An analysis method for broadband overvoltage of flexible DC transformers

Abstract

The present invention relates to the technical field of power systems, and discloses a method for analyzing broadband overvoltage of flexible DC transformers, comprising calculating the fitness values ​​of individuals in an attenuated sinusoidal quantity atom library; defining individuals as male or female according to the fitness values; generating new individuals according to reproductive behavior patterns; mixing new and old individuals, and recalculating the fitness values ​​of individuals; and eliminating some individuals according to the fitness values, keeping the population size unchanged. The atoms in the attenuated sinusoidal quantity atom library are regarded as individuals performing reproductive behavior, and the optimal linear combination is searched in the atom library based on the behavioral characteristics of individuals during reproduction in nature to approximate the signal to be measured. Optimizing the atomic decomposition algorithm based on reproductive competition behavior can simplify the analysis process and reduce its computational complexity. The method for analyzing broadband overvoltage of flexible DC transformers provided by the present invention has stronger adaptability and lower complexity compared to existing signal decomposition methods.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method for analyzing broadband overvoltage of a flexible direct current transformer. Background Art

[0002] Operating experience and research indicate that overvoltage can cause insulation breakdown in flexible DC transformers, disrupting the normal operation of the power system and ultimately leading to significant economic losses and personal injury. Therefore, rapidly and accurately identifying the type of overvoltage helps engineers promptly identify the cause of the accident and provides a basis for developing transient suppression methods and improving insulation coordination. Therefore, decomposing overvoltage signals is a key step in overvoltage signal identification. Atomic decomposition is an analytical method for non-stationary signals. When applied to overvoltage decomposition of flexible DC transformers, the atomic decomposition algorithm offers enhanced time-frequency analysis and noise immunity. However, exhaustive iterative atomic decomposition suffers from high computational complexity and low efficiency. Summary of the Invention

[0003] Based on this, it is necessary to provide an analysis method for broadband overvoltage of flexible DC transformers to address the problems of large computational complexity and low computational efficiency of exhaustive iterative atomic decomposition.

[0004] A method for analyzing broadband overvoltage in a flexible DC transformer comprises calculating fitness values ​​of individuals in a decaying sinusoidal quantity atomic library; defining the individuals as male or female based on the fitness values; generating new individuals based on reproductive behavior patterns; mixing new and old individuals and recalculating the fitness values ​​of the individuals; and eliminating some of the individuals based on the fitness values ​​to maintain a constant population size.

[0005] The above-mentioned analysis method of broadband overvoltage of flexible DC transformer regards the atoms in the attenuated sinusoidal quantity atomic library as individuals performing reproductive behavior, and searches for a set of optimal linear combinations in the atomic library according to the behavioral characteristics of individuals when reproducing in nature to approximate the signal to be measured, and regards the atom closest to the signal to be measured as the best matching atom. Optimizing the atomic decomposition algorithm based on the behavioral characteristics of reproductive competition behavior can simplify the analysis process and reduce its computational complexity. The analysis method of broadband overvoltage of flexible DC transformer provided by the present invention solves the problem by simulating the principle of reproductive behavior of organisms in nature. Compared with the existing signal decomposition method, it has stronger adaptability and lower complexity.

[0006] In one embodiment, defining the individuals as male or female based on the fitness values ​​includes sorting the fitness values ​​from large to small, defining individuals with larger values ​​in a preset proportion as males, and defining the remaining individuals as females.

[0007] In one embodiment, generating a new individual according to the reproductive behavior pattern includes:

[0008] The individual searches for a swamp and finds a location in the swamp to mate. This process can be expressed as:

[0009]

[0010] Where x k is the position of the individual in the solution space at the Kth iteration, x k+1 is the position of the individual in the solution space at the K+1th iteration, R is a random number, L is the step size of each jump of the individual, e is the base of the power function, and k is the current number of iterations;

[0011] Strong male individuals are more likely to attract females for mating; weak male individuals are less likely to attract females for mating. This process can be expressed as follows:

[0012]

[0013] Where, X N_new is a new individual, Q is the conversion coefficient, ξ is the volume of the male's courtship call, ψ is the water surface fluctuation caused by the male's courtship call, e -τ is the transmission damping of sound sleep fluctuations, D is the Euclidean distance between two opposite sexes, For the father, For the mother generation.

