation for dry-type transformers.

[0005] According to the first technical solution of this application, a method for calculating the vibration and acoustic properties of a dry-type transformer is provided, the method comprising:

[0006] Acquire the time-domain signals of the normal vibration velocity of the winding, clamps and core, and correct the phase of the time-domain signals of the normal vibration velocity;

[0007] Determine the superposition formula for the radiated sound pressure of rectangular units used for cores and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal units used for windings;

[0008] Based on the calculation results of the superposition formula of radiated sound pressure of rectangular unit and the superposition formula of radiated sound pressure of cylindrical conformal unit, as well as the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed.

[0009] Based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, a mirror source model considering the sound wave refraction and reflection effect is established, and the indirect radiated sound pressure and the direct radiated sound pressure are superimposed to obtain the total sound pressure value.

[0010] Furthermore, the formula for superimposing the radiated sound pressure of the rectangular unit is expressed as:

[0011] ;

[0012] In the formula, p rec Let j be the total sound pressure radiated from the rectangular element to the field point, where j is the imaginary unit. R n For the first n The distance from the center of each radiating unit to the field point i n For the first n The elevation angle from the center of each radiation unit to the field point For the first n The azimuth angle from the center of each radiation unit to the field point. r The static density of the medium in which the transformer is located. c This is the speed of sound propagation in the medium in which the transformer is located. k For sound wave number, N The total number of radiation units divided, n For the index of the radiating element, u n For the first n The normal vibration velocity of each radiating element, Δ w n and Δ h n represents the length and width of the rectangular unit, respectively; sinc is the Singer function; and e is the natural constant.

[0013] Furthermore, the superposition formula for the radiated sound pressure of the cylindrical conformal unit is expressed as:

[0014] ;

[0015] In the formula, p cyl This represents the total sound pressure radiated from the cylindrical element to the field point. R This represents the distance from the origin, located on the axis of the cylinder, to the field point. i The pitch angle from the origin to the field point on the axis of the cylinder. Let j be the azimuth angle from the origin on the axis of the cylinder to the field point, where j is the imaginary unit. r The static density of the medium in which the transformer is located. c This is the speed of sound propagation in the medium in which the transformer is located. k For sound wave number, NThe total number of radiation units divided, n For the index of the radiating element, u n For the first n The normal vibration velocity of each radiating element. α n and L n For the first n The circumferential angle and axial length of each radiating element β n and D n The first n The horizontal azimuth of the center of the first radiation unit and the first n The axial distance from the center of each radiating element to the origin, sinc is the Singer function, and e is the natural constant. Indicates the first class m The derivative of the second-order Hankel function.

[0016] Furthermore, based on the calculation results of the superposition formula of radiated sound pressure of rectangular unit and the superposition formula of radiated sound pressure of cylindrical conformal unit, as well as the corrected normal vibration velocity time-domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed, including:

[0017] 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 the frequency domain form to obtain the vibration radiation sound pressure frequency domain vector.

[0018] Based on the frequency domain vector of the vibration-radiated sound pressure, the expression for the frequency-decomposed vibration-acoustic coupling frequency domain calculation model is determined as follows:

[0019] ;

[0020] In the formula, G k For the sound transmission matrix, P k and U k These correspond to the frequency domain vector of the vibration radiation sound pressure and the frequency domain vector of the surface normal vibration velocity of the element, respectively.

[0021] P k and U k The expressions are as follows:

[0022] ;

[0023] ;

[0024] In the formula, Pki and U ki The time-domain signals of sound pressure and velocity are respectively Fourier transformed and then converted to frequency. f i The corresponding sound pressure and velocity spectral coefficients at that location, where i =1,2,……, I, I The total number of frequency points analyzed is T, where T is the matrix transpose.

[0025] Furthermore, the total sound pressure calculated using the rectangular element radiated sound pressure superposition formula and the cylindrical conformal element radiated sound pressure superposition formula is converted into a frequency domain form using the following formula:

[0026] ;

[0027] ;

[0028] In the formula, p cf This represents the frequency domain form of the total sound pressure level radiated from the cylindrical element to the field point. p rf This represents the frequency domain form of the total sound pressure level radiated from the rectangular element to the field point, where j is the imaginary unit. R n For the first n The distance from the center of each radiating unit to the field point i n For the first n The elevation angle from the center of each radiation unit to the field point For the first n The azimuth angle from the center of each radiation unit to the field point. R This represents the distance from the origin, located on the axis of the cylinder, to the field point. i The pitch angle from the origin to the field point on the axis of the cylinder. The azimuth angle from the origin to the field point on the axis of the cylinder. r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. k i For frequency f i The corresponding wave number, N The total number of radiation units divided, u n，i For the first n Each radiating element corresponds to a frequency f i Normal vibration velocity below, α n and L n In an infinitely long cylindrical baffle, the first nThe circumferential angle and axial length of each radiating element β n and D n The first n The horizontal azimuth of the center of the first radiation unit and the first n The axial distance Δ from the center of each radiating element to the origin. w n and Δ h n In an infinitely large planar baffle, the first n The length and width of each radiating element, where sinc is the sigma function. Indicates the first class m The derivative of the first-order Hankel function, where e is the natural constant.

