Excitation signal determination method for monitoring state of transformer winding
By injecting excitation signals of different amplitudes into the winding state of the transformer and analyzing the response signals, the optimal excitation signal is determined by quantization methods, which solves the problem that excitation signal selection depends on experience in the prior art, improves the accuracy and reliability of the monitoring results, and ensures the stable operation of the power system.
Patent Information
- Application Number
- CN202411953470.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-03-28
AI Technical Summary
The selection of the existing excitation signal for monitoring the winding state of the transformer depends on experience, resulting in the excitation signal being subjective and uncertain, affecting the accuracy and reliability of the monitoring results.
When the winding state of the transformer is the target state, excitation signals of different amplitudes are injected successively at the electromagnetic voltage transformer to obtain the excitation response signals corresponding to different amplitudes in the target state, and the most suitable excitation signal is determined in a quantized manner to avoid the influence of subjectivity and uncertainty.
The ability of the excitation signal to accurately reflect the transformer winding status is realized, the accuracy and reliability of monitoring results are improved, the risk of misjudgment is reduced, and the effectiveness and accuracy of monitoring is improved, and the stable operation of the power system is ensured.
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Figure CN119716182A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of power systems, and in particular to a method for determining an excitation signal for monitoring a transformer winding state. Background Art
[0002] Transformers are essential key equipment in power systems, used to transmit and distribute electrical energy in power systems. The health of transformer winding coils is crucial to the operational reliability of the system. Transformer winding coil accidents are one of the common types of faults in power systems, and their frequency of occurrence is relatively high, seriously affecting the stable operation of power systems. Therefore, strengthening the monitoring of transformer winding status and timely discovering and handling potential faults are of great practical significance for ensuring the stable operation of power systems.
[0003] Further research found that improper selection of excitation signals for monitoring the status of transformer windings will lead to reduced accuracy and reliability of monitoring results, and even cause misjudgment, thus affecting the effectiveness and accuracy of monitoring. Therefore, determining the appropriate excitation signal is a key technical issue that needs to be solved in practical applications.
[0004] However, the existing selection of excitation signals for monitoring the status of transformer windings mostly relies on the experience of relevant technicians. The excitation signals determined by this method have certain subjectivity and uncertainty, which may lead to reduced accuracy and reliability of monitoring results, or even cause misjudgment, thereby affecting the effectiveness and accuracy of monitoring. Summary of the invention
[0005] Based on this, it is necessary to propose a method for determining the excitation signal for monitoring the state of the transformer winding in response to the above-mentioned problems. By adopting a quantitative approach to determine the most appropriate excitation signal, the determined excitation signal is prevented from being affected by subjectivity and uncertainty, so that the determined excitation signal can accurately reflect the state of the transformer winding.
[0006] To achieve the above object, the present invention provides, in a first aspect, a method for determining an excitation signal for monitoring a transformer winding state, the method comprising:
[0007] When the winding state of the transformer is a target state, excitation signals of different amplitudes are sequentially injected into the electromagnetic voltage transformer to obtain excitation response signals corresponding to different amplitudes under the target state, wherein the target state includes a normal state and a fault state;
[0008] Determine the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state according to the excitation response signal corresponding to each amplitude under the target state;
[0009] Determine a determination factor corresponding to each amplitude according to the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state;
[0010] Determine the target determination factor according to the determination factors corresponding to all amplitudes;
[0011] An optimal excitation signal is determined according to the target determination factor and the excitation signal of the corresponding amplitude.
[0012] Optionally, determining the center of gravity frequency and mean square frequency corresponding to each amplitude in the target state according to the excitation response signal corresponding to each amplitude in the target state includes:
[0013] Performing Fourier transform on the excitation response signal corresponding to each amplitude under the target state to obtain a frequency domain excitation response signal corresponding to each amplitude under the target state;
[0014] Determine a power density spectrum corresponding to an excitation response data point of each amplitude at each frequency in the target state according to an excitation response data point of a frequency domain excitation response signal corresponding to each amplitude at each frequency in the target state;
[0015] The center of gravity frequency and mean square frequency corresponding to each amplitude in the target state are determined according to the power density spectrum corresponding to the excitation response data points of each amplitude at all frequencies in the target state.
[0016] Optionally, determining a power density spectrum corresponding to an excitation response data point of each amplitude at each frequency in the target state according to an excitation response data point of a frequency domain excitation response signal corresponding to each amplitude in the target state at each frequency includes:
[0017] Determine a standard excitation response signal corresponding to each amplitude in the target state according to the frequency domain excitation response signal corresponding to each amplitude in the target state and a preset frequency range;
[0018] The power density spectrum corresponding to the excitation response data point of each amplitude at each frequency in the target state is determined according to the excitation response data point of the standard excitation response signal at each frequency corresponding to each amplitude in the target state.
[0019] Optionally, determining the power density spectrum corresponding to the excitation response data point of each amplitude at each frequency in the target state according to the excitation response data point of the standard excitation response signal corresponding to each amplitude in the target state at each frequency includes:
[0020] Using the formula Determine a power density spectrum corresponding to an excitation response data point at each amplitude at each frequency in the target state;
[0021] Among them, N R,i (f R,i,n ) is the power density spectrum corresponding to the stimulus response data point of the ith amplitude at the nth frequency, T is the time of Fourier transform of the stimulus response signal corresponding to the ith amplitude, E is the preset expected value, N R,i (f R,i,n , T) is the excitation response data point of the standard excitation response signal corresponding to the ith amplitude at the nth frequency. When R is S, the target state is the normal state, and when R is M, the target state is the fault state.