[0014] In one embodiment, when generating new individuals according to the reproductive behavior pattern, the female is limited to generating only one new individual per mating.

[0015] In one embodiment, generating a new individual according to the reproductive behavior pattern further comprises:

[0016] In order to reproduce, weak male individuals sneakily ejaculate when females ovulate while other males are mating, forming mixed fertilized eggs. That is, the new individuals have genetic information from both fathers. This process can be expressed as follows:

[0017]

[0018] Where, X N_new is a new individual, Q is the conversion coefficient, ξ is the volume of the male's courtship call, ψ is the water surface fluctuation caused by the male's courtship call, e -τ is the sound sleep fluctuation transmission damping, D is the Euclidean distance between the parent generation 1 and the parent generation, For parent No. 1, is the parent No. 2, e is the base of the power function, L is the maximum single jump distance of the male individual, D ffis the Euclidean distance between the two parents, and σ is the variation factor.

[0019] A method for analyzing broadband overvoltage of a flexible DC transformer comprises: when the voltage amplitude of an electronic device is greater than a preset value, recording an electrical signal of the electronic device and defining the electrical signal of the electronic device as a signal to be measured; performing atomic decomposition on the signal to be measured using the method for analyzing broadband overvoltage of a flexible DC transformer as described in any one of the above embodiments to obtain effective atomic parameters; and extracting over-characteristic parameters of the electronic device based on the effective atomic parameters.

[0020] In one embodiment, the analysis method of the broadband overvoltage of the flexible DC transformer as described in any of the above embodiments is used to perform atomic decomposition on the signal to be measured to obtain effective atomic parameters, including designing an iterative formula and constructing an attenuated sinusoidal atomic library based on the signal to be measured; treating the atoms in the attenuated sinusoidal atomic library as individuals performing reproductive behavior; initializing the basic parameters of the reproductive behavior competition optimization algorithm; updating and iterating the individuals in the attenuated sinusoidal atomic library through the reproductive behavior competition optimization algorithm until the number of iterations reaches a preset number of iteration terminations; defining the optimal individual obtained in the last iteration as the best matching atom, and obtaining effective atomic parameters.

[0021] In one embodiment, the expression of the decaying sinusoidal quantity atomic library includes:

[0022]

[0023] Where g(t) is the Gaussian window function; definition Call γ g γ (t), where s is the scale parameter, τ is the displacement factor, and ξ is the frequency factor. is the phase factor, Z γ is the conversion coefficient, e is the base of the power function, ω is the frequency, φ is the phase angle, ρ is the damping coefficient, t s is the start time, t e is the termination time, and u(t) is the unit step.

[0024] In one embodiment, after performing n iterations, the expression of the signal to be measured includes:

[0025]

[0026] Where g γn is the optimal atom obtained in the nth iteration, R n f is the signal after n steps of iteration, <> is the inner product operator, <R n f,g γn >The absolute value of fitness value G, Rm+1 f is the residual after n steps of iteration, f t is the signal to be measured.

[0027] In one embodiment, the basic parameters include the population size and the number of iteration terminations. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the implementation methods of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 A schematic diagram of a method flow for analyzing a broadband overvoltage of a flexible DC transformer according to one embodiment of the present invention;

[0030] Figure 2 A schematic flow chart of a method for analyzing broadband overvoltage of a flexible DC transformer according to another embodiment of the present invention;

[0031] Figure 3 A schematic flow chart of a method for finding the atom that best matches the signal to be measured based on a reproductive behavior competition optimization algorithm according to one embodiment of the present invention;

[0032] Figure 4 A schematic diagram of an overvoltage waveform according to one embodiment of the present invention;

[0033] Figure 5 FIG1 is a statistical diagram of the cumulative distribution of overvoltage energy according to one embodiment of the present invention. DETAILED DESCRIPTION

