Capacitor bank fault diagnosis method, device, system and storage medium

Abstract

The application relates to the technical field of power systems, and specifically discloses a capacitor bank fault diagnosis method, device, system and storage medium, which comprises the following steps: acquiring full-cut residual reactive power and full-on response deviation of all to-be-tested capacitors in a capacitor bank; in response to at least one of the full-cut residual reactive power exceeding preset residual reactive power or the full-on response deviation being greater than preset full-cut deviation, collecting group response deviation of each capacitor group, and determining a fault capacitor group with group response deviation reaching preset group deviation; the capacitor bank comprises at least two capacitor groups; acquiring a diagnosis characteristic vector of each to-be-tested capacitor in the fault capacitor group, and determining that a to-be-tested capacitor with a feature component value in the diagnosis characteristic vector being in a preset fault value range is a fault capacitor. By introducing a joint criterion of full-cut and full-on reactive power, the problem range is quickly narrowed down through group diagnosis, and the accuracy of fault positioning is improved by using diagnosis characteristic vectors of branches in the group.

Description

Technical Field

[0001] This application relates to the field of power system technology, and in particular to a method, apparatus, system and storage medium for diagnosing capacitor bank faults. Background Technology

[0002] With the increasing proportion of renewable energy generation, the pressure on reactive power fluctuations, load disturbances, and power factor assessments at renewable energy power plant grid connection points is also increasing. Static Var Compensators (SVCs) can quickly adjust reactive power, thus enabling reactive power management in renewable energy grid-connected projects. Capacitor banks, as the actuators of the SVC low-voltage reactive power compensation unit, typically consist of an I / O control module, a composite switch, and capacitor branches; their switching status directly affects the accuracy of reactive power compensation.

[0003] In actual operation, capacitor banks may experience anomalies such as contact sticking of composite switches, failure of composite switches to operate, capacitor capacity decay, and disturbances in meter sampling. When faults are not detected in time, the system may continue to overcompensate or undercompensate, resulting in capacitor temperature rise, shortened lifespan, inaccurate compensation strategies, and increased on-site maintenance costs. In addition, circuit-by-circuit inspection takes a long time to diagnose when there are many capacitor branches, and the fixed testing strategy cannot adaptively narrow down the problem range based on intermediate results, failing to balance rapid and precise fault location. Summary of the Invention

[0004] The main purpose of this application is to provide a method for diagnosing capacitor bank faults, which aims to solve the technical problem that it is difficult to achieve both speed and accuracy in fault location of capacitor banks in the prior art.

[0005] To achieve the above objectives, this application provides a capacitor bank fault diagnosis method, which includes the following steps: Obtain the residual reactive power when all capacitors under test are switched off and the response deviation when all capacitors are switched on in the capacitor bank; In response to at least one of the following: the residual reactive power of a fully switched capacitor bank exceeds the preset residual reactive power or the full-on response deviation is greater than the preset full-switching deviation, the group response deviation of each capacitor bank is collected, and the faulty capacitor bank whose group response deviation reaches the preset group deviation is identified; the capacitor bank includes at least two capacitor banks. Obtain the diagnostic feature vector of each capacitor under test within the fault capacitor group, and determine the capacitor under test whose feature component value within the diagnostic feature vector is within the preset fault value range as the fault capacitor.

[0006] In one embodiment, obtaining the fully switched residual reactive power and fully switched response deviation of all capacitors under test in the capacitor bank includes: Generate and transmit a cut-off command to all capacitors under test in the capacitor bank, and collect the residual reactive power of each capacitor under test after the cut-off command is completed. In response to the fact that the residual reactive power of the fully switched capacitor does not exceed the preset residual reactive power, the power-on command is transmitted to all the capacitors under test, and the full-switching response deviation of each capacitor under test in response to the power-on command is collected.

[0007] In one embodiment, the deviation of the full-throw response of each capacitor under test in response to the completion of the throwing command action is collected, including: Collect the reactive power of each capacitor under test in response to the completion of the switching command action; The full-load response deviation is obtained by calculating the difference between the full-load reactive power and the historical capacitance reference of all capacitors under test.

[0008] In one embodiment, the capacitor bank fault diagnosis method further includes: Obtain the preset ratio value of the historical capacitance reference for all capacitors under test and the maximum allowable error value of the hardware; The maximum value of the preset ratio and the maximum allowable error value of the hardware is used as the preset residual reactive power.

[0009] In one embodiment, the group response deviation of each capacitor group is collected, including: Divide all capacitors under test into more than one capacitor group; In response to each capacitor bank returning to the fully switched-off state, a power-on command is transmitted to the capacitor bank. Collect the reactive capacity of each capacitor bank in response to the activation command, and calculate the reactive power of each capacitor bank. The group response deviation is obtained by calculating the difference between the reactive power of the group and the historical capacity reference of the capacitor under test in the capacitor group.

[0010] In one embodiment, all capacitors under test are divided into more than one capacitor group, including: In response to the average branch numbering of all capacitors under test in the capacitor bank, the capacitors are divided into at least two capacitor groups; or, The capacitor bank wiring partition corresponding to all the capacitors under test in the capacitor bank is divided into more than one capacitor group.

[0011] In one embodiment, obtaining the diagnostic feature vector of each capacitor under test within the faulty capacitor group includes: Each faulty capacitor group is cut out, and a connection command is transmitted to each capacitor under test in the faulty capacitor group. Collect the reactive power of each capacitor under test in response to the completion of the input command, and transmit the cut-off command to each capacitor under test in the fault capacitor group respectively. Collect the residual reactive power of each capacitor under test in response to the cut-off command. Diagnostic feature vectors for each capacitor under test are constructed based on the reactive power of the input response and the residual reactive power of the output response.

[0012] In one embodiment, a diagnostic feature vector for each capacitor under test is constructed using the input response reactive power and the cut-off residual reactive power, including: Calculate the capacity retention rate of the input response reactive power and the corresponding historical reference capacity of the capacitor under test; Diagnostic feature vectors for each capacitor under test are constructed based on capacitance retention rate, reactive power during input, and residual reactive power during output.

[0013] In one embodiment, the capacitor bank fault diagnosis method further includes: Based on the historical diagnostic records and preset smoothing coefficients of each capacitor under test, the prior probabilities corresponding to the normal state, the composite switch adhesion state and the capacitor capacity decay state are obtained. Based on the prior probability and diagnostic feature vector, the posterior probability corresponding to each fault state is calculated according to the Bayesian posterior probability formula. The fault type of the faulty capacitor is determined based on the fault state corresponding to the maximum posterior probability.

