Circuit interruption monitoring device and method for electrical safety protection

Abstract

The application relates to the technical field of circuit breaker monitoring, in particular to a circuit breaking monitoring device and method for electrical safety protection, which comprises the following steps: collecting vibration signals, closing and opening coil current signals and environmental parameters of a circuit breaker at each detection in a working process; calculating an environmental disturbance coefficient according to the relationship between the monitoring signals and environmental changes; calculating a time sequence stability coefficient according to the time sequence change characteristics of the monitoring signals; constructing a step for adaptive filtering of the signals based on the environmental disturbance coefficient and the time sequence stability coefficient, so as to perform adaptive filtering processing on the vibration signals and the current signals; and performing circuit breaker fault monitoring based on the filtered signals. Through adjustment of the adaptive filtering step of the signals, the application aims to eliminate environmental disturbance and excessive filtering and retain sufficient details in the signals.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit breaker monitoring, in particular to a circuit breaker monitoring device and method for electrical safety protection. BACKGROUND

[0002] As a key infrastructure, the safe and stable operation of the power system is particularly important, and the circuit breaker, as an important electrical safety protection device, plays a crucial role in the normal operation of the power system. It not only effectively prevents safety accidents caused by electrical faults such as overload and short circuit, but also quickly cuts off the circuit in abnormal conditions to ensure safety and reduce losses. However, the circuit breaker itself may also have various faults due to long-term use or external factors, such as mechanical component wear, poor contact, insulation aging, etc. If these problems are not discovered and addressed in a timely manner, they will pose a serious threat to the safety of the entire power system. Therefore, how to efficiently and accurately monitor the working state of the circuit breaker has become an important issue for improving the reliability of the power system, especially for monitoring mechanical faults of the operating mechanism.

[0003] Mechanical failure of the operating mechanism is one of the most common faults of the circuit breaker. Such faults usually cause changes in the movement mechanism of the mechanical transmission part, which in turn causes fluctuations in characteristic parameters such as vibration signals and closing / opening coil current signals. The existing technology achieves fault diagnosis of the circuit breaker by analyzing vibration signals and current signals. However, the existing technology also has a major drawback. When analyzing vibration signals and current signals, only the fluctuations of the signals themselves are considered, while the potential impact of environmental changes on the signals is often ignored. Environmental changes can also affect the mechanical movement process of the circuit breaker, causing non-fault fluctuations in the vibration signals or current signals. If the fault diagnosis of the circuit breaker is based solely on the fluctuations of the signals themselves, it will undoubtedly increase the misdiagnosis of the circuit breaker fault. Therefore, there is an urgent need for a more comprehensive circuit breaker fault detection method to improve the accuracy of circuit breaker fault detection and ensure the safe and stable operation of the power system. SUMMARY

[0004] To solve the above technical problems, the present application provides a circuit breaker monitoring device and method for electrical safety protection, and the technical solution adopted is as follows:

[0005] In a first aspect, one embodiment of the present application provides a circuit breaker monitoring method for electrical safety protection, which comprises the following steps:

[0006] Collecting vibration signals, closing / opening coil current signals and environmental parameters of the circuit breaker during each detection when it is working; the environmental parameters include environmental temperature and humidity;

[0007] The cross-correlation analysis method is used to analyze the vibration lags between the vibration signals and the current signals of all previous detections and the corresponding vibration signals and current signals of the first detection before each detection; and the environmental disturbance coefficients of each detection are calculated in combination with the correlation between the fluctuation characteristics of the vibration signals and the current signals and the environmental parameters;

[0008] The autocorrelation coefficient analysis method is used to analyze the autocorrelation coefficients of the vibration signals and the current signals of all previous detections before each detection; the autocorrelation coefficients of the two kinds of signals obtained by all previous detections before each detection are linearly fitted to analyze the trend changes of the fitting straight lines, and the time sequence stability coefficients of each detection are calculated;

[0009] The vibration signals and the current signals of the first detection are taken as the expected signals, the step of adaptive filtering of the signals is constructed by using the environmental disturbance coefficients and the time sequence stability coefficients, so as to filter the vibration signals and the current signals of each subsequent detection; and the circuit breaker fault monitoring is performed based on the filtered signals.

[0010] Preferably, the method for collecting the vibration signals and the on-off coil current signals in each detection is as follows: the vibration signals during the operation of the circuit breaker are collected, the vibration signals are amplified by using a charge amplifier, and the amplified signals are input into an oscilloscope; when the vibration signals are greater than a preset trigger value, the data of 100 ms before and after the vibration signals are automatically saved, the segment of data is taken as the vibration signals of one detection, and the time range of the segment is taken as the time period of one detection; and the on-off coil current signals in the time period are taken as the on-off coil current signals of the detection.

