An intensity inversion method and system for coherent noise sources of AC filters in a converter station

Abstract

The present invention discloses a method and system for intensity inversion of coherent noise sources of AC filters in a converter station. The method includes the following steps: obtaining a noise source position coordinate matrix and a measuring point coordinate matrix of the AC filter in the converter station to be intensity-inverted; based on the obtained noise source position coordinate matrix and the measuring point coordinate matrix, calculating and generating a Green's function matrix by using a coherent sound field model of the AC filter in the converter station; randomly assuming a set of noise source parameters and calculating a corresponding prediction result based on the Green's function matrix; comparing the obtained prediction result with the pre-obtained measured result to seek the optimal solution of a pre-constructed cost function, and the noise source parameters corresponding to the optimal solution are the intensity inversion result. The technical solution disclosed by the present invention can improve the accuracy of noise source data of UHV converter stations.

Description

Technical Field

[0001] The present invention belongs to the technical field of noise prediction, relates to noise prediction of converter stations, and particularly relates to a method and system for intensity inversion of coherent noise sources of AC filters in converter stations. Background Technique

[0002] UHV DC transmission has the characteristics of long transmission distance, large capacity, and high voltage level, and can realize large-scale transmission of electric energy; however, with the successive completion and commissioning of a number of UHV DC transmission projects, its noise problem has become increasingly prominent. In particular, the noise near AC filters is strong, which is the key and difficult point of noise control in UHV converter stations.

[0003] At present, the noise prediction of AC filters mainly adopts empirical and semi-empirical methods. Specifically, the contribution sound pressure level of point source i at measurement point j is L i,j =S i +D i -A i,j , where S i represents the source level of source i, D i is the directivity correction of source i, and A i,j is the total attenuation between source i and measurement point j, including the attenuation of noise caused by factors such as geometric divergence, atmospheric absorption, ground effect, and barrier attenuation. For the case of M point sources and N measurement points, the sound pressure level at measurement point j is the superposition of M point sources According to the conversion relationship between sound pressure level and sound pressure, it can be written in matrix form where represents the effective sound pressure value of the measurement point, represents the attenuation coefficient vector, represents the effective sound pressure value of the source, and the directivity compensation factor D i is ignored here. For all measurement points y=[y 1 ,...,y N T , then there is y=Ax, where A=[a 1 ,...,a M .

[0004] ​Theoretically, when the measurement points, the sound source positions, and the relevant environmental parameters are known, the attenuation coefficient matrix A can be obtained by querying the standard file. Taking the Moore-Penrose inverse of the above equation gives the solution for the sound power of the noise source. Due to the possible singularity of A, the Moore-Penrose inverse solution method is unstable, and a solution method based on iterative Tikhonov regularization is given. It should be noted that the above model superposes the contributions of multiple point sound sources at the same measurement point according to energy, without considering the phase information of the sound sources, and cannot calculate the possible interference phenomena between different sound sources. Therefore, the inversion results often have large errors. Summary of the Invention

[0005] The object of the present invention is to provide a method and system for intensity inversion of coherent noise sources of AC filters in a converter station to solve one or more of the above-mentioned technical problems. The present invention can improve the accuracy of noise source data of UHV converter stations.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for intensity inversion of coherent noise sources of AC filters in a converter station provided by the present invention includes the following steps:

[0008] Obtain the noise source position coordinate matrix and the measurement point coordinate matrix of the AC filter in the converter station to be intensity-inverted;

[0009] Based on the obtained noise source position coordinate matrix and the measurement point coordinate matrix, use the coherent sound field model of the AC filter in the converter station to calculate and generate the Green's function matrix; randomly assume a set of noise source parameters, and calculate the corresponding prediction results based on the Green's function matrix;

[0010] Compare the obtained prediction results with the pre-obtained measured results, and seek the optimal solution of the pre-constructed cost function. The noise source parameters corresponding to the optimal solution are the intensity inversion results;

[0011] Wherein, the coherent sound field model of the AC filter in the converter station is a coherent sound field model of the AC filter in the converter station constructed based on the complex sound pressure.

