Fault location method for low-voltage distribution network reactive power compensation capacitor bank based on difference thought

Abstract

The application provides a low-voltage distribution network reactive power compensation capacitor bank fault positioning method based on a difference idea, which comprises the following steps: in the case that the first current data is 0, determining that the internal fuse exists a fuse failure; in the case that the first current data is not 0, calculating second current data according to each first current data through the difference idea; in the case that the ratio of the first current data to the second current data is not in a first preset range, calculating a target capacitance value based on the first current data; determining a corresponding fuse current through simulation based on each capacitance to obtain third current data; in the case that the target capacitance value is not in a second preset range or the difference between the fourth current data and the third current data is greater than a first threshold value, determining that the capacitance corresponding to the target capacitance value exists a capacitance out-of-limit fault. The method solves the problem that the fault detection method in the prior art cannot perform early warning according to the actual running state of the reactive power compensation device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power grid fault monitoring, in particular to a low-voltage distribution network reactive power compensation capacitor bank fault positioning method and device based on differential thinking, a computer readable storage medium and a monitoring system. BACKGROUND

[0002] The reactive power compensation device is the most important reactive power source in the power network, and it plays an important role in improving power supply quality and reducing power generation loss even for the distribution network with complex working environment, so the working condition of the reactive power compensation device directly affects the stability and power supply quality of the distribution network. In recent years, accidents of reactive power compensation devices including parallel capacitor bank faults have occurred frequently, and many serious accidents of group explosion and group injury have occurred, and accidents of large-area power failure and personal injury have also occurred.

[0003] At present, the fault monitoring of the reactive power compensation capacitor bank in the distribution network still adopts the power-off and off-grid monitoring, and the disadvantages of this method are obvious. It cannot reflect the real working condition of the reactive power compensation device in complex environment, cannot ensure timely early warning when the reactive power compensation device has initial fault, and causes a large amount of resource waste in the monitoring process due to the complexity and universality of the distribution network layout environment. The main reason for the serious fault of the reactive power compensation device is that the cumulative damage to the capacitor caused by the switching operation overvoltage and closing inrush current during the switching process of the capacitor bank, long-time overvoltage or under-voltage operation of the device, etc. It is precisely because of the many defects of the current fault monitoring of the reactive power compensation device in the distribution network that most of the serious accidents are caused by the initial fault monitoring of the device. SUMMARY

[0004] The main purpose of the present application is to provide a low-voltage distribution network reactive power compensation capacitor bank fault positioning method and device based on differential thinking, a computer readable storage medium and a monitoring system, so as to at least solve the problem that the existing technology uses end-point off-grid detection to detect the fault of the capacitor bank of the reactive power compensation device, and cannot perform early warning according to the real running state of the reactive power compensation device.

[0005] To achieve the above object, according to one aspect of the present application, a low-voltage distribution network reactive power compensation capacitor bank fault positioning method based on the difference idea is provided, comprising: obtaining first current data, the first current data being obtained by monitoring each capacitor current value; in the case that the first current data is 0, determining that the corresponding capacitor internal fuse has a melting fault; in the case that the first current data is not 0, calculating the current arithmetic mean value according to each first current data through the difference idea to obtain second current data; in the case that the ratio of the first current data to the second current data is not within a first preset range, calculating the actual capacitor value of the capacitor based on the first current data to obtain a target capacitor value; constructing a corresponding capacitor circuit model according to each capacitor to obtain a first target model, and determining the melting current of each capacitor according to the first target model to obtain third current data; in the case that the target capacitor value is not within a second preset range or the difference value between fourth current data and the third current data is greater than a first threshold value, determining that the capacitor corresponding to the target capacitor value has a capacitor out-of-limit fault, the fourth current data being the reference current of the capacitor.

[0006] Optionally, calculating the corresponding current arithmetic mean value according to each first current data through the difference idea to obtain second current data comprises: determining fifth current data based on the first current data and historical current data, the fifth current data being the historical current data collected at a preset time length from the first current data collection time, and the historical current data being the first current data collected at a current time; calculating the difference value of each first current data and the corresponding fifth current data to obtain a difference value; obtaining the number of capacitors to obtain a target number, and calculating the ratio of the sum of each difference value to the target number to obtain the second current data.

