A 10kV capacitor bank circuit breaker non-full-phase opening monitoring method and device

Abstract

The present invention discloses a method and device for monitoring the non-full-phase opening of a 10kV capacitor bank circuit breaker, which relates to the field of circuit breaker control. The method includes: obtaining bus current data of the 10KV capacitor bank circuit breaker; performing wavelet transform on the bus current data to obtain wavelet coefficients; extracting energy distribution characteristics of the bus current according to the wavelet coefficients, and calculating the energy distribution mean square error of each phase according to the energy distribution characteristics; subtracting the energy distribution mean square error of each phase from the preset steady-state energy distribution mean square error when all phases are not opened, and comparing the difference results with preset thresholds to obtain a judgment vector of the 10KV capacitor bank circuit breaker; wherein the judgment vector includes three elements of three phases A, B, and C; and monitoring the non-full-phase opening state of the 10KV capacitor bank circuit breaker according to the judgment vector. The present invention solves the problem that the existing technology cannot accurately and reliably locate a phase fault in the monitoring of the non-full-phase opening fault of the circuit breaker.

Description

Technical Field

[0001] The present invention relates to the field of circuit breaker control, and more particularly to a method and device for monitoring non-full-phase opening of a 10kV capacitor bank circuit breaker. Background Art

[0002] In the field of reactive power compensation, shunt capacitors are widely used to compensate for reactive power, improve power factor, and maintain voltage levels. This leads to frequent operation of 10kV compensation capacitor bank circuit breakers, resulting in a failure rate far exceeding that of other types of circuit breakers, severely impacting the switching success rate of capacitor banks. Among common circuit breaker failures, partial phase tripping of vacuum circuit breakers is particularly complex and potentially hazardous. During maintenance or inspection, workers may mistakenly believe all phases are disconnected when, in fact, some phases are still energized, potentially causing electric shock. Partial phase tripping due to mechanical issues accounts for nearly 21% of all capacitor bank circuit breaker failures, posing a significant threat to maintenance personnel. However, because these failures are often accompanied by uneven voltage and current distribution within the three-phase circuit, traditional power grid fault detection methods struggle to monitor partial phase tripping of circuit breakers. Currently, circuit breaker maintenance relies primarily on regular preventive inspections, which are costly, require long maintenance cycles, and fail to accurately and promptly locate potential faults.

[0003] Currently, monitoring for capacitor bank circuit breaker partial phase trip faults utilizes logic digital circuits to display various partial phase trip conditions. However, this method requires measuring numerous electrical parameters and can only distinguish between one phase not tripped, two phases not tripped, all phases tripped, and no phases tripped, failing to distinguish between specific phases not tripped. Alternatively, real-time operating data from grid switchgear is collected to determine whether a switch is partially tripped. However, this approach requires an excessive amount of real-time operating data, complicates the process, and prevents a rapid response to a trip determination. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for monitoring the non-full-phase opening of a 10kV capacitor bank circuit breaker, so as to solve the problem that the existing technology cannot accurately and reliably locate a phase fault in the monitoring of the non-full-phase opening fault of the circuit breaker.

[0005] In a first aspect of the present application, a method for monitoring a non-full-phase opening of a 10KV capacitor bank circuit breaker is provided, the method comprising:

[0006] Obtain busbar current data of 10KV capacitor bank circuit breaker;

[0007] Perform wavelet transform on bus current data to obtain wavelet coefficients;

[0008] The energy distribution characteristic of the bus current is extracted according to the wavelet coefficient, and the mean square error of the energy distribution of each phase is calculated according to the energy distribution characteristic;

[0009] The energy distribution mean square error of each phase is subtracted from the preset steady-state energy distribution mean square error when all phases are not tripped. The difference is compared with the preset threshold value to obtain the judgment vector of the 10KV capacitor bank circuit breaker. The judgment vector includes three elements for the three phases A, B, and C.

[0010] Monitor the non-full-phase opening status of the 10KV capacitor bank circuit breaker based on the judgment vector.

[0011] In one implementation, wavelet transform is performed on bus current data to obtain wavelet coefficients, specifically by: determining the wavelet basis function and the number of decomposition levels;

[0012] The bus current data is decomposed by wavelet according to the wavelet basis function and the number of decomposition layers to obtain the wavelet coefficients.