[0012] A further improvement of the method of the present invention is that in the step of obtaining the noise source position coordinate matrix and the measurement point coordinate matrix of the AC filter in the converter station to be intensity-inverted, the reactor is treated as a point sound source, and the capacitor is discretized into multiple point sound sources along its height direction.

[0013] A further improvement of the method of the present invention is that the steps for obtaining the coherent sound field model of the AC filter in the converter station constructed based on the complex sound pressure include:

[0014] The reactor is equivalent to a point sound source model in a semi-free space, and the capacitor is equivalent to a line sound source model in a semi-free space. A coherent sound field model of the AC filter in the converter station is constructed;

[0015] The expression of the coherent sound field model of the AC filter in the converter station is y = Gw;

[0016] In the formula, y = [y(r 1 ),..., y(r M )] T represents the complex sound pressure vector at the measurement points r 1 ,..., r M ; G = [g 1 ,..., g M T represents the Green's function matrix between the sound source and the measurement points; M is the total number of measurement points;

[0017] represents the complex sound pressure at the measurement point;

[0018] represents the Green's function vector of the equivalent point sound sources of the three-phase filter;

[0019] respectively represent the phase differences of the filters of phase B and phase C relative to the filter of phase A.

[0020] A further improvement of the method of the present invention is that the sound field formed by the point sound source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound source and its mirror virtual source;

[0021] The line sound source model in the semi-free space is regarded as consisting of multiple point sound sources with equal intensity, the same phase, and uniform distribution; the sound field formed by the line sound source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound sources forming the line sound source and their mirror virtual sources.

[0022] A further improvement of the method of the present invention is that the expression of the pre-constructed cost function is

[0023]

[0024] In the formula, |·| 2 represents the 2-norm; represents the measured result; z model = [|y 1 | 2 ,..., |y N | 2 T represents the predicted result; respectively represent the measured sound pressure value and the complex sound pressure calculated by the model at the nth measurement point. ​​

[0025] A further improvement of the method of the present invention lies in that when seeking the optimal solution of the pre-constructed cost function, a simulated annealing algorithm is used for solution.

[0026] An intensity inversion system for coherent noise sources of AC filters in a converter station provided by the present invention includes:

[0027] A coordinate acquisition module for acquiring the noise source position coordinate matrix and the measuring point coordinate matrix of the AC filter in the converter station to be intensity-inverted;

[0028] A prediction result acquisition module for calculating and generating a Green's function matrix by using the coherent sound field model of the AC filter in the converter station based on the acquired noise source position coordinate matrix and the measuring point coordinate matrix; randomly assuming a set of noise source parameters and calculating the corresponding prediction results based on the Green's function matrix;

[0029] An intensity inversion result acquisition module for comparing the obtained prediction results with the pre-acquired measured results, seeking the optimal solution of the pre-constructed cost function, and the noise source parameters corresponding to the optimal solution are the intensity inversion results;

[0030] Among them, the coherent sound field model of the AC filter in the converter station is a coherent sound field model of the AC filter in the converter station constructed based on the complex sound pressure.

[0031] A further improvement of the system of the present invention lies in that the acquisition steps of the coherent sound field model of the AC filter in the converter station constructed based on the complex sound pressure include:

[0032] The reactor is equivalent to a point sound source model in a semi-free space, and the capacitor is equivalent to a line sound source model in a semi-free space, and a coherent sound field model of the AC filter in the converter station is constructed;

[0033] The expression of the coherent sound field model of the AC filter in the converter station is y = Gw;

[0034] In the formula, y = [y(r 1 ),..., y(r M )] T represents the complex sound pressure vector at the measuring points r 1 ,..., r M ; G = [g 1 ,..., g M )] T represents the Green's function matrix between the sound source and the measuring points; M is the total number of measuring points;

[0035] represents the complex sound pressure at the measuring point;

[0036] represents the Green's function vector of the equivalent point sound source of the three-phase filter;

[0037] They respectively represent the phase differences of the B-phase and C-phase filters relative to the A-phase filter.