[0007] Optionally, calculating the actual capacitor value of the capacitor based on the first current data to obtain a target capacitor value comprises: obtaining the voltage value of each capacitor to obtain target voltage data, and obtaining the angular velocity of each capacitor to obtain a target angular velocity; calculating the target capacitor value according to the first current data, the target voltage data and the target angular velocity.

[0008] Optionally, calculating the target capacitor value according to the first current data, the target voltage data and the target angular velocity comprises: substituting the first current data, the target voltage data and the target angular velocity into a first target formula to obtain the target capacitor value: wherein C i is the target capacitor value, I i is the first current data, ω i is the target angular velocity, and U ithe target voltage data.

[0009] Optionally, the corresponding capacitor circuit model is constructed according to each capacitor to obtain a first target model, and the fusing current of each capacitor is determined according to the first target model to obtain third current data, including: constructing a capacitor initial model based on MATLAB or PSPICE, the capacitor initial model being used to simulate the capacitor and circuit elements electrically connected with the capacitor; configuring parameters of the capacitor initial model according to a rated voltage and an initial capacitor value of the capacitor, and inputting at least the target voltage data into the capacitor initial model to determine the capacitor output current to obtain sixth current data; taking a difference between the sixth current data and the first current data as a loss function to optimize the initial capacitor model to obtain the capacitor circuit model; simulating the initial current of the second current data through the capacitor circuit model, and increasing the current by a preset step size until the internal fuse is fused, recording the output current of the capacitor circuit model at the current time to obtain the third current data.

[0010] Optionally, in a case where the target capacitor value is not within a second preset range, it is determined that the capacitor corresponding to the target capacitor value has a capacitor out-of-limit fault, including: obtaining a factory capacitor value of the capacitor to obtain an initial capacitor value; calculating a ratio of the target capacitor value to the initial capacitor value to obtain a first target value; in a case where the first target value is less than a second threshold value, it is determined that the capacitor has a capacitor lower-limit out-of-limit fault, and in a case where the first target value is greater than a third threshold value, it is determined that the capacitor has a capacitor upper-limit out-of-limit fault, the second threshold value being a lower-limit value of the second preset range, and the third threshold value being an upper-limit value of the second preset range.

[0011] Optionally, in a case where a difference between the fourth current data and the third current data is greater than a first threshold value, it is determined that the capacitor corresponding to the target capacitor value has a capacitor out-of-limit fault, including: in a case where the difference between the fourth current data and the third current data is greater than the first threshold value and the third current data is less than the fourth current data, it is determined that the capacitor has a capacitor lower-limit out-of-limit fault; and in a case where the difference between the fourth current data and the third current data is greater than the first threshold value and the third current data is greater than the fourth current data, it is determined that the capacitor has a capacitor upper-limit out-of-limit fault.

[0012] According to another aspect of the present application, there is provided a low-voltage distribution network reactive compensation capacitor bank fault locating device based on the differential idea, comprising: an acquisition unit configured to acquire first current data, the first current data being obtained by monitoring each capacitor current value; a first determination unit configured to determine that an internal fuse of the corresponding capacitor has a fuse failure in the case that the first current data is 0; a first calculation unit configured to calculate an arithmetic mean of the currents according to each first current data by the differential idea to obtain second current data in the case that the first current data is not 0; a second calculation unit configured to calculate an actual capacitance value of the capacitor based on the first current data to obtain a target capacitance value in the case that a ratio of the first current data to the second current data is not within a first preset range; a second determination unit configured to construct a corresponding capacitor circuit model according to each capacitor to obtain a first target model, and determine a fuse current of each capacitor according to the first target model to obtain third current data; and a third determination unit configured to determine that the capacitor corresponding to the target capacitance value has a capacitor out-of-limit fault in the case that the target capacitance value is not within a second preset range or a difference between fourth current data and the third current data is greater than a first threshold, the fourth current data being a reference current of the capacitor.

[0013] According to still another aspect of the present application, there is provided a computer-readable storage medium including a stored program, wherein the program, when executed, controls a device in which the computer-readable storage medium is located to perform any of the methods.