[0022] Optionally, determining the center of gravity frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data points of each amplitude at all frequencies in the target state includes:
[0023] Using the formula Determining the center of gravity frequency corresponding to each amplitude under the target state;
[0024] Among them, f R,i is the centroid frequency corresponding to the ith amplitude, N is the total number of frequencies of the ith amplitude, N R,i (f R,i,n ) is the power density spectrum corresponding to the stimulus response data point with the ith amplitude at the nth frequency, f R,i,n is the nth frequency of the ith amplitude, when R is S, the target state is the normal state, and when R is M, the target state is the fault state.
[0025] Optionally, determining the mean square frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data points of each amplitude at all frequencies in the target state includes:
[0026] Using the formula Determine the mean square frequency corresponding to each amplitude under the target state;
[0027] Among them, MSF R,i is the mean square frequency corresponding to the ith amplitude, [f min , f max ] is the preset frequency range, N R,i (f R,i,n ) is the power density spectrum corresponding to the excitation response data point with the ith amplitude at the nth frequency, f R,i,n is the nth frequency of the ith amplitude, when R is S, the target state is the normal state, and when R is M, the target state is the fault state.
[0028] Optionally, determining the determination factor corresponding to each amplitude according to the center of gravity frequency and the mean square frequency corresponding to each amplitude in the target state includes:
[0029] Using the formula Determine the determination factor corresponding to each amplitude;
[0030] Among them, λ i is the determination factor corresponding to the i-th amplitude, e is a natural constant, f M,i is the center of gravity frequency corresponding to the i-th amplitude under the fault state, f S,i is the center of gravity frequency corresponding to the ith amplitude in the normal state, MSF M,i is the mean square frequency corresponding to the i-th amplitude under the fault state, MSF S,i is the mean square frequency corresponding to the ith amplitude in the normal state, and tan() is the tangent function.
[0031] Optionally, determining the optimal excitation signal according to the target determination factor and the excitation signal of the corresponding amplitude includes:
[0032] Using the formula W s (t) = λ r W r (t) determining the optimal excitation signal;
[0033] Among them, W s (t) is the optimal excitation signal, λ r Determine the factor for the target, W r (t) is the excitation signal of the amplitude corresponding to the target determination factor.
[0034] Optionally, determining the target determination factor according to the determination factors corresponding to all amplitudes includes:
[0035] Among the determination factors corresponding to all amplitudes, the largest determination factor is used as the target determination factor.
[0036] Optionally, when the winding state of the transformer is a target state, injecting excitation signals of different amplitudes into the electromagnetic voltage transformer in sequence to obtain excitation response signals corresponding to different amplitudes under the target state includes:
[0037] When the winding state of the transformer is the normal state, an excitation signal is injected into the electromagnetic voltage transformer, and the amplitude of the injected excitation signal is adjusted according to a preset step size within a preset amplitude range to obtain excitation response signals corresponding to different amplitudes in the normal state;
[0038] When the winding state of the transformer is the fault state, an excitation signal is injected into the electromagnetic voltage transformer, and within the preset amplitude range, the amplitude of the injected excitation signal is adjusted according to the preset step size to obtain excitation response signals corresponding to different amplitudes in the fault state.
[0039] To achieve the above object, the present invention provides, in a second aspect, an excitation signal determination device for monitoring the state of a transformer winding, the device comprising:
[0040] A sequential injection module is used to sequentially inject excitation signals of different amplitudes at the electromagnetic voltage transformer when the winding state of the transformer is a target state, so as to obtain excitation response signals corresponding to different amplitudes under the target state, wherein the target state includes a normal state and a fault state;
[0041] A frequency determination module, used to determine the center of gravity frequency and mean square frequency corresponding to each amplitude in the target state according to the excitation response signal corresponding to each amplitude in the target state;
[0042] A factor determination module, used to determine a determination factor corresponding to each amplitude according to the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state;
[0043] A target factor determination module, used to determine a target determination factor according to the determination factors corresponding to all amplitudes;
[0044] The optimal determination module is used to determine the optimal excitation signal according to the target determination factor and the excitation signal of the corresponding amplitude.
[0045] To achieve the above-mentioned object, the present invention provides in a third aspect a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the method as described in any one of the first aspects.
[0046] To achieve the above-mentioned purpose, the present invention provides a computer device in a fourth aspect, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method as described in any one of the first aspects.
