A method and system for subsynchronous oscillation suppression of a mine site mining area power supply system

Abstract

The present application relates to the technical field of smart grid, and proposes a method and system for suppressing subsynchronous oscillation of a mining area power supply system, comprising: collecting different types of electric data of each power shovel in the mining area power supply system, and obtaining an electric data sequence of each power shovel; marking a target power shovel, performing multi-layer wavelet decomposition on the electric data sequence of the target power shovel, obtaining all detail coefficients of each layer, and determining an adaptive adjustment threshold of the detail coefficients of the same layer; determining a consistency eigenvalue of each type of electric data of the target power shovel, obtaining an adjustment value of the detail coefficients of each layer of the same type of electric data of the power shovel, and obtaining a denoised electric data sequence of the power shovel according to the detail coefficients and inverse discrete wavelet transform; and separating subsynchronous oscillation fault data according to the denoised electric data sequence, so as to realize suppression of subsynchronous oscillation of the mining area power supply system. The present application can improve the effect of suppressing subsynchronous oscillation of the power supply system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smart grid, in particular to a method and system for suppressing subsynchronous oscillation of a mining area power supply system. BACKGROUND

[0002] Subsynchronous oscillation refers to a kind of oscillation phenomenon of a power system at a frequency lower than the normal synchronous frequency. Subsynchronous oscillation can cause abnormal vibration of key equipment such as motors and transformers in the mining area, and can also cause fluctuations in the voltage and frequency of the power supply system in the mining area, and even can affect the safety production in the mining area. Due to the influence of different operating states of the electric shovel in the mining area, the electric signals collected by the power supply system in the mining area often contain problems such as spike interference and modal aliasing, so that the SPDMD sparse enhanced dynamic modal decomposition cannot accurately identify the dominant oscillation and the false oscillation. Therefore, in order to accurately extract the electric signals, it is necessary to eliminate the influence of noise interference in the collected electric signals.

[0003] Generally, a wavelet with strong time-frequency localization ability is used for denoising of the electric signals. However, the wavelet denoising needs to process the electric signals of the same type separately, and cannot combine the correlation of electric signals of different types for denoising. In addition, the spike and high frequency of the electric signals are close to the main modal frequency, and when the frequency domain threshold is not reasonably selected, the real oscillation mode is easily misjudged as noise removal or weakening, and the invalid interference signal is retained, which affects the data quality of the denoised electric signals, and further leads to inaccurate identification of the dominant oscillation and the false oscillation, and affects the effect of suppressing subsynchronous oscillation of the power supply system. SUMMARY

[0004] The present application provides a method and system for suppressing subsynchronous oscillation of a mining area power supply system, to solve the problem that the denoising effect of the electric signals of the power supply system is affected due to the unreasonable selection of the frequency domain threshold without considering the correlation of the electric signals of different types, leading to inaccurate identification of the dominant oscillation and the false oscillation, and affecting the effect of suppressing subsynchronous oscillation of the power supply system. The technical solution adopted is as follows:

[0005] In a first aspect, an embodiment of the present application provides a method for suppressing subsynchronous oscillation of a mining area power supply system, which comprises the following steps:

[0006] Collecting different types of electric data of each electric shovel in the mining area power supply system, and obtaining the electric data sequence of each electric shovel;

[0007] Taking any one of all electric shovels as a target electric shovel, performing multi-layer wavelet decomposition on the electric data sequence of the target electric shovel, obtaining all detail coefficients of each layer, and determining the adaptive adjustment threshold of the detail coefficients of the same layer according to the difference between the detail coefficients of the same layer;

[0008] According to the difference between all the same kind of electric data of the target electric shovel, a consistency feature value of each kind of electric data of the target electric shovel is determined, according to the numerical relationship between the detail coefficient of each layer of the same kind of electric data of the electric shovel and the corresponding adaptive adjustment threshold value, and the consistency feature value of the same kind of electric data of the electric shovel, an adjustment value of the detail coefficient of each layer of the same kind of electric data of the electric shovel is obtained, the detail coefficient is assigned to the value of the corresponding detail coefficient adjustment value, and the inverse discrete wavelet transform is used to obtain the denoised electric data sequence of each electric shovel respectively.