[0014] According to yet another aspect of the present application, there is provided a monitoring system, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing any of the methods.

[0015] With the technical solution of the application, in the low-voltage distribution network reactive power compensation capacitor bank fault positioning method based on the difference idea, first, the first current data is obtained, which is obtained by monitoring each capacitor current value; then, in the case that the first current data is 0, it is determined that the corresponding internal fuse of the capacitor has a fuse failure; then, in the case that the first current data is not 0, the arithmetic mean of the current is calculated according to each first current data by the difference idea to obtain second current data; then, in the case that the ratio of the first current data to the second current data is not within a first preset range, the actual capacitance value of the capacitor is calculated based on the first current data to obtain a target capacitance value; then, a corresponding capacitor circuit model is constructed according to each capacitor to obtain a first target model, and the fuse current of each capacitor is determined according to the first target model to obtain third current data; finally, in the case that the target capacitance value is not within a second preset range or the fourth current data and the third current data difference is greater than a first threshold, it is determined that the capacitor corresponding to the target capacitance value has a capacitor out-of-limit fault, and the fourth current data is the reference current of the capacitor. The method takes the early fault characteristics of the reactive power compensation device as the judgment basis, and performs initial fault positioning on the faulty capacitor based on the difference idea according to the current value, solving the problem that the end point off-network detection is used for fault detection of the capacitor bank of the reactive power compensation device in the prior art, and the problem that early warning cannot be performed according to the actual operation state of the reactive power compensation device. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A hardware structure block diagram of a mobile terminal of a low-voltage distribution network reactive power compensation capacitor bank fault positioning method based on a difference idea is shown according to an embodiment of the application;

[0017] Figure 2 A flowchart of a low-voltage distribution network reactive power compensation capacitor bank fault positioning method based on a difference idea is shown according to an embodiment of the application;

[0018] Figure 3 A structure block diagram of a low-voltage distribution network reactive power compensation capacitor bank fault positioning device based on a difference idea is shown according to an embodiment of the application.

[0019] Among them, the above-mentioned drawings include the following reference signs:

[0020] 102, processor; 104, memory; 106, transmission device; 108, input and output device. DETAILED DESCRIPTION

[0021] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in the case of no conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0022] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0023] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] As introduced in the background, the prior art uses the breakpoint disconnection method to detect the fault of the reactive compensation capacitor bank, which has the problems of being unable to reflect the real working state under complex environment, being unable to give timely early warning in the initial stage of the fault, and causing resource waste due to power grid disconnection. In order to solve the problem that the end-point disconnection detection is used to detect the fault of the capacitor bank of the reactive compensation device and cannot give early warning according to the real running state of the reactive compensation device, the embodiments of the present application provide a low-voltage distribution network reactive compensation capacitor bank fault positioning method, device, computer readable storage medium and monitoring system based on the difference idea.

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0026] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking the case of running on a mobile terminal, Figure 1 is a hardware structure block diagram of a mobile terminal of a low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the difference idea. As shown in Figure 1 , the mobile terminal can include one or more Figure 1The mobile terminal can further include a transmission device 106 for communication function and an input / output device 108. Those skilled in the art can understand that, Figure 1 The structure shown is only schematic and does not limit the structure of the mobile terminal. For example, the mobile terminal can include more or less components than those shown, or have a different configuration of components than those shown. Figure 1 The mobile terminal can include more or less components than those shown, or have a different configuration of components than those shown. Figure 1 The mobile terminal can include more or less components than those shown, or have a different configuration of components than those shown.

[0027] The memory 104 can be used to store computer programs, such as software programs of application software and modules, such as a computer program corresponding to the device information display method in the embodiments of the present application. The processor 102 can execute various function applications and data processing by running the computer programs stored in the memory 104, i.e., implement the method described above. The memory 104 can include a high-speed random access memory, and can further include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include a memory remotely arranged with respect to the processor 102, and the remote memory can be connected to the mobile terminal through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific examples of the network can include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet in a wireless manner.