[0047] The embodiment of the present invention has the following beneficial effects: the above method injects excitation signals of different amplitudes at the electromagnetic voltage transformer in sequence when the winding state of the transformer is the target state, obtains excitation response signals corresponding to different amplitudes under the target state, wherein the target state includes a normal state and a fault state, and then determines the centroid frequency and mean square frequency corresponding to each amplitude under the target state according to the excitation response signal corresponding to each amplitude under the target state, and then determines the determination factor corresponding to each amplitude according to the centroid frequency and mean square frequency corresponding to each amplitude under the target state, and then determines the target determination factor according to the determination factors corresponding to all amplitudes, and finally determines the optimal excitation according to the target determination factor and the excitation signal of the corresponding amplitude signal; that is, by injecting excitation signals of different amplitudes in sequence when the winding state of the transformer is in a normal state and a fault state, and determining the center of gravity frequency and the mean square frequency, the determination factor and the target determination factor in sequence based on the excitation response signals obtained after the injection of different amplitudes, and finally determining the best excitation signal based on the target determination factor and the excitation signal of the corresponding amplitude, that is, using a quantitative method to determine the most appropriate excitation signal, avoiding the determined excitation signal from being affected by subjectivity and uncertainty, so that the determined excitation signal can accurately reflect the winding state of the transformer, so as to improve the accuracy and reliability of the monitoring results, effectively reduce the risk of misjudgment, and then improve the effectiveness and accuracy of monitoring, thereby ensuring the stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS
[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0049] in:
[0050] Figure 1 A schematic diagram of a method for determining an excitation signal for monitoring a transformer winding state in an embodiment of the present application;
[0051] Figure 2 A schematic diagram of an excitation signal determination device for monitoring the state of a transformer winding in an embodiment of the present application;
[0052] Figure 3 1 is a diagram of the internal structure of a computer device in some embodiments. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0054] Transformers are essential key equipment in power systems, used to transmit and distribute electrical energy in power systems. The health of transformer winding coils is crucial to the operational reliability of the system. Transformer winding coil accidents are one of the common types of faults in power systems, and their frequency of occurrence is relatively high, seriously affecting the stable operation of power systems. Therefore, strengthening the monitoring of transformer winding status and timely discovering and handling potential faults are of great practical significance for ensuring the stable operation of power systems.
[0055] Further research found that improper selection of excitation signals for monitoring the status of transformer windings will lead to reduced accuracy and reliability of monitoring results, and even cause misjudgment, thus affecting the effectiveness and accuracy of monitoring. Therefore, determining the appropriate excitation signal is a key technical issue that needs to be solved in practical applications.
[0056] However, the existing selection of excitation signals for monitoring the status of transformer windings mostly relies on the experience of relevant technicians. The excitation signals determined by this method have certain subjectivity and uncertainty, which may lead to reduced accuracy and reliability of monitoring results, or even cause misjudgment, thereby affecting the effectiveness and accuracy of monitoring.
[0057] In response to the above problems, the present application proposes a method for determining an excitation signal for monitoring the state of a transformer winding. The most suitable excitation signal is determined in a quantitative manner to avoid the determined excitation signal being affected by subjectivity and uncertainty, so that the determined excitation signal can accurately reflect the state of the transformer winding. The specific implementation principle will be described in detail in the following embodiments.
[0058] In a first aspect, the present application provides a method for determining an excitation signal for monitoring a transformer winding state.
[0059] See also Figure 1 , is a schematic diagram of a method for determining an excitation signal for monitoring a transformer winding state in an embodiment of the present application, the method comprising:
[0060] Step 110: When the winding state of the transformer is the target state, excitation signals of different amplitudes are sequentially injected into the electromagnetic voltage transformer to obtain excitation response signals corresponding to different amplitudes under the target state, wherein the target state includes a normal state and a fault state.
[0061] It should be noted that the excitation signals of different amplitudes in the present application all belong to the same frequency.
[0062] In some embodiments, the present application may preferably use a broadband pulse signal as an excitation signal.
[0063] In some embodiments, when the winding state of the transformer is normal, excitation signals of different amplitudes can be injected into the electromagnetic voltage transformer in sequence to obtain excitation response signals corresponding to different amplitudes in the normal state; and when the winding state of the transformer is a fault state, excitation signals of different amplitudes can be injected into the electromagnetic voltage transformer in sequence to obtain excitation response signals corresponding to different amplitudes in the fault state.
[0064] Step 120: Determine the center of gravity frequency and mean square frequency corresponding to each amplitude in the target state according to the excitation response signal corresponding to each amplitude in the target state.
[0065] Among them, the center of gravity frequency and the mean square frequency are both indicators used to describe the frequency characteristics of the signal. The center of gravity frequency focuses on the energy distribution of the signal in the frequency domain, while the mean square frequency focuses on the energy distribution of the signal in the time domain. This application uses the center of gravity frequency and the mean square frequency to analyze the frequency characteristics of the excitation response signal from different angles, so that the optimal excitation signal determined subsequently has sensitivity and accuracy when monitoring the transformer winding status.
[0066] In some embodiments, the centroid frequency and mean square frequency corresponding to each amplitude in the normal state can be determined based on the excitation response signal corresponding to each amplitude in the normal state, and the centroid frequency and mean square frequency corresponding to each amplitude in the fault state can be determined based on the excitation response signal corresponding to each amplitude in the fault state.
[0067] Step 130: Determine the determination factor corresponding to each amplitude according to the centroid frequency and mean square frequency corresponding to each amplitude under the target state.
[0068] It should be noted that the determination factor reflects the degree of correlation between the signal characteristics and the winding state. By determining the factor, the present application can combine the frequency characteristics of the excitation response signals at different angles so that the optimal excitation signal determined subsequently has better sensitivity and accuracy when monitoring the transformer winding state.
[0069] In some embodiments, the determination factor corresponding to each amplitude may be determined according to the center of gravity frequency and mean square frequency corresponding to each amplitude in a normal state, and the center of gravity frequency and mean square frequency corresponding to each amplitude in a fault state.
[0070] Step 140: Determine the target determination factor according to the determination factors corresponding to all amplitudes.
