A circuit breaker contact failure monitoring device, method and medium

Abstract

The present application relates to the technical field of circuit breaker contact failure monitoring, and specifically to a circuit breaker contact failure monitoring device, method and medium, the method comprising: determining the non-stationary characteristic value of the current signal in the circuit breaker contact; determining the abnormal factor of the current signal in the circuit breaker contact according to the similarity between the current frequency domain signal and the current time-frequency signal, and the discrete degree of the time difference of all adjacent peaks in the current time-frequency signal, and in combination with the non-stationary characteristic value; based on the abnormal factor, determine the dynamic change threshold of the current signal in the circuit breaker contact in combination with a preset threshold, and monitor the circuit breaker contact. The present application improves the accuracy of judging the failure state of the circuit breaker by analyzing the energy distribution difference and periodic stability of the current signal in the frequency domain.

Description

Technical Field

[0001] The present application relates to the technical field of circuit breaker contact failure monitoring, and in particular to a circuit breaker contact failure monitoring device, method and medium. Background Art

[0002] With the continuous expansion and complexity of the power system, the reliability of the circuit breaker, as an important control and protection device in the power system, is directly related to the stability and safety of the power grid. The contact is the core component of the circuit breaker. The failure of the circuit breaker contact may cause damage to the power equipment, power outages, and even fires. With the advancement of sensor technology, signal processing technology, and artificial intelligence algorithms, modern circuit breaker contact failure monitoring technology has been able to achieve real-time, online monitoring. By analyzing the current, voltage, temperature and other parameters of the contact, abnormalities can be detected and warned in time, thereby improving the pertinence and efficiency of maintenance. The application of circuit breaker contact failure monitoring technology can not only reduce the failure rate of power equipment and extend the service life of equipment, but also improve the reliability and stability of the power system, and reduce the economic losses and social impact caused by equipment failure.

[0003] During the use of the circuit breaker, it is easy to be eroded by the electric arc, which may cause the contact of the circuit breaker to fail. The arc erosion is when the circuit breaker disconnects a large current and an arc is generated between the contacts. The high temperature of the arc can quickly erode the circuit breaker contact material, causing the contact surface to melt or burn, thereby affecting its conductive performance. The prior art determines whether the circuit breaker contact has failed by monitoring the current of the circuit breaker. In the process of analyzing the current data, the arc generated by the failure of the circuit breaker contact and the normal load changes will affect the current data information. Using a fixed threshold to determine the abnormality of the current data and thus determine the state of the circuit breaker contact will lead to misjudgment of the state of the circuit breaker contact, thereby reducing the accuracy of the judgment of the state of the circuit breaker contact. Summary of the invention

[0004] In a first aspect, an embodiment of the present application provides a circuit breaker contact failure monitoring method, the method comprising the following steps:

[0005] Acquire a current signal flowing through the circuit breaker contacts within a preset time period;

[0006] The current signal is converted into the frequency domain to obtain a current frequency domain signal, and the power spectrum density at each frequency in the current frequency domain signal is obtained, all the maximum values ​​and all the minimum values ​​in all the power spectrum densities are extracted, and the distribution characteristic value of the current signal in the circuit breaker contact is determined based on the distribution of all the power spectrum densities between any two adjacent minimum values, and the non-stationary characteristic value of the current signal in the circuit breaker contact is determined in combination with the difference in the distribution of all the maximum values ​​and all the minimum values;

[0007] Based on the current signal and using a time-frequency analysis algorithm to obtain the current time-frequency signal, determine the difference index of the current signal in the circuit breaker contact according to the difference between the peak values ​​of the current frequency domain signal and the current time-frequency signal at the same frequency, and determine the periodicity factor of the current signal in the circuit breaker contact in combination with the discrete degree of the time difference between all adjacent peak values ​​in the current time-frequency signal; based on the periodicity factor and the non-stationary eigenvalue, determine the abnormality factor of the current signal in the circuit breaker contact;

[0008] Based on the abnormal factor and in combination with a preset threshold, a dynamic change threshold of the current signal in the circuit breaker contact is determined to monitor the circuit breaker contact.