[0028] In the embodiments, a low-voltage distribution network reactive compensation capacitor bank fault locating method based on differential idea is provided, which is run on a mobile terminal, a computer terminal or similar computing device. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0029] Figure 2 is a flowchart of the low-voltage distribution network reactive compensation capacitor bank fault locating method based on differential idea according to the embodiments of the present application. As shown in the flowchart, Figure 2As shown, the method comprises the following steps:

[0030] In step S201, first current data is acquired, which is obtained by monitoring each capacitor current value;

[0031] Specifically, the current flowing through each capacitor of the running reactive power compensation device is the same in theory because the capacitance values of each capacitor are the same. Therefore, the application judges the fault based on the current value deviation of the capacitor. In actual operation, the current flowing through each capacitor during actual operation is sampled to obtain the first current data.

[0032] In step S202, if the first current data is 0, it is determined that the internal fuse of the corresponding capacitor has a melting fault;

[0033] Specifically, whether the internal fuse of the capacitor has a melting fault is determined by zero-crossing comparison, that is, in the case that the first current data is 0, the faulty capacitor is located according to the number corresponding to the current signal, and the corresponding faulty capacitor is determined.

[0034] In step S203, if the first current data is not 0, the arithmetic mean of the current is calculated based on the first current data by difference thinking to obtain second current data;

[0035] Specifically, based on the collection period of the first current data, the continuous first current data is discretized, and then the first current data collected at the current time and the first current data collected at the last time are differentially calculated to obtain the arithmetic mean of the current of all capacitors at the current time, and the second current data is obtained for comparison to determine the capacitors at risk of failure.

[0036] It can be understood that the starting point of capacitor bank fault location based on difference thinking is that the surrounding environment at different times will cause unpredictable errors in the measurement of the capacitor capacitance value, which is easy to cause misoperation and false alarm. At the same time, the influence of each capacitor in the capacitor bank is the same, that is, the current value change trend flowing through different capacitors at different times should be almost the same, that is, the deviation of the first current data and the second current data should be within the allowable range.

[0037] In specific implementation, when each capacitor is connected to the power grid, there is no first current data collected at the last time. The application sets the current value detected based on each capacitor at the factory as a reference value for differential calculation to determine the arithmetic mean of the current at the initial time.

[0038] Step S204, in the case that the ratio of the first current data to the second current data is not in the first preset range, calculating the actual capacitance value of the capacitor based on the first current data to obtain a target capacitance value;

[0039] Specifically, the ratio of the first current data to the second current data is between 0.945 and 0.964, if the ratio is in this interval, wait for the next sampling, if the ratio is not in this interval, calculate the actual capacitance value of the target capacitor based on the first current data.

[0040] Step S205, constructing a corresponding capacitor circuit model according to each capacitor to obtain a first target model, and determining the fusing current of each capacitor according to the first target model to obtain third current data;

[0041] Specifically, a simulation model is constructed based on each capacitor, and then the environmental parameters of each capacitor are configured, and the parameter optimization of the model is performed based on the first current data, and then the current is gradually increased based on the first current data until the internal fuse is fused, and the capacitor current jumps to 0, and the current at the time of fusing is recorded, that is, the third current data is obtained.

[0042] Step S206, in the case that the target capacitance value is not in the second preset range or the difference between the fourth current data and the third current data is greater than the first threshold value, it is determined that the capacitor corresponding to the target capacitance value has a capacitor out-of-limit fault, and the fourth current data is the reference current of the capacitor.

[0043] Specifically, according to the target capacitance value, it is judged whether to issue a capacitor out-of-limit warning signal, when C i ≤0.95C n , a lower limit warning signal of the capacitor value is issued, when C i ≥1.05C n , an upper limit warning signal of the capacitor value is issued, when 0.95C n ≤C i ≤1.05C n , the capacitor value is in a reasonable range, continue to monitor, C n is the factory capacitance value of the capacitor, C i is the target capacitance value corresponding to the capacitor, and a capacitor out-of-limit warning is issued.

[0044] In addition, the application also sets the above fuse current obtained according to simulation to judge the capacitor over-limit. Generally, the fuse current is in a proportional relationship with the capacitor value, that is, the larger the capacitor value is, the larger the fuse current will be. This is because the larger the capacitor value is, the stronger the heat dissipation capacity of the fuse will be, which can bear larger current, thereby improving the fuse capacity of the fuse. It should be noted that the relationship between the fuse current and the capacitor value is not linear, so the application sets to calibrate the above first threshold value through experiment, and in the case that the difference between the fourth current data and the above third current data is greater than the first threshold value, the capacitor over-limit alarm is sent.