[0071] It should be noted that the determination factor reflects the degree of correlation between the signal characteristics and the winding state, and the target determination factor is the determination factor that reflects the highest degree of correlation between the signal characteristics and the winding state. Through the target determination factor, the present application can highly combine the frequency characteristics of the excitation response signals at different angles, so that the optimal excitation signal determined subsequently has the best sensitivity and accuracy when monitoring the transformer winding state.
[0072] Regarding the method of determining the target determination factor, in some embodiments, the present application may preferably use the largest determination factor among the determination factors corresponding to all amplitudes as the target determination factor; of course, in other embodiments, the smallest determination factor may also be used as the target determination factor, or the determination factor in the middle may be used as the target determination factor, which is not limited here.
[0073] Step 150: Determine the optimal excitation signal according to the target determination factor and the excitation signal of the corresponding amplitude.
[0074] It should be noted that the use of the optimal excitation signal determined in the present application can achieve optimal sensitivity and accuracy when monitoring the transformer winding state.
[0075] Regarding the method for determining the optimal excitation signal, in some embodiments, the present application may preferably take the product between the target determination factor and the excitation signal of the corresponding amplitude as the optimal excitation signal; of course, in other embodiments, the quotient between the target determination factor and the excitation signal of the corresponding amplitude may be taken as the optimal excitation signal, or the sum of the target determination factor and the excitation signal of the corresponding amplitude may be taken as the optimal excitation signal, or the difference between the target determination factor and the excitation signal of the corresponding amplitude may be taken as the optimal excitation signal, which is not limited here.
[0076] In an embodiment of the present application, by injecting excitation signals of different amplitudes in sequence when the winding state of the transformer is in a normal state and a fault state, and determining the center of gravity frequency and mean square frequency, the determination factor and the target determination factor in sequence based on the excitation response signals obtained after the injection of different amplitudes, and finally determining the optimal excitation signal based on the target determination factor and the excitation signal of the corresponding amplitude, that is, a quantitative method is used to determine the most appropriate excitation signal, so as to avoid the determined excitation signal being affected by subjectivity and uncertainty, so that the determined excitation signal can accurately reflect the winding state of the transformer, so as to improve the accuracy and reliability of the monitoring results, effectively reduce the risk of misjudgment, and further improve the effectiveness and accuracy of monitoring, thereby ensuring the stable operation of the power system.
[0077] In addition, the method of the present application also has the following advantages: by adopting a scientifically verified optimal excitation signal, the number of unnecessary equipment inspections and maintenance caused by misjudgment is reduced, thereby reducing maintenance costs; based on a comprehensive analysis of the center of gravity frequency and the mean square frequency, the transformer winding status can be judged more accurately, the sensitivity of fault judgment can be improved, and the power system operation risks caused by inaccurate judgment can be reduced; by accurately monitoring the winding status, the power system operation strategy can be optimized, the imbalance of power supply and demand caused by faults can be avoided, and the economic benefits and stability of the power system can be improved; by timely discovering and handling winding faults, the further development of faults can be effectively reduced, thereby extending the service life of the equipment and reducing the frequency and cost of equipment replacement; by determining the quantitative excitation signal, the monitoring process can be simplified, the need for manual intervention can be reduced, operation and maintenance management can be optimized, and operation and maintenance efficiency can be improved.
[0078] In a feasible implementation, step 120 in the above embodiment determines the centroid frequency and mean square frequency corresponding to each amplitude in the target state according to the excitation response signal corresponding to each amplitude in the target state, including: performing Fourier transform on the excitation response signal corresponding to each amplitude in the target state to obtain the frequency domain excitation response signal corresponding to each amplitude in the target state; determining the power density spectrum corresponding to the excitation response data point of each amplitude in the target state at each frequency according to the excitation response data point of the frequency domain excitation response signal corresponding to each amplitude in the target state at each frequency; determining the centroid frequency and mean square frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data point of each amplitude in the target state at all frequencies.
[0079] In some embodiments, the excitation response signal corresponding to each amplitude in the normal state can be Fourier transformed to obtain the frequency domain excitation response signal corresponding to each amplitude in the normal state, and the excitation response signal corresponding to each amplitude in the fault state can be Fourier transformed to obtain the frequency domain excitation response signal corresponding to each amplitude in the fault state, and then the power density spectrum corresponding to the excitation response data point of each amplitude in the normal state at each frequency is determined according to the excitation response data point of the frequency domain excitation response signal corresponding to each amplitude in the normal state at each frequency, and the power density spectrum corresponding to the excitation response data point of each amplitude in the fault state at each frequency is determined according to the excitation response data point of the frequency domain excitation response signal corresponding to each amplitude in the fault state, and finally the centroid frequency and mean square frequency corresponding to each amplitude in the normal state are determined according to the power density spectrum corresponding to the excitation response data point of each amplitude in all frequencies in the normal state, and the centroid frequency and mean square frequency corresponding to each amplitude in the fault state are determined according to the power density spectrum corresponding to the excitation response data point of each amplitude in all frequencies in the fault state.
[0080] In an embodiment of the present application, by introducing Fourier transform and converting the time domain signal into a frequency domain signal, the characteristics of the signal at different frequencies can be analyzed more accurately, which helps to accurately determine the center of gravity frequency and the mean square frequency, thereby improving the accuracy of monitoring. Furthermore, the introduction of the power density spectrum can better reflect the energy distribution of the signal at different frequencies, and thus can more comprehensively describe the frequency characteristics of the excitation response signal, thereby further improving the accuracy of monitoring.