[0038] A further improvement of the system of the present invention lies in that the sound field formed by the semi-free space point sound source model is regarded as the coherent superposition of the sound fields radiated by the point sound source and its mirror virtual source;

[0039] The semi-free space line sound source model is regarded as being composed of multiple point sound sources with equal intensity, the same phase, and uniform distribution; the sound field formed by the line sound source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound sources constituting the line sound source and their mirror virtual sources.

[0040] A further improvement of the system of the present invention lies in that the expression of the pre-constructed cost function is

[0041]

[0042] In the formula, |·| 2 represents the 2-norm; represents the measured result; z model =[|y 1 | 2 ,...,|y N | 2 T represents the predicted result; respectively represent the measured sound pressure value at the nth measurement point and the complex sound pressure calculated by the model.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The method of the present invention can solve the technical problem that it is difficult to determine the sound source parameters of AC filters in UHV converter stations, can improve the accuracy of noise source data in UHV converter stations, and can be applied to aspects such as noise prediction and verification of noise control schemes in converter stations. Specifically, the present invention models with complex sound pressure as a parameter, which can not only consider the coherence between phase filters, but also consider the coherence between different point sound sources within the same phase filter, and the calculation accuracy is higher.

[0045] In addition, the present invention considers the coherence characteristics of the noise of UHV AC filters and solves the cost function based on the simulated annealing algorithm, and has higher accuracy compared with the traditional far-field measured noise. Description of the Drawings

[0046] ​To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following provides a brief introduction to the drawings required for the description of the embodiments or the prior art; obviously, the drawings described below are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 It is a schematic flowchart of a method for inverting the intensity of the coherent noise source of the AC filter in a converter station according to an embodiment of the present invention;

[0048] Figure 2 It is a schematic diagram of a point sound source model in a semi-free space according to an embodiment of the present invention;

[0049] Figure 3 It is a schematic diagram of a line sound source model in a semi-free space according to an embodiment of the present invention;

[0050] Figure 4 It is a schematic diagram of the equivalent circuit of a single-phase AC filter according to an embodiment of the present invention;

[0051] Figure 5 It is a schematic diagram of the field layout of the AC filter in a converter station according to an embodiment of the present invention;

[0052] Figure 6 It is a schematic diagram of the measured noise data according to an embodiment of the present invention;

[0053] Figure 7 It is a schematic diagram for comparing the inversion results according to an embodiment of the present invention; among them, Figure 7 in (a) is a schematic diagram of the results of 10 independent inversions, Figure 7 in (b) is a schematic diagram of the predicted value of the sound field at the measurement point. Detailed implementation manners

[0054] In order to enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0056] The present invention will be further described in detail below with reference to the accompanying drawings:

[0057] Please refer to Figure 1 , a method for inverting the intensity of coherent noise sources of AC filters in a UHV converter station of the present invention mainly includes processes such as calculating spatial coordinates, generating a Green's function matrix, constructing a cost function, and finding the optimal solution of the objective function, and specifically includes the following steps:

[0058] (1) Obtain the noise source position coordinate matrix and measurement point coordinate matrix of the AC filter of the converter station to be intensity-inverted.

[0059] Specifically in the embodiment of the present invention, a suitable coordinate origin is selected, and the position coordinates of the noise source are determined based on the CAD site plan of the AC filter and the building geometric dimensions (or the measured geometric relationship) Among them, the reactor is treated as a point source, and the capacitor is discretized into multiple point sources along its height direction; the measurement point coordinates are determined and denoted as

[0060] (2) Based on the obtained noise source position coordinate matrix and measurement point coordinate matrix, use the coherent sound field model of the AC filter of the converter station to calculate and generate a Green's function matrix; randomly assume a set of noise source parameters, and calculate the corresponding prediction results based on the Green's function matrix.

[0061] Specifically in the embodiment of the present invention, according to the positional relationship between the noise source and the measurement point, the Green's function between each pair is calculated to generate the Green's function matrix G.