[0009] According to the denoised electric data sequence, the subsynchronous oscillation fault data is separated out, and the subsynchronous oscillation suppression of the mine area power supply system is realized according to the subsynchronous oscillation fault data.

[0010] Further, the method for obtaining the electric data sequence of the electric shovel comprises the following steps:

[0011] All kinds of electric data collected by the same electric shovel are reconstructed to obtain the electric data sequence of the same electric shovel.

[0012] Further, the method for determining the adaptive adjustment threshold value of the detail coefficient of the same layer according to the difference between all the detail coefficients of the same layer comprises the following specific method:

[0013] The mean value of all the detail coefficients of the same layer is denoted as the first feature value of the same layer.

[0014] According to the difference between all the detail coefficients of the same layer, the second feature value and the third feature value of the same layer are determined respectively.

[0015] The positive correlation processing result of the first feature value, the second feature value and the third feature value of the same layer is denoted as the adaptive adjustment threshold value of the detail coefficient of the same layer.

[0016] Further, the method for obtaining the second feature value comprises the following steps:

[0017] According to all the detail coefficients of the same layer, a detail coefficient sequence of the same layer is obtained, and the mean value of all the values contained in the first-order difference sequence of the detail coefficient sequence of the same layer is denoted as the second feature value of the same layer.

[0018] Further, the method for obtaining the third feature value comprises the following steps:

[0019] The normalized value of the information entropy of all the detail coefficients of the same layer is denoted as the third feature value of the same layer.

[0020] Further, the method for determining the consistency feature value of each kind of electric data of the target electric shovel comprises the following steps:

[0021] According to the difference between the electric data of the same kind of the target shovel, the interference degree of the electric data of the same kind of the target shovel is determined;

[0022] The difference between the interference degree of the electric data of the target kind of the target shovel and the interference degree of the electric data of other kinds is recorded as the interference degree difference of the electric data of the target kind of the target shovel;

[0023] The sum of the interference degree difference of the electric data of the target kind of the target shovel and the interference degree difference of the electric data of the target kind of all other shovels is recorded as the cumulative interference degree difference;

[0024] The ratio of the interference degree difference of the electric data of the target kind of the target shovel and the cumulative interference degree difference is recorded as the consistency feature value of the electric data of the target kind of the target shovel.

[0025] Further, the method for obtaining the interference degree of the electric data of the same kind of the target shovel is as follows:

[0026] The electric data of the same kind of the target shovel is arranged according to the order of collection, the same kind electric data sequence of the electric data of the same kind is obtained, and the mean of all values contained in the first difference sequence of the same kind electric data sequence is recorded as the first mean of the electric data of the same kind.

[0027] The variance of all values contained in the first difference sequence of the same kind electric data sequence is recorded as the first variance of the electric data of the same kind.

[0028] The sum of the first mean and the first variance of the electric data of the same kind is recorded as the interference degree of the electric data of the same kind of the target shovel.

[0029] Further, the calculation formula of the adjustment value of the detail coefficient of each layer of the electric data of the same kind of the shovel is as follows:

[0030]

[0031] wherein, d represents the adjustment value of the jth layer and the tth detail coefficient of the electric data of the cth kind of the nth shovel; d n,c,j,t τ represents the jth layer and the tth detail coefficient of the electric data of the cth kind of the nth shovel; τ n,c,j sgn() represents a sign function; ω n,c ω represents the consistency feature value of the electric data of the cth kind of the nth shovel.

[0032] Further, the method for separating the subsynchronous oscillation fault data from the denoised electric data sequence comprises the following specific steps:

[0033] The SPDMD algorithm is used to separate the subsynchronous oscillation fault data from the denoised electric data sequence.

[0034] In a second aspect, the embodiment of the present application further provides a subsynchronous oscillation suppression system of a mining area power supply system, comprising a memory, a processor and a computer program stored in the memory and running on the processor, and the processor implements the steps of the method according to any one of the above aspects when executing the computer program.