[0081] In a feasible implementation, the above-mentioned embodiment determines the power density spectrum corresponding to the excitation response data point of each amplitude in the target state at each frequency according to the excitation response data point of the frequency domain excitation response signal corresponding to each amplitude in the target state at each frequency, including: determining the standard excitation response signal corresponding to each amplitude in the target state according to the frequency domain excitation response signal corresponding to each amplitude in the target state and a preset frequency range; determining the power density spectrum corresponding to the excitation response data point of each amplitude in the target state at each frequency according to the excitation response data point of the standard excitation response signal corresponding to each amplitude in the target state.
[0082] The preset frequency range may be obtained and pre-set by an operator based on a large amount of experience, experiments or statistics.
[0083] Regarding the method for determining the standard excitation response signal, in some embodiments, the excitation response data points that exceed a preset frequency range can be removed from the excitation response data points of the frequency domain excitation response signal corresponding to each amplitude in the target state at all frequencies to obtain the standard excitation response signal corresponding to each amplitude in the target state.
[0084] Regarding the setting method of the preset frequency range, in some embodiments, the present application may preferably set the preset frequency range to [100 kHz, 1 MHz].
[0085] In some embodiments, the standard excitation response signal corresponding to each amplitude in the normal state can be determined based on the frequency domain excitation response signal corresponding to each amplitude in the normal state and the preset frequency range, and the standard excitation response signal corresponding to each amplitude in the fault state can be determined based on the frequency domain excitation response signal corresponding to each amplitude in the fault state and the preset frequency range. Then, the power density spectrum corresponding to the excitation response data point of each amplitude in the normal state at each frequency can be determined based on the excitation response data point of the standard excitation response signal corresponding to each amplitude in the normal state at each frequency, and the power density spectrum corresponding to the excitation response data point of each amplitude in the fault state at each frequency can be determined based on the excitation response data point of the standard excitation response signal corresponding to each amplitude in the fault state at each frequency.
[0086] In an embodiment of the present application, by processing the frequency domain excitation response signal, the excitation response data points that exceed the preset frequency range are removed, thereby obtaining a standard excitation response signal. This helps to remove unnecessary data that is not required for monitoring, so that the subsequently determined power density spectrum more accurately reflects useful information, thereby improving the accuracy of monitoring. Furthermore, determining the power density spectrum based on the standard excitation response signal can better reflect the energy distribution of the signal at different frequencies, thereby being able to more comprehensively describe the frequency characteristics of the excitation response signal, further improving the accuracy of monitoring.
[0087] In a feasible implementation, the above embodiment determines the power density spectrum corresponding to the excitation response data point of each amplitude at each frequency in the target state according to the excitation response data point of the standard excitation response signal corresponding to each amplitude in the target state at each frequency, including:
[0088] Using the formula Determine the power density spectrum corresponding to the excitation response data point at each amplitude at each frequency in the target state;
[0089] Among them, N R,i (f R,i,n ) is the power density spectrum corresponding to the stimulus response data point of the ith amplitude at the nth frequency, T is the time of Fourier transform of the stimulus response signal corresponding to the ith amplitude, E is the preset expected value, N R,i (f R,i,n ,T) is the excitation response data point of the standard excitation response signal corresponding to the ith amplitude at the nth frequency. When R is S, the target state is normal, and when R is M, the target state is faulty.
[0090] It should be noted that the preset expected value can be obtained and pre-set by the operator based on a large amount of experience, experiments or statistics. Of course, it can also be set by the operator according to actual needs, and this application does not limit it here.
[0091] In the embodiments of the present application, a rigorous calculation formula for the power density spectrum is provided from a mathematical perspective. The accuracy of the calculated power density spectrum can be ensured from the rigor of mathematical logic, and the above calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel.
[0092] In addition, by adopting the calculation formula of the power density spectrum preferably provided in the above-mentioned application to calculate the power density spectrum, the power density spectrum corresponding to the excitation response data point at each frequency can be accurately calculated, so as to clearly convert the data changes of the standard excitation response signal at different frequency points into the power density spectrum, thereby being able to more accurately describe the energy distribution of the signal at different frequencies and further improve the monitoring accuracy.
[0093] In a feasible implementation, the method of determining the center of gravity frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data points of each amplitude in the target state at all frequencies in the above embodiment includes:
[0094] Using the formula Determine the center of gravity frequency corresponding to each amplitude in the target state;
[0095] Among them, f R,i is the centroid frequency corresponding to the ith amplitude, N is the total number of frequencies of the ith amplitude, N R,i (f R,i,n ) is the power density spectrum corresponding to the excitation response data point with the ith amplitude at the nth frequency, f R,i,n is the nth frequency of the ith amplitude. When R is S, the target state is normal. When R is M, the target state is faulty.
[0096] In the embodiments of the present application, a rigorous calculation formula for the center of gravity frequency is provided from a mathematical perspective. The accuracy of the calculated center of gravity frequency can be ensured from the rigor of mathematical logic, and the above calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel.
[0097] In addition, by adopting the calculation formula of the center of gravity frequency preferably provided in the above-mentioned application to calculate the center of gravity frequency, the obtained center of gravity frequency has a higher accuracy, which can avoid the errors caused by subjective judgment, thereby improving the precision and accuracy of monitoring. Moreover, since the center of gravity frequency can more objectively reflect the energy distribution of the signal at different frequencies, the accurate center of gravity frequency can further improve the sensitivity and accuracy of monitoring the transformer winding status.