[0009] Preferably, the method for determining the distribution characteristic value of the current signal in the circuit breaker contact is:

[0010] In the current frequency domain signal, the range of all power spectrum densities between any two adjacent minimum values ​​is calculated, and the discreteness of all ranges is analyzed. The distribution characteristic value of the current signal in the circuit breaker contact is the result of the fusion of the number of all adjacent minimum value pairs and the discreteness.

[0011] Preferably, the non-stationary characteristic value expression of the current signal in the circuit breaker contact is: ; In the formula, A represents the non-stationary characteristic value of the current signal in the circuit breaker contact; m represents the difference between the average level of all maximum values ​​and the average level of all minimum values ​​in the current frequency domain signal in the circuit breaker contact; n represents the distribution characteristic value of the current signal in the circuit breaker contact.

[0012] Preferably, the difference index of the current signal in the circuit breaker contact is an average level of the difference between the current frequency domain signal and all peak values ​​at the same frequency in the current time-frequency signal.

[0013] Preferably, the periodicity factor of the current signal in the circuit breaker contact is the reciprocal of the product of the difference index and the time difference between all adjacent peaks in the current time-frequency signal.

[0014] Preferably, the expression of the abnormal factor of the current signal in the circuit breaker contact is: ; In the formula, B represents the abnormal factor of the current signal in the circuit breaker contact; A represents the non-stationary characteristic value of the current signal in the circuit breaker contact; c represents the periodic factor of the current signal in the circuit breaker contact.

[0015] Preferably, the expression of the dynamic change threshold value of the current signal in the circuit breaker contact is: ; In the formula, represents the dynamic change threshold of the current signal in the circuit breaker contact; B represents the abnormal factor of the current signal in the circuit breaker contact; K represents the preset threshold; exp( ) represents an exponential function with a natural constant as the base.

[0016] Preferably, the monitoring of the circuit breaker contacts includes:

[0017] If the extreme difference of all current data in the current signal of the preset time length is greater than the dynamic change threshold, the circuit breaker contact fails, otherwise, the circuit breaker contact does not fail.

[0018] In a second aspect, an embodiment of the present application provides a circuit breaker contact failure monitoring device, the device comprising:

[0019] A current data acquisition module is used to obtain the current signal flowing through the circuit breaker contacts within a preset time period;

[0020] A data analysis and acquisition module, used to convert the current signal into the frequency domain to obtain the current frequency domain signal, and obtain the power spectrum density at each frequency in the current frequency domain signal, extract all the maximum values ​​and all the minimum values ​​in all the power spectrum densities, determine the distribution characteristic value of the current signal in the circuit breaker contact based on the distribution of all the power spectrum densities between any two adjacent minimum values, and determine the non-stationary characteristic value of the current signal in the circuit breaker contact in combination with the difference in the distribution of all the maximum values ​​and all the minimum values;

[0021] Based on the current signal and using a time-frequency analysis algorithm to obtain the current time-frequency signal, determine the difference index of the current signal in the circuit breaker contact according to the difference between the peak values ​​of the current frequency domain signal and the current time-frequency signal at the same frequency, and determine the periodicity factor of the current signal in the circuit breaker contact in combination with the discrete degree of the time difference between all adjacent peak values ​​in the current time-frequency signal; based on the periodicity factor and the non-stationary eigenvalue, determine the abnormality factor of the current signal in the circuit breaker contact;

[0022] The circuit breaker contact monitoring module is used to determine the dynamic change threshold of the current signal in the circuit breaker contact based on the abnormal factor and the preset threshold, and monitor the circuit breaker contact.

[0023] In a third aspect, an embodiment of the present application further provides a circuit breaker contact failure monitoring medium, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, the steps of a circuit breaker contact failure monitoring method described in any one of the above items are implemented.