[0034] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be an element centered thereon. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an element centered thereon at the same time. The terms "vertical", "horizontal", "left", "right", "up", "down", "front", "rear", "circumferential" and similar expressions used herein are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] Overvoltage signal decomposition is a key step in overvoltage signal identification. Existing overvoltage signal decomposition methods primarily include wavelet transform, Prony algorithm, empirical mode decomposition (EMD) combined with Hilbert-Huang transform (HHT), and S-transform. When using wavelet transform to decompose overvoltage signals and calculate energy signatures within the high-frequency band for identification, the selection of the wavelet basis and the signal decomposition scale must be manually configured, resulting in a complex algorithm. When using the Prony algorithm to analyze overvoltage signals, it exhibits certain errors when identifying non-stationary signals, potentially resulting in missing information. When using the EMD-Hilbert transform to calculate the amplitude spectrum, marginal spectrum, and time-frequency spectrum of overvoltage signals, modal aliasing is prone to occur. When using the S-transform to perform spectral analysis of overvoltage signals and extract features within the time-frequency matrix, the computational speed of the S-transform is too low when there are too many signal sampling points. Furthermore, its parameter settings lack unified regulations and are susceptible to variations in the type of object under investigation.

[0038] Atomic decomposition is an analysis method for nonstationary signals. It offers advantages such as enhanced time-frequency analysis and noise immunity when analyzing transient features. However, exhaustive iterative atomic decomposition is computationally intensive, resulting in low computational efficiency. Therefore, this paper simplifies the atomic decomposition algorithm based on a competitive optimization method based on reproductive behavior, reducing its computational complexity.

[0039] Figure 11 is a flow chart of a method for analyzing a broadband overvoltage of a flexible DC transformer according to one embodiment of the present invention. In one embodiment, the method for analyzing a broadband overvoltage of a flexible DC transformer includes the following steps S10 to S50.

[0040] Step S10: Calculate the fitness values ​​of individuals in the decaying sine atom library.

[0041] The atoms in the decaying sine atom library are regarded as individuals performing reproductive behavior, and the fitness value G of the individuals in the decaying sine atom library is calculated. The fitness value G is <R n f,g γn > is the absolute value of the product operator, which means that when calculating the fitness value G of an individual, the signal R after the nth iteration is required. n f and the optimal atom g obtained by the nth iteration γn Perform the inner product operation and take the absolute value.

[0042] Step S20: Define the individual as male or female according to the fitness value.

[0043] In the reproductive behavior competition optimization algorithm, individuals have two sexes, and the sex of each individual needs to be marked. The sex is divided according to the numerical value of each individual's fitness.

[0044] Step S30: Generate new individuals according to the reproductive behavior pattern.

[0045] In this embodiment, the decaying sinusoidal atomic library is discretized and placed in the solution space. The position of the individual in the solution space in this iteration and the position of the generated new individual in the solution space are calculated based on the reproduction behavior.

[0046] In one embodiment, in nature, the behavior pattern of individuals during reproduction includes the following characteristics.

[0047] When individuals are preparing to reproduce, they search for swamps and find a location in the swamp to mate. This movement process is simulated to calculate the individual's position information in the solution space. The above process can be expressed using the following equation:

[0048]

[0049] Where x k is the position of the individual in the solution space at the Kth iteration, x k+1 is the position of the individual in the solution space at the K+1th iteration, R is a random number, L is the step size of each jump of the individual, e is the base of the power function, and k is the current iteration number. In this embodiment, the value range of R is [-1, 1].

[0050] According to the law of survival of the fittest in nature, strong males are more likely to attract females to mate with them, while weak males are less likely to attract females to mate with them. After a male and a female mate, a new individual is produced. The above process can be expressed using the following equation:

[0051]

[0052] Where, X N_new is a new individual, Q is the conversion coefficient, ξ is the volume of the male's courtship call, ψ is the water surface fluctuation caused by the male's courtship call, e - τ is the transmission damping of sound sleep fluctuations, D is the Euclidean distance between two opposite sexes, For the father, For the mother generation.

[0053] In one embodiment, it is assumed that the larger the fitness value G of a male individual is, the stronger the male individual is. Conversely, the smaller the fitness value G of a male individual is, the weaker the male individual is.

[0054] Step S40: Mix the new and old individuals and recalculate the fitness values ​​of the individuals.

[0055] Put all the new individuals and old individuals together to form a new population. At this time, recalculate the fitness value G of each individual in the new population.

[0056] Step S50: Eliminate some individuals according to their fitness values ​​to keep the population size unchanged.

[0057] According to the numerical arrangement of the newly calculated fitness values ​​G of each individual, the new population is adaptively eliminated to keep the population size unchanged.