[0029] Furthermore, the main diagonal elements in the vibrational sound transmission matrix are represented as follows:

[0030] ;

[0031] In the formula, a ii and b ii Vibrational transmission matrices for rectangular and cylindrical elements, respectively. G k The i One main diagonal element, where j is the imaginary unit. R n For the first n The distance from the center of each radiating unit to the field point i n For the first n The elevation angle from the center of each radiation unit to the field point For the first n The azimuth angle from the center of each radiation unit to the field point. R This represents the distance from the origin, located on the axis of the cylinder, to the field point. i The pitch angle from the origin to the field point on the axis of the cylinder. The azimuth angle from the origin to the field point on the axis of the cylinder. r The static density of the medium in which the transformer is located. c This is the speed of sound propagation in the medium in which the transformer is located. k i For frequency f i The corresponding wave number, N The total number of radiation units divided, α n and L n In an infinitely long cylindrical baffle, the first nThe circumferential angle and axial length of each radiating element β n and D n The first n The horizontal azimuth of the center of the first radiation unit and the first n The axial distance Δ from the center of each radiating element to the origin. w n and Δ h n In an infinitely large planar baffle, the first n The length and width of each radiating element, where sinc is the sigma function. Indicates the first class m The derivative of the second-order Hankel function.

[0032] Furthermore, the formula for calculating the total sound pressure value by superimposing the indirect radiated sound pressure and the direct radiated sound pressure is as follows:

[0033] ;

[0034] In the formula, P sum This is the frequency domain vector of the total sound pressure level at the field point. P d This is the frequency domain vector of the total sound pressure directly radiated at the field point. P i This is the frequency domain vector of the total sound pressure level indirectly radiated at the field point. N The total number of radiation units divided, O This represents the total number of mirror sources. K The total number of harmonic orders. q o,n,k 、G o,n,k and U o,n,k The first o Among the mirror sources n The unit corresponds to the first k Reflection coefficient, vibration transmission matrix, and frequency domain vector of surface normal vibration velocity under subharmonics.

[0035] According to the second technical solution of this application, a dry-type transformer vibration and sound calculation system is provided, the system comprising:

[0036] The velocity phase correction module is configured to acquire the time-domain signal of the normal vibration velocity of the winding, clamp and core, and correct the phase of the time-domain signal of the normal vibration velocity.

[0037] The sound pressure superposition calculation module is configured to determine the superposition formula for the radiated sound pressure of rectangular units for the core and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal units for the windings.

[0038] The coupled frequency domain calculation module is configured to construct a vibration-acoustic coupled frequency domain calculation model based on frequency decomposition, based on the calculation results of the superposition formula of the radiated sound pressure of the rectangular unit and the superposition formula of the radiated sound pressure of the cylindrical conformal unit, as well as the corrected normal vibration velocity time domain signal.

[0039] The total sound pressure calculation module is configured to establish a mirror source model that takes into account the sound wave refraction and reflection effect based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, and to superimpose the indirect radiated sound pressure and the direct radiated sound pressure to obtain the total sound pressure value.

[0040] According to the third technical solution of this application, an electronic device is provided, the electronic device comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the method described above.

[0041] According to the fourth technical solution of this application, a non-transitory computer-readable storage medium storing instructions is provided, which, when executed by a processor, performs the method described above.

[0042] The dry-type transformer vibration and acoustic calculation methods, systems, equipment, and media according to the various schemes in this application have at least the following technical effects:

[0043] This application models the sound propagation process of dry-type transformers by introducing the differences in the propagation characteristics of mechanical vibration at different frequencies and the reflection and refraction effects of sound waves in the environment. At the same time, it applies the improved unit radiation superposition method to the vibration-sound coupling frequency domain modeling of dry-type power transformers, so as to achieve efficient and accurate calculation of the sound propagation process of dry-type power transformers, effectively improve the efficiency of sound field calculation, and is applicable to a variety of different dry-type transformer models and environments.

[0044] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0045] Figure 1 A flowchart illustrating a method for calculating the vibration and acoustic characteristics of a dry-type transformer, as provided in this application embodiment;

[0046] Figure 2 This is a schematic diagram of the principle of the dry-type transformer vibration measurement platform provided in the embodiments of this application;

[0047] Figure 3 This is a schematic diagram illustrating the principle of phase correction for vibration signals of dry-type transformers provided in an embodiment of this application.

[0048] Figure 4 A schematic diagram of a planar baffle and its surface rectangular units provided in an embodiment of this application;

[0049] Figure 5 A schematic diagram of a cylindrical baffle and its surface conformal unit provided in an embodiment of this application;

[0050] Figure 6 This is a schematic diagram illustrating the propagation principle of noise reflection and refraction in a dry-type transformer, provided in an embodiment of this application.