[0014] Furthermore, to achieve the above objectives, this application also provides a capacitor bank fault diagnosis device, the device comprising: The overall screening module is used to obtain the residual reactive power when all capacitors under test are switched off and the response deviation when all capacitors are switched on in the capacitor bank. The group positioning module is used to collect the group response deviation of each capacitor group in response to at least one of the following: the residual reactive power of full switching exceeds the preset residual reactive power or the full switching response deviation is greater than the preset full switching deviation; and to determine the faulty capacitor group whose group response deviation reaches the preset group deviation; the capacitor group includes at least two capacitor groups. The fine diagnosis module is used to obtain the diagnostic feature vector of each capacitor under test within the fault capacitor group, and to determine the capacitor under test whose feature component value within the diagnostic feature vector is within the preset fault value range as the fault capacitor.

[0015] In addition, to achieve the above objectives, this application also provides a capacitor bank fault diagnosis system, which includes: a metering meter, a patrol meter, a capacitor bank, and a controller, the controller being used to execute the steps of the capacitor bank fault diagnosis method described above. The capacitor bank includes: an input / output module, at least one capacitor, and a composite switch with the same number of capacitors; Each capacitor is connected to its corresponding composite switch. The control terminal of the composite switch is connected to the input / output module. The electrical terminal of the composite switch is connected to the low-voltage bus via a patrol meter. The metering meter is installed on the low-voltage bus. The input / output module, the metering meter, and the patrol meter are all connected to the controller.

[0016] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the capacitor bank fault diagnosis method described above.

[0017] The above-mentioned one or more technical solutions provided in this application may have the following advantages or at least achieve the following technical effects: This application discloses a method, apparatus, system, and storage medium for diagnosing capacitor bank faults. The method includes: acquiring the full-cut residual reactive power and full-on response deviation of all capacitors under test in the capacitor bank; in response to at least one of the following: the full-cut residual reactive power exceeds a preset residual reactive power or the full-on response deviation is greater than a preset full-cut deviation, collecting the group response deviation of each capacitor group, and identifying the faulty capacitor group whose group response deviation reaches the preset group deviation; the capacitor bank includes at least two capacitor groups; acquiring the diagnostic feature vector of each capacitor under test in the faulty capacitor group, and identifying the capacitor under test whose feature component value in the diagnostic feature vector is within a preset fault value range as the faulty capacitor. The method employs a strategy of overall rapid screening, group location, and precise testing of problematic branch circuits. In fault-free scenarios, only two tests (full-cut and full-on) are required to complete the test; in faulty scenarios, normal branches can be eliminated first through grouping, significantly reducing the number of tests per circuit. Furthermore, the introduction of full-cut residual reactive power and single-circuit bidirectional response allows for simultaneous location of the capacitor bank fault and differentiation of fault causes. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the first embodiment of the capacitor bank fault diagnosis method of this application; Figure 2 This is a schematic diagram of the first process of the second embodiment of the capacitor bank fault diagnosis method of this application; Figure 3 This is a second flowchart illustrating the second embodiment of the capacitor bank fault diagnosis method of this application; Figure 4 This is a flowchart illustrating the third embodiment of the capacitor bank fault diagnosis method of this application; Figure 5 This is a schematic diagram of the first process of the fourth embodiment of the capacitor bank fault diagnosis method of this application; Figure 6 This is a schematic diagram of the second process of the fourth embodiment of the capacitor bank fault diagnosis method of this application; Figure 7 This is a schematic diagram of the module structure of the capacitor bank fault diagnosis device of this application; Figure 8 This is a schematic diagram of the capacitor bank fault diagnosis system of this application.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0024] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or a capacitor bank fault diagnosis system capable of performing the above functions. The following description uses a capacitor bank fault diagnosis system as an example to illustrate this embodiment and the subsequent embodiments.

[0025] Based on this, embodiments of this application provide a capacitor bank fault diagnosis method, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the capacitor bank fault diagnosis method of this application.

[0026] Step S10: Obtain the residual reactive power when all capacitors under test are switched off and the response deviation when all capacitors are switched on in the capacitor bank.

[0027] It should be understood that the capacitor under test can be a single capacitor branch that constitutes a capacitor bank. Each capacitor under test is connected to the low-voltage bus via a composite switch. The composite switch is controlled by the input / output (IO) control module to achieve input or output actions.

[0028] It should be noted that "residual reactive power after full disconnection" refers to the reactive power value measured by the monitoring meter on the capacitor bank side after issuing a disconnection command to all capacitors under test and waiting for stabilization. Theoretically, this value should be close to zero. A large residual reactive power indicates a possible fault such as a stuck composite switch. "Response deviation after full connection" refers to the difference between the change in reactive power measured by the monitoring meter after issuing a connection command to all capacitors under test and waiting for stabilization, and the sum of the historical capacity baselines for all capacitors under test. This difference reflects the overall capacity response.

[0029] Step S20: In response to at least one of the following: the residual reactive power of full disconnection exceeds the preset residual reactive power or the response deviation of full disconnection is greater than the preset full disconnection deviation, the group response deviation of each capacitor group is collected, and the faulty capacitor group whose group response deviation reaches the preset group deviation is determined.

[0030] It should be understood that capacitor grouping can be achieved by dividing multiple capacitors under test within a capacitor bank into several subsets according to branch sequence numbers or capacitor bank wiring zones. Each subset includes at least one capacitor under test, and the capacitor bank includes at least two capacitor groups. The division method can be either an equal distribution of branch sequence numbers or a division according to capacitor bank wiring zones. Group response deviation can refer to the difference between the reactive power change measured by the monitoring meter after a capacitor group is put into operation and the sum of the historical capacity baselines of the capacitors under test within that group.

[0031] It should be noted that the preset residual reactive power can be a threshold determined based on the minimum branch capacity within the capacitor bank or the maximum permissible error of the meter, used to determine whether the residual reactive power is abnormal under full disconnection conditions. The preset full disconnection deviation can be a threshold determined based on a certain proportion of the overall historical capacity benchmark of the capacitor bank, used to determine whether the capacity response deviation under full connection conditions exceeds the normal range. The preset group deviation can be a capacity response deviation threshold set for a single capacitor group, used to determine whether the group has a fault. At least one of the following conditions must be met: the full disconnection residual reactive power exceeds the preset residual reactive power, or the full connection response deviation is greater than the preset full disconnection deviation. Meeting any one of these conditions triggers the group diagnosis process.