[0011] Preferably, the environmental parameters are obtained at the last data collection time in the detection time period.

[0012] Preferably, the vibration lags between the vibration signals and the current signals of all previous detections and the corresponding vibration signals and current signals of the first detection before each detection are analyzed; and the environmental disturbance coefficients of each detection are calculated in combination with the correlation between the fluctuation characteristics of the vibration signals and the current signals and the environmental parameters, including:

[0013] The vibration signals of each detection are formed into a vibration sequence, and the vibration lags between the vibration sequences of all previous detections and the vibration sequence of the first detection before each detection are calculated;

[0014] The current signals of each detection are formed into a current sequence, and the current lags between the vibration sequences of all previous detections and the vibration sequence of the first detection before each detection are calculated; and a trend sequence of the current lag sequence is obtained;

[0015] The variances of the vibration sequences of each detection are calculated to form a vibration fluctuation sequence.

[0016] The mean value of the current sequence at each detection constitutes a current fluctuation sequence;

[0017] The temperature data at each detection and all previous detections constitutes a temperature sequence;

[0018] The humidity data at each detection and all previous detections constitutes a humidity sequence;

[0019] Based on the correlation between the first-order difference sequence of the trend sequence, the vibration lag amount, the vibration fluctuation sequence and the current fluctuation sequence and the temperature sequence and the humidity sequence, the environmental disturbance coefficient at each detection is calculated.

[0020] Preferably, the vibration lag amount is the lag amount corresponding to the maximum cross-correlation coefficient when the cross-correlation analysis method is used between the two vibration sequences.

[0021] Preferably, based on the correlation between the first-order difference sequence of the trend sequence, the vibration lag amount, the vibration fluctuation sequence and the current fluctuation sequence and the temperature sequence and the humidity sequence, the environmental disturbance coefficient at each detection is calculated, including:

[0022] : is the environmental disturbance coefficient at the n-th detection, is the correlation between the temperature sequence and the vibration lag sequence at the n-th detection, is the correlation between the temperature sequence and the vibration fluctuation sequence at the n-th detection, is the correlation between the humidity sequence and the current fluctuation sequence at the n-th detection, , is the correlation between the temperature sequence and the vibration lag sequence at the n-th detection, is the correlation between the temperature sequence and the vibration fluctuation sequence at the n-th detection, is the mean value of the first-order difference sequence of the trend sequence of the current lag sequence at the n-th detection, is the correlation between the humidity sequence and the current fluctuation sequence at the n-th detection, is the correlation between the humidity sequence and the current fluctuation sequence at the n-th detection, is the trend measure of the correlation between the humidity sequence and the current fluctuation sequence at the n-th detection.

[0023] Preferably, the autocorrelation coefficients of the vibration signal and the current signal at all previous detections before each detection are analyzed using the autocorrelation coefficient; the autocorrelation coefficients of the two signals obtained at all previous detections before each detection are respectively linearly fitted to analyze the trend change of the fitted straight line, and the timing stability coefficient at each detection is calculated, including:

[0024] The vibration sequences at each detection and all previous detections are combined into a total vibration sequence according to the detection order;

[0025] The autocorrelation coefficient of the total vibration sequence is calculated as the ordinate, the detection order is taken as the abscissa, linear fitting is performed, and a fitting straight line of the vibration autocorrelation coefficient is obtained;

[0026] The current sequence of each detection and all previous detections is constructed into a total current sequence according to the detection order;

[0027] The autocorrelation coefficient of the total current sequence is calculated as the ordinate, the detection order is taken as the abscissa, linear fitting is performed, and a fitting straight line of the current autocorrelation coefficient is obtained;

[0028] The time sequence stability coefficient at each detection is calculated by using the slope change of the fitting straight line of the vibration and current autocorrelation coefficients and the average change rate of adjacent elements in the trend sequence of the total vibration sequence and the total current sequence.

[0029] Preferably, the time sequence stability coefficient at each detection is calculated by using the slope change of the fitting straight line of the vibration and current autocorrelation coefficients and the average change rate of adjacent elements in the trend sequence of the total vibration sequence and the total current sequence, comprising:

[0030] : is the time sequence stability coefficient at the i th detection, , is the time sequence change measure of the vibration signal at the i th detection, , , is the slope of the fitting straight line of the vibration autocorrelation coefficient at the i th detection, is the slope of the fitting straight line of the current autocorrelation coefficient at the i th detection, is the average change rate of adjacent elements in the trend sequence of the total vibration sequence at the i th detection; , is the average change rate of adjacent elements in the trend sequence of the total current sequence at the i th detection.