[0051] Figure 7 This is a structural diagram of a dry-type transformer vibration and sound calculation system provided in an embodiment of this application. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solution of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] One aspect of this application provides a method for calculating the vibration and acoustic characteristics of a dry-type transformer. Please refer to... Figure 1 This is a flowchart of a method for calculating the vibration and acoustic characteristics of a dry-type transformer, provided in an embodiment of this application. The method includes the following steps S10 to S40.

[0054] S10: Obtain the time-domain signal of the normal vibration velocity of the winding, clamp and core, and correct the phase of the time-domain signal of the normal vibration velocity.

[0055] In this embodiment, based on the structural characteristics of the dry-type transformer, the time-domain signals of the normal vibration velocity of the windings, clamps, and core can be collected and their phases corrected.

[0056] In some embodiments, step S10 specifically includes:

[0057] S11: Build a vibration test platform for dry-type power transformers and collect time-domain signals of the normal vibration velocity of the core, windings and clamps.

[0058] S12: The phase of the measured vibration signal is corrected using a phase correction method commonly used in deformation mode measurement.

[0059] Specifically, the surface vibration of a dry-type transformer mainly originates from the exposed core and the external winding and clamping structures, as well as the assembly... Figure 2 The dry-type power transformer vibration test platform shown is used to measure the normal vibration signals of the core, windings and clamp surfaces of the dry-type transformer under different external excitation power supplies. In order to obtain the vibration characteristics of each position more comprehensively, the measuring points are arranged as densely as possible.

[0060] Ideally, when acquiring vibration signals from the transformer surface, the normal vibration signals of all measuring points should be obtained simultaneously. However, due to limitations in the number of sensors, simultaneous measurement of all measuring points is difficult. To obtain synchronous vibration data at the equivalent vibration source, this paper employs a phase correction method commonly used in Operating Deflection Shapes (ODS) measurements to process the normal vibration velocity signal, such as... Figure 3 As shown in the figure. The specific procedure is as follows: select a certain measuring point as the reference signal, and record the fixed phase difference between the other measuring points and the reference measuring point; after completing the data acquisition of all measuring points, use the phase of the reference measuring point as a reference to perform unified phase correction on the signals of other measuring points, thereby achieving phase consistency of vibration signals of all measuring points.

[0061] S20: Determine the superposition formula for the radiated sound pressure of rectangular units used for cores and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal units used for windings.

[0062] In this embodiment, based on the improved unit radiation superposition method, the radiation sound pressure superposition formula with conformal unit vibration as the model can be derived, resulting in the rectangular unit radiation sound pressure superposition formula for the core and clamps, as well as the cylindrical conformal unit radiation sound pressure superposition formula for the winding.

[0063] In some embodiments, the derivation process of the formula for superposition of radiated sound pressure of rectangular units for core and clamps and the formula for superposition of radiated sound pressure of cylindrical conformal units for windings is as follows:

[0064] Considering the surrounding medium of the dry-type transformer to be a homogeneous, isotropic, and non-viscous ideal acoustic environment, and that this medium space is sufficiently extended to eliminate the need to consider boundary effects, the wave equation satisfied by the sound pressure can be derived from the classical acoustic wave equation under these assumptions:

[0065] (1);

[0066] In the formula p Indicates sound pressure level. c The speed at which sound waves propagate in the medium. t Let be time, and ▽ be the gradient operator. It is assumed that dry-type transformers are typically exposed to air, and their dielectric parameters are taken as the standard physical parameters of air. Therefore... r =1.29kg / m 3 , c =344m / s 2 .

[0067] The surface of a dry-type transformer can be considered as a radiating surface composed of an infinite number of pulsating spherical sound sources. For a single pulsating spherical source, its wave equation in spherical coordinates is expressed as:

[0068] (2);

[0069] In the formula p The sound pressure at a point in the coordinate system. r Let the distance be the straight line length from that point to the center of the ball source. c The speed at which sound waves propagate in the medium. t For time. Solving this equation yields the sound pressure level. p The expression form is:

[0070] (3);

[0071] In the formula, j is the imaginary unit. p The sound pressure at a point in the coordinate system. r Let this be the straight-line length from the point to the center of the ball source. k = oh / c =2π / l For sound wave number, l It is the wavelength of the sound wave. c The speed at which sound waves propagate in the medium. oh Angular frequency, t For time. A and B Let be the amplitudes of the forward and reverse waves related to the sound source intensity. Since inward radiation is neglected, the second term on the right-hand side of the equation can be ignored.