[0024] It can be seen from the above embodiments that the circuit breaker contact failure monitoring method provided in the embodiments of the present application has at least the following beneficial effects:

[0025] The present application determines the distribution characteristic value of the current signal in the circuit breaker contact by analyzing the distribution of all power spectrum densities between any two adjacent minimum values ​​in the current frequency domain signal, and determines the non-stationary characteristic value of the current signal in the circuit breaker contact in combination with the difference in distribution between all maximum values ​​and all minimum values. The beneficial effect is that the current change caused by normal load change and the current characteristic change caused by contact failure can be distinguished. The present application determines the abnormal factor of the current signal in the circuit breaker contact based on the similarity between the current frequency domain signal and the current time-frequency signal, and the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal, and in combination with the non-stationary characteristic value. The beneficial effect is that the interference of normal load change on current change can be eliminated, and whether the circuit breaker contact has failed can be judged more accurately.

[0026] The present application determines the dynamic change threshold of the current signal by analyzing the energy distribution difference and periodic stability of the current signal in the frequency domain, reduces the interference of normal load changes on the judgment of the circuit breaker failure state, and improves the accuracy of the judgment of the circuit breaker failure state. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A flowchart of a circuit breaker contact failure monitoring method provided by an embodiment of the present application;

[0029] Figure 2 A schematic diagram of an abnormal factor extraction process provided by an embodiment of the present application;

[0030] Figure 3 A block diagram of a circuit breaker contact failure monitoring system provided for one embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of a circuit breaker contact failure monitoring device, method and medium proposed in the present application, its specific implementation, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0032] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0033] The specific scheme of a circuit breaker contact failure monitoring device, method and medium provided by the present application is described in detail below with reference to the accompanying drawings.

[0034] See also Figure 1 , which shows a flow chart of a circuit breaker contact failure monitoring method provided by an embodiment of the present application, the method comprising the following steps:

[0035] Step S1: obtaining a current signal flowing through a circuit breaker contact within a preset time period.

[0036] A current transformer is installed at the output end of the circuit breaker to monitor the current passing through the circuit breaker in real time, collect the current data flowing through the circuit breaker contacts at all times within a preset time, set the data collection frequency to f, and normalize all the current data collected within the preset time. All normalized results constitute the current signal of the circuit breaker contacts within the preset time. The current signal is composed of multiple discrete current data.

[0037] Among them, the value of the preset time length t and the value of the data collection frequency f are both manually set. In this embodiment, the value of the preset time length t is 5 minutes, and the value of the data collection frequency f is 30 Hz. The implementer can set them according to the specific situation, and this embodiment does not impose any special restrictions.

[0038] It should be noted that there are many commonly used normalization processing methods. The z-score normalization method is used in this embodiment. The implementer can also use other normalization processing methods such as maximum and minimum value normalization method. Regarding the selection of normalization processing method, this embodiment does not make any special restrictions.

[0039] Among them, the z-score normalization method is a well-known technology, and the specific process of normalizing the data is not repeated here.

[0040] Step S2: Based on the distribution of all power spectrum densities between any two adjacent minimum values, determine the distribution characteristic value of the current signal in the circuit breaker contact, and combine the difference in distribution between all maximum values ​​and all minimum values ​​to determine the non-stationary characteristic value of the current signal in the circuit breaker contact.

[0041] When the contacts of the circuit breaker are not failed, the current changes caused by normal load changes in the circuit system usually appear as a relatively smooth spectrum in the frequency domain. However, when the contacts of the circuit breaker fail, the spectrum may have additional peaks or energy concentrated on certain specific frequencies. These peaks may indicate an increase in vibration noise caused by contact failure.

[0042] Therefore, in order to analyze the change of current caused by load change in the frequency domain, a frequency domain conversion algorithm is used to convert the current signal of a preset time length into the frequency domain, and output a current frequency domain signal.