[0032] Step S30: Obtain the diagnostic feature vector of each capacitor under test within the fault capacitor group, and determine the capacitor under test whose feature component value within the diagnostic feature vector is within the preset fault value range as the fault capacitor.

[0033] It should be understood that the diagnostic feature vector can be a mathematical vector composed of multiple physical quantities such as the reactive power of the input response, the residual reactive power of the output response, and the capacity retention rate of a single capacitor under test, used to characterize the electrical response characteristics of the capacitor under test.

[0034] It should be noted that the preset fault value range can be the numerical range of each component of the diagnostic feature vector pre-set for different fault types. For example, when the residual reactive power cut off under the state of composite switch adhesion is close to the historical capacity benchmark of the branch, and when the reactive power input under the state of capacity decay is lower than the historical capacity benchmark.

[0035] In one possible implementation, the capacitor bank may consist of six capacitors under test, with historical capacity benchmarks of 10kvar, 10kvar, 20kvar, 20kvar, 30kvar, and 30kvar respectively. The minimum branch capacity is 10kvar, the preset residual reactive power can be 8kvar, and the preset full-cut deviation can be 15% of the sum of the historical capacity benchmarks of all capacitors under test. The controller first issues a cut-off command to all capacitors under test and waits for stabilization time. The monitoring meter measures a full-cut residual reactive power of 20.8kvar, which exceeds the preset residual reactive power of 8kvar, triggering the group diagnostic process. Channels 1 to 3 are assigned to Group 1, and channels 4 to 6 are assigned to Group 2. After Group 1 is put into operation, the reactive power change is 39.5 kvar, the sum of the historical capacity benchmarks for Group 1 is 40 kvar, and the group response deviation rate is 1.25%, so Group 1 is judged to be normal. After Group 2 is put into operation, the reactive power change is 42.1 kvar, the sum of the historical capacity benchmarks for Group 2 is 80 kvar, and the group response deviation rate is 47.4%, which exceeds the preset group deviation of 15%, so Group 2 is judged to be a faulty capacitor group. Single-channel bidirectional tests were performed on capacitors 4, 5, and 6 in Group 2. The reactive power of the input response and the residual reactive power of the output were collected to form a diagnostic feature vector. The residual reactive power of the output of the 4th capacitor was 20.8 kvar, close to its historical capacity benchmark of 20 kvar, and the reactive power of the input response was 0.4 kvar. The feature component value fell within the preset fault value range of composite switch adhesion, and the capacitor under test in the 4th capacitor was determined to have a composite switch adhesion fault. The reactive power of the input response of the 6th capacitor was 12.3 kvar, the historical capacity benchmark was 30 kvar, and the capacity retention rate was 0.41. The feature component value fell within the preset fault value range of capacitor capacity decay, and the capacitor under test in the 6th capacitor was determined to have a severe capacitor capacity decay fault.

[0036] This embodiment acquires the residual reactive power after full disconnection and the response deviation after full connection of all capacitors under test in the capacitor bank. In response to at least one of the following: the residual reactive power after full disconnection exceeds a preset residual reactive power or the response deviation after full connection is greater than a preset full disconnection deviation, the group response deviation of each capacitor group is collected, and the faulty capacitor group whose group response deviation reaches the preset group deviation is identified. The capacitor bank includes at least two capacitor groups. The diagnostic feature vectors of each capacitor under test within the faulty capacitor group are acquired, and the capacitors under test whose feature component values ​​within the diagnostic feature vectors are within a preset fault value range are identified as faulty capacitors. Employing a strategy of overall rapid screening, group location, and precise testing of problematic branch circuits, only two tests (full disconnection and full connection) are required in fault-free scenarios. In faulty scenarios, normal branches can be excluded first through grouping, significantly reducing the number of tests per circuit. Furthermore, the introduction of residual reactive power after full disconnection and bidirectional response of a single circuit allows for simultaneous location of the fault location in the capacitor bank and differentiation of the fault cause.

[0037] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in Embodiment 1 above can be referred to the above description, and will not be repeated hereafter. Please refer to Figure 2 , Figure 2 This is a schematic diagram of the first process of the second embodiment of the capacitor bank fault diagnosis method of this application. In this embodiment, the runtime constraint set is generated based on a configurable rule base with a three-level hierarchical tree structure. The three-level hierarchical tree structure includes drawing type-level rules, annotation element-level rules, and project specification-level rules. Step 10 includes: Step S201: Generate and transmit a cut-off command to all capacitors under test in the capacitor bank, and collect the residual reactive power of each capacitor under test after the cut-off command is completed.

[0038] It should be understood that the cut-off command can be a control signal issued by the controller through the IO control module to the corresponding composite switch of each capacitor under test. This signal causes the composite switch to open, and the capacitor under test is disconnected from the low-voltage bus. The residual reactive power after the cut-off command is issued can be the reactive power value measured by the monitoring meter on the capacitor bank side after the cut-off command is issued and the stabilization time is waited. Theoretically, this value should be close to zero. If there is a large residual reactive power, it indicates that some composite switches failed to respond to the cut-off command.

[0039] It should be noted that collecting the residual reactive power of each capacitor under test after responding to the cut-off command means simultaneously issuing the cut-off command to all capacitors under test, and then reading the reactive power value from the monitoring meter after a stabilization period. This reactive power value is the total residual reactive power, not the residual reactive power collected from each capacitor under test individually. The operation of transmitting the connection command will only continue if the total residual reactive power is less than or equal to the preset residual reactive power. If the total residual reactive power exceeds the preset residual reactive power, the group diagnosis process will be entered directly, and the full connection test will not be performed.

[0040] Step S202: In response to the fact that the residual reactive power of the full cut does not exceed the preset residual reactive power, the power-on command is transmitted to all the capacitors under test, and the full-on response deviation of each capacitor under test in response to the power-on command is collected.

[0041] It should be understood that the activation command can be a control signal issued by the controller through the IO control module to the corresponding composite switch of each capacitor under test. This signal causes the composite switch to close, and the capacitor under test is connected to the low-voltage bus. The overall activation response deviation after the activation command is issued can be the difference between the reactive power change measured by the monitoring meter and the sum of the historical capacity references of all capacitors under test after the activation command is issued and the stabilization time is waited. This difference reflects the overall activation response.