[0072] Furthermore, based on 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 medium particles, the radial vibration velocity of the spherical source surface can be derived as follows:

[0073] (4);

[0074] In the formula, j is the imaginary unit. r 0 is the radius of the pulsating sphere source, ( u r ) r=r0 The radial velocity of the sphere source surface is... u a The radial velocity amplitude of the outer surface of the pulsating sphere source. k For sound wave number, oh Angular frequency, t For time, r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. r The distance from the point of play to the center of the ball's origin. A This represents the amplitude of a positive wave. For a point sound source, it typically satisfies... kr0 << 1, meaning the size of the sphere source is much smaller than the wavelength of the sound wave. Therefore, the radiated sound pressure of the pulsating sphere source can be obtained as:

[0075] (5);

[0076] In the formula p The radiated sound pressure at the field point is given by j, which is the imaginary unit. r 0 represents the radius of the pulsating sphere source. u a The radial velocity amplitude of the outer surface of the pulsating sphere source. k For sound wave number, oh Angular frequency, t For time, r The distance from the point of play to the center of the ball's origin. r The static density of the medium in which the transformer is located. c Let the speed of sound wave propagation in the medium be defined as the point source intensity. Q 0 = 4π r 0 2 u a This represents the ability of a small pulsating sphere to radiate sound waves in free space. If the small pulsating sphere is embedded in an infinitely large baffle, it can only radiate into half-space. Q 0 = 2π r 0 2 u a .

[0077] Suppose there is a surface sound source of arbitrary shape, and the surface of the sound source... S Divided into an infinite number of small facets dS In each face element dS The vibrations at each point can be approximated as uniformly distributed. Therefore, each surface element can be considered as an equivalent point sound source. Thus, the sound pressure generated at any external point by the entire surface sound source can be expressed as the integral superposition of the contributions from all point sound sources, i.e.

[0078] (6);

[0079] In the formula, j is the imaginary unit. p The field point radiated sound pressure. r The distance from the point of play to the center of the ball's origin. u 0 represents the amplitude of the surface vibration velocity of the element. oh Angular frequency, t For time, r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. l The wavelength of the sound wave. dS The area of ​​a unit surface.

[0080] For near-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 certain point in space p 0 can be represented as the coherent superposition of the sound pressures produced by all radiating elements at that point:

[0081] (7);

[0082] In the formula, j is the imaginary unit. p 0 represents the total sound pressure level at the field point. t For time, r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. k For sound wave number, N The total number of radiation units divided, u n For the first n The normal vibration velocity of each radiating element, Δ w n and Δ h n These represent the length and width of the rectangular element, respectively. The distance from the element center to the field point is represented using rectangular coordinates. r n for:

[0083] (8);

[0084] In the formula ( x 0, y 0, z 0) represents the coordinates of the field point. x n , y n ) No. n The coordinates of the center point of each radiating element.

[0085] Since the main frequency of the transformer surface vibration signal is low, usually concentrated in the range of 50-1000Hz, and the size of the rectangular unit is small, the distance from each point on the unit to the field point can be approximated as the distance from the center of the unit to the field point. Therefore, equation (7) can be further simplified to:

[0086] (9);

[0087] In the formula, j is the imaginary unit. R n For the first n The distance from the center of each radiating unit to the field point i n To correspond to the pitch angle, For the corresponding azimuth angle,p rec This represents the total sound pressure radiated from the rectangular element to the field point. r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. k For sound wave number, N The total number of radiation units divided, u n For the first n The normal vibration velocity of each radiating element, Δ w n and Δ h n These are the length and width of the rectangular unit, respectively, and the Singer function sinc( x )=sin( x ) / x .

[0088] Similarly, for cylindrical shell-like sound sources such as dry-type transformer windings, several conformal units can be divided on their surface, such as... Figure 4 As shown, for this type of structure, the far-field radiated sound pressure model of the conformal element in an infinitely long cylindrical baffle can be used for calculation:

[0089] (10);

[0090] In the formula, j is the imaginary unit. R This represents the distance from the origin, located on the axis of the cylinder, to the field point. i To correspond to the pitch angle, For the corresponding azimuth angle, p cyl This represents the total sound pressure radiated from the cylindrical element to the field point. r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. k For sound wave number, N The total number of radiation units divided, u n For the first n The normal vibration velocity of each radiating element. α n and L n For the first n The circumferential angle and axial length of each radiating element β n and D n The first n The horizontal azimuth of the center of the first radiation unit and the first n The axial distance from the center of each radiating element to the origin, denoted by the Singer function sinc( x )=sin(x ) / x , Indicates the first class m The derivative of the second-order Hankel function.

[0091] S30: Based on the calculation results of the superposition formula of radiated sound pressure of rectangular element and the superposition formula of radiated sound pressure of cylindrical conformal element, as well as the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed.

[0092] In this embodiment, considering the differences in the propagation characteristics of mechanical waves at different frequencies, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed according to the calculation results of the superposition formula of radiated sound pressure of rectangular unit and the superposition formula of radiated sound pressure of cylindrical conformal unit, as well as the corrected normal vibration velocity time domain signal.