[0043] It should be noted that there are many commonly used frequency domain conversion algorithms. In this embodiment, discrete Fourier transform is used to convert the current signal in the time domain into the frequency domain. The implementer may also use other frequency domain conversion algorithms such as fast Fourier transform. Regarding the selection of frequency domain conversion algorithm, this embodiment does not impose any special restrictions.

[0044] Among them, discrete Fourier transform is a well-known technology, and the specific process of converting time domain data into frequency domain is not repeated here.

[0045] Furthermore, in order to distinguish the current change caused by normal load change from the current characteristic change caused by contact failure, the non-stationary characteristic value of the current signal in the circuit breaker contact is determined by analyzing the distribution of all power spectrum densities between any two adjacent minima and combining the difference in the distribution of all maxima and all minima to quantify the possibility of circuit breaker contact failure. The specific determination process of the non-stationary characteristic value is as follows:

[0046] (1) Calculate the power spectrum density at each frequency in the current frequency domain signal. The calculation process of the power spectrum density is a well-known technology and its specific calculation process will not be repeated here.

[0047] (2) Furthermore, the power spectrum density at all frequencies is used as the input of the extreme point detection algorithm, and all the maximum values ​​and all the minimum values ​​in the power spectrum density at all frequencies are output.

[0048] (3) Furthermore, in the current frequency domain signal, the range of all power spectrum densities between any two adjacent minimum values ​​is calculated, and the discreteness of all the ranges is analyzed. The distribution characteristic value of the current signal in the circuit breaker contact is the result of the fusion of the number of all adjacent minimum value pairs and the discreteness.

[0049] It should be noted that there are many methods for measuring the degree of discreteness of a set of data. In this embodiment, the degree of discreteness of all the extremes is measured by calculating the standard deviation of all the extremes. In actual application, as other implementation methods, the implementer may also use other methods for measuring the degree of discreteness of data such as variance or coefficient of dispersion. Regarding the selection of the method for measuring the degree of discreteness, this embodiment does not impose any special restrictions. Preferably, in this embodiment, the distribution characteristic value of the current signal in the circuit breaker contact is the product of the number of all adjacent minimum value pairs and the degree of discreteness; in actual application, as other implementation methods, the distribution characteristic value of the current signal in the circuit breaker contact is an exponential function value with a natural constant as the base and the sum of the number of all adjacent minimum value pairs and the degree of discreteness as the independent variable.

[0050] The more pairs of adjacent minimum values, the greater the degree of discreteness of all extreme differences, which means that the energy distribution in the current frequency domain signal is more uneven, and the more likely it is caused by contact failure, and the larger the distribution characteristic value; conversely, the more pairs of adjacent minimum values, the smaller the degree of discreteness of all extreme differences, which means that the energy distribution in the current frequency domain signal is more uniform, and the less likely it is caused by contact failure, and the smaller the distribution characteristic value.

[0051] (4) The non-stationary characteristic value expression of the current signal in the circuit breaker contact is: ; In the formula, A represents the non-stationary characteristic value of the current signal in the circuit breaker contact; m represents the difference between the average level of all maximum values ​​and the average level of all minimum values ​​in the current frequency domain signal in the circuit breaker contact; n represents the distribution characteristic value of the current signal in the circuit breaker contact.

[0052] It should be noted that there are many ways to measure the differences between data. In this embodiment, the difference between the average level of all maximum values ​​and the average level of all minimum values ​​is measured by calculating the absolute value of the difference between the average level of all maximum values ​​and the average level of all minimum values. Implementers can also use other methods of measuring differences such as ratios, and this embodiment does not impose any special restrictions.

[0053] In addition, there are many ways to measure the average level of a set of data. In this embodiment, the average distribution of the maximum values ​​and the average distribution of the minimum values ​​are measured by calculating the mean of all the maximum values ​​and the mean of all the minimum values, respectively. The implementer can also use other methods such as the geometric mean to measure the average level of data. Regarding the choice of method for measuring the average level of data, this embodiment does not impose any special restrictions.