[0045] Through the embodiment, first, the first current data is obtained, the first current data is obtained by monitoring each capacitor current value; then, in the case that the first current data is 0, it is determined that the internal fuse of the corresponding capacitor has a fuse failure; then, in the case that the first current data is not 0, the arithmetic mean of the current is calculated according to each first current data by the difference idea, and the second current data is obtained; then, in the case that the ratio of the first current data to the second current data is not in the first preset range, the actual capacitor value of the capacitor is calculated based on the first current data, and the target capacitor value is obtained; then, according to each capacitor, a corresponding capacitor circuit model is constructed, a first target model is obtained, and the fuse current of each capacitor is determined according to the first target model, and the third current data is obtained; finally, in the case that the target capacitor value is not in the second preset range or the difference between the fourth current data and the third current data is greater than the first threshold value, it is determined that the capacitor corresponding to the target capacitor value has a capacitor over-limit fault, and the fourth current data is the reference current of the capacitor. The method takes the early fault feature of the reactive power compensation device as the judgment basis, and locates the fault capacitor according to the current value based on the difference idea, which solves the problem that the end point off-network detection is used for fault detection of the capacitor group of the reactive power compensation device in the prior art, and cannot perform early warning according to the actual operation state of the reactive power compensation device.

[0046] To locate the fault capacitor, in an optional embodiment, the step S203 includes:

[0047] In step S2031, the fifth current data is determined based on the first current data and the historical current data, the fifth current data is the historical current data collected at a time point that is different from the first current data collection time point by a preset time length, and the historical current data is the first current data collected at a time point before the current time;

[0048] Specifically, based on the historical data corresponding to the first current data, the first current data of the last detection period is calibrated to obtain the fifth current data.

[0049] Step S2032, calculating the difference between each of the first current data and the corresponding fifth current data to obtain a difference value;

[0050] Specifically, the difference value is calculated based on the difference between each of the first current data and the corresponding fifth current data.

[0051] Step S2033, obtaining the number of capacitors to obtain a target number, and calculating the ratio of the sum of each of the difference values to the target number to obtain the second current data.

[0052] Specifically, each of the difference values is used to represent the change trend of each capacitor relative to the previous time, and the average value is calculated based on the difference values to obtain the second current data.

[0053] To monitor the state of the target capacitor, in an optional embodiment, the step S204 includes:

[0054] Step S2041, obtaining the voltage value of each of the capacitors to obtain target voltage data, and obtaining the angular velocity of each of the capacitors to obtain a target angular velocity;

[0055] Specifically, the voltage value of each of the capacitors is obtained to obtain target voltage data U i , and the angular velocity of each of the capacitors is obtained to obtain a target angular velocity ω i .

[0056] Step S2042, calculating the target capacitor value based on the first current data, the target voltage data, and the target angular velocity.

[0057] Specifically, the change of the capacitor value can intuitively reflect the real working condition of the capacitor. Since the active loss and dielectric loss of the capacitor are almost zero, the current flowing through the capacitor can be regarded as a capacitive current. Therefore, the target capacitor value is calculated based on the first current data, the target voltage data, and the target angular velocity through a capacitive current calculation formula.

[0058] To accurately obtain the target capacitor value, in an optional embodiment, the step S2042 includes:

[0059] Step S20421, substituting the first current data, the target voltage data, and the target angular velocity into a first target formula to obtain the target capacitor value:

[0060]

[0061] wherein C i is the target capacitor value, I i is the first current data, ω i is the target angular velocity, and Ui The target voltage data is used for the above-mentioned target voltage data.

[0062] Specifically, the first current data, the target voltage data and the target angular velocity are substituted into the capacitive current calculation formula to calculate the actual capacitance value C of the capacitor i i , i.e. the target capacitance value.

[0063] To determine the predicted melting current of each capacitor, in an optional embodiment, the step S205 includes:

[0064] In step S2051, a capacitor initial model is constructed based on MATLAB or PSPICE, and the capacitor initial model is used to simulate the capacitor and the circuit elements electrically connected to the capacitor.