[0013] In one implementation, extracting the energy distribution characteristic of the bus current based on the wavelet coefficients includes: determining the wavelet coefficients of the low-frequency part of each layer and the wavelet coefficients of the high-frequency part of each layer;

[0014] The energy distribution characteristic of the bus current is obtained by summing the squares of the wavelet coefficients of the low-frequency part and the high-frequency part respectively.

[0015] In one implementation, the expression for calculating the mean square error of energy distribution is:

[0016] Among them, V is the mean square error of energy distribution, N is the number of decomposition layers, and v i is the energy distribution characteristic of each layer, and μ is the mean of all energies.

[0017] In one implementation, monitoring the non-full-phase tripping state of a 10KV capacitor bank circuit breaker according to a judgment vector includes:

[0018] If the difference result is less than the preset threshold, the corresponding element of the judgment vector is set to 0, indicating that the circuit breaker of the corresponding phase is not opened;

[0019] If the difference result is greater than the preset threshold, the corresponding element of the judgment vector takes the value of 1, indicating that the circuit breaker of the corresponding phase is open.

[0020] In a second aspect of the present application, a 10KV capacitor bank circuit breaker non-full-phase opening monitoring device is provided, the device comprising:

[0021] Data acquisition module, used to obtain bus current data of 10KV capacitor bank circuit breaker;

[0022] A data processing module is used to perform wavelet transform on bus current data to obtain wavelet coefficients;

[0023] A mean square error calculation module is used to extract the energy distribution characteristic quantity of the bus current based on the wavelet coefficients, and calculate the mean square error of the energy distribution of each phase based on the energy distribution characteristic quantity;

[0024] The judgment vector calculation module is used to subtract the mean square error of the energy distribution of each phase from the preset mean square error of the steady-state energy distribution when all phases are not tripped, and compare the difference results with the preset threshold value to obtain the judgment vector of the 10KV capacitor bank circuit breaker. The judgment vector includes three elements of the three phases A, B, and C.

[0025] The status monitoring module is used to monitor the non-full-phase opening status of the 10KV capacitor bank circuit breaker based on the judgment vector.

[0026] In one implementation, the data processing module further includes:

[0027] Selection module, used to determine the wavelet basis function and the number of decomposition layers;

[0028] The decomposition module is used to perform wavelet decomposition on the bus current data according to the wavelet basis function and the number of decomposition layers to obtain wavelet coefficients.

[0029] In one implementation, the mean square error calculation module further includes:

[0030] A coefficient determination module is used to determine the wavelet coefficients of the low-frequency part of each layer and the wavelet coefficients of the high-frequency part of each layer;

[0031] The characteristic quantity calculation module is used to sum the squares of the wavelet coefficients of the low-frequency part and the high-frequency part respectively to obtain the energy distribution characteristic quantity of the bus current.

[0032] In one implementation, the expression for calculating the mean square error of energy distribution is:

[0033] Among them, V is the mean square error of energy distribution, N is the number of decomposition layers, and v i is the energy distribution characteristic of each layer, and μ is the mean of all energies.

[0034] In one implementation, the status monitoring module is specifically configured to:

[0035] If the difference result is less than the preset threshold, the corresponding element of the judgment vector is set to 0, indicating that the circuit breaker of the corresponding phase is not opened;

[0036] If the difference result is greater than the preset threshold, the corresponding element of the judgment vector takes the value of 1, indicating that the circuit breaker of the corresponding phase is open.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This application addresses the problem of insufficient accuracy and reliability in monitoring the non-full-phase opening of existing capacitor bank circuit breakers. The bus current data near the circuit breaker is obtained through the relevant current measuring device of the distribution network automation technology, and the wavelet transform technology is used for data processing. Then, the energy distribution characteristic quantity is calculated based on the wavelet coefficient. The energy distribution mean square error of each phase is determined in combination with the energy distribution characteristic quantity. The steady-state energy distribution mean square error when all three phases are not disconnected is used as the comparison vector. Finally, the judgment vector is calculated to realize the monitoring of the non-full-phase opening of the circuit breaker through the judgment vector. Therefore, the present application can accurately identify the non-full-phase opening fault of the circuit breaker, and compared with the existing technology, the present method can accurately locate a specific phase. Even when the harmonic content of the power system changes, the non-full-phase opening state of the circuit breaker can still be accurately identified with high reliability. In addition, since the required data can be directly obtained from the current measuring device of the distribution network automation system, this greatly simplifies the data acquisition process, thereby reducing the overall cost of technical implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0040] Figure 1 A flow chart of a method for monitoring non-full-phase opening of a 10KV capacitor bank circuit breaker provided in an embodiment of the present application;