[0042] It should be noted that transmitting the connection command to all capacitors under test can mean simultaneously issuing connection commands to all capacitors under test within the capacitor bank, causing all composite switches to close and all capacitors under test to be connected to the low-voltage bus.

[0043] It is easy to understand that by first generating and transmitting a cut-off command to all capacitors under test and collecting the residual reactive power after full cut-off, composite switch sticking issues can be detected in the early stages of diagnosis. This avoids performing a full-connection test when the sticking branch is not disconnected, improving the logical integrity of the diagnosis. Only when the residual reactive power after full cut-off does not exceed the preset residual reactive power is a connection command transmitted to all capacitors under test and the full-connection response deviation collected. This sequential testing strategy can complete the overall screening in scenarios with no faults or only capacity decay, through two tests, which helps to shorten the diagnosis time. If the residual reactive power after full cut-off exceeds the preset residual reactive power, it indicates composite switch sticking or baseline abnormality. In this case, there is no need to perform a full-connection test; the process can directly enter the group diagnosis process, which can avoid obtaining incorrect full-connection response deviations when the baseline is inaccurate, improving the accuracy and robustness of the diagnosis.

[0044] Furthermore, referring to Figure 3 , Figure 3 This is a second flowchart illustrating a second embodiment of the capacitor bank fault diagnosis method of this application. Step S202 includes: Step S301: Collect the reactive power of each capacitor under test in response to the completion of the switching command.

[0045] It should be understood that "full-load reactive power" can be the reactive power value measured by the inspection meter on the capacitor bank side after issuing a command to all capacitors under test and waiting for a stabilization time. This value reflects the overall reactive power output after all capacitors under test are connected to the low-voltage bus.

[0046] It should be noted that the total reactive power of all capacitors under test in response to the commissioning command is collected by reading the reactive power value of the inspection meter after the commissioning command is issued and the stabilization time is waited. This reactive power value is the total reactive power, rather than collecting the commissioning response reactive power of each capacitor under test one by one.

[0047] It is understandable that the preset ratio value and the maximum permissible error value of the hardware are obtained from the historical capacitance reference of all capacitors under test; the maximum value of the preset ratio value and the maximum permissible error value of the hardware is used as the preset residual reactive power.

[0048] It should be understood that the preset ratio value can be a value calculated based on the historical capacity benchmark of all capacitors under test according to a certain ratio coefficient. This ratio coefficient can be determined according to the minimum branch capacity or the overall capacity distribution within the capacitor bank, for example, 0.8 times the historical capacity benchmark of the minimum branch. The maximum permissible error value of the hardware can be the maximum permissible deviation in reactive power measurement caused by hardware factors such as the measurement accuracy of the inspection meter, capacitor capacity error, and contact resistance error of the composite switch.

[0049] Step S302: Calculate the difference between the total reactive power and the historical capacitance reference of all capacitors under test to obtain the total reactive power response deviation.

[0050] It should be understood that the historical capacity baseline can be the nominal reactive power capacity of each capacitor under test at its factory calibration or during historical normal operation, usually in kvar, and can be stored in the controller's memory. The historical capacity baseline of all capacitors under test can refer to the sum of the historical capacity baselines of all capacitors under test within the capacitor bank. The difference can be a value obtained through mathematical subtraction, i.e., the total reactive power minus the total historical capacity baseline of all capacitors under test.

[0051] It should be noted that the difference between the total reactive power and the historical capacity benchmark of all tested capacitors can be calculated through mathematical subtraction. That is, the total reactive power deviation equals the total reactive power minus the sum of the historical capacity benchmarks of all tested capacitors. The absolute value of the difference reflects the degree of deviation of the overall capacity response from the historical benchmark. The total reactive power deviation can be positive or negative. A positive value indicates that the measured total reactive power is greater than the historical capacity benchmark, which may indicate meter sampling error or an increase in the capacity of some branches. A negative value indicates that the measured total reactive power is less than the historical capacity benchmark, which may indicate capacitor capacity decay or failure of some composite switches to operate.

[0052] It is understandable that the formula for the full-investment response deviation can be expressed as: ; Among them, D all It could be the full-investment response bias, Q all It could be a complete failure, Q0 could be, C h，i It can be the historical baseline capacity.

[0053] The concept of "full-load response deviation" is readily understood. It calculates the difference between the total reactive power output and the historical capacity baseline of all tested capacitors. This difference quantitatively reflects the degree of deviation between the overall capacity response and the historical baseline, allowing for the determination of whether the capacitor bank exhibits faults such as capacity decay or failure of composite switches to operate. The historical capacity baseline, serving as a reference, can be adaptively adjusted based on the capacity configuration of different capacitor banks, avoiding misjudgments caused by fixed thresholds and improving the applicability and accuracy of the diagnosis. The full-load response deviation, as a criterion for overall screening, together with the residual reactive power output after full disconnection, constitutes a joint criterion. This enables rapid identification of abnormalities in the capacitor bank during the initial diagnostic phase, providing a basis for subsequent group diagnosis and precise localization.

[0054] Based on the above embodiments of this application, in the third embodiment of this application, the same or similar content as the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 4 , Figure 4 This is a flowchart illustrating the third embodiment of the capacitor bank fault diagnosis method of this application. In this embodiment, step 20 includes: Step S401: Divide all capacitors under test into more than one capacitor group.

[0055] It should be understood that more than one capacitor group can be the division of the capacitors under test within the capacitor group into at least two subsets, each subset being a capacitor group. Specifically, it can be the division into at least two capacitor groups in response to the average branch number of all capacitors under test in the capacitor group; or, the division into more than one capacitor group in response to the capacitor cabinet wiring partition corresponding to all capacitors under test in the capacitor group.

[0056] Step S402: In response to each capacitor group returning to the fully switched-off state, transmit the activation command to the capacitor group.

[0057] It should be understood that restoring a capacitor group to a fully disconnected state can mean issuing a disconnect command to all capacitors under test within the capacitor group before conducting group connection tests, ensuring that all capacitors under test are in a disconnected state and providing consistent initial conditions for group connection tests. Transmitting a connection command to a capacitor group can mean issuing a connection command only to the capacitors under test within a specific capacitor group, causing the composite switch within that group to close, connecting the capacitors under test to the low-voltage bus, while keeping the capacitors under test in other groups disconnected.