[0031] Preferably, the construction formula of the step size of adaptive filtering of the signal is: : is the step size of adaptive filtering of the signal at the i th detection, , is the maximum and minimum step size set in advance, is the step size of adaptive filtering of the signal at the i th detection.​​​​​​​​​ the normalized environmental disturbance coefficient and the timing stability coefficient in the secondary detection, is a preset smoothing factor, preventing the denominator from being zero and controlling the transition slope.

[0032] In a second aspect, another embodiment of the present application also provides a circuit breaker monitoring device for electrical safety protection, comprising a collection module, a filtering module and a monitoring module; wherein the collection module is configured to collect the vibration signal, the closing and opening coil current signal and the environmental parameters of the circuit breaker in each detection during operation; the environmental parameters include the temperature and humidity of the environment;

[0033] The filtering module is configured to analyze the various data collected by the monitoring module to realize the filtering processing of the vibration signal and the current signal, and the filtering processing realizes the steps in the circuit breaker monitoring method for electrical safety protection described above;

[0034] The monitoring module is configured to monitor the circuit breaker fault based on the filtered signal.

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

[0036] The present application first calculates the environmental disturbance coefficient according to the changes of the monitoring signal and the environment, which quantifies the disturbance of the environmental change to the monitoring signal, thereby helping to enhance the signal filtering quality according to the environmental disturbance, and further reducing the misjudgment probability of the mechanical fault of the operating mechanism; then the timing stability coefficient is calculated according to the timing change characteristics of the monitoring signal, which quantifies the change trend of the monitoring signal, helps to further distinguish the correlation between the disturbance and the fault of the signal in the subsequent, and further constructs the adaptive step to adjust the filtering strength according to the signal condition. Through this method, the characteristics of the monitoring signal are measured according to the environmental disturbance and the timing change, and the step adjustment of the adaptive filtering is performed according to this, which helps to eliminate certain environmental disturbance, avoids excessive filtering, and retains enough detailed characteristics of the signal, so that the circuit breaker fault detection result is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0038] Figure 1 The flowchart of the circuit breaker monitoring method for electrical safety protection provided by an embodiment of the present application. DETAILED DESCRIPTION

[0039] Example 1

[0040] One embodiment of this application provides a circuit breaker monitoring method for electrical safety protection, which can be found in the following reference: Figure 1 The method includes the following steps:

[0041] Step 1: Collect vibration signals, opening and closing coil current signals, and environmental parameters during each test of the circuit breaker during operation.

[0042] A piezoelectric accelerometer installed on the surface of the circuit breaker's operating mechanism is used to collect vibration signals during circuit breaker operation. The sampling frequency is set to 100kHz. The vibration signal is amplified using a charge amplifier, and the amplified signal is input into an oscilloscope with a sampling frequency of 25M / s. When the vibration signal exceeds a preset trigger value, the data before and after the vibration signal for 100ms is automatically saved. This data segment is used as the vibration signal for one detection, and this time range is used as the detection time period. It should be noted that the trigger value can be selected as needed. In this embodiment, it is set to 1.5 times the maximum value of the background noise. Background noise extraction is a common technique in the field of signal processing, and will not be described in detail here.

[0043] The circuit breaker dynamic characteristic analyzer was used to collect the opening and closing coil current signals during each test. Then, temperature and humidity sensors placed around the circuit breaker were used to collect environmental parameters during each test: ambient temperature and humidity data. Specifically, the environmental parameters were acquired at the last data collection moment within the test period; that is, one ambient temperature and one ambient humidity data point were obtained per test. Finally, each type of data was normalized.

[0044] Thus, by step one, we can obtain the vibration signal, opening and closing coil current signal, and environmental parameters detected each time the circuit breaker is in operation.

[0045] Step 2: Calculate the environmental disturbance coefficient based on the relationship between the monitoring signal and environmental changes; calculate the time series stability coefficient based on the time series variation characteristics of the monitoring signal.