[0035] The present application has the following beneficial effects:

[0036] Firstly, the electric data sequence of the electric shovel is reconstructed according to different types of electric data of the electric shovel, in order to avoid that the threshold value of wavelet denoising is too high, so that the denoised data is distorted, and in order to avoid that the threshold value of wavelet denoising is too low, so that the noise is not completely removed, the adaptive adjustment threshold value of the detail coefficient of the corresponding layer is determined according to the overall average intensity, the overall change degree and the complexity of the value of the detail coefficient of the same layer, the value of the adaptive adjustment threshold value is increased when strong peak interference occurs in the electric data, so as to suppress the influence of the peak interference, and at the same time, the value of the adaptive adjustment threshold value is reduced when the value of the electric data is stable and concentrated, so as to avoid the problem that the oscillation mode signal is eliminated. Further, the different types of electric data collected by the wide area measurement system have strong modal consistency, and have synchronous amplitude response and phase response under the same oscillation mode, and other noise effects will destroy this consistency. According to the difference between all the same types of electric data of the target electric shovel, the significant degree of the modal consistency of the electric data is evaluated, the consistency characteristic value of each type of electric data of the target electric shovel is determined, and the detail coefficient is adjusted according to the numerical relationship between the detail coefficient of each layer of the same type of electric data of the electric shovel and the corresponding adaptive adjustment threshold value, and the consistency characteristic value of the same type of electric data of the electric shovel, to obtain the adjustment value of the detail coefficient of each layer of the same type of electric data of the electric shovel, and then to obtain the denoised electric data sequence of each electric shovel. Finally, the subsynchronous oscillation fault data is separated from the denoised electric data sequence, and the subsynchronous oscillation suppression of the mining area power supply system is realized according to the subsynchronous oscillation fault data, so as to solve the problem that the electric signal of the power supply system is not considered in the correlation of different types of electric signals, the frequency domain threshold value is not reasonably selected, the denoising effect of the electric signal is affected, the identification of the dominant oscillation and the false oscillation is not accurate, and the effect of the subsynchronous oscillation suppression of the power supply system is affected, so as to improve the accuracy of the subsynchronous oscillation suppression of the power supply system. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0038] Figure 1 A flowchart of a method for suppressing subsynchronous oscillation of a mine area power supply system according to an embodiment of the present application is shown in FIG. 1.

[0039] Figure 2 An adaptive threshold adjustment flowchart according to an embodiment of the present application is shown in FIG. 2. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0041] Please refer to Figure 1 which shows a flowchart of a method for suppressing subsynchronous oscillation of a mine area power supply system according to an embodiment of the present application. The method comprises the following steps:

[0042] In step S001, different types of electrical data of each power shovel in the mine area power supply system are collected to obtain an electrical data sequence of each power shovel.

[0043] Different types of electrical data of each power shovel in the mine area are collected through a wide-area measurement system.

[0044] The types of electrical data include voltage phasor of the power shovel, current phasor of the power shovel, total voltage of the power supply system, total current of the power supply system, voltage THD of the power shovel, and current THD of the power shovel. Collection of different types of electrical data through the wide-area measurement system is a known technology and will not be described again. In this embodiment, the data sampling frequency of the electrical data is 5 kHz, and electrical data within 10 minutes is collected. In actual application, as other implementation manners, the implementer can determine the data sampling frequency and the value of the number of samples according to actual conditions on the premise that the sampling frequency setting meets the Nyquist sampling theorem, and the present application does not have special limitations. The value of the number of samples can be calculated according to the data sampling frequency and the sampling time length.

[0045] The electrical data of all kinds are preprocessed, including format conversion, standardization and abnormal value interpolation of the electrical data of each kind respectively, and alignment of the electrical data sequences of all kinds. Specifically, the electrical data are converted into real number form by decomposing complex phasor into real part and imaginary part; the electrical data are standardized to avoid dimension influence, and Z-Score standard normalization method is used to remove dimension of the electrical data of each kind respectively; moving average interpolation method is used to interpolate abnormal values with a window width of 2; and dynamic time warping algorithm is used to align the electrical data of all kinds. The preprocessing of the electrical data is a known technology and will not be described in detail.

[0046] The electrical data of all kinds collected by the same electrical shovel are reconstructed by using sinc interpolation method to obtain the electrical data sequence of the same electrical shovel.

[0047] The electrical data sequence of each electrical shovel is a continuous time sequence, and the time sequence is obtained by using sinc interpolation method, which is a known technology and will not be described in detail.

[0048] Thus, the electrical data sequence of each electrical shovel in the power supply system of the mining area is collected.