[0058] It should be noted that before putting each capacitor group into operation, all capacitors under test must be ensured to be in the off state to avoid mutual interference between different groups. The input command to the capacitor group can be transmitted via the IO control module, which sends input signals to the composite switches corresponding to each capacitor under test within that group, while the composite switches of other groups remain in the off state.

[0059] Step S403: Collect the reactive capacity of each capacitor group in response to the activation command, and calculate the reactive power of each capacitor group.

[0060] It should be understood that the reactive power capacity of a capacitor bank can be the reactive power value measured by the monitoring meter on the capacitor bank side. This value reflects the overall reactive power output of all capacitors currently connected to the low-voltage bus. Grouped reactive power can be the reactive power change caused by the activation of a certain group of capacitors, obtained through calculation. It can be the reactive power capacity of the capacitor bank after the group of capacitors is activated minus the residual reactive power under the fully disconnected state.

[0061] It should be noted that after the activation command is issued and a stabilization period is waited, the reactive power value of the inspection meter is read. The reactive power of each capacitor bank can be calculated by subtracting the residual reactive power under the fully off state from the reactive power capacity of the capacitor bank after the activation of the capacitor bank, thus obtaining the reactive power change caused by the activation of the capacitor bank.

[0062] Step S404: Calculate the difference between the reactive power of the group and the historical capacitance reference of the capacitor under test in the capacitor group to obtain the group response deviation.

[0063] It should be understood that the historical capacitance reference of the capacitor under test in a capacitor group can be the sum of the historical capacitance references of all capacitors under test within that capacitor group.

[0064] It should be noted that the difference between the reactive power of the capacitor group and the historical capacity benchmark of the capacitor under test can be obtained by mathematical subtraction to obtain the group response deviation. This difference reflects the degree of deviation of the capacity response of the capacitor group from the historical benchmark.

[0065] It is understandable that the formula for calculating the group response bias can be: ; Among them, E g Let ΔQ be the group response deviation of the g-th capacitor group. g For the reactive power of group g, C h，g This represents the historical baseline total capacitance of the g-th group of capacitors.

[0066] By dividing all capacitors under test into more than one group, a comprehensive connection test can be performed on each group first, quickly identifying faulty groups, narrowing down the problem scope, and improving diagnostic efficiency. Transmitting the connection command to each group only after all groups have returned to a fully disconnected state ensures consistent initial testing conditions for each group, avoids interference between different group tests, and improves the accuracy of group response deviation measurement. The reactive power of each capacitor group in response to the connection command is collected, and the difference between the group's reactive power and the historical capacity baseline of the capacitors under test in that group is calculated to obtain the group response deviation. This deviation quantitatively reflects the capacity response of the capacitor group and determines whether the group is faulty. For faulty capacitor groups whose response deviation reaches the preset deviation, further fine-tuning tests can be performed. For normal capacitor groups whose response deviation does not reach the preset deviation, individual testing is unnecessary, reducing the number of tests and further shortening the diagnostic time.

[0067] Based on the above embodiments of this application, in the fourth embodiment of this application, the same or similar content as the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 5 , Figure 5 This is a schematic diagram of the first process of the fourth embodiment of the capacitor bank fault diagnosis method of this application. In this embodiment, step 30 includes: Step S501: Cut out each fault capacitor group and transmit the activation command to each capacitor under test in the fault capacitor group respectively.

[0068] It should be understood that disconnecting each faulty capacitor group can be achieved by issuing a disconnect command to all capacitors under test within the faulty capacitor group, ensuring that all capacitors under test within the faulty capacitor group are in a disconnected state, thus providing consistent initial conditions for subsequent single-channel connection tests. Alternatively, a connection command can be issued to each capacitor under test within the faulty capacitor group individually, connecting only one capacitor under test at a time, while keeping the other capacitors under test disconnected.

[0069] It should be noted that "switching out of each faulty capacitor group" can mean issuing a switch-out command to all capacitors under test within that group before performing detailed diagnosis. This avoids interference from the engagement status of other capacitors under test with the single-channel test results. A single-channel engagement test strategy is adopted, meaning that only one capacitor under test is engaged at a time. After a settling period, the engagement response reactive power is collected. Then, that capacitor is switched out, and the residual reactive power is collected. The next capacitor under test is then engaged, and so on, completing the single-channel bidirectional test of all capacitors under test within the faulty capacitor group.

[0070] Step S502: Collect the reactive power of each capacitor under test in response to the completion of the input command, and transmit the cut-off command to each capacitor under test in the fault capacitor group respectively.

[0071] It should be understood that the reactive power response to being put into operation can be the change in reactive power measured by the monitoring meter after a single capacitor under test responds to the action of the input command. This value reflects the increase in reactive power caused by the capacitor under test being connected to the low-voltage bus. The transmission of the cut-out command can be a cut-out command issued to the capacitor under test that has been put into operation, causing the capacitor under test to be disconnected from the low-voltage bus.

[0072] It should be noted that the reactive power of the input response can be obtained by calculating the difference between the reactive power of the capacitor bank after the capacitor under test is put into operation and the reactive power of the capacitor bank before it is put into operation, or it can be obtained by directly reading the reactive power change of the inspection meter.

[0073] Step S503: Collect the residual reactive power of each capacitor under test after the cut-off command is completed.

[0074] It should be understood that the residual reactive power after disconnection can be the reactive power change or residual reactive power measured by the monitoring meter after a single capacitor under test responds to the disconnection command. This value reflects whether there is still reactive power residue after the capacitor under test is disconnected.

[0075] It should be noted that the residual reactive power can be obtained by calculating the difference between the reactive capacity of the capacitor bank after the capacitor under test is cut off and the theoretical residual reactive power after full cut-off, or by directly reading the residual reactive power of the inspection meter.

[0076] Step S504: Construct diagnostic feature vectors for each capacitor under test based on the reactive power of the input response and the residual reactive power of the output.

[0077] It should be understood that the diagnostic feature vector can be a mathematical vector composed of multiple physical quantities such as input response reactive power and cut-out residual reactive power, used to characterize the electrical response characteristics of a single capacitor under test.

[0078] It should be noted that the input response reactive power and the cut-out residual reactive power can be used as two components of the diagnostic feature vector, or derived features such as capacity retention rate can be further calculated as additional components of the diagnostic feature vector.

[0079] Furthermore, the capacity retention rate of the input response reactive power and the corresponding historical reference capacity of the capacitor under test can be calculated; based on the capacity retention rate, input response reactive power and cut-off residual reactive power, a diagnostic feature vector of each capacitor under test can be constructed.