[0062] Please refer to Figure 2 , the reactor uses a point source in a semi-free space, including: considering a semi-free space composed of air and the earth, the sound speed in the air is c 1 m / s, the density is ρ 1 kg / m^3, the sound speed on the ground is c 2 m / s, and the density is ρ 2 . When located at rs = [x s , y s , z s T When a point sound source at s emits a simple harmonic sound wave outward at frequency f, according to the virtual source method, the sound pressure value at the measurement point p n = [x n , y n , z n T is

[0063]

[0064] where A is the sound source intensity (without loss of generality, it can be assumed that A = 1. For a point sound source in free space, A is equal to the effective sound pressure value at a distance of 1 m from the sound source); g(r n , r s ) is also called the Green's function of a point sound source with sound source intensity A in semi-free space, k = 2πf / c 1 represents the wave number; represents the direct path length;

[0065] represents the reflection path length; represents the reflection coefficient; θ(r n , r s ) represents the incident angle when ground reflection occurs in this transceiver configuration, and there is

[0066] Please refer to Figure 3 , the capacitor adopts a semi-free space line sound source, including: The line sound source can be regarded as a large number of point sound sources with equal intensity, the same phase, and uniform distribution; The sound field formed by the line sound source in semi-free space can be regarded as the coherent superposition of the sound fields radiated by the point sound sources and their mirror virtual sources that make up the line sound source. If an M-point sound source located at is used to represent a line sound source, then the sound field at the measurement point r = [x, y, z] T is Here, it is assumed that the intensity of the entire line sound source is uniform, and the intensity of each point sound source is 1 / M.

[0067] In the embodiments of the present invention, the steps of constructing the coherent sound field model of the AC filter include: A typical AC filter bank includes three phases A, B, and C. The equivalent circuit diagram of a single-phase filter is as Figure 4 shown, the high-voltage filter capacitor C 1 , the low-voltage filter capacitor C 2 , the high-end reactor L 1 , the low-end reactor L 2 , and the resistor R 1 ​​. According to previous studies, C in these devices 1 , L 1 , L 2 are the main noise sources. Considering that the currents flowing through the three-phase filter have a constant phase difference, and the radiation noise is mainly caused by the vibration of the device under the excitation of harmonic currents, the radiation sound fields of the three-phase filter also have a constant phase difference and are typical coherent sound fields. Taking the A-phase filter as a reference, the capacitor C 1 is equivalent to a line source, and the reactors L 1 , L 2 are equivalent to point sources. Assuming the position of the reactor is where represents the center height of the reactor; the capacitor is approximated by N discrete point sources, and the coordinates of the point sources are Then the total sound field generated by the A-phase filter at r can be expressed as where, N s = N + 2 represents the total number of point sources, represents the sound source intensity vector of the point source, and the phase factor φ 1 , φ 2 respectively represent the phase differences of the two reactors relative to the capacitor, represents the Green's function vector of the unit intensity point source. Similarly, the sound field contributions of the B-phase and C-phase filters to the measurement point r can be obtained as y B (r) and y C (r) respectively, and the total sound field at the measurement point r is the coherent superposition of the contributions of the three-phase filter, expressed as, where respectively represent the phase differences of the B-phase and C-phase filters relative to the A-phase filter. Considering that the sound source intensities of the three-phase filter are basically the same in practice, only the phases are different. The above formula can be simplified to where For M measurement points in space then there is y = Gw, where y = [y(r 1 ),..., y(r M )] T , G = [g 1 ,..., g M T .