[0098] In a feasible implementation, the above embodiment determines the mean square frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data point of each amplitude in the target state at all frequencies, including:
[0099] Using the formula Determine the mean square frequency corresponding to each amplitude under the target state;
[0100] Among them, MSF R,iis the mean square frequency corresponding to the ith amplitude, [f min , f max ] is the preset frequency range, N R,i (f R,i,n ) is the power density spectrum corresponding to the excitation response data point with the ith amplitude at the nth frequency, f R,i,n is the nth frequency of the ith amplitude. When R is S, the target state is normal. When R is M, the target state is faulty.
[0101] Regarding the setting method of the preset frequency range, in some embodiments, the present application may preferably set the preset frequency range to [100kHz, 1MHz], that is, f min Set it to 100kHz, and f max Set to 1MHz.
[0102] In the embodiments of the present application, a rigorous formula for calculating the mean square frequency is provided from a mathematical perspective. The accuracy of the calculated mean square frequency can be ensured from the rigor of mathematical logic, and the above-mentioned calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel.
[0103] In addition, by adopting the calculation formula of the mean square frequency preferably provided in the above-mentioned application to calculate the mean square frequency, the obtained mean square frequency has a higher accuracy, which can avoid the errors caused by subjective judgment, thereby improving the precision and accuracy of monitoring. Moreover, since the mean square frequency can more objectively reflect the energy distribution of the signal at different frequencies, the accurate mean square frequency can further improve the sensitivity and accuracy of monitoring the transformer winding status.
[0104] In a feasible implementation, step 130 in the above embodiment, determining the determination factor corresponding to each amplitude according to the center of gravity frequency and mean square frequency corresponding to each amplitude in the target state, includes:
[0105] Using the formula Determine the determination factor corresponding to each amplitude;
[0106] Among them, λ i is the determination factor corresponding to the i-th amplitude, e is a natural constant, f M,i is the center of gravity frequency corresponding to the i-th amplitude under fault condition, f S,i is the center of gravity frequency corresponding to the ith amplitude in the normal state, MSF M,i is the mean square frequency corresponding to the i-th amplitude under fault conditions, MSF S,i is the mean square frequency corresponding to the ith amplitude under normal conditions, and tan() is the tangent function.
[0107] In the embodiments of the present application, a rigorous calculation formula for the determination factor is provided from a mathematical perspective. The accuracy of the calculated determination factor can be ensured from the rigor of mathematical logic, and the above calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel.
[0108] In addition, by adopting the calculation formula of the determination factor preferably provided in the above-mentioned application to calculate the determination factor, the obtained determination factor has higher accuracy and can more comprehensively reflect the relationship between the signal and the winding state, so as to improve the sensitivity and accuracy of monitoring the transformer winding state.
[0109] In a feasible implementation, step 150 in the above embodiment, determining the optimal excitation signal according to the target determination factor and the excitation signal of the corresponding amplitude, includes:
[0110] Using the formula W s (t) = λ r W r (t) determining the optimal excitation signal;
[0111] Among them, W s (t) is the optimal excitation signal, λ r is the target determination factor, W r (t) is the excitation signal with the amplitude corresponding to the target determination factor.
[0112] In the embodiments of the present application, a rigorous calculation formula for the optimal excitation signal is provided from a mathematical perspective. The accuracy of the calculated optimal excitation signal can be ensured from the rigor of mathematical logic, and the above calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel.
[0113] In addition, by adopting the calculation formula of the optimal excitation signal preferably provided in the above-mentioned application to calculate the optimal excitation signal, the obtained optimal excitation signal has a higher accuracy, which can ensure that the excitation signal used subsequently can best reflect the characteristics of the transformer winding state, improve the accuracy and reliability of monitoring, thereby reducing the risk of misjudgment, improving the effectiveness and accuracy of monitoring, and ensuring the stable operation of the power system.
[0114] In a feasible implementation, step 140 in the above embodiment, determining the target determination factor according to the determination factors corresponding to all amplitudes, includes: among the determination factors corresponding to all amplitudes, taking the largest determination factor as the target determination factor.
[0115] In the embodiment of the present application, by taking the maximum determination factor as the target determination factor, it is ensured that the selected determination factor can reflect the strongest correlation between the signal characteristics and the transformer winding state, which means that the selected optimal excitation signal can have higher sensitivity and accuracy when monitoring the transformer winding state, thereby improving the accuracy and reliability of monitoring.
[0116] In a feasible implementation, step 110 in the above embodiment, when the winding state of the transformer is the target state, injecting excitation signals of different amplitudes into the electromagnetic voltage transformer in sequence to obtain excitation response signals corresponding to different amplitudes in the target state, includes: when the winding state of the transformer is a normal state, injecting an excitation signal into the electromagnetic voltage transformer, and adjusting the amplitude of the injected excitation signal within a preset amplitude range according to a preset step size to obtain excitation response signals corresponding to different amplitudes in the normal state; when the winding state of the transformer is a fault state, injecting an excitation signal into the electromagnetic voltage transformer, and adjusting the amplitude of the injected excitation signal within a preset amplitude range according to a preset step size to obtain excitation response signals corresponding to different amplitudes in the fault state.
[0117] Among them, the preset amplitude range and the preset step size can be obtained and pre-set by the operator based on a lot of experience, experiments or statistics. Of course, they can also be set by the operator according to actual needs, and this application does not limit this.