[0080] It is understandable, and should be understood, that the capacity retention rate can be the ratio of the reactive power of a single capacitor under test to its historical reference capacity. This ratio reflects the degree to which the current capacity of the capacitor under test is retained relative to its historical reference capacity, and is usually expressed as a percentage or decimal.

[0081] It should be noted that the capacity retention rate of the input response reactive power and the corresponding historical reference capacity of the capacitor under test can be achieved through mathematical division. That is, the capacity retention rate is equal to the input response reactive power divided by the historical reference capacity. When the input response reactive power is equal to the historical reference capacity, the capacity retention rate is 1 or 100%, indicating that the capacity of the capacitor under test is normal. When the input response reactive power is lower than the historical reference capacity, the capacity retention rate is less than 1, indicating that the capacitor under test may have capacity decay.

[0082] It is easy to understand that by disconnecting each faulty capacitor group, transmitting a connection command to each capacitor under test within the faulty capacitor group, and collecting the reactive power of the connection response, the reactive power response characteristics of a single capacitor under test after connection to the low-voltage bus can be obtained. By transmitting a disconnection command to each capacitor under test within the faulty capacitor group, and collecting the residual reactive power after disconnection, the residual reactive power characteristics of a single capacitor under test after disconnection from the low-voltage bus can be obtained, identifying composite switch sticking faults. When a large residual reactive power remains after disconnection of a capacitor under test, it indicates that the composite switch corresponding to that capacitor under test failed to respond to the disconnection command, and is preferentially judged as composite switch sticking. Using the connection response reactive power and the residual reactive power after disconnection to construct the diagnostic feature vector of each capacitor under test can comprehensively reflect the bidirectional electrical response characteristics of a single capacitor under test, improving the accuracy and interpretability of fault type identification.

[0083] Furthermore, referring to Figure 6 , Figure 6 This is a second flowchart illustrating the fourth embodiment of the capacitor bank fault diagnosis method of this application. The method further includes: Step S601: Based on the historical diagnostic records and preset smoothing coefficients of each capacitor under test, obtain the prior probabilities corresponding to the normal state, the composite switch sticking state, and the capacitor capacity decay state.

[0084] It should be understood that historical diagnostic records can be statistics recorded in the controller's memory of the number of times each capacitor under test was determined to be in a normal state, a combined switch sticking state, or a capacitor capacitance decay state in each diagnostic iteration. This record reflects the historical fault frequency of each capacitor under test. The preset smoothing coefficient can be a numerical parameter used to smooth the calculation of prior probabilities, avoiding zero prior probabilities for certain states when the number of historical diagnostic iterations is low; it is typically a small value greater than zero. Prior probabilities can be the probability of each fault state occurring, calculated based on historical diagnostic records and the preset smoothing coefficient, before the current diagnostic feature vector is observed; it reflects the historical frequency of each fault state.

[0085] It should be noted that a normal state can refer to a state where the capacitance retention rate of the capacitor under test is close to 100%, the reactive power response is close to the historical baseline capacity, and the residual reactive power after disconnection is close to zero. A composite switch sticking state can refer to a state where the contacts of the composite switch corresponding to the capacitor under test are stuck together, and the composite switch fails to open after the disconnection command is issued, resulting in the residual reactive power after disconnection being close to the historical baseline capacity of the capacitor under test. A capacitor capacitance decay state can refer to a state where the capacitance retention rate of the capacitor under test is lower than the normal range, the reactive power response is lower than the historical baseline capacity, and the residual reactive power after disconnection is close to zero. The prior probability is obtained by statistically analyzing the frequency of each state in historical diagnostic records and performing Laplace smoothing calculations using a preset smoothing coefficient. The calculation formula can be: the prior probability equals the number of state occurrences plus the smoothing coefficient divided by the total number of historical diagnostics plus the total number of states multiplied by the smoothing coefficient.

[0086] Step S602: Based on the prior probability and diagnostic feature vector, calculate the posterior probability corresponding to each fault state according to the Bayesian posterior probability formula.

[0087] It should be understood that the Bayesian posterior probability formula can be a mathematical expression of Bayes' theorem, used to calculate the posterior probability based on prior probabilities and observational evidence. The posterior probability can be the probability of each fault state occurring, calculated using the Bayesian posterior probability formula after observing the current diagnostic feature vector, comprehensively reflecting the degree of support for the fault state from historical prior knowledge and current observational evidence.

[0088] It should be noted that, according to Bayes' theorem, the posterior probability is equal to the prior probability multiplied by the likelihood probability divided by the normalization constant. The likelihood probability can be calculated using the Gaussian probability density function based on the deviation between the values ​​of each component of the diagnostic feature vector and the expected values ​​of each fault state.

[0089] Step S603: Determine the fault type of the fault capacitor based on the fault state corresponding to the maximum posterior probability.

[0090] It should be understood that the maximum posterior probability can be the largest among the posterior probabilities corresponding to the three states: normal state, combined switch sticking state, and capacitor capacitance decay state. The fault type can be the current fault category of the capacitor under test determined based on the fault state corresponding to the maximum posterior probability, including normal, combined switch sticking, capacitor capacitance decay, etc.

[0091] It should be noted that using the fault state corresponding to the fault state with the maximum posterior probability to determine the fault type of the faulty capacitor can be achieved by comparing the posterior probabilities of three states: normal state, composite switch sticking state, and capacitor capacity decay state, and selecting the state with the highest posterior probability as the fault type of the capacitor under test.

[0092] In one possible implementation, three mutually exclusive states are set for the i-th branch: This indicates that it is normal. This indicates that the composite switch is stuck together. This indicates that the capacitor's capacitance has decreased. State The prior probability can be determined by historical diagnostic records, equipment operating years, number of switching operations, and failure rate of the same model. The specific formula can be found in the following formula: ; in, Indicates historical state Number of occurrences This indicates the total number of historical diagnoses. This is a smoothing coefficient used to avoid a prior probability of 0 when historical samples are insufficient. In engineering, the power measurement error of an electricity meter approximately follows a Gaussian distribution, then the state... The likelihood function under the given conditions can be expressed as: ; in, The states in Table 2 The corresponding expected value of the j-th observation, The standard deviation of this observation can be determined by meter accuracy, historical sampling fluctuations, and field experience. According to Bayes' theorem, the standard deviation of the i-th capacitance diagnostic feature vector... Under these conditions, the capacitor bank is in a state of... The posterior probability is: ; like If the probability is ≥0.95, then a high-confidence diagnostic result will be output according to the state corresponding to the maximum posterior probability; if 0.80 ≤ If the result is less than 0.95, output a medium confidence level result and suggest a retest; if... If the value is less than 0.80, it is marked as uncertain and manual verification is recommended.