[0049] In step S002, any one of the electrical shovels is recorded as a target electrical shovel, and the electrical data sequence of the target electrical shovel is decomposed by using multi-layer wavelet to obtain all detail coefficients of each layer, and the adaptive adjustment threshold of the detail coefficients of the same layer is determined according to the difference between the detail coefficients of the same layer.

[0050] In the mining area, multiple electrical shovels may run simultaneously. When the electrical shovels are started and stopped quickly, the load changes suddenly, the current changes sharply, the electrical data collected by the power supply system will have non-stationary disturbances such as peak interference and harmonic voltage distortion, these disturbances will alias with the system oscillation modal frequency, at the same time, the running state of different electrical shovels will also change constantly, the electrical shovel load will exist in low frequency, medium frequency and high frequency at the same time, forming strong load impact and frequency disturbance, so that the collected electrical signal shows significant modal overlap and non-uniform distribution of modal energy in the frequency domain. Therefore, the weak and important dominant oscillation modal characteristics in the electrical data collected in the mining area are easily covered.

[0051] In order to avoid that the threshold value of wavelet denoising is too high to distort the denoised data, and to avoid that the threshold value of wavelet denoising is too low to incompletely remove noise, the threshold value of wavelet denoising needs to be determined according to the stationary degree and concentration degree of the value of the electrical data.

[0052] Any one of all the electric shovels is recorded as a target electric shovel, the multi-layer wavelet decomposition is carried out on the electric data sequence of the target electric shovel by using a sym5 wavelet base function, and all the detail coefficients of each layer are obtained. In this embodiment, the number of wavelet decomposition layers is set to 5.

[0053] Wherein, the detail coefficients of each layer obtained by using wavelet decomposition are well-known technologies and will not be repeated; the detail coefficients represent the high-frequency part of the data on a finer time scale, which contains the detailed characteristics of the data, such as sudden changes, peaks or short-period fluctuations, etc.

[0054] The mean value of all the detail coefficients of the same layer is recorded as the first characteristic value of the same layer; all the detail coefficients of the same layer are arranged in sequence to obtain the detail coefficient sequence of the same layer, and the mean value of all the values contained in the first-order difference sequence of the detail coefficient sequence of the same layer is recorded as the second characteristic value of the same layer; the normalized value of the information entropy of all the detail coefficients of the same layer is recorded as the third characteristic value of the same layer.

[0055] Wherein, the calculation of the first-order difference sequence and the calculation of the information entropy are well-known technologies and will not be repeated.

[0056] It should be noted that the Z-Score standard normalization method is used to calculate the normalized value in this embodiment, and other methods such as the maximum and minimum value normalization method, sigmoid function and other methods of prior art can be used to calculate the normalized value in actual application, which is not limited here.

[0057] The first characteristic value is used to evaluate the overall average intensity of the detail coefficients of the corresponding layer, the second characteristic value is used to evaluate the overall change degree of the detail coefficients of the corresponding layer, and the third characteristic value is used to evaluate the complexity of the values of the detail coefficients of the corresponding layer. In the start-stop stage of the electric shovel, there will be strong peak interference and the distribution frequency band of the peak interference is wide, so the first characteristic value, the second characteristic value and the third characteristic value are all large.

[0058] The positive correlation processing result of the first characteristic value, the second characteristic value and the third characteristic value of the same layer is recorded as the adaptive adjustment threshold of the detail coefficients of the same layer.

[0059] The adaptive adjustment threshold acquisition flow chart is shown in Figure 2 .

[0060] It can be understood that the first characteristic value, the second characteristic value and the third characteristic value of the same layer are positively correlated, that is, the first characteristic value, the second characteristic value and the third characteristic value of the same layer are positively correlated with the adaptive adjustment threshold of the detail coefficient of the same layer. It can be understood that the positive correlation of the present application refers to the relationship between the independent variable and the dependent variable, the independent variable is the first characteristic value, the second characteristic value and the third characteristic value of the same layer, and the dependent variable is the adaptive adjustment threshold of the detail coefficient of the same layer. The positive correlation is that the dependent variable increases (decreases) with the increase (decrease) of the independent variable, which can be an additive relationship, a multiplication relationship, etc.