[0068] ​In summary, the main differences between the existing modeling in the background art and the above-mentioned modeling of the present invention are as follows: the former models with the sound pressure level as a parameter and cannot consider the coherence between sound sources; while the latter models with the complex sound pressure as a parameter, which can not only consider the coherence between phase filters, but also consider the coherence between different point sound sources within the same phase filter. In theory, if G is known, the Moore-Penrose inverse or iterative Tikhonov regularization method mentioned above can be used to invert the noise source intensity. However, Equation is a frequency-domain signal model, which represents the complex sound pressure distribution of all measurement points at a certain moment. This requires that the data of the measurement points be synchronously measured. For the measurement point data obtained by asynchronous measurement, this equation cannot be directly used for inversion. In fact, under the assumption that the operating state of the equipment remains stable, it can be considered that the noise power at the measurement point remains constant during the measurement. Therefore, the inversion problem is to find the noise source intensity under the condition of known

[0069] (3) Compare the obtained prediction results with the pre-acquired measured results, and seek the optimal solution of the pre-constructed cost function. The noise source parameters corresponding to the optimal solution are the intensity inversion results.

[0070] Specifically, in an embodiment of the present invention, a group of noise source parameters is randomly assumed. At this time, let z model =[|y 1 | 2 ,...,|y N | 2 T represents the prediction result, represents the measured result. In order to solve the noise source intensity from the data of multiple known measurement points, a cost function is constructed. In the formula, |·| 2 represents the 2-norm. The set of parameters that minimizes the cost function value is the noise source intensity to be sought. Further preferably, in an embodiment of the present invention, the optimal solution of the cost function is found, and the noise source intensity at this time is the inversion result. In an embodiment of the present invention, taking the simulated annealing algorithm as an example, a method for solving the optimal solution of the cost function is introduced.

[0071] The simulated annealing algorithm is a search algorithm based on the thermodynamic crystallization process, which consists of a series of iterations involving random perturbations of model parameters. During the iteration process, perturbations that reduce the objective function value are received. For perturbations that increase the objective function value, the acceptance probability is set according to the Boltzmann probability distribution as P(Δf)=exp(-Δf / T), where Δf represents the change in the cost function; T represents the temperature, which is a control parameter that gradually decreases in each iteration. Receiving perturbations that increase the function value with a certain probability can jump out of the local minimum and obtain a better solution. For the l-th parameter m to be searched​l , given a search interval [-Δm l , Δm l , the parameter value after one iteration is m l := m l + ξΔ i , where Δ l is a random number uniformly distributed in the interval [-Δm l , Δm l , ξ is a random number subject to the Cauchy distribution, and ξ = [T j / T 0 1 / 2 tan(π(η - 0.5)), η is a random number uniformly distributed on [0, 1], and T j represents the system temperature at the j-th iteration.

[0072] Please refer to Figures 1 to 7 , a method for inverting the intensity of the coherent noise source of the AC filter in a converter station according to an embodiment of the present invention includes the following steps:

[0073] (1) Establish a coherent sound field model of the AC filter of the UHV converter station based on the complex sound pressure;

[0074] The reactor is equivalent to a point sound source in a semi-free space, and the sound field formed by the point sound source in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound source and its mirror virtual source.

[0075] The capacitor tower is a line sound source in a semi-free space, regarded as composed of a large number of point sound sources with equal intensity, the same phase, and uniform distribution. The sound field formed by the line sound source in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound sources constituting the line sound source and their mirror virtual sources.

[0076] A typical AC filter bank includes three phases A, B, and C. The equivalent circuit diagram of a single-phase filter is as Figure 4 shown, with a high-voltage filter capacitor C 1 , a low-voltage filter capacitor C 2 , a high-end reactor L 1 , a low-end reactor L 2 , and a resistor R 1 . According to previous studies, C 1 , L 1 , L 2 in these devices are the main noise sources. Considering that the currents flowing through the three-phase filters have a constant phase difference, and the radiated noise is mainly caused by the vibration of the equipment excited by the harmonic current, the radiated sound fields of the three-phase filters also have a constant phase difference and are typical coherent sound fields.