[0054] Further, according to the non-stationary eigenvalue of the current signal, it can be understood that the distribution eigenvalue reflects the uneven degree of energy distribution of the current signal in the frequency domain. The more adjacent minimum value pairs in the current frequency domain signal, the greater the discrete degree of all extreme differences, the larger the distribution eigenvalue, and the greater the difference between the average level of all maximum values ​​and the average level of all minimum values ​​in the current frequency domain signal, indicating that the difference in power spectrum density at different frequencies is greater, then the non-stationary eigenvalue of the current signal is greater, indicating that the possibility of failure of the circuit breaker contact is greater; conversely, the fewer adjacent minimum value pairs in the current frequency domain signal, the smaller the discrete degree of all extreme differences, the smaller the distribution eigenvalue, and the smaller the difference between the average level of all maximum values ​​and the average level of all minimum values ​​in the current frequency domain signal, indicating that the difference in power spectrum density at different frequencies is smaller, then the non-stationary eigenvalue of the current signal is smaller, indicating that the possibility of failure of the circuit breaker contact is smaller.

[0055] Step S3: Based on the similarity between the current frequency domain signal and the current time-frequency signal, determine the difference index of the current signal in the circuit breaker contact, and determine the periodic factor of the current signal in the circuit breaker contact in combination with the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal; based on the periodic factor and the non-stationary eigenvalue, determine the abnormal factor current time-frequency signal of the current signal in the circuit breaker contact.

[0056] In addition to having smooth signal characteristics, the current signal generated by normal load changes in the circuit system also has a certain periodicity due to the periodicity of the load operation. When the circuit breaker contacts fail, due to poor contact or arc discharge, the current signal will show non-periodic fluctuations and transient changes. These abnormal phenomena destroy the periodicity of the current during normal operation, causing the periodicity characteristics of the current signal to be inconsistent with the normal periodicity.

[0057] In order to analyze the dynamic information of the current signal in the time and frequency domain, the current signal is used as the input of the time-frequency analysis algorithm, and the current time-frequency signal is output. The periodic current time-frequency signal usually shows a repetitive pattern at a specific frequency.

[0058] It should be noted that there are many commonly used time-frequency analysis algorithms. In this embodiment, the Wigner-Ville distribution algorithm is used to obtain the current time-frequency signal of the current signal. In actual application, as other implementation methods, the implementer may also use other time-frequency analysis algorithms such as short-time Fourier transform or wavelet transform according to specific circumstances. This embodiment does not impose any special restrictions on the selection of the time-frequency analysis algorithm.

[0059] The Wigner-Ville distribution algorithm is a well-known technology, and the specific process of performing time-frequency transformation is not described in detail.

[0060] Furthermore, in order to quantify the abnormality of the current signal in the circuit breaker contact, the periodicity factor of the current signal in the circuit breaker contact is determined according to the similarity between the current frequency domain signal and the current time-frequency signal, and combined with the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal; based on the periodicity factor and the non-stationary eigenvalue, the abnormality factor of the current signal in the circuit breaker contact is determined to more accurately judge whether the circuit breaker contact has failed, specifically:

[0061] (1) Analyze the average level of the difference between the current frequency domain signal and all peak values ​​at the same frequency in the current time-frequency signal, and record it as the difference index of the current signal in the circuit breaker contact.

[0062] (2) Further, analyze the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal;

[0063] It should be noted that there are many methods for measuring the degree of discreteness of a set of data. In this embodiment, the standard deviation of the time differences between all adjacent peaks is calculated to measure the degree of discreteness of the time differences between all adjacent peaks. The implementer may also use other methods for measuring the degree of discreteness such as variance or dispersion coefficient. Regarding the selection of the method for measuring the degree of discreteness of data, this embodiment does not impose any special restrictions.