[0093] In some embodiments, the derivation or construction process of the frequency-decomposition-based vibration-acoustic coupling frequency domain calculation model is as follows:

[0094] In actual operation, the excitation source of a dry-type transformer is typically a 50Hz AC voltage. The resulting surface vibration is mainly caused by electromagnetic force and magnetostriction, and the vibration signal primarily consists of a second harmonic (100Hz) of the power frequency and higher harmonics. When the transformer experiences non-ideal operating conditions such as DC bias or harmonic currents, the vibration spectrum will further expand, containing more frequency components. According to the wavenumber calculation formula... k =2π f / c It is known that mechanical vibration waves of different frequencies correspond to different wavelengths. Therefore, in the process of sound pressure calculation, it is necessary to consider the influence of frequency on wave propagation characteristics and to model and analyze each frequency component separately. Equations (9) and (10) can be further extended to the frequency domain form to achieve accurate calculation of vibration sound radiation at different frequencies.

[0095] (11);

[0096] (12);

[0097] In the formula p cf This represents the frequency domain form of the total sound pressure level radiated from the cylindrical element to the field point. p rf This represents the frequency domain form of the total sound pressure level radiated from the rectangular element to the field point, where j is the imaginary unit. R n For the first n The distance from the center of each radiating unit to the field point i n To correspond to the pitch angle, For the corresponding azimuth angle,R This represents the distance from the origin, located on the axis of the cylinder, to the field point. i To correspond to the pitch angle, For the corresponding azimuth angle, r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. k i For frequency f i The corresponding wave number, N The total number of radiation units divided, u n For the first n The normal vibration velocity of each radiating element. α n and L n In an infinitely long cylindrical baffle, the first n The circumferential angle and axial length of each radiating element β n and D n The first n The horizontal azimuth of the center of the first radiation unit and the first n The axial distance Δ from the center of each radiating element to the origin. w n and Δ h n In an infinitely large planar baffle, the first n The length and width of each radiating element, and the Singer function sinc( x )=sin( x ) / x , Indicates the first class m The derivative of the second-order Hankel function.

[0098] To facilitate subsequent calculations and analysis, the vibration and acoustic transmission relationship of a single unit is modeled in the frequency domain, and its frequency domain calculation formula can be expressed as:

[0099] (13);

[0100] In the formula G k For the sound transmission matrix, P k and U k The specific expressions for the frequency domain vectors of the vibration radiation sound pressure and the surface normal vibration velocity of the corresponding element are as follows:

[0101] (14);

[0102] (15);

[0103] In the formula P k and U k These correspond to the frequency domain vector of the vibration radiation sound pressure and the frequency domain vector of the surface normal vibration velocity of the element, respectively. P ki and U ki The time-domain signals of sound pressure and velocity are respectively Fourier transformed and then converted to frequency. f i The corresponding sound pressure and velocity spectral coefficients at that location, where i =1,2,……, I, I This represents the total number of frequency points analyzed. Vibrational transfer matrix. G k As a diagonal matrix, the vibration and acoustic transmission matrices corresponding to the rectangular and cylindrical elements can be derived from equations (11) and (12). G k Main diagonal elements G ii They are respectively

[0104] (16);

[0105] In the formula a ii and b ii Vibrational transmission matrices for rectangular and cylindrical elements, respectively. G k The i One main diagonal element, where j is the imaginary unit. R n For the first n The distance from the center of each radiating unit to the field point i n To correspond to the pitch angle, For the corresponding azimuth angle, R This represents the distance from the origin, located on the axis of the cylinder, to the field point. i To correspond to the pitch angle, For the corresponding azimuth angle, r The static density of the medium in which the transformer is located. c The speed at which sound waves propagate in the medium. k i For frequency f i The corresponding wave number, N The total number of radiation units divided, α n and L nIn an infinitely long cylindrical baffle, the first n The circumferential angle and axial length of each radiating element β n and D n The first n The horizontal azimuth of the center of the first radiation unit and the first n The axial distance Δ from the center of each radiating element to the origin. w n and Δ h n In an infinitely large planar baffle, the first n The length and width of each radiating element, and the Singer function sinc( x )=sin( x ) / x , Indicates the first class m The derivative of the second-order Hankel function.

[0106] S40: Based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, establish a mirror source model that takes into account the sound wave refraction and reflection effect, and superimpose the indirect radiated sound pressure and the direct radiated sound pressure to obtain the total sound pressure value.

[0107] In some embodiments, based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, a mirror source model considering the sound wave refraction and reflection effect is established, and the derivation process of superimposing the indirect radiated sound pressure and the direct radiated sound pressure to obtain the total sound pressure value is as follows:

[0108] Dry-type transformers are typically installed indoors, and the vibrations and noise they generate encounter obstacles such as the ground and walls during propagation, resulting in reflection and refraction effects. Figure 6 As shown, the superposition of reflected and directly radiated sound waves in space will further enhance the noise sound pressure in the local area. For a plane sound wave, its reflection coefficient at the interface can be expressed as:

[0109] (17);

[0110] In the formula r The reflection coefficient of a plane wave, Z 1 and Z 2 represents the characteristic impedance of the incident medium and the transmitted medium, respectively. i i and i t Let the angle of incidence and the angle of refraction be the interface angles. According to Snell's law, they satisfy the following relationship: k 1sin i i = k 2sin i t ,k 1 and k 2 represents the wave number in the two media, respectively.