[0046] The circuit breaker is essential to the electrical safety of the power grid, and as a complex mechanical transmission device, the mechanical failure of its operating structure is one of the most common failures, which can seriously affect the operation of the circuit breaker, and therefore the accuracy of the mechanical failure detection of the operating structure of the circuit breaker needs to be improved. As a complex mechanical transmission device, the circuit breaker will change the movement mechanism when the mechanical failure of the operating structure occurs, and this change will change the vibration of the entire device and the on-off coil current signal, so the working state of the circuit breaker is often detected by using the change of the vibration signal and the current signal. However, this method analyzes the vibration and current signals collected during detection, without considering the change of the signals in the time dimension, and ignores the influence of environmental changes on signal fluctuations, so that environmental disturbances exist in the collected detection signals. Due to the complexity of the working environment of the circuit breaker, the environmental stability is poor, which further affects the accuracy of the mechanical failure detection of the operating structure of the circuit breaker and increases the probability of misjudgment.

[0047] First step: using cross-correlation analysis to analyze the vibration hysteresis between the vibration signal and the current signal of each detection before each detection and the corresponding vibration signal and current signal of the first detection; and combining the correlation between the fluctuation characteristics of the vibration signal and the current signal and the environmental parameters, the environmental disturbance coefficient of each detection is calculated.

[0048] For the mechanical transmission device of the circuit breaker, the frictional resistance between the components in the device has a great influence on the movement and vibration, and the on-off coil current will also change due to the change of the resistance in the device, and these will fluctuate under the influence of environmental factors, among which the environmental temperature and humidity have a greater influence. The circuit breaker controls the on-off through the conversion of high and low pressure oil circuits, and in this process, the oil pressure generated by the high pressure oil has a great influence on the response speed and movement of the on-off, and when the temperature decreases, the viscosity of the hydraulic oil will also increase, which will increase the friction and the loss of the oil pressure generated by the high pressure oil, and further slow down the response speed of the on-off and increase the time; at the same time, the viscosity of the lubricating oil between the mechanical devices will also increase in the low temperature environment, and the gap between the components will also increase in the low temperature environment, which will increase the vibration of the circuit breaker during mechanical movement.

[0049] When the environmental humidity changes, the oxidation and corrosion of the metal parts of the circuit breaker will increase in a high humidity environment, which will make the resistance fluctuate and rise, and with the change of the metal parts, the influence of the fluctuation of the environmental humidity on the change of the resistance will become more and more obvious, and the correlation will become stronger; at the same time, the change of humidity will also increase the friction between the components, and with the oxidation and corrosion of the metal parts, the vibration fluctuation during the mechanical movement of the on-off will gradually increase.

[0050] Accordingly, the application respectively constructs corresponding vibration sequences according to time sequence by collecting vibration signal data in each detection of circuit breaker opening and closing mechanical movement, and constructs corresponding current sequences according to time sequence by collecting opening and closing coil current data.

[0051] Taking the detection of the first circuit breaker opening and closing mechanical movement as an example, the first vibration sequence and the second vibration sequence are taken as inputs, and the cross-correlation analysis method is used to respectively output the cross-correlation coefficients corresponding to each lag, and the lag corresponding to the maximum cross-correlation coefficient is taken as the vibration lag between the two detections. The value range of the vibration lag is 0 to 1000. The value range of the vibration lag is 0 to 1000. The vibration lags of each detection before the first detection are respectively obtained in the above manner, and all the vibration lags are constructed into a vibration lag sequence according to the detection order from front to back. It should be noted that the first element in the sequence is 0, indicating the vibration lag of the vibration sequence obtained in the first detection. Similarly, the current data is processed in the above manner to obtain a current lag sequence. The cross-correlation analysis is a known technology and will not be described in detail. The vibration lags of each detection before the first detection are respectively obtained in the above manner, and all the vibration lags are constructed into a vibration lag sequence according to the detection order from front to back. It should be noted that the first element in the sequence is 0, indicating the vibration lag of the vibration sequence obtained in the first detection. Similarly, the current data is processed in the above manner to obtain a current lag sequence. The cross-correlation analysis is a known technology and will not be described in detail. The vibration lags of each detection before the first detection are respectively obtained in the above manner, and all the vibration lags are constructed into a vibration lag sequence according to the detection order from front to back. It should be noted that the first element in the sequence is 0, indicating the vibration lag of the vibration sequence obtained in the first detection. Similarly, the current data is processed in the above manner to obtain a current lag sequence. The cross-correlation analysis is a known technology and will not be described in detail. The vibration lags of each detection before the first detection are respectively obtained in the above manner, and all the vibration lags are constructed into a vibration lag sequence according to the detection order from front to back. It should be noted that the first element in the sequence is 0, indicating the vibration lag of the vibration sequence obtained in the first detection. Similarly, the current data is processed in the above manner to obtain a current lag sequence. The cross-correlation analysis is a known technology and will not be described in detail.