[0064] (3) Further, based on the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal and the difference index, the periodic factor of the current signal in the circuit breaker contact is determined. Specifically, the periodic factor of the current signal in the circuit breaker contact is the inverse of the product of the difference index and the time difference between all adjacent peaks in the current time-frequency signal.

[0065] According to the periodic factor of the current signal in the circuit breaker contact, it can be understood that the smaller the difference index of the current signal, the more similar the current frequency domain signal is to the current time-frequency signal, indicating that the current signal is more stable, and the smaller the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal, the more stable the periodicity of the current signal, and the larger the periodicity factor of the current signal; conversely, the larger the difference index of the current signal, the greater the difference between the current frequency domain signal and the current time-frequency signal, indicating that the current signal is more unstable, and the larger the discrete degree of the time difference between all adjacent peaks in the current time-frequency signal, the more unstable the periodicity of the current signal, and the smaller the periodicity factor of the current signal.

[0066] (4) Further, based on the non-stationary characteristic value and the periodic factor, an abnormal factor of the current signal in the circuit breaker contact is determined, specifically:

[0067] The expression of the abnormal factor of the current signal in the circuit breaker contact is: ; In the formula, B represents the abnormal factor of the current signal in the circuit breaker contact; A represents the non-stationary characteristic value of the current signal in the circuit breaker contact; c represents the periodic factor of the current signal in the circuit breaker contact.

[0068] Further, according to the abnormal factor of the current signal in the circuit breaker contact, it can be understood that the larger the non-stationary eigenvalue, the worse the smoothness of the current signal, indicating that the circuit breaker contact is more likely to be in a failure state, and the smaller the periodicity factor, the periodicity of the current frequency domain signal is destroyed, indicating that the current signal is more likely to change abnormally, and the circuit breaker contact is more likely to be in a failure state, and the larger the abnormal factor of the current signal in the circuit breaker contact; conversely, the smaller the non-stationary eigenvalue, the better the smoothness of the current signal, indicating that the circuit breaker contact is less likely to be in a failure state, and the larger the periodicity factor, the stable periodicity of the current signal, indicating that the current signal has not changed abnormally, the smaller the possibility that the circuit breaker contact is in a failure state, and the smaller the abnormal factor of the current signal in the circuit breaker contact.

[0069] Preferably, the schematic diagram of the abnormal factor extraction process provided in this embodiment is as follows Figure 2 shown.

[0070] Step S4: Based on the abnormal factor and in combination with a preset threshold, a dynamic change threshold of the current signal in the circuit breaker contact is determined, and the circuit breaker contact is monitored.

[0071] When the circuit breaker contacts are abnormal, the current in the circuit will change significantly. If the contacts are in poor contact, the path through which the current passes may be blocked, causing the current to decrease or become unstable. In this case, the resistance in the circuit increases, and the current decreases when the voltage remains unchanged. In addition, abnormal contacts may cause arcs to be generated, which consume additional energy, further affecting the stability and size of the current.

[0072] The expression of the dynamic change threshold of the current signal in the circuit breaker contact is: ; In the formula, represents the dynamic change threshold of the current signal in the circuit breaker contact; B represents the abnormal factor of the current signal in the circuit breaker contact; K represents the preset threshold; exp( ) represents an exponential function with a natural constant as the base.

[0073] It should be noted that the value of the preset threshold is artificially set. In this embodiment, the value of the preset threshold is 10A. The implementer can set it by himself according to the specific situation, and this embodiment does not impose any special restrictions.

[0074] The greater the abnormal factor of the current signal, the greater the possibility of circuit breaker contact failure, resulting in a lower tolerance to abnormal current changes, and the threshold should be lowered.

[0075] If the extreme difference of all current data in the current signal of the preset time length is greater than the current dynamic change threshold, the circuit breaker contact fails; otherwise, the circuit breaker contact does not fail.