[0065] Specifically, based on MATLAB or PSPICE software, a capacitor circuit model, i.e. the initial model, is constructed, which includes the capacitor itself and the circuit elements electrically connected thereto.

[0066] In step S2052, parameters of the capacitor initial model are configured according to the rated voltage and the initial capacitance value of the capacitor, and at least the target voltage data is input into the capacitor initial model to determine the capacitor output current, thereby obtaining sixth current data.

[0067] Specifically, the initial conditions of the model are set according to the rated voltage and the capacity parameters of the capacitor. Based on the capacitor initial model and the current environment of the capacitor, the simulation predicted current, i.e. the sixth current data, is determined.

[0068] In step S2053, the initial capacitor model is optimized by taking the difference between the sixth current data and the first current data as a loss function, thereby obtaining the capacitor circuit model.

[0069] Specifically, the simulation deviation of the capacitor initial model is determined based on the sixth current data and the fifth current data, and the capacitor initial model is adjusted to obtain the capacitor circuit model.

[0070] In step S2054, the second current data initial current is simulated through the capacitor circuit model, and the current is increased by a preset step size until the internal fuse is melted, and the output current of the capacitor circuit model at the current time is recorded to obtain the third current data.

[0071] Specifically, the second current data is used as the initial current value of the capacitor circuit model, and the current flowing through the capacitor is gradually increased during the simulation process to observe the melting process of the internal fuse of the capacitor. By continuously adjusting the current value, the melting current of the internal fuse is observed, and the current value at this time is recorded, i.e. the melting current of the internal fuse of the capacitor.

[0072] To accurately locate the fault, in an optional embodiment, the step S206 includes:

[0073] Step S20611, obtaining the factory capacitance value of the capacitor to obtain an initial capacitance value;

[0074] Specifically, the factory capacitance value of the capacitor is obtained to obtain an initial capacitance value C n .

[0075] Step S20612, calculating the ratio of the target capacitance value to the initial capacitance value to obtain a first target value;

[0076] Specifically, the ratio of the target capacitance value to the initial capacitance value is calculated to obtain a first target value.

[0077] Step S20613, in the case that the first target value is less than a second threshold value, it is determined that the capacitor has a capacitance lower limit fault, and in the case that the first target value is greater than a third threshold value, it is determined that the capacitor has a capacitance upper limit fault, the second threshold value is the lower limit value of the second preset range, and the third threshold value is the upper limit value of the second preset range.

[0078] Specifically, the second threshold value is 0.95, and the third threshold value is 1.05. In the case that the first target value is less than the second threshold value, a capacitance value lower limit warning signal is sent, and in the case that the first target value is greater than the third threshold value, a capacitance value upper limit warning signal is sent.

[0079] To accurately locate the fault, in an optional embodiment, the step S206 includes:

[0080] Step S20621, in the case that the difference between the fourth current data and the third current data is greater than a first threshold value and the third current data is less than the fourth current data, it is determined that the capacitor has a capacitance lower limit fault;

[0081] Specifically, in the case that the difference between the fourth current data and the third current data is greater than a first threshold value and the third current data is less than the fourth current data, based on the correlation between the fourth current data and the capacitance value of the capacitor, it is determined that the capacitor has a capacitance lower limit fault.

[0082] Step S20622, in the case that the difference between the fourth current data and the third current data is greater than a first threshold value and the third current data is greater than the fourth current data, it is determined that the capacitor has a capacitance upper limit fault.

[0083] Specifically, in the case that the fourth current data minus the third current data is greater than the first threshold value and the third current data is greater than the fourth current data, based on the correlation between the fourth current data and the capacitance value of the capacitance, it is determined that the capacitance has a capacitance upper limit fault.

[0084] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the implementation process of the low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the differential idea of the present application will be described in detail below in combination with specific embodiments.

[0085] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in a different order.

[0086] The present application also provides a low-voltage distribution network reactive compensation capacitor bank fault positioning device based on the differential idea, and it should be noted that the low-voltage distribution network reactive compensation capacitor bank fault positioning device based on the differential idea of the present application can be used to execute the low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the differential idea provided by the present application. The device is used to implement the above embodiments and preferred embodiments, which have been described. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware can also be implemented and conceived.