[0041] Figure 2 Schematic diagram of a reactive power compensation simulation circuit for a 10kV container group circuit breaker provided in an embodiment of the present application;

[0042] Figure 3 A schematic diagram of energy distribution characteristics when all three phases are not disconnected and all three phases are disconnected, provided in an embodiment of the present application;

[0043] Figure 4 A schematic diagram of energy distribution characteristics when not all phases are fully tripped according to an embodiment of the present application;

[0044] Figure 5 This is a principle block diagram of a non-full-phase opening monitoring device for a 10KV capacitor bank circuit breaker provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0046] It should be noted that the terms "include" or "may include" used in various embodiments of the present application indicate the presence of the claimed function, operation or element, and do not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present application, the terms "include", "have" and their cognates are only intended to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0047] Please refer to Figure 1 , Figure 1 A flow chart of a method for monitoring a non-full-phase opening of a 10KV capacitor bank circuit breaker provided in an embodiment of the present application is shown as follows: Figure 1 As shown, the method includes:

[0048] S101, obtaining busbar current data of a 10KV capacitor bank circuit breaker.

[0049] In this embodiment, the bus current data of the 10KV capacitor bank circuit breaker can be obtained by using relevant current measurement devices, such as a supervisory control and data acquisition (SCADA) system, a feeder automation (FA) system, and the like, which will not be described in detail in this embodiment.

[0050] S102, performing wavelet transform on the bus current data to obtain wavelet coefficients.

[0051] In this embodiment, when performing wavelet transform, it is necessary to first determine a suitable wavelet basis function and the number of decomposition levels. Therefore, this embodiment selects the Db4 wavelet basis function as the basic wavelet function.

[0052] When determining the number of decomposition layers, the present invention sets the sampling frequency to 6400 Hz and the fundamental frequency to 50 Hz. In order to make the fundamental frequency located at the center of the lowest sub-band and limit the influence of the fundamental frequency component on other sub-bands, the wavelet decomposition band division method can be expressed as formula (1):

[0053] Among them, f s is the sampling frequency, and f0 is the fundamental frequency of the signal. Substituting into the calculation, we can get P = 6. Therefore, in order to achieve good classification accuracy, a 7-layer wavelet decomposition is used.

[0054] Then, the bus current data can be decomposed by wavelet according to the determined wavelet basis function and decomposition layer number to obtain the wavelet coefficients.

[0055] S103 , extracting energy distribution characteristics of the bus current according to the wavelet coefficients, and calculating the mean square error of energy distribution of each phase according to the energy distribution characteristics.

[0056] In this embodiment, a set of energy distribution characteristics is constructed based on the wavelet coefficients determined in the above embodiment. The construction process is specifically as follows: determining the wavelet coefficients of the low-frequency part of each layer and the wavelet coefficients of the high-frequency part of each layer; summing the squares of the wavelet coefficients of the low-frequency part and the high-frequency part respectively to obtain the energy distribution characteristics of the bus current.

[0057] The following formula describes the above process:

[0058] in, c j (n) represents the wavelet coefficient of the low-frequency approximation part of the jth layer, d x (n) represents the wavelet coefficient representing the high-frequency detail part of the j-th layer.

[0059] In order to quantify the feature extraction results and better distinguish the feature extraction results in different situations, this embodiment calculates the mean square error of energy distribution based on the wavelet coefficients. The expression for calculating the mean square error of energy distribution is:

[0060] Among them, V is the mean square error of energy distribution, N is the number of decomposition layers, and v i is the energy distribution characteristic of each layer, and μ is the mean of all energies.

[0061] S104: Subtract the mean square error of the energy distribution of each phase from the preset mean square error of the steady-state energy distribution when all phases are not tripped, and compare the difference results with the preset thresholds to obtain a judgment vector for the 10KV capacitor bank circuit breaker; wherein the judgment vector includes three elements of the three phases A, B, and C.