[0058] The above-mentioned analysis method of broadband overvoltage of flexible DC transformer regards the atoms in the attenuated sinusoidal quantity atomic library as individuals performing reproductive behavior, and searches for a set of optimal linear combinations in the atomic library according to the behavioral characteristics of individuals when reproducing in nature to approximate the signal to be measured, and regards the atom closest to the signal to be measured as the best matching atom. Optimizing the atomic decomposition algorithm based on the behavioral characteristics of reproductive competition behavior can simplify the analysis process and reduce its computational complexity. The analysis method of broadband overvoltage of flexible DC transformer provided by the present invention solves the problem by simulating the principle of reproductive behavior of organisms in nature. Compared with the existing signal decomposition method, it has stronger adaptability and lower complexity.

[0059] In one embodiment, when classifying individuals by gender, the fitness values ​​G of the individuals are arranged from largest to smallest, and the individuals ranked at the top by a predetermined proportion are defined as male individuals, while the rest are defined as female individuals. In this embodiment, the individuals ranked in the top 1 / 3 are defined as male, and the rest are defined as female.

[0060] In one embodiment, for the convenience of calculation, it is assumed that each female produces only one fertilized egg per mating. That is, when a new individual is produced by reproductive behavior, it is assumed that each female produces only one new individual per mating.

[0061] In one embodiment, observations of reproductive behavior in nature reveal that weak individuals can also engage in sneak ejaculation. Because weak male individuals are less attractive to female individuals, they attempt to reproduce by sneaking ejaculating during mating with other males and females, while the female is ovulating. This results in the formation of mixed fertilized eggs, meaning the new individual has genetic information from both fathers. This process can be expressed using the following equation:

[0062]

[0063] Where, X N_new is a new individual, Q is the conversion coefficient, ξ is the volume of the male's courtship call, ψ is the water surface fluctuation caused by the male's courtship call, e -τ is the sound sleep fluctuation transmission damping, D is the Euclidean distance between the parent generation 1 and the parent generation, For parent No. 1, is the parent No. 2, e is the base of the power function, L is the maximum single jump distance of the male individual, D ff is the Euclidean distance between the two parents, and σ is the variation factor.

[0064] Figure 2 1 is a flow chart of a method for analyzing a broadband overvoltage of a flexible DC transformer according to another embodiment of the present invention. In one embodiment, the method for analyzing a broadband overvoltage of a flexible DC transformer includes the following steps S100 to S300 .

[0065] Step S100: When the voltage amplitude of the electronic device is greater than a preset value, the electrical signal of the electronic device is recorded and the electrical signal of the electronic device is defined as a signal to be measured.

[0066] In this embodiment, the electronic device is a flexible DC transformer. Overvoltage can be determined based on the voltage amplitude of the flexible DC transformer. Therefore, the electrical signal of the flexible DC transformer is monitored in real time. When the voltage amplitude at a certain moment exceeds a preset value, the electrical signal of the flexible DC transformer is recorded. The electrical signal obtained by the recording is the overvoltage signal to be analyzed, and this overvoltage signal is defined as the measured signal.

[0067] Step S200: performing atomic decomposition on the signal to be measured using a flexible DC transformer broadband overvoltage analysis method to obtain effective atomic parameters.

[0068] The atomic decomposition algorithm approximates the original signal using a sparse data representation. It decomposes the signal using an overcomplete, redundant function library (called an atom library) instead of an orthogonal function basis. Because overcomplete functions do not need to meet any orthogonal requirements, the elements in the atom library are not called function bases, but atoms. There are no restrictions on the composition of atoms, allowing for optimal approximation of the signal under test.

[0069] In this embodiment, the problem is solved by simulating the reproductive behavior of organisms in nature. The atomic decomposition algorithm is optimized based on the behavioral characteristics of reproductive competition, simplifying the analysis process and reducing its computational complexity. The optimal linear combination is searched within the atom library to approximate the signal to be measured. The atom closest to the signal to be measured is considered the best match, thereby obtaining the effective atomic parameters.

[0070] Step S300: extracting over-characteristic parameters of the electronic device according to the effective atomic parameters.

[0071] The decomposed effective atomic parameters can accurately deduce the components of the signal under test and provide excellent time location capabilities, enabling the decomposition of overvoltage signals. After decomposing the signal under test, different overvoltage types can be distinguished, enabling power quality analysis and fault location.