[0061] Preferably, as an embodiment of the present application, the calculation formula of the adaptive adjustment threshold of the detail coefficient of the same layer is:

[0062]

[0063] Wherein, τ j represents the adaptive adjustment threshold of the detail coefficient of the jth layer; α represents a preset first weight; β represents a preset second weight, and the sum of the first weight and the second weight is 1. In this embodiment, the values of the first weight and the second weight are 0.4 and 0.6 respectively; a j represents the first characteristic value of the jth layer; b j represents the second characteristic value of the jth layer; θ j represents the third characteristic value of the jth layer; e represents a natural constant.

[0064] By the overall average intensity, the overall change degree and the complexity of the value of the detail coefficient of the same layer, the adaptive adjustment threshold of the detail coefficient of the corresponding layer is determined. When strong peak interference occurs in the electrical data, the value of the adaptive adjustment threshold is increased to suppress the influence of the peak interference. At the same time, when the value of the electrical data is smooth and concentrated, the value of the adaptive adjustment threshold is reduced to avoid the problem that the oscillation modal signal is eliminated.

[0065] At this point, the adaptive adjustment threshold of the detail coefficient of each layer of the target electric shovel is obtained.

[0066] The adaptive adjustment threshold of the detail coefficient of each layer of each electric shovel in all electric shovels can be obtained by the same method.

[0067] At this point, the adaptive adjustment threshold of the detail coefficient of each layer of each electric shovel in all electric shovels is obtained.

[0068] S003, according to the difference between all the same kind of electric data of the target electric shovel, determine the consistency feature value of each kind of electric data of the target electric shovel, according to the numerical relationship between the detail coefficient of each layer of the same kind of electric data of the electric shovel and the corresponding adaptive adjustment threshold value, and the consistency feature value of the same kind of electric data of the electric shovel, obtain the adjustment value of the detail coefficient of each layer of the same kind of electric data of the electric shovel, assign the detail coefficient to the value of the corresponding detail coefficient adjustment value, and use the inverse discrete wavelet transform to obtain the denoised electric data sequence of each electric shovel respectively.

[0069] Further, the different kinds of electric data collected by the wide area measurement system have strong modal consistency, have synchronous amplitude response and phase response under the same oscillation mode, and local oscillation mode will gradually affect the entire power supply system, causing damage to the power supply system. Therefore, the consistency between different kinds of point data is evaluated to improve the denoising effect of electric signal.

[0070] According to the difference between the same kind of electric data of the target electric shovel, determine the interference degree of the same kind of electric data of the target electric shovel.

[0071] Arrange the same kind of electric data of the target electric shovel according to the order of collection, obtain the same kind of electric data sequence of the same kind of electric data, the mean value of all values contained in the first difference sequence of the same kind of electric data sequence is recorded as the first mean value of the same kind of electric data, the variance of all values contained in the first difference sequence of the same kind of electric data sequence is recorded as the first variance of the same kind of electric data, and the sum of the first mean value and the first variance of the same kind of electric data is recorded as the interference degree of the same kind of electric data of the target electric shovel.

[0072] The interference degree is obtained according to the change degree of the value of the same kind of electric data, and is used to evaluate the possibility of interference of the same kind of electric data. The smaller the interference degree, the smaller the possibility of interference of the corresponding kind of electric data, and the more stable the value of the electric data.

[0073] According to the difference between the interference degree of each kind of electric data of the target electric shovel, respectively determine the consistency feature value of each kind of electric data of the target electric shovel.

[0074] The absolute value of the difference between the interference degree of the target type of electrical data of the target shovel and the interference degree of the electrical data of other types is denoted as the interference degree difference of the target type of electrical data of the target shovel, the cumulative interference degree difference is denoted as the cumulative sum of the interference degree difference of the target type of electrical data of all other shovels, and the consistency feature value of the target type of electrical data of the target shovel is denoted as the ratio of the interference degree difference of the target type of electrical data of the target shovel to the cumulative interference degree difference.

[0075] The consistency feature value of each type of electrical data of each shovel can be obtained in the same way.

[0076] The adjustment value of the detail coefficient of each layer of the same type of electrical data of the shovel is obtained according to the numerical relationship between the detail coefficient of each layer of the same type of electrical data of the shovel and the corresponding adaptive adjustment threshold value, and the consistency feature value of the same type of electrical data of the shovel.