[0062] In this embodiment, the preset energy distribution mean square error threshold when each phase is not disconnected can be defined as a comparison vector, and accordingly, the calculated energy distribution mean square error is the actual vector, wherein the ABC three-phase of the circuit breaker has a comparison vector and an actual vector. In order to weaken the influence of factors such as load size and current size, the actual vector and the comparison vector can be made to differ. If there is no influence of factors such as power system noise, the difference between the two can only be zero and non-zero. However, due to the dynamic changes of the power system and the difficulty in completely eliminating noise, the difference between the two is difficult to be zero. Therefore, the energy distribution mean square error threshold M is set. When the difference result is less than M, the judgment vector can be considered to be zero. Therefore, the judgment vector X=[X m , X n , X r] describes the difference result, and the elements of X can only be 0 or 1. The value of M can be determined by randomly adding white noise to the power system and performing simulation tests.

[0063] S105: Monitor the non-full-phase opening state of the 10KV capacitor bank circuit breaker according to the judgment vector.

[0064] In this embodiment, the circuit breaker non-full-phase opening state is distinguished according to the judgment vector, and the specific implementation method is: if X a -X A If the vector X is smaller than the preset vector threshold, then the vector X is judged to be m If it is 0, it means that the current of phase A has not changed and phase A is not disconnected; if X a -X A Is not equal to 0, then the vector X m Taking 1 indicates that the current of phase A changes and phase A is disconnected. The same principle applies to the remaining two phases BC.

[0065] In addition, this embodiment also makes a monitoring example analysis based on the actual data of the substation, as follows:

[0066] First, set the parameters of each electrical device in the simulation model. The specific parameters of the reactive power compensation device are shown in Table 1:

[0067] Table 1 Simulation parameters

[0068] electrical equipment Equivalent parameters Parallel capacitors Q=8000kvar,C=106uF Series reactor Reactance 5%, L = 2.169mH

[0069] According to the parameters in Table 1, a simulation circuit is built in MATLAB. The simulation circuit schematic is as follows: Figure 2 As shown, in the simulation circuit under normal operation, the non-full-phase disconnection is simulated by controlling the circuit breaker disconnection time of the reactive compensation device. By measuring the bus current, data simulating the three-phase current in actual operation can be obtained. It should be noted that the circuit breaker status is divided into the following three types, namely, all three-phase disconnection, non-full-phase disconnection and all three-phase non-disconnection, for non-full-phase disconnection. Simulations were carried out separately for the different circuit breaker states listed above. The circuit breaker was disconnected at t = 0.5 seconds, and the bus current before and after the circuit breaker was disconnected was subjected to wavelet transform analysis. First, the three-phase current of the bus was decomposed by wavelet, and then the characteristic quantity was extracted. In order to compare with the normal non-disconnection and all-disconnection situations, Figure 3 Firstly, the feature extraction results of the bus three-phase current under these two states are presented. Figure 3(a) shows the extraction results of busbar current characteristics during normal operation of the circuit breaker. Taking phase A as an example, after seven layers of wavelet decomposition, the results of each layer correspond to a wavelet coefficient. By calculating these wavelet coefficients, the energy distribution values ​​corresponding to each layer of phase A can be obtained. These values ​​specifically reflect the distribution of phase A current energy in each layer. From the extraction results, it can be seen that the energy is mainly concentrated in the fifth, sixth, and seventh layers, while the low-frequency energy distribution in the first four layers is relatively small. This change in energy distribution from the first to the seventh layer reflects the trend of energy distribution. Figure 3 (b) shows the busbar current characteristic extraction results when all circuit breakers are normally opened. Its energy distribution trend is similar to Figure 3 (a) Similar, but with energy distribution values Figure 3 (b) with Figure 3 (a) The minimum difference is about 50%, and the relative positions of the three-phase characteristic results are also quite different, such as Figure 3 The curve of the extraction result of phase B in (a) is above the other two phases, while Figure 3 In (b), the extraction results of phase A are plotted above the other two phases. Figure 3 The two extraction results in represent the common states of the circuit breaker and can therefore be compared and analyzed with the non-full-phase tripping state.