[0093] when When the maximum a posteriori state is reached, it is determined that the i-th composite switch has a risk of sticking, and it is recommended to prioritize checking or replacing the composite switch; when When the maximum a posteriori state is reached, further consideration is given based on the capacity retention rate. Subdivided into severely degraded ( <0.5), slight attenuation (0.5≤ <0.85) or normal aging observation ( ≥0.85).

[0094] It is easy to understand that by obtaining the prior probability corresponding to each fault state based on the historical diagnostic records of each capacitor under test and a preset smoothing coefficient, the historical fault frequency can be introduced into the diagnostic process as prior knowledge, improving the statistical rationality of the diagnostic results. When a capacitor under test has experienced multiple capacity decay faults in the past, the prior probability of the capacitor's capacity decay state is high, and the current diagnosis is more inclined to judge it as capacity decay even when the features are not obvious. By calculating the posterior probability corresponding to each fault state based on the prior probability and diagnostic feature vector according to the Bayesian posterior probability formula, the historical prior knowledge and current observation evidence can be integrated, reducing the risk of misjudgment caused by a single threshold judgment and improving the robustness of the diagnosis. The posterior probability, as a probability value, can quantitatively reflect the confidence of the diagnostic result. When the maximum posterior probability is close to 1, it indicates that the confidence of the diagnostic result is high, and an alarm or maintenance suggestion can be directly triggered; when the maximum posterior probability is low, it indicates that the diagnostic result is uncertain, and retesting or manual verification can be suggested, improving the interpretability and practicality of the diagnostic system. Using the fault state corresponding to the maximum posterior probability to determine the fault type of the faulty capacitor enables quantitative comparison among multiple fault states, allowing the selection of the most probable fault state as the diagnostic conclusion, and further improving the accuracy of fault type identification.

[0095] This application also provides a capacitor bank fault diagnosis device, please refer to... Figure 7 The capacitor bank fault diagnosis device includes: The overall screening module 10 is used to obtain the full-cut residual reactive power and full-on response deviation of all capacitors under test in the capacitor bank. The group positioning module 20 is used to collect the group response deviation of each capacitor group in response to at least one of the following: the residual reactive power of full switching exceeds the preset residual reactive power or the full switching response deviation is greater than the preset full switching deviation; and to determine the faulty capacitor group whose group response deviation reaches the preset group deviation; the capacitor group includes at least two capacitor groups. The fine diagnosis module 30 is used to obtain the diagnostic feature vector of each capacitor under test in the fault capacitor group, and to determine the capacitor under test whose feature component value in the diagnostic feature vector is within the preset fault value range as the fault capacitor.

[0096] The capacitor bank fault diagnosis device provided in this application, employing the capacitor bank fault diagnosis method in the above embodiments, can solve the technical problem that it is difficult to simultaneously achieve speed and accuracy in capacitor bank fault location. Compared with the prior art, the beneficial effects of the capacitor bank fault diagnosis device provided in this application are the same as those of the capacitor bank fault diagnosis method provided in the above embodiments, and other technical features in the capacitor bank fault diagnosis device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0097] This application provides a capacitor bank fault diagnosis system, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the capacitor bank fault diagnosis method in Embodiment 1 above.

[0098] The following is for reference. Figure 8 The diagram illustrates a structural schematic suitable for implementing a capacitor bank fault diagnosis system according to embodiments of this application. The capacitor bank fault diagnosis system in this application may include: a metering meter 101, a monitoring meter 102, a capacitor bank 103, and a controller 104, the controller 104 being used to execute the steps of the capacitor bank fault diagnosis method described above.

[0099] It should be noted that the capacitor bank 103 includes: an IO module 1031, at least one capacitor 1032, and a composite switch 1033 with the same number of capacitors; each capacitor 1032 is connected to the corresponding composite switch 1033, the control terminal of the composite switch 1033 is connected to the IO module 1031, the electrical terminal of the composite switch 1033 is connected to the low-voltage bus via a patrol meter 102, the metering meter 101 is installed on the low-voltage bus, and the IO module 1031, the metering meter 101, and the patrol meter 102 are all connected to the controller 104.

[0100] It should be understood that the low-voltage busbar can be the AC busbar output from the low-voltage side of the transformer, used to supply power to loads such as capacitor banks. It is typically a three-phase AC busbar with a voltage level of 400V or 690V. The metering device can be an energy meter or wattmeter installed on the low-voltage busbar, used to measure electrical parameters such as active power, reactive power, and power factor at the grid connection point. The inspection meter can be an energy meter or wattmeter installed on the capacitor bank side, used to measure the reactive power changes caused by capacitor bank switching. The input / output module can be an I / O control module, used to receive digital signals from the controller and convert them into control voltage signals recognizable by the composite switch. It typically includes input ports and output ports. The composite switch can be a hybrid switch composed of a contactor and a thyristor connected in parallel, or a single contactor, relay, or other switching device, used to control the connection and disconnection of capacitors. The capacitor can be a reactive power compensation capacitor, typically a parallel capacitor, used to provide reactive power to the low-voltage busbar. The control terminal can be the port of the composite switch that receives control signals, used to receive the control voltage signals output from the input / output module. The electrical terminal can be the port of the composite switch connected to the power circuit, used to control the electrical connection between the capacitor and the low-voltage bus.

[0101] The capacitor bank fault diagnosis system provided in this application adopts the capacitor bank fault diagnosis method in the above embodiments. Compared with the prior art, the beneficial effects of the capacitor bank fault diagnosis system provided in this application are the same as the beneficial effects of the capacitor bank fault diagnosis method provided in the above embodiments. Moreover, other technical features of the capacitor bank fault diagnosis system are the same as the features disclosed in the method of the previous embodiment, and will not be repeated here.

[0102] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0103] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0104] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the capacitor bank fault diagnosis method in the above embodiments.

[0105] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0106] The aforementioned computer-readable storage medium may be included in the capacitor bank fault diagnosis system; or it may exist independently and not be assembled into the capacitor bank fault diagnosis system.