[0087] The low-voltage distribution network reactive compensation capacitor bank fault positioning device based on the differential idea provided by the present application is described below.

[0088] Figure 3 is a structural block diagram of the low-voltage distribution network reactive compensation capacitor bank fault positioning device based on the differential idea according to the present application. The above-mentioned reactive compensation capacitor bank includes a plurality of capacitors, as shown in Figure 3 The device includes:

[0089] The acquisition unit 10 is used to acquire first current data, and the first current data is obtained by monitoring the current value of each capacitor.

[0090] Specifically, the current flowing through each capacitor of the running reactive compensation device, the theoretical capacitance value of each capacitor is the same, and the current flowing through each capacitor is also the same, therefore, the present application is based on the current value deviation of the capacitor to judge the fault, in the actual operation process, the current value flowing through each capacitor during actual operation is sampled to obtain the first current data.

[0091] The first determining unit 20 is configured to determine that the internal fuse of the corresponding capacitor has a melting fault in the case that the first current data is 0.

[0092] Specifically, whether the internal fuse of the capacitor has a melting fault is determined by zero-crossing comparison, that is, in the case that the first current data is 0, the faulty capacitor is located according to the number corresponding to the current signal, and the corresponding faulty capacitor is determined.

[0093] The first calculating unit 30 is configured to calculate the current arithmetic mean value according to the first current data in the case that the first current data is not 0, and obtain second current data.

[0094] Specifically, the continuous first current data is discretized based on the collection period of the first current data, and then the first current data collected at the current moment and the first current data collected at the last moment are differentially calculated to obtain the current arithmetic mean value of all capacitors at the current moment, and the second current data is obtained, which is used for comparison to determine the capacitor with a risk of fault.

[0095] It can be understood that the starting point of capacitor bank fault location based on the differential idea is that the surrounding environment at different moments will cause unpredictable errors in the measurement of the capacitor value, which is easy to cause misoperation and false alarm. At the same moment, the influence of each capacitor in the capacitor bank is the same, that is, the current value flowing through different capacitors at different moments should be almost consistent, that is, the deviation of the first current data and the second current data should be within the allowable range.

[0096] In specific implementation, when each capacitor is connected to the power grid, there is no first current data collected at the last moment, and the application sets the current value detected at the factory as a reference value for differential calculation to determine the current arithmetic mean value at the initial moment.

[0097] The second calculating unit 40 is configured to calculate the actual capacitance value of the capacitor based on the first current data to obtain a target capacitance value in the case that the ratio of the first current data to the second current data is not within a first preset range.

[0098] Specifically, the first preset range is that the ratio of the first current data to the second current data is between 0.945 and 0.964. If the ratio is within this interval, the next sampling is waited for, and if the ratio is not within this interval, the actual capacitance value of the target capacitor is calculated based on the first current data.

[0099] The second determining unit 50 is configured to construct a corresponding capacitor circuit model according to each capacitor, obtain a first target model, and determine the fusing current of each capacitor according to the first target model to obtain third current data.

[0100] Specifically, a simulation model is constructed based on each capacitor, and then the simulation model is configured based on the environmental parameters of each capacitor, and the parameters of the simulation model are optimized based on the first current data. Then, the current is gradually increased based on the first current data until the internal fuse is fused and the capacitor current jumps to 0. The current at the time of fusing is recorded, and the third current data is obtained.

[0101] The third determining unit 60 is configured to determine that the capacitor corresponding to the target capacitance value has a capacitance out-of-limit fault when the target capacitance value is not within a second preset range or the difference between the fourth current data and the third current data is greater than a first threshold value. The fourth current data is the reference current of the capacitor.

[0102] Specifically, whether to issue a capacitance out-of-limit warning signal is determined according to the target capacitance value. When C i ≤0.95C n , a lower limit warning signal of the capacitance value is issued; when C i ≥1.05C n , an upper limit warning signal of the capacitance value is issued; and when 0.95C n ≤C i ≤1.05C n , the capacitance value is within a reasonable range, and the monitoring continues. C n is the factory capacitance value of the capacitor, and C i is the target capacitance value corresponding to the capacitor. The capacitance out-of-limit warning is issued.