[0077]

[0078] wherein, represents the adjustment value of the jth layer and the tth detail coefficient of the cth type of electrical data of the nth shovel; d n,c,j,t represents the jth layer and the tth detail coefficient of the cth type of electrical data of the nth shovel; τ n,c,j represents the adaptive adjustment threshold value of the detail coefficient of the jth layer of the cth type of electrical data of the nth shovel; sgn() represents the sign function; ω n,c represents the consistency feature value of the cth type of electrical data of the nth shovel.

[0079] wherein, the sign function is a well-known mathematical function and will not be described in detail.

[0080] The adjustment value of the detail coefficient can be based on the value of the detail coefficient, combined with the consistency evaluation between different types of point data, to suppress strong peak interference while avoiding elimination of oscillation modal signals.

[0081] The detail coefficient is assigned to the value of the corresponding adjustment value of the detail coefficient, and the denoised electrical data sequence of each shovel is obtained using inverse discrete wavelet transform.

[0082] The denoised electrical data sequence can suppress strong peak interference while avoiding elimination of oscillation modal signals, improving data quality and improving the accuracy of subsequent identification of subsynchronous oscillation signals.

[0083] Thus, the denoised electrical data sequence of each shovel is obtained.

[0084] Step S004, according to the denoised electric data sequence, the subsynchronous oscillation fault data is separated, and according to the subsynchronous oscillation fault data, the subsynchronous oscillation suppression of the mine field mining area power supply system is realized.

[0085] The denoised electric data sequence of each electric shovel is respectively used for separation of the dominant oscillation mode and the false mode by using the SPDMD algorithm, and the electric data corresponding to the separated dominant oscillation mode is recorded as the subsynchronous oscillation fault data.

[0086] Among them, the data corresponding to the dominant oscillation mode separated by using the SPDMD algorithm is a known technology, and will not be repeated.

[0087] The subsynchronous oscillation fault data is suppressed on the power supply system and the load level by using the subsynchronous oscillation suppression governance idea combining “system defense” and “hierarchical governance”, and the subsynchronous oscillation of the power supply system is suppressed, and the key critical load is locally defended and protected. The specific scheme is: on the power supply system level, the electric shovel feed-out circuit where the electric data corresponding to the subsynchronous oscillation fault data is located is additionally provided with a subsynchronous low-frequency oscillation suppression device SLOP-06 / 1000T; on the load level, the electric shovel control circuit where the electric data corresponding to the subsynchronous oscillation fault data is located is additionally provided with a voltage transient defense device TOVS, to ensure that on the basis of the main loop oscillation suppression, the secondary control circuit is protected.

[0088] At this time, the subsynchronous oscillation suppression of the mine field mining area power supply system is realized.

[0089] Based on the same inventive concept as the above method, the embodiment of the present application also provides a subsynchronous oscillation suppression system of a mine field mining area power supply system, which comprises a memory, a processor and a computer program stored in the memory and running on the processor, and the processor realizes the steps of any one of the above-mentioned methods when executing the computer program.

[0090] The above is only the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for suppressing subsynchronous oscillations in a power supply system for a mining area, characterized in that, The method includes the following steps: Collect different types of electrical data from each electric shovel in the power supply system of the mining area, and obtain the electrical data sequence of each electric shovel; Denote any one of the electric shovels as the target electric shovel. Perform multi-level wavelet decomposition on the electrical data sequence of the target electric shovel to obtain all detail coefficients of each level. Based on the differences between all detail coefficients of the same level, determine the adaptive adjustment threshold of the detail coefficients of the same level. Based on the differences between all electrical data of the same type for the target electric shovel, determine the consistency feature value of electrical data of each type for the target electric shovel. Based on the numerical relationship between the detail coefficients of each layer of electrical data of the same type for the electric shovel and the corresponding adaptive adjustment threshold, and the consistency feature value of electrical data of the same type for the electric shovel, obtain the adjustment value of the detail coefficients of each layer of electrical data of the same type for the electric shovel. Assign the detail coefficients to the values ​​of the corresponding adjustment values ​​of detail coefficients. Use inverse discrete wavelet transform to obtain the denoised electrical data sequence of each electric shovel. Subsynchronous oscillation fault data is separated from the denoised electrical data sequence, and subsynchronous oscillation suppression is achieved in the power supply system of the mining area based on the subsynchronous oscillation fault data.