[0052] Then, the variance of each vibration sequence is calculated, and all the variances are constructed into a vibration fluctuation sequence according to the detection order. The mean of each current sequence is calculated, and all the means are constructed into a current fluctuation sequence according to the detection order.

[0053] Then, the current lag sequence is taken as input, and the STL time series decomposition is used to output the trend sequence, and the first difference sequence of the trend sequence is calculated. The STL time series decomposition is a known technology and will not be described in detail. Finally, the environmental temperature and humidity data in the first detection are constructed into a temperature sequence and a humidity sequence according to the detection order. The vibration lags of each detection before the first detection are respectively obtained in the above manner, and all the vibration lags are constructed into a vibration lag sequence according to the detection order from front to back. It should be noted that the first element in the sequence is 0, indicating the vibration lag of the vibration sequence obtained in the first detection. Similarly, the current data is processed in the above manner to obtain a current lag sequence. The cross-correlation analysis is a known technology and will not be described in detail. The vibration lags of each detection before the first detection are respectively obtained in the above manner, and all the vibration lags are constructed into a vibration lag sequence according to the detection order from front to back. It should be noted that the first element in the sequence is 0, indicating the vibration lag of the vibration sequence obtained in the first detection. Similarly, the current data is processed in the above manner to obtain a current lag sequence. The cross-correlation analysis is a known technology and will not be described in detail.

[0054] Based on the above analysis, the environmental disturbance coefficient in the first detection is calculated, which is used to measure the degree of influence of vibration and current signals on environmental changes.

[0055] : is the environmental disturbance coefficient in the first detection, is the correlation measure between the temperature sequence and the vibration lag sequence in the first detection, , is the correlation measure between the temperature sequence and the vibration lag sequence in the first detection, , is the correlation measure between the temperature sequence and the vibration lag sequence in the first detection, ​​The correlation between the temperature and humidity sequences and the vibration wave sequence during each detection. It is the first The mean of elements within the first-order difference sequence of the trend sequence of the current hysteresis sequence during the second detection. It is the first A trend measure of the correlation between the humidity sequence and the current fluctuation sequence during the first detection.

[0056] In this embodiment , , They are the first sequence The correlation measurement between the humidity sequence and the current fluctuation sequence detected in this study. It is a sign function. In different processing methods, correlation measures can include, but are not limited to, Pearson correlation coefficient, Spearman correlation coefficient, and cosine similarity.

[0057] Understandably, a decrease in temperature can slow down the response time of vibration data and increase vibration fluctuations. In other words, there is a negative correlation between temperature and vibration response lag and fluctuations. The stronger the negative correlation, the more likely that the abnormal fluctuations of the circuit breaker are caused by the environment. Secondly, humidity will increase the resistance of the circuit breaker, which will lead to a gradual increase in the current response time. Therefore, the current lag shows a significant increasing trend. As the oxidation of the circuit breaker's metal components becomes more obvious, it will enhance the negative correlation between current changes and humidity. At the same time, humidity will also lead to larger vibration fluctuations. Therefore, the greater the impact of environmental changes on the circuit breaker, the lower the possibility of the circuit breaker having an abnormal state, and the larger the corresponding environmental disturbance coefficient.

[0058] Step 2: Use autocorrelation coefficient analysis to obtain the autocorrelation coefficients of vibration and current signals from all previous tests. Perform linear fitting on the autocorrelation coefficients of the two signals obtained from all previous tests to analyze the trend of the fitted lines and calculate the time-series stability coefficient for each test.

[0059] Under normal operating conditions, the movement of a circuit breaker is primarily affected by environmental fluctuations. In this case, the vibration and current signals exhibit a high correlation with the environment, and this phenomenon is a normal fluctuation in the circuit breaker's detection signals. Therefore, when using vibration and current signals for mechanical fault diagnosis of the circuit breaker's operating mechanism under these conditions, it is necessary to minimize the impact of signal changes caused by environmental fluctuations to reduce the probability of false fault diagnosis. However, when a mechanical fault exists in the circuit breaker, in addition to the influence of environmental fluctuations, the mechanical fault itself has a major impact on the circuit breaker's mechanical movement. This weakens the correlation between vibration and current signal fluctuations and environmental changes. In this case, the signal fluctuations and included errors are mainly caused by the fault. To ensure the accuracy and sensitivity of fault detection, it is necessary to retain more signal fluctuations.