[0070] When one phase of the circuit breaker is not open, Figure 4 (a) as an example, compared with Figure 4 (a), since phase A is not disconnected, the fluctuation of phase A current on the busbar is small, while the fluctuation of phase B and C current is large. Therefore, Figure 4 In (a), the energy distribution trend and value change of phase A current are relatively small, while the differences between phases B and C are relatively large. Taking the results of the seventh layer as an example, the value change of phase A is about 1.5%, while that of phase B is about 56.4%, and that of phase C is about 93.7%. This also leads to changes in the relative positions of the three-phase characteristic quantity results. Figure 4 (b) and Figure 4 (c) Similarly, because one phase is not disconnected, the relative positions of the energy distribution values ​​of the three-phase current and the three-phase characteristic quantity results are different.

[0071] When the two phases of the circuit breaker are not disconnected, Figure 4 For example, in (d), since phases A and B are not disconnected, the fluctuation of the current of phases A and B on the bus is small, while the fluctuation of the current of phase C is large. Figure 3 (a), the difference is mainly concentrated in phase C, where the energy distribution value changes by 93.7%, and the relative positions of the three-phase characteristic results also change. Figure 4 (e) and Figure 4 (f) with Figure 3The differences in (a) are concentrated in phases B and A, respectively. In summary, there are significant differences in the feature extraction results for the busbar three-phase current when the circuit breaker is not open in one phase and when it is not open in two phases. The energy distribution trends of the currents in each phase are similar, but the energy distribution values ​​and the relative positions of the three-phase feature results vary when the circuit breaker is in different states. This feature can be used to clearly distinguish between states where the circuit breaker is not fully open.

[0072] After calculating the feature quantity, according to formula (3) Figure 3 and Figure 4 The extracted results are further processed to calculate the corresponding energy distribution mean square error. The results are shown in Table 2.

[0073] Table 2 Summary of energy distribution mean square error

[0074]

[0075] After obtaining Table 2, the comparison vector X0 is defined as [1.2536, 2.5536, 0.2288], and the threshold is M = 0.25, then the judgment vector can be obtained as shown in Table 3.

[0076] Table 3 Summary of judgment vectors

[0077]

[0078] According to Table 3, it can be seen that no matter one phase or two phases are not opened, they can be distinguished in detail by judging the vector, and a specific phase can be found to be not opened, and the final result is consistent with the actual situation.

[0079] Since the harmonic content in the actual power system is constantly changing, the harmonic content is changed and white noise is randomly added to study and analyze whether the harmonic content has an impact on the accuracy of the proposed method.

[0080] Similarly, based on the actual recorded data of a 10kV substation, the third and fifth voltage harmonic contents injected into the simulation system are changed, and then the classification results of phase A without disconnection are summarized, as shown in Table 4.

[0081] Table 4 Summary of the results of differentiating phase A when it is not tripped under different harmonic contents

[0082]

[0083] In Table 4, Y1 and Y2 represent the third and fifth voltage harmonic contents respectively. a -X A are all less than the energy distribution mean square error threshold M, and X b -X B 、X c -XC All of them are greater than the energy distribution mean square error threshold M. According to the previous analysis, all the final judgment vectors X = [0, 1, 1]. This shows that even if the harmonic content continues to change, the judgment vector X = [0, 1, 1] can be obtained, that is, it can distinguish that phase A is not open and phases B and C are open.

[0084] Therefore, while changes in harmonic content will cause changes in the energy distribution mean square error of the tripped phase current, the energy distribution mean square error of the untripped phase remains unchanged. Therefore, even with changes in harmonic content, the method provided in this embodiment can still accurately and reliably identify the circuit breaker status, and the harmonic content does not affect the accuracy of the proposed method.

[0085] It can be seen that the method provided in this embodiment aims to address the problem of insufficient accuracy and reliability in the monitoring of non-full-phase disconnection of existing capacitor group circuit breakers, and proposes a technology for realizing non-full-phase disconnection monitoring and identification through judgment vectors. The specific implementation method is: the bus current data near the circuit breaker is obtained through the relevant current measurement device of the distribution network automation technology, the wavelet transform technology is used for data processing, and then the energy distribution mean square error is calculated according to the wavelet coefficient. The mean square error of the three-phase current energy distribution when all three phases are not disconnected is used as the comparison vector, and finally the judgment vector is calculated to realize the monitoring of non-full-phase disconnection of the circuit breaker through the judgment vector.