2. The method for suppressing subsynchronous oscillations in a mine power supply system according to claim 1, characterized in that, The method for obtaining the electrical data sequence of the electric shovel is as follows: Reconstruct all types of electrical data collected by the same electric shovel to obtain the electrical data sequence of the same electric shovel.

3. The method for suppressing subsynchronous oscillations in a mine power supply system according to claim 1, characterized in that, The method for determining the adaptive adjustment threshold of detail coefficients for the same layer based on the differences among all detail coefficients in the same layer includes the following specific methods: The mean of all detail coefficients in the same layer is denoted as the first feature value of the same layer; Based on the differences among all detail coefficients of the same layer, the second and third eigenvalues ​​of the same layer are determined respectively; The positive correlation processing results of the first, second, and third eigenvalues ​​of the same layer are denoted as the adaptive adjustment threshold of the detail coefficients of the same layer.

4. The method for suppressing subsynchronous oscillations in a mine power supply system according to claim 3, characterized in that, The method for obtaining the second feature value is as follows: Based on all detail coefficients of the same layer, obtain the detail coefficient sequence of the same layer, and denote the mean of all values ​​contained in the first difference sequence of the detail coefficient sequence of the same layer as the second feature value of the same layer.

5. The method for suppressing subsynchronous oscillations in a mine power supply system according to claim 3, characterized in that, The method for obtaining the third feature value is as follows: The normalized value of the information entropy of all detail coefficients in the same layer is denoted as the third feature value of the same layer.

6. The method for suppressing subsynchronous oscillations in a mine power supply system according to claim 1, characterized in that, The method for determining the consistency characteristic value of each type of electrical data of the target electric shovel is as follows: Based on the differences between electrical data of the same type of target electric shovel, determine the degree of interference of electrical data of the same type of target electric shovel; The type of any electrical data is denoted as the target type. The sum of the absolute values ​​of the differences between the interference degree of the target type of electrical data and the interference degree of other types of electrical data is denoted as the interference degree difference of the target type of electrical data. The sum of the interference difference of the electrical data of the target electric shovel for the target type and the interference difference of the electrical data of all other electric shovels for the target type is denoted as the cumulative interference difference. The ratio of the difference in interference level to the cumulative difference in interference level of the electrical data of the target type of the electric shovel is denoted as the consistency characteristic value of the electrical data of the target type of the electric shovel.

7. A method for suppressing subsynchronous oscillations in a mine power supply system according to claim 6, characterized in that, The method for obtaining the interference level of the same type of electrical data of the target electric shovel is as follows: Arrange the electrical data of the same type of target electric shovel in the order of collection to obtain the electrical data sequence of the same type of electrical data. The mean of all values ​​contained in the first difference sequence of the electrical data sequence of the same type is recorded as the first mean of the electrical data of the same type. The variance of all values ​​contained in the first difference sequence of electrical data sequences of the same type is denoted as the first variance of the electrical data of the same type. The sum of the first mean and the first variance of electrical data of the same type is denoted as the interference degree of the electrical data of the same type of target electric shovel.

8. The method for suppressing subsynchronous oscillations in a mine power supply system according to claim 1, characterized in that, The formula for calculating the adjustment value of the detail factor for each layer of the same type of electrical data of the electric shovel is as follows: in, This represents the adjustment value of the t-th detail coefficient at the j-th layer of the electrical data of the c-th type of the n-th electric shovel; d n,c,j,t τ represents the j-th level t-th detail coefficient of the c-th type of electrical data for the n-th electric shovel; n,c,j The adaptive adjustment threshold for the detail coefficients of the c-th type of electrical data for the nth electric shovel at the j-th layer; sgn() represents the sign function; ω n,c This represents the consistency characteristic value of the electrical data of the c-th type of the nth electric shovel.

9. A method for suppressing subsynchronous oscillations in a mine power supply system according to claim 1. Its features are, The specific method for separating subsynchronous oscillation fault data based on the denoised electrical data sequence includes: The SPDMD algorithm was used to separate subsynchronous oscillation fault data from a denoised electrical data sequence.

10. A subsynchronous oscillation suppression system for a power supply system in a mining area, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as claimed in any one of claims 1-9.

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