[0077] Taking the A-phase filter as a reference, the capacitor C 1 ​Equivalent to a line sound source, reactor L 1 , L 2 Equivalent to a point sound source. Assume the position of the reactor is where represents the center height of the reactor; the capacitor is approximated by N discrete point sound sources, and the coordinates of the point sound sources are respectively

[0078] Then the total sound field generated by the phase A filter at r can be expressed as N s = N + 2 represents the total number of point sound sources, represents the sound source intensity vector of the point sound source, and the phase factor φ 1 , φ 2 respectively represent the phase differences of the two reactors relative to the capacitor, represents the Green's function vector of the unit intensity point sound source.

[0079] Similarly, the sound field contributions of the phase B and phase C filters to the measurement point r can be obtained as y B (r) and y C (r), then the total sound field at the measurement point r is the coherent superposition of the contributions of the three-phase filters where respectively represent the phase differences of the phase B and phase C filters relative to the phase A filter. Considering that the sound source intensities of the three-phase filters are basically the same in practice, only the phases are different. The above formula can be simplified to where

[0080] For M measurement points in space then there is y = Gw, where y = [y(r 1 ),..., y(r M )] T , G = [g 1 ,..., g M T .

[0081] (2) Solve the cost function based on the simulated annealing algorithm to obtain the intensity of the noise source to be solved.

[0082] In a specific embodiment of the present invention, taking the measured noise of a certain ±800 kV UHV converter station as an example, a method for inverse intensity of coherent noise sources of AC filters in a UHV converter station proposed by the present invention is introduced.

[0083] 1) Spatial layout of noise sources: The layout of the AC filter field in the converter station is as Figure 5 ​As shown, where the positive x-axis points due north and the positive y-axis points due west. The dashed lines in the figure represent the fences, all with dimensions of 28.1m × 36.15m × 1.8m, and the origin of coordinates is the southeast corner of the fence of filter 5664. The equipment layouts of AC filters 5663 and 5664 are exactly the same, and the position coordinates of each equipment are given in Table 1 and Table 2 respectively. For the reactor, Z1 represents the center height; for the capacitor, Z1 represents the bottom height and Z2 represents the top height. Here, C1 consists of two capacitor towers.

[0084] Table 1. Position coordinates of equipment of AC filter 5664

[0085]

[0086] Table 2. Position coordinates of equipment of AC filter 5663

[0087]

[0088] 2) Description of the distribution of measuring points:

[0089] Measuring points on the north and south sides of the fence: 1m away from the fence. Taking the easternmost fence as the reference, there is one measuring point every 1m from east to west. At each measuring point, the noise at heights of 1.2m and 2.5m is measured simultaneously.

[0090] Measuring points on the east side of the fence: 4 large groups of tests were carried out using 4 roads outside the filter yard. In the direction from south to north, the starting point coordinates of each large group are (9.1, -1), (16.1, -1), (39.1, -1), (46, -1). Each large group contains 10 small groups from west to east, with an interval of 1m between the small groups; each small group contains 3 measuring points, with an interval of 1m between adjacent measuring points. At each measuring point, the noise at heights of 1.2m and 2.5m is measured simultaneously.

[0091] Measuring points on the west side of the fence: 6.75m away from the west fence. Taking the north fence of filter 5663 as the reference, there is one measuring point every 1m in the order from north to south. At each measuring point, the noise at heights of 1.2m and 2.5m is measured simultaneously.

[0092] 3) Results of parameter inversion:

[0093] The data of the first measuring point is as Figure 6 shown, and there are obvious line spectrum components at 100Hz, 200Hz, 300Hz, 400Hz, 500Hz, 600Hz, 700Hz, 1100Hz, 1200Hz, 1300Hz. Among them, 100Hz, 500Hz, 600Hz, 700Hz, 1100Hz, 1200Hz, 1300Hz are the characteristic frequencies of the noise of the capacitor. Taking the 500Hz spectral line for parameter inversion, the reactor L1 The sound source intensity and phase of are w 1 and φ 1 , and for the reactor L 2 The sound source intensity and phase are w 2 and φ 2 , and the sound source intensity of the capacitor is w 3 . The 10 independent inversion results are as shown in Figure 7 (a). It can be seen that at this time, the noise source intensity of the capacitor is much greater than that of the reactor. It can be considered that the noise at 500 Hz is mainly generated by the capacitor tower. Also, due to the small contribution of the reactor, the inversion results of the phase parameters of the reactor vary greatly in each experiment. Using the noise source parameters obtained from the first experiment for prediction, the predicted values of the sound field at the measurement points are as shown in Figure 7 (b). In summary, it can be seen that the consistency between the predicted values and the sampled values is good, verifying the effectiveness of the inversion algorithm.