[0118] In some embodiments, within a preset amplitude range, the amplitude of the injected excitation signal may be adjusted incrementally or incrementally according to a preset step size, which is not limited here.
[0119] In the embodiment of the present application, by adjusting the amplitude of the injected excitation signal within the preset amplitude range according to the preset step size, it is possible to comprehensively cover different situations within the amplitude range and obtain more data points, thereby improving the comprehensiveness and accuracy of the data. By adjusting according to the preset step size, the continuity from low amplitude to high amplitude is ensured, covering various possible states, increasing the diversity of the excitation signal, and providing a basis for more comprehensive analysis.
[0120] In a second aspect, the present application provides an excitation signal determination device for monitoring the state of a transformer winding.
[0121] See also Figure 2 , is a schematic diagram of an excitation signal determination device for monitoring the state of a transformer winding in an embodiment of the present application, the device 210 includes:
[0122] A sequential injection module 211 is used to sequentially inject excitation signals of different amplitudes at the electromagnetic voltage transformer when the winding state of the transformer is a target state, so as to obtain excitation response signals corresponding to different amplitudes under the target state, wherein the target state includes a normal state and a fault state;
[0123] A frequency determination module 212, for determining the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state according to the excitation response signal corresponding to each amplitude under the target state;
[0124] A factor determination module 213, used to determine a determination factor corresponding to each amplitude according to the centroid frequency and mean square frequency corresponding to each amplitude under the target state;
[0125] A target factor determination module 214 is used to determine a target determination factor according to the determination factors corresponding to all amplitudes;
[0126] The optimal determination module 215 is used to determine the optimal excitation signal according to the target determination factor and the excitation signal of the corresponding amplitude.
[0127] In the embodiment of the present application, the related contents of the above-mentioned sequential injection module 211, frequency determination module 212, factor determination module 213, target factor determination module 214 and optimal determination module 215 can be referred to. Figure 1 The contents in the illustrated embodiment will not be described in detail here.
[0128] It should be noted that the device 210 of the present application also includes some other modules. It can be understood that the method of the present application and the device 210 have a one-to-one correspondence. Therefore, some other modules of the device 210 of the present application are the contents corresponding to the method of the present application in the above-mentioned embodiment.
[0129] In an embodiment of the present application, by injecting excitation signals of different amplitudes in sequence when the winding state of the transformer is in a normal state and a fault state, and determining the center of gravity frequency and mean square frequency, the determination factor and the target determination factor in sequence based on the excitation response signals obtained after the injection of different amplitudes, and finally determining the optimal excitation signal based on the target determination factor and the excitation signal of the corresponding amplitude, that is, a quantitative method is used to determine the most appropriate excitation signal, so as to avoid the determined excitation signal being affected by subjectivity and uncertainty, so that the determined excitation signal can accurately reflect the winding state of the transformer, so as to improve the accuracy and reliability of the monitoring results, effectively reduce the risk of misjudgment, and further improve the effectiveness and accuracy of monitoring, thereby ensuring the stable operation of the power system.
[0130] In addition, the method of the present application also has the following advantages: by adopting a scientifically verified optimal excitation signal, the number of unnecessary equipment inspections and maintenance caused by misjudgment is reduced, thereby reducing maintenance costs; based on a comprehensive analysis of the center of gravity frequency and the mean square frequency, the transformer winding status can be judged more accurately, the sensitivity of fault judgment can be improved, and the power system operation risks caused by inaccurate judgment can be reduced; by accurately monitoring the winding status, the power system operation strategy can be optimized, the imbalance of power supply and demand caused by faults can be avoided, and the economic benefits and stability of the power system can be improved; by timely discovering and handling winding faults, the further development of faults can be effectively reduced, thereby extending the service life of the equipment and reducing the frequency and cost of equipment replacement; by determining the quantitative excitation signal, the monitoring process can be simplified, the need for manual intervention can be reduced, operation and maintenance management can be optimized, and operation and maintenance efficiency can be improved.
[0131] In a third aspect, the present application further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes a method for determining an excitation signal for monitoring the state of a transformer winding in the above method embodiment.
[0132] In a fourth aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes a method for determining an excitation signal for monitoring the state of a transformer winding in the above method embodiment.
[0133] Figure 3 The internal structure diagram of a computer device in some embodiments is shown. The computer device may be a terminal, a server, or a gateway. Figure 3 As shown, the computer device includes a processor, a memory and a network interface connected through a system bus.
[0134] The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement each step in the above method embodiment. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can implement each step in the above method embodiment. Those skilled in the art can understand that Figure 3 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.
[0135] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods.
[0136] Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synch li nk) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).
[0137] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above 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.
[0138] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.
Claims
1. A method for determining an excitation signal for monitoring a transformer winding state, characterized in that: The method comprises: When the winding state of the transformer is a target state, excitation signals of different amplitudes are sequentially injected into the electromagnetic voltage transformer to obtain excitation response signals corresponding to different amplitudes under the target state, wherein the target state includes a normal state and a fault state; Determine the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state according to the excitation response signal corresponding to each amplitude under the target state; Determine a determination factor corresponding to each amplitude according to the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state; Determine the target determination factor according to the determination factors corresponding to all amplitudes; An optimal excitation signal is determined according to the target determination factor and the excitation signal of the corresponding amplitude.