[0086] Actual calculation results demonstrate that the method provided by this embodiment can accurately identify a circuit breaker's partial-phase trip fault and, compared to existing technologies, can pinpoint the fault to a specific phase. Even when the system's harmonic content varies, this method can still accurately identify the circuit breaker's partial-phase trip state, demonstrating high reliability. Furthermore, since the required data can be directly obtained from the current measurement device in the distribution automation system, this greatly simplifies the data collection process, thereby reducing the overall cost of technical implementation.

[0087] Please refer to Figure 5 , Figure 5 The principle block diagram of a 10KV capacitor bank circuit breaker non-full-phase opening monitoring device provided in the embodiment of the present application is as follows: Figure 5 As shown, the device includes:

[0088] The data acquisition module 510 is used to acquire bus current data of the 10KV capacitor bank circuit breaker;

[0089] The data processing module 520 is used to perform wavelet transform on the bus current data to obtain wavelet coefficients;

[0090] A mean square error calculation module 530 is used to extract the energy distribution characteristic quantity of the bus current according to the wavelet coefficient, and calculate the mean square error of the energy distribution of each phase according to the energy distribution characteristic quantity;

[0091] The judgment vector calculation module 540 is configured to subtract the mean square error of the energy distribution of each phase from the predetermined mean square error of the steady-state energy distribution when all phases are not tripped, and compare the difference with a predetermined threshold value to obtain a judgment vector for the 10KV capacitor bank circuit breaker. The judgment vector includes three elements for phases A, B, and C.

[0092] The state monitoring module 550 is used to monitor the non-full-phase opening state of the 10KV capacitor bank circuit breaker according to the judgment vector.

[0093] It can be seen that the embodiment of the present application provides a 10KV capacitor bank circuit breaker non-full-phase opening monitoring device. To address the problem of insufficient accuracy and reliability of the existing capacitor bank circuit breaker non-full-phase opening monitoring, the bus current data near the circuit breaker is obtained through the relevant current measuring device of the distribution network automation technology, and the wavelet transform technology is used for data processing. Then, the energy distribution mean square error is calculated based on the wavelet coefficient, and the three-phase current energy distribution mean square error when all three phases are not disconnected is used as the comparison vector. Finally, the judgment vector is calculated to realize the monitoring of the non-full-phase opening of the circuit breaker through the judgment vector. Therefore, the present application can accurately identify the non-full-phase opening fault of the circuit breaker, and compared with the existing technology, the present method can accurately locate a specific phase. Even when the harmonic content of the power system changes, the non-full-phase opening state of the circuit breaker can still be accurately identified, with high reliability. In addition, since the required data can be directly obtained from the current measuring device of the distribution network automation system, this greatly simplifies the data acquisition process, thereby reducing the overall cost of technical implementation.

[0094] In some embodiments, the data processing module 520 further includes:

[0095] Selection module, used to determine the wavelet basis function and the number of decomposition layers;

[0096] The decomposition module is used to perform wavelet decomposition on the bus current data according to the wavelet basis function and the number of decomposition layers to obtain wavelet coefficients.

[0097] In some embodiments, the mean square error calculation module 530 further includes:

[0098] A coefficient determination module is used to determine the wavelet coefficients of the low-frequency part of each layer and the wavelet coefficients of the high-frequency part of each layer;

[0099] The characteristic quantity calculation module is used to sum the squares of the wavelet coefficients of the low-frequency part and the high-frequency part respectively to obtain the energy distribution characteristic quantity of the bus current.

[0100] In some embodiments, the expression for calculating the mean square error of energy distribution is:

[0101] Among them, V is the mean square error of energy distribution, N is the number of decomposition layers, and v i is the energy distribution characteristic of each layer, and μ is the mean of all energies.

[0102] In some embodiments, the status monitoring module 550 is specifically configured to:

[0103] If the difference result is less than the preset threshold, the corresponding element of the judgment vector is set to 0, indicating that the circuit breaker of the corresponding phase is not opened;

[0104] If the difference result is greater than the preset threshold, the corresponding element of the judgment vector takes the value of 1, indicating that the circuit breaker of the corresponding phase is open.

[0105] It should be noted that the embodiment of the present application provides a 10KV capacitor bank circuit breaker non-full-phase opening monitoring device, which is similar to the above Figure 1 The shown method for monitoring the non-full-phase opening of a 10KV capacitor group circuit breaker is a technical solution based on the same inventive concept. Through the detailed description of the non-full-phase opening monitoring method of a 10KV capacitor group circuit breaker provided in the above embodiment, those skilled in the art can clearly understand the implementation process of each module in the non-full-phase opening monitoring device of a 10KV capacitor group circuit breaker in this embodiment, so for the sake of brevity of the specification, it will not be repeated here.