[0094] In summary, the embodiments of the present invention disclose a method for inverting the intensity of the coherent noise source of the AC filter in a UHV converter station, including: establishing a coherent sound field model of the AC filter in the UHV converter station based on complex sound pressure; solving the cost function based on the simulated annealing algorithm to obtain the intensity of the noise source to be solved; where the reactor can be equivalent to a point sound source in a semi-free space, and the capacitor tower can be equivalent to a line sound source in a semi-free space, and establishing the corresponding relationship between the AC filter noise source and the measurement point with complex sound pressure and Green's function; establishing a cost function composed of the model prediction results and the measured noise data, and solving the minimum value of the cost function through the simulated annealing algorithm to obtain the corresponding noise source intensity. The present invention can improve the accuracy of the coherent noise source intensity of the AC filter and is applied to aspects such as noise prediction and noise control scheme verification in the converter station.

[0095] The following is the device embodiment of the present invention, which can be used to execute the method embodiment of the present invention. For the details not disclosed in the device embodiment, please refer to the method embodiment of the present invention.

[0096] An intensity inversion system for the coherent noise source of the AC filter in a converter station provided by the embodiments of the present invention includes:

[0097] A coordinate acquisition module, configured to acquire the noise source position coordinate matrix and the measurement point coordinate matrix of the AC filter in the converter station for which the intensity is to be inverted;

[0098] A prediction result acquisition module, configured to calculate and generate a Green's function matrix based on the acquired noise source position coordinate matrix and the measurement point coordinate matrix by using the coherent sound field model of the AC filter in the converter station; randomly assume a set of noise source parameters, and calculate and obtain the corresponding prediction results based on the Green's function matrix;

[0099] The intensity inversion result acquisition module is used to compare the obtained prediction results with the pre-acquired measured results, seek the optimal solution of the pre-constructed cost function, and the noise source parameters corresponding to the optimal solution are the intensity inversion results.

[0100] Among them, the AC filter coherent sound field model of the converter station is the AC filter coherent sound field model of the converter station constructed based on the complex sound pressure.

[0101] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0102] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0103] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0104] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. An intensity inversion method for the coherent noise source of a converter station AC filter, characterized in that, it includes the following steps: Obtain the noise source position coordinate matrix and the measuring point coordinate matrix of the converter station AC filter to be intensity-inverted; Based on the obtained noise source position coordinate matrix and the measuring point coordinate matrix, use the coherent sound field model of the converter station AC filter to calculate and generate the Green's function matrix; randomly assume a set of noise source parameters, and calculate the corresponding prediction results based on the Green's function matrix; Compare the obtained prediction results with the pre-obtained measured results, and seek the optimal solution of the pre-constructed cost function. The noise source parameters corresponding to the optimal solution are the intensity inversion results; wherein, the coherent sound field model of the converter station AC filter is a coherent sound field model of the converter station AC filter constructed based on the complex sound pressure; wherein, The expression of the pre-constructed cost function is where, |·| 2 represents the 2-norm; represents the measured result; z model = [|y 1 | 2 ,..., |y N | 2 T represents the predicted result; respectively represent the measured sound pressure value and the complex sound pressure calculated by the model at the nth measurement point.​ 2. The intensity inversion method for the coherent noise source of a converter station AC filter according to claim 1, characterized in that, in the step of obtaining the noise source position coordinate matrix and the measuring point coordinate matrix of the converter station AC filter to be intensity-inverted, the reactor is treated as a point source, and the capacitor is discretized into multiple point sources along its height direction.