2. The method according to claim 1, characterized in that The step of determining the center of gravity frequency and mean square frequency corresponding to each amplitude in the target state according to the excitation response signal corresponding to each amplitude in the target state includes: Performing Fourier transform on the excitation response signal corresponding to each amplitude under the target state to obtain a frequency domain excitation response signal corresponding to each amplitude under the target state; Determine a power density spectrum corresponding to an excitation response data point of each amplitude at each frequency in the target state according to an excitation response data point of a frequency domain excitation response signal corresponding to each amplitude at each frequency in the target state; The center of gravity frequency and mean square frequency corresponding to each amplitude in the target state are determined according to the power density spectrum corresponding to the excitation response data points of each amplitude at all frequencies in the target state.
3. The method according to claim 2, characterized in that The step of determining the power density spectrum corresponding to the excitation response data point of each amplitude at each frequency in the target state according to the excitation response data point of the frequency domain excitation response signal corresponding to each amplitude at each frequency in the target state comprises: Determine a standard excitation response signal corresponding to each amplitude in the target state according to the frequency domain excitation response signal corresponding to each amplitude in the target state and a preset frequency range; The power density spectrum corresponding to the excitation response data point of each amplitude at each frequency in the target state is determined according to the excitation response data point of the standard excitation response signal corresponding to each amplitude at each frequency in the target state.
4. The method according to claim 3, characterized in that Determining the power density spectrum corresponding to the excitation response data point of each amplitude at each frequency in the target state according to the excitation response data point of the standard excitation response signal corresponding to each amplitude in the target state at each frequency includes: Using the formula Determine a power density spectrum corresponding to an excitation response data point at each amplitude at each frequency in the target state; Among them, N R,i (f R,i,n ) is the power density spectrum corresponding to the stimulus response data point of the ith amplitude at the nth frequency, T is the time of Fourier transform of the stimulus response signal corresponding to the ith amplitude, E is the preset expected value, N R,i (f R,i,n , T) is the excitation response data point of the standard excitation response signal corresponding to the ith amplitude at the nth frequency. When R is S, the target state is the normal state, and when R is M, the target state is the fault state.
5. The method according to claim 2 or 3, characterized in that: Determining the center of gravity frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data points of each amplitude at all frequencies in the target state includes: Using the formula Determining the center of gravity frequency corresponding to each amplitude under the target state; Among them, f R,i is the centroid frequency corresponding to the ith amplitude, N is the total number of frequencies of the ith amplitude, N R,i (f R,i,n ) is the power density spectrum corresponding to the stimulus response data point with the ith amplitude at the nth frequency, f R,i,n is the nth frequency of the ith amplitude, when R is S, the target state is the normal state, and when R is M, the target state is the fault state.
6. The method according to claim 2 or 3, characterized in that: Determining the mean square frequency corresponding to each amplitude in the target state according to the power density spectrum corresponding to the excitation response data points of each amplitude at all frequencies in the target state includes: Using the formula Determine the mean square frequency corresponding to each amplitude under the target state; Among them, MSF R,i is the mean square frequency corresponding to the ith amplitude, [f min , f max ] is the preset frequency range, N R,i (f R,i,n ) is the power density spectrum corresponding to the stimulus response data point with the ith amplitude at the nth frequency, f R,i,n is the nth frequency of the ith amplitude, when R is S, the target state is the normal state, and when R is M, the target state is the fault state.
7. The method according to claim 1, characterized in that The determining factor corresponding to each amplitude according to the center of gravity frequency and mean square frequency corresponding to each amplitude under the target state includes: Using the formula Determine the determination factor corresponding to each amplitude; Among them, λ i is the determination factor corresponding to the i-th amplitude, e is a natural constant, f M,i is the center of gravity frequency corresponding to the i-th amplitude under the fault state, f S,i is the center of gravity frequency corresponding to the ith amplitude in the normal state, MSF M,i is the mean square frequency corresponding to the i-th amplitude under the fault state, MSF S,i is the mean square frequency corresponding to the ith amplitude in the normal state, and tan() is the tangent function.
8. The method according to claim 1, characterized in that The step of determining the optimal excitation signal according to the target determination factor and the excitation signal of the corresponding amplitude includes: Using the formula W s (t) = λ r W r (t) determining the optimal excitation signal; Among them, W s (t) is the optimal excitation signal, λ r Determine the factor for the target, W r (t) is the excitation signal of the amplitude corresponding to the target determination factor.
9. The method according to claim 1, characterized in that: The step of determining the target determination factor according to the determination factors corresponding to all amplitudes includes: Among the determination factors corresponding to all amplitudes, the largest determination factor is used as the target determination factor.
10. The method according to claim 1, characterized in that When the winding state of the transformer is the target state, the excitation signals of different amplitudes are sequentially injected into the electromagnetic voltage transformer to obtain the excitation response signals corresponding to the different amplitudes under the target state, including: When the winding state of the transformer is the normal state, an excitation signal is injected into the electromagnetic voltage transformer, and the amplitude of the injected excitation signal is adjusted according to a preset step size within a preset amplitude range to obtain excitation response signals corresponding to different amplitudes in the normal state; When the winding state of the transformer is the fault state, an excitation signal is injected into the electromagnetic voltage transformer, and within the preset amplitude range, the amplitude of the injected excitation signal is adjusted according to the preset step size to obtain excitation response signals corresponding to different amplitudes in the fault state.