[0060] Secondly, the temporal variation characteristics of signals have a significant impact on subsequent signal processing. Under normal circumstances, although the temporal variations of vibration and current signals also exhibit some trend fluctuations, the trend is relatively weak, the overall trend is relatively stable, and the rate of trend change is slow. Furthermore, the operation of circuit breakers is relatively similar, meaning that the signal data between different detections show relatively strong periodic variations. However, when a circuit breaker has a mechanical fault, the temporal variation trend of vibration and current signals becomes more pronounced. Moreover, the impact of the fault leads to further deterioration of the circuit breaker, resulting in a faster rate of trend change. Simultaneously, due to the faster trend and speed of change, the periodicity becomes weaker.

[0061] Accordingly, this application is filed with reference to Article [number missing]. Taking the secondary circuit breaker test as an example, the previous... The vibration sequence and current sequence are arranged in the detection order to form the first... The total vibration sequence and total current sequence of the second detection. Then, the first... Using the total vibration sequence and total current sequence from the previous test as input, the autocorrelation coefficient sequence of each sequence was obtained using the autocorrelation coefficient method. The autocorrelation coefficient with the largest value among all autocorrelation coefficient sequences was taken as the first value. The vibration coefficient and current coefficient were measured in this test.

[0062] Each will be the front The vibration coefficient and current coefficient of each test are used as the vertical axis, and the corresponding test order is used as the horizontal axis. A straight line is fitted, and the fitted straight line equation is output, which is denoted as the fitted straight line of the vibration autocorrelation coefficient at the i-th test.

[0063] The total vibration sequence and total current sequence at the i-th detection are then used as inputs, and STL time series decomposition is applied to output the corresponding trend sequence. The autocorrelation coefficient method, linear fitting, and STL time series decomposition are well-known techniques and will not be elaborated further.

[0064] : It is the first The time stability coefficient during the second detection. , They are the first The temporal variation measurement of vibration and current signals during each detection. In this embodiment, , , The first sequence The slope of the fitted line of the vibration autocorrelation coefficient during the second test. The average rate of change of adjacent elements in the trend sequence of the total vibration sequence at the i-th detection time; Similarly, calculations are performed on the current signal. , , The first sequence The slope of the fitted line of the current autocorrelation coefficient during the second detection. is the average rate of change of adjacent elements in the trend sequence of the total current sequence at the i-th detection.

[0065] Under normal circumstances, the trend of vibration signal changes is relatively slow and exhibits strong periodicity, meaning the corresponding vibration coefficient changes relatively smoothly, resulting in a relatively large timing stability coefficient. Conversely, when a circuit breaker malfunctions, the signal changes faster and faster, and the periodicity worsens, leading to a smaller timing stability coefficient.

[0066] Step 3: Construct a step size for adaptive filtering of the signal based on the environmental disturbance coefficient and the time-series stability coefficient, so as to perform adaptive filtering processing on the vibration signal and the current signal; and perform circuit breaker fault monitoring based on the filtered signal.

[0067] Due to the complexity of the circuit breaker's operating environment, it is difficult to perform completely accurate prior statistical analysis. Among various signal processing methods, adaptive filtering algorithms can achieve better filtering effects even when prior statistical characteristics are insufficient. Therefore, this application adopts adaptive filtering for signal processing.

[0068] First, the vibration signal and the closing and opening coil current signal are taken as the input respectively, the vibration signal and the closing and opening coil current signal at the first detection are taken as the expected signal, the step length of adaptive filtering is obtained by using the following step length formula, the adaptive filtering algorithm is adopted, and the filtered vibration signal and current signal are output. The adaptive filtering algorithm is a known technology and will not be described in detail.

[0069] is the step length of adaptive filtering of the signal at the first detection, , is the maximum and minimum step length set in advance, , is the step length of adaptive filtering of the signal at the first detection, is the normalized environmental disturbance coefficient and the time sequence stability coefficient at the first detection, is a preset smoothing factor to prevent the denominator from being zero and to control the transition slope. In the embodiment, the upper quartile value of the sum of the first normalized environmental disturbance coefficients and time sequence stability coefficients is taken. In the embodiment, , take the values 0.1 and 0.001 respectively.