[0111] For the propagation of a spherical wave on a single reflecting plane, its complex form of sound wave reflection coefficient can be approximated using the corresponding plane wave reflection coefficient:

[0112] (18);

[0113] In the formula r The reflection coefficient of a plane wave, q The reflection coefficient of a spherical wave. F bl The boundary loss coefficient for a plane is defined as follows:

[0114] (19);

[0115] In the formula F bl For the boundary loss coefficient of the plane, R The distance from the center of the mirror unit to the field point. Let g be the proportional auxiliary error function, defined as:

[0116] (20);

[0117] In the formula, j is the imaginary unit. R The distance from the center of the mirror unit to the field point. For proportional auxiliary error function, Z 1 and Z 2 represents the characteristic impedance of the incident medium and the transmitted medium, respectively. i i and i t For the incident angle and refraction angle at the interface, k Let be the wavenumber of the sound source.

[0118] As mentioned earlier, the total sound pressure generated by a surface sound source at any external point can be considered as the integral superposition of contributions from all point sound sources on its surface. Therefore, this sound radiation process exhibits the characteristics of spherical wave propagation. To more accurately simulate the propagation behavior of sound waves near the boundary, a coherent virtual source sound model is constructed using the mirror method. This model equates the reflection effect to the sound field response generated by the combined action of the mirror source and the actual sound source, with the total sound field considered as the superposition of the combined actions of all mirror sources and the actual sound source.

[0119] (twenty one);

[0120] In the formula P sum This is the frequency domain vector of the total sound pressure level at the field point. Pd This is the frequency domain vector of the total sound pressure directly radiated at the field point. P i This is the frequency domain vector of the total sound pressure level indirectly radiated at the field point. N The total number of radiation units divided, O This represents the total number of mirror sources. K The total number of harmonic orders. q o,n,k 、G o,n,k and U o,n,k The first o Among the mirror sources n The unit corresponds to the first k Reflection coefficient, vibration transmission matrix, and frequency domain vector of surface normal vibration velocity under subharmonics.

[0121] Furthermore, the frequency domain vector of the total sound pressure level at the field point... P sum The inverse Fourier transform yields the time-domain vector of the total sound pressure at the field point. p sum The time-domain signal was then subjected to A-weighted filtering and converted into sound pressure level form to achieve an objective assessment and analysis of the radiated noise of the dry-type transformer.

[0122] It should be noted that the components used in the model proposed in this application are all built-in components in the simulation software. Equivalents are achieved 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 operating conditions and environments.

[0123] Another aspect of this application embodiment provides a dry-type transformer vibration and sound calculation system, such as... Figure 7 The diagram shown is a structural diagram of a dry-type transformer vibration and sound calculation system provided in an embodiment of this application. The dry-type transformer vibration and sound calculation system includes:

[0124] The velocity phase correction module 701 is configured to acquire the time-domain signal of the normal vibration velocity of the winding, clamp and core, and correct the phase of the time-domain signal of the normal vibration velocity.

[0125] The sound pressure superposition calculation module 702 is configured to determine the superposition formula for the radiated sound pressure of rectangular units for the core and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal units for the windings.

[0126] The coupled frequency domain calculation module 703 is configured to construct a vibration-acoustic coupled frequency domain calculation model based on frequency decomposition, based on the calculation results of the superposition formula of the radiated sound pressure of the rectangular unit and the superposition formula of the radiated sound pressure of the cylindrical conformal unit, as well as the corrected normal vibration velocity time domain signal.

[0127] The total sound pressure calculation module 704 is configured to establish a mirror source model that takes into account the sound wave refraction and reflection effect based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, and to superimpose the indirect radiated sound pressure and the direct radiated sound pressure to obtain the total sound pressure value.

[0128] It should be noted that the dry-type transformer vibration and sound calculation device provided in the above embodiments and the dry-type transformer vibration and sound calculation method provided in the aforementioned embodiments belong to the same concept. The specific way in which each module and unit performs operations has been described in detail in the method embodiments, and will not be repeated here.

[0129] Another aspect of this application provides an electronic device, including: a controller; and a memory for storing one or more programs, which, when executed by the controller, perform the methods described in the various embodiments above.

[0130] Another aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned method. This computer-readable storage medium may be included in the electronic device described in the above embodiments, or it may exist independently and not incorporated into the electronic device.

[0131] It should be noted that the computer-readable medium shown in the embodiments of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying a computer-readable computer program. The transmitted data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0132] Another aspect of this application provides a computer program product or computer program that 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 the various embodiments described above.