[0076] So far, this embodiment aims at the interference of normal load changes in the circuit on the judgment of the failure of the circuit breaker contacts. By analyzing the energy distribution difference and disorder degree of the current signal in the frequency domain, the accuracy of the circuit breaker contact failure status assessment is improved. In view of the influence of current changes caused by normal load changes, the interference of normal load changes on the current change monitoring is eliminated by analyzing the periodic stability of the current signal. By dynamically adjusting the current change threshold, accurate monitoring of the failure status of the circuit breaker contacts is achieved.

[0077] Based on the same inventive concept as the above method, the embodiment of the present application further provides a circuit breaker contact failure monitoring device, comprising:

[0078] A current data acquisition module is used to obtain the current signal flowing through the circuit breaker contacts within a preset time period;

[0079] A data analysis and acquisition module, used to convert the current signal into the frequency domain to obtain the current frequency domain signal, and obtain the power spectrum density at each frequency in the current frequency domain signal, extract all the maximum values ​​and all the minimum values ​​in all the power spectrum densities, determine the distribution characteristic value of the current signal in the circuit breaker contact based on the distribution of all the power spectrum densities between any two adjacent minimum values, and determine the non-stationary characteristic value of the current signal in the circuit breaker contact in combination with the difference in the distribution of all the maximum values ​​and all the minimum values;

[0080] Based on the current signal and using a time-frequency analysis algorithm to obtain the current time-frequency signal, determine the difference index of the current signal in the circuit breaker contact according to the difference between the peak values ​​of the current frequency domain signal and the current time-frequency signal at the same frequency, and determine the periodicity factor of the current signal in the circuit breaker contact in combination with the discrete degree of the time difference between all adjacent peak values ​​in the current time-frequency signal; based on the periodicity factor and the non-stationary eigenvalue, determine the abnormality factor of the current signal in the circuit breaker contact;

[0081] The circuit breaker contact monitoring module is used to determine the dynamic change threshold of the current signal in the circuit breaker contact based on the abnormal factor and the preset threshold, and monitor the circuit breaker contact.

[0082] A circuit breaker contact failure monitoring system block diagram provided in an embodiment of the present application is as follows: Figure 3 shown.

[0083] Based on the same inventive concept as the above method, an embodiment of the present application also provides a circuit breaker contact failure monitoring medium, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned circuit breaker contact failure monitoring methods are implemented.

[0084] It should be noted that the above sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0085] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0086] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application should be included in the protection scope of the present application.