[0107] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0108] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0109] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0110] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described capacitor bank fault diagnosis method. This solves the technical problem that it is difficult to simultaneously achieve speed and accuracy in capacitor bank fault location. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the capacitor bank fault diagnosis method provided in the above embodiments, and will not be repeated here.

[0111] The above are only some embodiments of this application and do not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for diagnosing capacitor bank faults, characterized in that, The capacitor bank fault diagnosis method includes: Obtain the residual reactive power when all capacitors under test are switched off and the response deviation when all capacitors are switched on in the capacitor bank; In response to at least one of the following: the residual reactive power of the full switch exceeds the preset residual reactive power or the full switch response deviation is greater than the preset full switch deviation, the group response deviation of each capacitor group is collected, and the faulty capacitor group whose group response deviation reaches the preset group deviation is identified; the capacitor group includes at least two capacitor groups. Obtain the diagnostic feature vector of each capacitor under test within the fault capacitor group, and determine the capacitor under test whose feature component value within the diagnostic feature vector is within a preset fault value range as the fault capacitor.

2. The capacitor bank fault diagnosis method as described in claim 1, characterized in that, The acquisition of the fully switched residual reactive power and fully switched response deviation of all capacitors under test in the capacitor bank includes: Generate and transmit a cut-off command to all capacitors under test in the capacitor bank, and collect the residual reactive power of each capacitor under test after the complete cut-off action in response to the cut-off command. In response to the fact that the residual reactive power of the full cut does not exceed the preset residual reactive power, a power-on command is transmitted to all the capacitors under test, and the full-power response deviation of each capacitor under test in response to the power-on command is collected.

3. The capacitor bank fault diagnosis method as described in claim 2, characterized in that, The acquisition of the full-throw response deviation of each of the capacitors under test in response to the completion of the throwing command includes: Collect the reactive power of each of the capacitors under test in response to the completion of the switching command action; The full-load response deviation is obtained by calculating the difference between the full-load reactive power and the historical capacitance reference of all the capacitors under test.

4. The capacitor bank fault diagnosis method as described in claim 3, characterized in that, The capacitor bank fault diagnosis method further includes: Obtain the preset ratio value of the historical capacitance reference of all the capacitors under test and the maximum allowable error value of the hardware; The maximum value of the preset ratio and the maximum allowable error value of the hardware is taken as the preset residual reactive power.

5. The capacitor bank fault diagnosis method as described in claim 1, characterized in that, The acquisition of the group response deviation of each capacitor group includes: All the capacitors under test are divided into more than one capacitor group; In response to each capacitor group returning to the fully switched-off state, a power-on command is transmitted to the capacitor group; Collect the reactive capacity of each capacitor group in response to the activation command, and calculate the group reactive power corresponding to each capacitor group. The group response deviation is obtained by calculating the difference between the reactive power of the group and the historical capacity reference of the capacitor under test in the capacitor group.

6. The capacitor bank fault diagnosis method as described in claim 5, characterized in that, The step of dividing all the capacitors under test into more than one capacitor group includes: In response to the average branch numbering of all capacitors under test in the capacitor bank, the capacitors are divided into at least two capacitor groups; or, In response to the fact that all the capacitors under test in the capacitor bank are divided into capacitor bank wiring zones, the capacitor bank wiring zones are divided into more than one capacitor group.

7. The capacitor bank fault diagnosis method as described in claim 1, characterized in that, The step of obtaining the diagnostic feature vector of each capacitor under test within the faulty capacitor group includes: Each of the faulty capacitor groups is cut out, and an activation command is transmitted to each of the capacitors under test in the faulty capacitor group respectively. Collect the reactive power of each capacitor under test in response to the completion of the input command action, and transmit the cut-off command to each capacitor under test in the fault capacitor group respectively. Collect the residual reactive power of each of the capacitors under test in response to the cut-off command action; Diagnostic feature vectors for each capacitor under test are constructed based on the input response reactive power and the cut-off residual reactive power.

8. The capacitor bank fault diagnosis method as described in claim 7, characterized in that, The construction of diagnostic feature vectors for each capacitor under test based on the input response reactive power and the cut-off residual reactive power includes: Calculate the capacity retention rate between the input response reactive power and the corresponding historical reference capacity of the capacitor under test; Diagnostic feature vectors for each capacitor under test are constructed based on the capacitance retention rate, the reactive power of the input response, and the residual reactive power of the output.

9. The capacitor bank fault diagnosis method as described in claim 1, characterized in that, The capacitor bank fault diagnosis method further includes: Based on the historical diagnostic records and preset smoothing coefficients of each capacitor under test, the prior probabilities corresponding to the normal state, the composite switch adhesion state and the capacitor capacity decay state are obtained. Based on the prior probability and the diagnostic feature vector, the posterior probability corresponding to each fault state is calculated according to the Bayesian posterior probability formula. The fault type of the faulty capacitor is determined based on the fault state corresponding to the maximum posterior probability.

10. A capacitor bank fault diagnosis device, characterized in that, The device includes: The overall screening module is used to obtain the residual reactive power when all capacitors under test are switched off and the response deviation when all capacitors are switched on in the capacitor bank. The group positioning module is used to collect the group response deviation of each capacitor group in response to at least one of the following: the residual reactive power of the full switch exceeds the preset residual reactive power or the full switch response deviation is greater than the preset full switch deviation; and to determine the faulty capacitor group whose group response deviation reaches the preset group deviation; the capacitor group includes at least two capacitor groups. The fine diagnosis module is used to obtain the diagnostic feature vector of each capacitor under test in the fault capacitor group, and to determine the capacitor under test whose feature component value in the diagnostic feature vector is within a preset fault value range as a fault capacitor.

11. A capacitor bank fault diagnosis system, characterized in that, The capacitor bank fault diagnosis system includes: a metering meter, a patrol meter, a capacitor bank, and a controller, wherein the controller is used to execute the steps of the capacitor bank fault diagnosis method as described in any one of claims 1 to 9; The capacitor bank includes: an input / output module, at least one capacitor, and a composite switch with the same number of capacitors; Each capacitor is connected to its corresponding composite switch. The control terminal of the composite switch is connected to the input / output module. The electrical terminal of the composite switch is connected to the low-voltage busbar through the inspection meter. The metering meter is installed on the low-voltage busbar. The input / output module, the metering meter, and the inspection meter are all connected to the controller.

12. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the capacitor bank fault diagnosis method as described in any one of claims 1 to 9.

Images