[0133] According to one aspect of the embodiments of this application, a computer system is also provided, including a Central Processing Unit (CPU), which can perform various appropriate actions and processes based on a program stored in read-only memory (ROM) or a program loaded from storage into random access memory (RAM), such as performing the methods described above. Various programs and data required for system operation are also stored in the RAM. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0134] For example, a computer system includes a Central Processing Unit (CPU), which can perform various appropriate actions and processes based on programs stored in read-only memory (ROM) or loaded from storage into random access memory (RAM), such as executing the methods described in the above embodiments. The RAM also stores various programs and data required for system operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0135] The following components are connected to the I / O interface: input components including keyboards, mice, etc.; output components including cathode ray tubes (CRTs), liquid crystal displays (LCDs), and speakers; storage components including hard drives; and communication components including network interface cards such as LAN (Local Area Network) cards and modems. The communication components perform communication processing via networks such as the Internet. Drives are also connected to the I / O interface as needed. Removable media, such as disks, optical discs, magneto-optical discs, semiconductor memories, etc., are installed on the drive as needed so that computer programs read from them can be installed into the storage components as required.

[0136] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program including a computer program for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), it performs various functions defined in the system of this application.

[0137] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0138] The module units described in the embodiments of this application can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0139] The above embodiments are only used to illustrate this application and are not intended to limit this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this application. Therefore, all equivalent technical solutions also fall within the scope of this application, and the patent protection scope of this application should be defined by the claims.

Claims

1. A method for calculating the vibration and sound of a dry-type transformer, characterized in that, The method includes: The normal vibration velocity time-domain signals of the winding, clamps and core are obtained, and the phase of the normal vibration velocity time-domain signals is corrected. Determine the superposition formula for the radiated sound pressure of rectangular units used for cores and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal units used for windings; Based on the calculation results of the superposition formula of radiated sound pressure of rectangular unit and the superposition formula of radiated sound pressure of cylindrical conformal unit, as well as the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed. Based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, a mirror source model considering the sound wave refraction and reflection effect is established, and the indirect radiated sound pressure and the direct radiated sound pressure are superimposed to obtain the total sound pressure value. The formula for superimposing the radiated sound pressure of the rectangular unit is expressed as follows: In the formula, p rec R represents the total sound pressure radiated from the rectangular element to the field point, where j is the imaginary unit. n Let θ be the distance from the center of the nth radiating element to the field point. n Let φ be the elevation angle from the center of the nth radiating element to the field point. n Let be the azimuth angle from the center of the nth radiating unit to the field point, ρ be the static density of the medium in which the transformer is located, c be the propagation speed of sound waves in the medium in which the transformer is located, k be the wave number of the sound wave, N be the total number of radiating units, n be the index of the radiating unit, and u be the azimuth angle from the center of the nth radiating unit to the field point. n Let Δw be the normal vibration velocity of the nth radiating element. n and Δh n Here, represents the length and width of the rectangular unit, sinc is the Singer function, and e is the natural constant. The formula for superimposing the radiated sound pressure of the cylindrical conformal unit is expressed as follows: In the formula, p cyl R is the total sound pressure radiated from the cylindrical element to the field point, θ is the pitch angle from the origin on the cylindrical axis to the field point, φ is the azimuth angle from the origin on the cylindrical axis to the field point, j is the imaginary unit, ρ is the static density of the medium in which the transformer is located, c is the speed of sound in the medium in which the transformer is located, k is the wavenumber of the sound wave, N is the total number of radiating elements, n is the index of the radiating element, and u n Let α be the normal vibration velocity of the nth radiating element. n and L n Let β be the circumferential angle and axial length of the nth radiating element. n and D n Let be the horizontal azimuth angle of the center of the nth radiating element and the axial distance from the center of the nth radiating element to the origin, respectively; let sinc be the sigma function and e be the natural constant H(·)'. m Let denote the derivative of the first-order m-th order Hankel function.

2. The method according to claim 1, characterized in that, Based on the calculation results of the superposition formula of radiated sound pressure of rectangular unit and the superposition formula of radiated sound pressure of cylindrical conformal unit, as well as the corrected normal vibration velocity time domain signal, a vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is constructed, including: The total sound pressure calculated by the superposition formula of the radiated sound pressure of the rectangular unit and the superposition formula of the radiated sound pressure of the cylindrical conformal unit is converted into the frequency domain form to obtain the frequency domain vector of the vibration radiated sound pressure. Based on the frequency domain vector of the vibration-radiated sound pressure, the expression of the vibration-acoustic coupling frequency domain calculation model based on frequency decomposition is determined as follows: P k =G k U k In the formula, G k For the acoustic transmission matrix, P k and U k These correspond to the frequency domain vector of the vibration radiation sound pressure and the frequency domain vector of the surface normal vibration velocity of the element, respectively. P k and U k The expressions are as follows: P k =(P k0 ,P k1 ,P k2 ,…,P kI ) T IN k =(U k0 ,IN k1 ,IN k2 ,…,IN kI ) T In the formula, P ki and U ki The sound pressure and velocity time-domain signals are respectively Fourier transformed at frequency f. i The corresponding sound pressure and velocity spectral coefficients at each point are given, where i = 1, 2, ..., I, I is the total number of frequency points analyzed, and T is the matrix transpose.