[0072] The characteristic analysis method for overvoltage signals provided in this embodiment utilizes an atomic decomposition algorithm to decompose the overvoltage signal of a flexible DC transformer. Applying the analysis method for broadband overvoltage in flexible DC transformers to the decomposition of overvoltage signals in flexible DC transformers provides enhanced time-frequency analysis capabilities and noise immunity. Furthermore, compared to existing signal decomposition methods, the analysis method for broadband overvoltage in flexible DC transformers provided in this embodiment offers greater adaptability and lower complexity.

[0073] Figure 3The present invention is a flowchart of a method for obtaining effective atomic parameters by analyzing a broadband overvoltage of a flexible DC transformer according to one embodiment of the present invention. In one embodiment, the method for analyzing a broadband overvoltage of a flexible DC transformer is used to perform atomic decomposition on a test signal to obtain effective atomic parameters, including the following steps S210 to S240.

[0074] Step S210: design an iterative formula, and construct an attenuated sinusoidal quantity atom library according to the signal to be measured; the atoms in the attenuated sinusoidal quantity atom library are regarded as individuals performing reproductive behavior.

[0075] The atoms in the atom library can be constructed based on the characteristics of the signal to be measured to improve the signal decomposition effect and reduce the amount of calculation. In each iterative calculation, the atom library is scanned according to the index method to obtain the atoms that are most relevant to the analysis signal in this iteration. Then, the optimal atomic components are extracted from the signal to be measured to form a new residual signal. The iterative relationship is:

[0076] R m+1 f=R m f- <R m f,g γm >g γm

[0077] Where R m+1 f is the residual after m steps of iteration, R m f is the signal after m steps of iteration, g γn is the optimal atom obtained in the mth iteration.

[0078] In one embodiment, after performing n iterations, the current residual value is R m+1 f, then the original signal f t It can be expressed as:

[0079]

[0080] Where g γn is the optimal atom obtained in the nth iteration, R n f is the signal after n steps of iteration, <> is the inner product operator, <R n f,g γn >The absolute value of fitness value G, R m+1 f is the residual after n steps of iteration, f t is the signal to be measured.

[0081] in addition, <R n f,g γn >g γn is the projection of the original signal on the atom, and the residual signal is the new signal to be measured. In each iteration, a new atom and its residual signal can be obtained until the number of iterations reaches the preset iteration termination number m.

[0082] An attenuated sinusoidal quantity atomic library is constructed according to the characteristics of the signal to be measured. The overvoltage signal is composed of high-frequency sinusoidal oscillations and low-frequency sinusoidal harmonics, which can be decomposed and expressed by a group of sinusoidal waveforms with attenuation characteristics (damping characteristics) or pure sinusoidal waveforms without attenuation. Based on this feature, the atomic library used in this embodiment is a group of parameterized damped sinusoidal atoms, and the sinusoidal function atomic library is used as the atomic library model.

[0083] Based on the atomic library, this embodiment constructs a damped sinusoidal atomic library and its parameter range, suitable for hybrid overvoltage decomposition applications, based on the parameter characteristic range of overvoltage. When subsequently indexing the damped sinusoidal atomic library, the atoms in the library are treated as individuals undergoing reproductive behavior, and an optimal solution is found based on the behavioral characteristics of individuals undergoing reproductive behavior in nature.

[0084] In one embodiment, the expression of the decaying sinusoidal quantity atomic library includes:

[0085]

[0086] Where g(t) is the Gaussian window function; definition Call γ g γ (t), where s is the scale parameter, τ is the displacement factor, and ξ is the frequency factor. is the phase factor, Z γ is the conversion coefficient, e is the base of the power function, ω is the frequency, φ is the phase angle, ρ is the damping coefficient, t s is the start time, t e is the termination time, and u(t) is the unit step.

[0087] Step S220: Initialize basic parameters of the breeding behavior competition optimization algorithm.

[0088] Initialize the basic parameters of the breeding behavior competition optimization algorithm. In this embodiment, the population number N, the number of iteration terminations m and other related parameters are set. Build an optimization object library and set the frequency ω, phase angle φ, damping coefficient ρ, start time t s , end time t e As the optimization object. That is, the parameter information of the best matching atom is used as the optimization object.

[0089] Step S230: updating and iterating the individuals in the attenuated sinusoidal quantity atom library through the reproduction behavior competition optimization algorithm until the number of iterations reaches the preset number of iteration terminations.