[0106] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A 10KV capacitor bank circuit breaker non-full phase opening monitoring method, characterized in that the method include: Obtain busbar current data of 10KV capacitor bank circuit breaker; Perform wavelet transform on bus current data to obtain wavelet coefficients; Performing wavelet transform on bus current data to obtain wavelet coefficients, specifically: determining wavelet basis functions and decomposition levels; performing wavelet decomposition on bus current data according to the wavelet basis functions and decomposition levels to obtain wavelet coefficients; The energy distribution characteristic quantity of the bus current is extracted based on the wavelet coefficients, and the energy distribution mean square error of each phase is calculated based on the energy distribution characteristic quantity. The energy distribution characteristic quantity of the bus current is extracted based on the wavelet coefficients, including: determining the wavelet coefficients of the low-frequency part of each layer and the wavelet coefficients of the high-frequency part of each layer; summing the squares of the wavelet coefficients of the low-frequency part and the high-frequency part respectively to obtain the energy distribution characteristic quantity of the bus current; the expression for calculating the energy distribution mean square error is: ,in, V is the mean square error of energy distribution, N is the number of decomposition layers, v i is the energy distribution characteristic of each layer, is the mean of all energies; The energy distribution mean square error of each phase is subtracted from the preset steady-state energy distribution mean square error when all phases are not tripped. The difference is compared with the preset threshold value to obtain the judgment vector of the 10KV capacitor bank circuit breaker. The judgment vector includes three elements for the three phases A, B, and C. Monitor the non-full-phase opening status of the 10KV capacitor bank circuit breaker based on the judgment vector.

2. The method according to claim 1, characterized in that Monitor the non-full-phase tripping status of the 10KV capacitor bank circuit breaker based on the judgment vector, including: If the difference result is less than the preset threshold, the corresponding element of the judgment vector is set to 0, indicating that the circuit breaker of the corresponding phase is not opened; If the difference result is greater than the preset threshold, the corresponding element of the judgment vector takes the value of 1, indicating that the circuit breaker of the corresponding phase is open.

3. A 10KV capacitor bank circuit breaker non-full-phase opening monitoring device, characterized in that: The device includes: Data acquisition module, used to obtain bus current data of 10KV capacitor bank circuit breaker; The data processing module also includes: a selection module for determining a wavelet basis function and a decomposition layer number; a decomposition module for performing wavelet decomposition on the bus current data according to the wavelet basis function and the decomposition layer number to obtain wavelet coefficients; A data processing module is used to perform wavelet transform on bus current data to obtain wavelet coefficients; The mean square error calculation module is used to extract the energy distribution characteristic quantity of the bus current based on the wavelet coefficients, and calculate the mean square error of the energy distribution of each phase based on the energy distribution characteristic quantity. The mean square error calculation module also includes: a coefficient determination module, which is used to determine the wavelet coefficients of the low-frequency part of each layer, and the wavelet coefficients of the high-frequency part of each layer; a characteristic quantity calculation module, which is used to sum the squares of the wavelet coefficients of the low-frequency part and the high-frequency part respectively to obtain the energy distribution characteristic quantity of the bus current. The expression for calculating the mean square error of the energy distribution is: ,in, V is the mean square error of energy distribution, N is the number of decomposition layers, v i is the energy distribution characteristic of each layer, is the mean of all energies; The judgment vector calculation module is used to subtract the mean square error of the energy distribution of each phase from the preset mean square error of the steady-state energy distribution when all phases are not tripped, and compare the difference results with the preset threshold value to obtain the judgment vector of the 10KV capacitor bank circuit breaker. The judgment vector includes three elements of the three phases A, B, and C. The status monitoring module is used to monitor the non-full-phase opening status of the 10KV capacitor bank circuit breaker based on the judgment vector.

4. The device according to claim 3, characterized in that Condition monitoring module, specifically used for: If the difference result is less than the preset threshold, the corresponding element of the judgment vector is set to 0, indicating that the circuit breaker of the corresponding phase is not opened; If the difference result is greater than the preset threshold, the corresponding element of the judgment vector takes the value of 1, indicating that the circuit breaker of the corresponding phase is open.

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