3. The method according to claim 2, characterized in that, The total sound pressure calculated using the superposition formulas of the rectangular element radiated sound pressure and the cylindrical conformal element radiated sound pressure is converted into a frequency domain form using the following formula: In the formula, p cf p represents the frequency domain form of the total sound pressure level radiated from the cylindrical element to the field point. rf The frequency domain form of the total sound pressure level radiated from the rectangular element to the field point, where j is the imaginary unit, R n Let θ be the distance from the center of the nth radiating element to the field point. n Let φ be the elevation angle from the center of the nth radiating element to the field point. n Let R be the azimuth angle from the center of the nth radiating unit to the field point, R be the distance from the origin on the cylindrical axis to the field point, θ be the elevation angle from the origin on the cylindrical axis to the field point, φ be the azimuth angle from the origin on the cylindrical axis to the field point, ρ be the static density of the medium in which the transformer is located, c be the speed of sound in the medium, and k be the velocity of sound. i For frequency f i The corresponding wave number, where N is the total number of radiative units in the division, u n,i The frequency f corresponding to the nth radiating element i Normal vibration velocity under the current, α n and L n Let β be the circumferential angle and axial length of the nth radiating element in an infinitely long cylindrical baffle. n and D n These are the horizontal azimuth angle of the center of the nth radiating element and the axial distance of the center of the nth radiating element from the origin, respectively. n and Δh n Let H(·)' be the length and width of the nth radiating element in an infinitely large planar barrier, sinc be the sigma function, and H(·)' be the radiating element. m Let denote the derivative of the first-order m-th order Hankel function, where e is the natural constant.

4. The method according to claim 2, characterized in that, The main diagonal elements in the vibrational sound transmission matrix are represented as follows: In the formula, a ii and b ii The acoustic transmission matrices G for rectangular and cylindrical elements, respectively. k The i-th element on the main diagonal, j is the imaginary unit, R n Let θ be the distance from the center of the nth radiating element to the field point. n Let φ be the elevation angle from the center of the nth radiating element to the field point. n Let be the azimuth angle from the center of the nth radiating unit to the field point, R be the distance from the origin on the cylindrical axis to the field point, θ be the elevation angle from the origin on the cylindrical axis to the field point, φ be the azimuth angle from the origin on the cylindrical axis to the field point, ρ be the static density of the medium in which the transformer is located, c be the propagation speed of sound in the medium in which the transformer is located, and k be the velocity of sound. i For frequency f i The corresponding wave number, N is the total number of radiative units in the division, α n and L n Let β be the circumferential angle and axial length of the nth radiating element in an infinitely long cylindrical baffle. n and D n These are the horizontal azimuth angle of the center of the nth radiating element and the axial distance of the center of the nth radiating element from the origin, respectively. n and Δh n Let H(·)' be the length and width of the nth radiating element in an infinitely large planar barrier, sinc be the sigma function, and H(·)' be the radiating element. m Let denote the derivative of the first-order m-th order Hankel function.

5. The method according to claim 1, characterized in that, The formula for calculating the total sound pressure value by superimposing the indirect radiated sound pressure and the direct radiated sound pressure is as follows: In the formula, P sum P is the frequency domain vector of the total sound pressure level at the field point. d P is the frequency domain vector of the total sound pressure level directly radiated at the field point. i Let N be the frequency domain vector of the total sound pressure level indirectly radiated at the field point, N be the total number of radiating elements, O be the total number of image sources, K be the total number of harmonic orders, and q be the frequency domain vector of the field point indirect radiation. o,n,k G o,n,k and U o,n,k These are the reflection coefficient, vibrational transmission matrix, and surface normal vibrational velocity frequency domain vector of the n elements in the m-th mirror source corresponding to the k-th harmonic.

6. A dry-type transformer vibration and sound calculation system, used to implement the method as described in any one of claims 1 to 5, characterized in that, The system includes: The velocity phase correction module is configured to acquire the time-domain signals of the normal vibration velocity of the winding, clamps and core, and correct the phase of the time-domain signals of the normal vibration velocity. The sound pressure superposition calculation module is configured to determine the superposition formula for the radiated sound pressure of rectangular units for the core and clamps, and the superposition formula for the radiated sound pressure of cylindrical conformal units for the windings. The coupled frequency domain calculation module is configured to construct a vibration-acoustic coupled frequency domain calculation model based on frequency decomposition, based on the calculation results of the superposition formula of radiated sound pressure of rectangular element and the superposition formula of radiated sound pressure of cylindrical conformal element, as well as the corrected normal vibration velocity time domain signal. The total sound pressure calculation module is configured to establish a mirror source model that takes into account the sound wave refraction and reflection effect based on the calculation results of the vibration-acoustic coupling frequency domain calculation model, and to superimpose the indirect radiated sound pressure and the direct radiated sound pressure to obtain the total sound pressure value.

7. An electronic device, characterized in that, The electronic device includes: Memory, used to store computer programs; A processor for executing the computer program to implement the method as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium storing instructions, characterized in that, When the instructions are executed by the processor, the method according to any one of claims 1 to 5 is performed.

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