[0070] It can be understood that when the circuit breaker is in a normal state, the correlation between the circuit breaker and the environment is strong, and the signal change trend is relatively slow and the periodicity is strong. At this time, when filtering is performed, the main factor affecting the accuracy of the vibration signal and the current signal is the error caused by environmental fluctuations. Therefore, a relatively small step length can be used at this time to improve the noise elimination capability and avoid excessive error leading to subsequent misdiagnosis problems. Conversely, when the circuit breaker is more likely to have mechanical faults, the faults are more dominant to the signal fluctuations. At this time, a larger step length should be used to avoid excessive filtering of noise, retain more details, and improve the sensitivity and accuracy of fault identification.

[0071] When monitoring the circuit breaker, the closing and opening movement process of the circuit breaker is monitored, the vibration signal and the current signal collected according to the closing and opening movement process are filtered according to the step length of the adaptive filtering, and the features of the filtered signals are extracted and analyzed, so as to realize the detection of the mechanical faults of the operating structure of the circuit breaker.

[0072] It should be noted that the method of realizing fault detection by extracting and analyzing the features of the vibration signal and the current signal is a known technology in the related field, and will not be described in detail. In different processing methods, the feature extraction and analysis method can include but is not limited to principal component analysis, time-frequency domain analysis, and grey correlation analysis.

[0073] Embodiment 2

[0074] ​​Another embodiment of the present application also provides a circuit breaker monitoring device for electrical safety protection, comprising a collection module, a filtering module and a monitoring module; wherein the collection module is configured to collect vibration signals, closing and opening coil current signals and environmental parameters of the circuit breaker during each detection; the environmental parameters include environmental temperature and humidity; the filtering module is configured to analyze the various data collected by the monitoring module to realize filtering processing of the vibration signals and the current signals, and the filtering processing is configured to realize the steps in the circuit breaker monitoring method for electrical safety protection; and the monitoring module is configured to monitor the circuit breaker failure based on the filtered signals.

[0075] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope of the application being indicated by the following claims.

[0076] It should be understood that the application is not limited to the precise construction and methods described above and shown in the attached drawings, and various modifications and changes can be made without departing from the scope thereof.

Claims

1. A method for monitoring the opening of a circuit for electrical safety protection, characterized in that, The method comprises the following steps: Collecting the vibration signal, the closing and opening coil current signal and the environmental parameter of the circuit breaker in each detection during operation; the environmental parameter comprises the environmental temperature and humidity; Using the cross-correlation analysis method to analyze the vibration lag and current lag between the vibration signal and current signal of each detection before all detections and the corresponding vibration signal and current signal of the first detection; and combining the correlation between the fluctuation characteristics of the vibration signal and current signal and the environmental parameter, calculating the environmental disturbance coefficient of each detection; Using the autocorrelation coefficient to analyze the autocorrelation coefficient of the vibration signal and current signal of each detection before all detections; linearly fitting the autocorrelation coefficients of the two kinds of signals obtained by each detection before all detections to analyze the trend change of the fitting straight line, and calculating the time sequence stability coefficient of each detection; Taking the vibration signal and current signal of the first detection as the expected signal, using the environmental disturbance coefficient and the time sequence stability coefficient to construct the step of adaptive filtering of the signal, to filter the vibration signal and current signal of each subsequent detection; and based on the filtered signal, monitoring the circuit breaker fault; The vibration signal of each detection is used to form a vibration sequence, and the vibration lag is the lag corresponding to the maximum cross-correlation coefficient when the cross-correlation analysis method is used between two vibration sequences.

2. The circuit interruption monitoring method for electrical safety protection of claim 1, wherein, The method for collecting the vibration signal, the closing and opening coil current signal in each detection is as follows: collecting the vibration signal during the operation of the circuit breaker, amplifying the vibration signal by using a charge amplifier, inputting the amplified signal into an oscilloscope, automatically saving the data 100 ms before and after the vibration signal when the vibration signal is greater than a preset trigger value, taking the segment of data as the vibration signal of one detection, and taking the time range of the segment as the time period of one detection; and taking the closing and opening coil current signal in the time period as the closing and opening coil current signal of the detection.

3. The circuit interruption monitoring method for electrical safety protection of claim 2, wherein, The environmental parameter is obtained at the last data collection time in the detection time period.