[0090] In this embodiment, the approximation of an atom to the signal to be measured is described by a fitness value G. The atom with the largest fitness value G in the atom library is the atom that best matches the signal to be measured. The individuals in the attenuated sinusoidal atom library are updated using a reproductive behavior competition optimization algorithm, and the fitness values ​​G of the individuals in the attenuated sinusoidal atom library are recalculated each time. The atom with the largest fitness value G is the atom that best matches the signal to be measured. This optimal atomic component is then extracted from the signal to be measured to form a new residual signal, which is then used as the new signal to be measured.

[0091] Repeat the steps of updating the individuals in the attenuated sinusoidal atom library and using the residual information as the new signal to be measured. In each iteration, an optimal atom and its residual signal that best matches the signal to be measured are found. The residual signal in this iteration is used as the signal to be measured in the next iteration, and the atom that best matches the new signal to be measured is searched again in the attenuated sinusoidal atom library. Repeat steps S230 and S240. When the number of iterations reaches the preset number of iteration terminations m, the iteration terminates.

[0092] In one embodiment, it is also possible to set the iteration to stop when the energy of the residual signal is less than a certain threshold.

[0093] Step S240: defining the optimal individual obtained in the last iteration as the best matching atom, and obtaining effective atom parameters.

[0094] The final optimal atom obtained in the last iteration is taken as the best matching atom. Since the optimal atom obtained in each iteration is the best matching atom, the residual signal in the last iteration is ignored and the best matching atom information is substituted into the original signal f t In the expression of , the signal can be decomposed into The best matching atom information refers to the parameter information of the best individual position (Gmax) in the last iteration, including frequency f, damping coefficient ρ, phase angle φ, start time t s , end time t e and other parameters.

[0095] In one embodiment, the basic parameters of the above flexible DC transformer broadband overvoltage analysis method include the population number n and the number of iteration terminations T. In this embodiment, the values ​​of the parameters are set according to the algorithm parameter setting table shown in Table 1. The algorithm parameters shown in Table 1 are used to analyze the Figure 4 The transient overvoltage signal of the converter transformer is decomposed as shown. Figure 4 FIG. 1 is a schematic diagram of an overvoltage waveform according to one embodiment of the present invention.

[0096] Table 1 Algorithm parameter setting table

[0097]

[0098] In this embodiment, the above parameter values ​​are substituted into the characteristic analysis method of the transient process, and the population number n is set to 150, the number of iteration terminations T is set to 130, the step length L of each individual jump is set to 0.03, the conversion coefficient Q is set to 0.36, the sound size ξ of the male's courtship call is set to 1.37, the water surface fluctuation ψ caused by the male's courtship call is set to 1.07, the displacement factor τ is set to 1.26, and the variation factor σ is set to 0.57.

[0099] right Figure 4 After decomposing the transient overvoltage signal of the converter transformer shown in Figure 5 The energy distribution diagram is shown. Figure 5 This is a statistical diagram of the cumulative distribution of overvoltage energy according to one embodiment of the present invention. Figure 5 It is known that Figure 4 After decomposing the complex signal shown, the various frequency components mixed in the signal can be distinguished. This shows that the flexible DC transformer broadband overvoltage analysis method provided by the present invention can accurately decompose the various components of the signal. After decomposing the broadband overvoltage signal of the flexible DC transformer, the overvoltage type can be quickly and accurately identified, helping engineers and technicians to promptly identify the cause of the accident. It also provides a basis for proposing overvoltage suppression methods and improving insulation coordination.

[0100] It should be understood that although Figure 1-Figure 3 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1-Figure 3 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The order of execution of these steps or stages is not necessarily one by one, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0101] Throughout this specification, references to terms such as "some embodiments," "other embodiments," and "desired embodiments" indicate that a particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Although these terms are used interchangeably throughout this specification, they do not necessarily refer to the same embodiment or example.