3. The intensity inversion method for the coherent noise source of a converter station AC filter according to claim 1, characterized in that, the steps for obtaining the coherent sound field model of the converter station AC filter constructed based on the complex sound pressure include: The reactor is equivalent to a point source model in a semi-free space, and the capacitor is equivalent to a line source model in a semi-free space, and a coherent sound field model of the converter station AC filter is constructed; The expression of the coherent sound field model of the converter station AC filter is y = Gw; where \(y = [y(r 1 ),\cdots,y(r M )] T denotes the complex sound pressure vector at measurement points \(r 1 ,\cdots,r M \), and \(G=[g 1 ,\cdots,g M T denotes the Green's function matrix between the sound source and the measurement points; \(M\) is the total number of measurement points;​ Represents the complex sound pressure at the measurement point; The Green's function vector representing the equivalent point sound source of the three-phase filter; They respectively represent the phase differences of the B-phase and C-phase filters relative to the A-phase filter.

4. The intensity inversion method for the coherent noise source of a converter station AC filter according to claim 3, characterized in that, the sound field formed by the point source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point source and its mirror image virtual source; The line source model in the semi-free space is regarded as being composed of multiple point sources with equal intensity, the same phase, and uniform distribution; the sound field formed by the line source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sources and their mirror image virtual sources that make up the line source.

5. The intensity inversion method for the coherent noise source of a converter station AC filter according to claim 1, characterized in that, when seeking the optimal solution of the pre-constructed cost function, a simulated annealing algorithm is used for solution.

6. An intensity inversion system for the coherent noise source of a converter station AC filter, characterized in that, it includes: A coordinate acquisition module for obtaining the noise source position coordinate matrix and the measuring point coordinate matrix of the converter station AC filter to be intensity-inverted; A prediction result acquisition module for calculating and generating the Green's function matrix based on the obtained noise source position coordinate matrix and the measuring point coordinate matrix using the coherent sound field model of the converter station AC filter; randomly assuming a set of noise source parameters, and calculating the corresponding prediction results based on the Green's function matrix; An intensity inversion result acquisition module for comparing the obtained prediction results with the pre-obtained measured results, seeking the optimal solution of the pre-constructed cost function, and the noise source parameters corresponding to the optimal solution are the intensity inversion results; Among them, the coherent sound field model of the converter station AC filter is a coherent sound field model of the converter station AC filter constructed based on complex sound pressure; Among them, The expression of the pre-constructed cost function is where, |·| 2 represents the 2-norm; represents the measured result; z model = [|y 1 | 2 ,..., |y N | 2 T represents the predicted result; respectively represent the measured sound pressure value and the complex sound pressure calculated by the model at the nth measurement point.​ 7. An intensity inversion system for the coherent noise source of a converter station AC filter according to claim 6, characterized in that, the steps for obtaining the coherent sound field model of the converter station AC filter constructed based on complex sound pressure include: The reactor is equivalent to a point sound source model in a semi-free space, and the capacitor is equivalent to a line sound source model in a semi-free space, and a coherent sound field model of the converter station AC filter is constructed; The expression of the coherent sound field model of the converter station AC filter is y = Gw; where y = [y(r 1 ),..., y(r M )] T represents the complex sound pressure vector at measurement points r 1 ,..., r M , G = [g 1 ,…, g M T represents the Green's function matrix between the sound source and the measurement points; M is the total number of measurement points;​ Denote the complex sound pressure at the measurement point; The Green's function vector representing the equivalent point source of the three-phase filter; They respectively represent the phase differences of the B-phase and C-phase filters relative to the A-phase filter.

8. An intensity inversion system for the coherent noise source of a converter station AC filter according to claim 7, characterized in that, the sound field formed by the point sound source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound source and its mirror virtual source; The line sound source model in the semi-free space is regarded as composed of multiple point sound sources with equal intensity, the same phase, and uniform distribution; the sound field formed by the line sound source model in the semi-free space is regarded as the coherent superposition of the sound fields radiated by the point sound sources and their mirror virtual sources that make up the line sound source.

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