Claims

1. A circuit breaker contact failure monitoring method, characterized in that: The method comprises the following steps: Acquire a current signal flowing through the circuit breaker contacts within a preset time period; The current signal is converted into the frequency domain to obtain a current frequency domain signal, and the power spectrum density at each frequency in the current frequency domain signal is obtained, all the maximum values ​​and all the minimum values ​​in all the power spectrum densities are extracted, and the distribution characteristic value of the current signal in the circuit breaker contact is determined based on the distribution of all the power spectrum densities between any two adjacent minimum values, and the non-stationary characteristic value of the current signal in the circuit breaker contact is determined in combination with the difference in the distribution of all the maximum values ​​and all the minimum values; Based on the current signal and using a time-frequency analysis algorithm to obtain the current time-frequency signal, determine the difference index of the current signal in the circuit breaker contact according to the difference between the peak values ​​of the current frequency domain signal and the current time-frequency signal at the same frequency, and determine the periodicity factor of the current signal in the circuit breaker contact in combination with the discrete degree of the time difference between all adjacent peak values ​​in the current time-frequency signal; based on the periodicity factor and the non-stationary eigenvalue, determine the abnormality factor of the current signal in the circuit breaker contact; Based on the abnormal factor and in combination with a preset threshold, a dynamic change threshold of the current signal in the circuit breaker contact is determined to monitor the circuit breaker contact; The method for determining the distribution characteristic value of the current signal in the circuit breaker contact is: In the current frequency domain signal, the range of all power spectrum densities between any two adjacent minimum values ​​is calculated, and the discreteness of all the ranges is analyzed. The distribution characteristic value of the current signal in the circuit breaker contact is the result of the fusion of the number of all adjacent minimum value pairs and the discreteness. The distribution characteristic value of the current signal in the circuit breaker contact is the product of the number of all adjacent minimum value pairs and the discrete degree, or an exponential function value with a natural constant as the base and the sum of the number of all adjacent minimum value pairs and the discrete degree as the independent variable; The non-stationary characteristic value expression of the current signal in the circuit breaker contact is: ; In the formula, A represents the non-stationary characteristic value of the current signal in the circuit breaker contact; m represents the difference between the average level of all maximum values ​​and the average level of all minimum values ​​in the current frequency domain signal in the circuit breaker contact; n represents the distribution characteristic value of the current signal in the circuit breaker contact; The difference index of the current signal in the circuit breaker contact is the average level of the difference between the current frequency domain signal and all the peak values ​​at the same frequency in the current time-frequency signal; The standard deviation of the time differences between all adjacent peaks is calculated to measure the degree of dispersion of the time differences between all adjacent peaks; The periodicity factor of the current signal in the circuit breaker contact is the reciprocal of the product of the difference index and the time difference of all adjacent peaks in the current time-frequency signal; The expression of the abnormal factor of the current signal in the circuit breaker contact is: ; In the formula, B represents the abnormal factor of the current signal in the circuit breaker contact; A represents the non-stationary characteristic value of the current signal in the circuit breaker contact; c represents the periodic factor of the current signal in the circuit breaker contact; The expression of the dynamic change threshold value of the current signal in the circuit breaker contact is: ; In the formula, represents the dynamic change threshold of the current signal in the circuit breaker contact; B represents the abnormal factor of the current signal in the circuit breaker contact; K represents the preset threshold; exp( ) represents an exponential function with a natural constant as the base.

2. A circuit breaker contact failure monitoring method according to claim 1, characterized in that: The monitoring of the circuit breaker contacts comprises: If the extreme difference of all current data in the current signal of the preset time length is greater than the dynamic change threshold, the circuit breaker contact fails, otherwise, the circuit breaker contact does not fail.

3. A circuit breaker contact failure monitoring device, characterized in that: To implement a circuit breaker contact failure monitoring method as claimed in claim 1, the device comprises: A current data acquisition module is used to obtain the current signal flowing through the circuit breaker contacts within a preset time period; A data analysis and acquisition module, used to convert the current signal into the frequency domain to obtain the current frequency domain signal, and obtain the power spectrum density at each frequency in the current frequency domain signal, extract all the maximum values ​​and all the minimum values ​​in all the power spectrum densities, determine the distribution characteristic value of the current signal in the circuit breaker contact based on the distribution of all the power spectrum densities between any two adjacent minimum values, and determine the non-stationary characteristic value of the current signal in the circuit breaker contact in combination with the difference in the distribution of all the maximum values ​​and all the minimum values; Based on the current signal and using a time-frequency analysis algorithm to obtain the current time-frequency signal, determine the difference index of the current signal in the circuit breaker contact according to the difference between the peak values ​​of the current frequency domain signal and the current time-frequency signal at the same frequency, and determine the periodicity factor of the current signal in the circuit breaker contact in combination with the discrete degree of the time difference between all adjacent peak values ​​in the current time-frequency signal; based on the periodicity factor and the non-stationary eigenvalue, determine the abnormality factor of the current signal in the circuit breaker contact; The circuit breaker contact monitoring module is used to determine the dynamic change threshold of the current signal in the circuit breaker contact based on the abnormal factor and the preset threshold, and monitor the circuit breaker contact.

4. A circuit breaker contact failure monitoring medium, 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, the steps of the circuit breaker contact failure monitoring method as described in any one of claims 1-2 are implemented.

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