4. The circuit interruption monitoring method for electrical safety protection of claim 1, wherein, The vibration lag and current lag between the vibration signal and current signal of each detection before all detections and the corresponding vibration signal and current signal of the first detection are analyzed; and combining the correlation between the fluctuation characteristics of the vibration signal and current signal and the environmental parameter, the environmental disturbance coefficient of each detection is calculated, which comprises: The vibration signal of each detection is used to form a vibration sequence, and the vibration lag between the vibration sequence of each detection before all detections and the vibration sequence of the first detection is calculated; The current signal of each detection is used to form a current sequence, and the current lag between the vibration sequence of each detection before all detections and the vibration sequence of the first detection is calculated; the trend sequence of the current lag sequence is obtained; The variance of the vibration sequence of each detection is calculated to form a vibration fluctuation sequence; The mean of the current sequence of each detection is calculated to form a current fluctuation sequence; The temperature data of each detection and all detections before the detection are obtained to form a temperature sequence; The humidity data of each detection and all detections before the detection are obtained to form a humidity sequence; The environmental disturbance coefficient at each detection is calculated based on the correlation of the first-order difference sequence of the trend sequence, the vibration lag amount, the vibration fluctuation sequence and the current fluctuation sequence with the temperature sequence and the humidity sequence, including:

5. The circuit interruption monitoring method for electrical safety protection of claim 4, wherein, The environmental disturbance coefficient at each detection is calculated based on the correlation of the first-order difference sequence of the trend sequence, the vibration lag amount, the vibration fluctuation sequence and the current fluctuation sequence with the temperature sequence and the humidity sequence, including: : It is the first Environmental disturbance coefficient during the second test. It is the first A measure of the correlation between the temperature sequence and the vibration hysteresis sequence at the time of the first detection. , It is the first The correlation between the temperature and humidity sequences and the vibration wave sequence during each detection. It is the first The mean of elements within the first-order difference sequence of the trend sequence of the current hysteresis sequence during the second detection. It is the first A trend measure of the correlation between the humidity sequence and the current fluctuation sequence during the first detection.

6. The circuit interruption monitoring method for electrical safety protection of claim 4, wherein, The autocorrelation coefficients of the vibration signals and the current signals at all detections before each detection are analyzed by using the autocorrelation coefficient; the autocorrelation coefficients of the two kinds of signals obtained at all detections before each detection are linearly fitted respectively to analyze the trend change of the fitting straight line, and the time sequence stability coefficient at each detection is calculated, including: The vibration sequences at each detection and all detections before each detection are arranged into a total vibration sequence according to the detection order; The autocorrelation coefficient of the total vibration sequence is calculated as the ordinate, the detection order is taken as the abscissa, linear fitting is performed, and a fitting straight line of the vibration autocorrelation coefficient is obtained; The current sequences at each detection and all detections before each detection are arranged into a total current sequence according to the detection order; The autocorrelation coefficient of the total current sequence is calculated as the ordinate, the detection order is taken as the abscissa, linear fitting is performed, and a fitting straight line of the current autocorrelation coefficient is obtained; The time sequence stability coefficient at each detection is calculated by using the slope change of the fitting straight line of the vibration and current autocorrelation coefficients and the average change rate of adjacent elements in the trend sequence of the total vibration sequence and the total current sequence.

7. The circuit interruption monitoring method for electrical safety protection of claim 6, wherein, The time sequence stability coefficient at each detection is calculated by using the slope change of the fitting straight line of the vibration and current autocorrelation coefficients and the average change rate of adjacent elements in the trend sequence of the total vibration sequence and the total current sequence, including: : is the first time detection timing stability coefficient, , is the first time detection timing change measure of the vibration signal and the current signal respectively; wherein, , , is the first time detection and the first time detection slope of the fitting straight line of the vibration autocorrelation coefficient, is the average change rate of adjacent elements in the trend sequence of the total vibration sequence in the i-th detection; , , is the first time detection and the first time detection slope of the fitting straight line of the current autocorrelation coefficient, is the average change rate of adjacent elements in the trend sequence of the total current sequence in the i-th detection.

8. The circuit interruption monitoring method for electrical safety protection of claim 1, wherein, The construction formula of the step of adaptive filtering of the signal is: : is the step of adaptive filtering of the signal in the first detection, , is the preset maximum and minimum step, , is the step of adaptive filtering of the signal in the first detection, is a preset smoothing factor, preventing zero in the denominator and controlling the transition slope.​​ 9. A circuit breaking monitoring device for electrical safety protection, the device comprising an acquisition module, a filtering module and a monitoring module; wherein, The acquisition module is used to acquire the vibration signal, the on-off coil current signal and the environmental parameter of the circuit breaker at each detection when working; the environmental parameter includes the environmental temperature and humidity; The filter module is used to filter the vibration signal and the current signal by analyzing the various data collected by the monitoring module, and the filter processing is performed to realize the steps in the circuit breaker monitoring method for electrical safety protection in any one of claims 1-8; The monitoring module is used to monitor the circuit breaker fault based on the filtered signal.

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