[0102] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for analyzing broadband overvoltage of a flexible DC transformer, characterized in that: include: When the voltage amplitude of the electronic device is greater than a preset value, recording the electrical signal of the electronic device and defining the electrical signal of the electronic device as a signal to be measured; Performing atomic decomposition on the signal to be measured to obtain effective atomic parameters; extracting over-characteristic parameters of the electronic device according to the effective atomic parameters; The over-characteristic parameters include components of different frequencies of the signal to be measured, and the over-characteristic parameters are used to distinguish overvoltage types; The step of performing atomic decomposition on the signal to be measured to obtain effective atomic parameters includes: An iterative formula is designed, and an attenuated sinusoidal quantity atom library is constructed according to the signal to be measured; atoms in the attenuated sinusoidal quantity atom library are regarded as individuals performing reproductive behavior; Initialize the basic parameters of the breeding behavior competition optimization algorithm, including the population size and the number of iteration terminations. The population size is set to 150, and the number of iteration terminations is set to 130. Iterate the individuals in the decaying sinusoidal quantity atomic library by using a reproductive behavior competition optimization algorithm until the number of iterations reaches the number of iteration terminations; The optimal individual obtained in the last iteration is defined as the best matching atom, and the effective atomic parameters are obtained; The expression of the attenuated sinusoidal quantity atomic library includes: Where g(t) is the Gaussian window function; definition Call γ g γ (t), where s is the scale parameter, τ is the displacement factor and takes the value as 1.26, and ξ is the frequency factor. is the phase factor, Z γ is the conversion coefficient, e is the base of the power function, ω is the frequency, φ is the phase angle, ρ is the damping coefficient, t s is the start time, t e is the end time, u(t) is a unit step, and the frequency, the phase angle, the damping coefficient, the start time and the end time are optimization objects; The updating and iterating of the individuals in the attenuated sinusoidal quantity atomic library by the reproduction behavior competition optimization algorithm includes: Calculating the fitness values ​​of individuals in the decaying sinusoidal quantity atomic library; Defining the individual as male or female according to the fitness value; Generate new individuals based on reproductive behavior patterns; Mix new and old individuals and recalculate the fitness values ​​of the individuals; Eliminate some individuals according to their fitness values ​​to keep the population size unchanged; The generating of new individuals according to the reproductive behavior pattern includes: The individual seeks a swamp and finds a location in the swamp to mate. The courtship process is expressed as follows: Where x k is the position of the individual in the solution space at the kth iteration, x k+1 is the position of the individual in the solution space at the k+1th iteration, R is a random number, L is the step length of each jump of the individual and its value is 0.03, e is the base of the power function, and k is the current iteration number; Strong male individuals are more likely to attract females for mating; weak male individuals are less likely to attract females for mating. The mating process can be expressed as follows: Where, X N_new is a new individual, Q is the conversion coefficient and is set to 0.36, ξ is the volume of the male's courtship call and is set to 1.37, ψ is the water surface fluctuation caused by the male's courtship call and is set to 1.07, e -τ is the transmission damping of sound sleep fluctuations, D is the Euclidean distance between two opposite sexes, For the father, For the mother generation; Generating a new individual according to the reproductive behavior pattern further comprises: In order to reproduce, weak male individuals sneakily ejaculate when females ovulate while other males are mating, forming mixed fertilized eggs. That is, the new individual has the genetic information of two fathers. The mating process can be expressed using the equation: Where, X N_new is a new individual, Q is the conversion coefficient and is set to 0.36, ξ is the volume of the male's courtship call and is set to 1.37, ψ is the water surface fluctuation caused by the male's courtship call and is set to 1.07, e -τ is the sound sleep fluctuation transmission damping, D is the Euclidean distance between the parent generation 1 and the mother generation, For parent No. 1, is the parent No. 2, e is the base of the power function, L is the maximum single jump distance of the male individual, D ff is the Euclidean distance between the two parents, σ ​​is the variation factor and its value is 0.57; After performing n iterations, the expression of the signal to be measured includes: Where g γn is the optimal atom obtained in the nth iteration, R n f is the signal after n steps of iteration, <> is the inner product operator, <R n f,g γn >The absolute value of fitness value G, R m+1 f is the residual after n steps of iteration, f t is the signal to be measured.

2. The method for analyzing broadband overvoltage of a flexible DC transformer according to claim 1, characterized in that: Defining the individual as male or female according to the fitness value includes: The fitness values ​​are sorted from large to small, and individuals with larger values ​​in a preset proportion are defined as males, and the remaining individuals are defined as females.

3. The method for analyzing broadband overvoltage of a flexible DC transformer according to claim 1, characterized in that: When generating new individuals according to the reproductive behavior pattern, the female is limited to generating only one new individual per mating.

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