[0103] In addition, the application also sets the fusing current obtained through simulation to determine the capacitance out-of-limit. Generally, the fusing current is proportional to the capacitance value, that is, the larger the capacitance value, the larger the fusing current. This is because the larger the capacitance value, the stronger the heat dissipation capacity of the fuse, which can withstand larger current, thereby improving the fusing capacity of the fuse. It should be noted that the relationship between the fusing current and the capacitance value is not linear, and therefore, the application sets the first threshold value through experiments. When the difference between the fourth current data and the third current data is greater than the first threshold value, the capacitance out-of-limit warning is issued.

[0104] By the embodiment, the acquisition unit acquires first current data, the first current data being obtained by monitoring each capacitor current value; the first determination unit determines that the internal fuse of the corresponding capacitor exists a fuse failure in a case that the first current data is 0; the first calculation unit calculates an arithmetic mean of current according to each first current data by a difference idea to obtain second current data in a case that the first current data is not 0; the second calculation unit calculates an actual capacitance value of the capacitor based on the first current data to obtain a target capacitance value in a case that a ratio of the first current data to the second current data is not within a first preset range; the second determination unit is configured to construct a corresponding capacitor circuit model according to each capacitor to obtain a first target model, and determine a fuse current of each capacitor according to the first target model to obtain third current data; and the third determination unit is configured to determine that the capacitor corresponding to the target capacitance value exists a capacitor out-of-limit fault in a case that the target capacitance value is not within a second preset range or a difference between fourth current data and the third current data is greater than a first threshold, the fourth current data being a reference current of the capacitor. The device takes early fault features of the reactive power compensation device as a judgment basis, and locates the fault capacitor according to the current value based on the difference idea, thereby solving the problem that the end-point off-network detection is used for fault detection of the capacitor group of the reactive power compensation device in the prior art, and the problem that early warning cannot be performed according to the actual operation state of the reactive power compensation device.

[0105] To locate the fault capacitor, in an alternative embodiment, the first calculation unit comprises:

[0106] The first determination module is configured to determine fifth current data based on the first current data and historical current data, the fifth current data being the historical current data collected at a time point that is different from a collection time point of the first current data by a preset time length, and the historical current data being the first current data collected before the current time point.

[0107] Specifically, the first current data of the last detection period is calibrated based on the historical data corresponding to the first current data to obtain the fifth current data.

[0108] The first calculation module is configured to calculate a difference between each first current data and corresponding fifth current data to obtain a difference value.

[0109] Specifically, the difference value is obtained by calculating the difference between each first current data and corresponding fifth current data.

[0110] The second calculation module is configured to obtain a target number of the capacitors to obtain a target number, and calculate a ratio of a sum of the difference values to the target number to obtain the second current data.

[0111] Specifically, each of the differential values is used to represent a change trend of each capacitor relative to a previous time, and the second current data is obtained by calculating an average value based on the differential values.

[0112] To monitor the state of the target capacitor, in an optional implementation, the second calculation unit includes:

[0113] The first obtaining module is configured to obtain voltage values of each of the capacitors to obtain target voltage data, and obtain angular velocities of each of the capacitors to obtain target angular velocities.

[0114] Specifically, the voltage values of each of the capacitors are obtained to obtain the target voltage data U i , and the angular velocities of each of the capacitors are obtained to obtain the target angular velocities ω i .

[0115] The third calculation module is configured to calculate the target capacitor value based on the first current data, the target voltage data, and the target angular velocities.

[0116] Specifically, the change of the capacitor value can intuitively reflect the real working condition of the capacitor. Since the active loss and dielectric loss of the capacitor are almost zero, the current flowing through the capacitor can be regarded as a capacitive current. Then, the target capacitor value is calculated based on the first current data, the target voltage data, and the target angular velocities by using a capacitive current calculation formula.

[0117] To accurately obtain the target capacitor value, in an optional implementation, the second calculation module includes:

[0118] The calculation submodule is configured to substitute the first current data, the target voltage data, and the target angular velocities into a first target formula to obtain the target capacitor value.

[0119]

[0120] wherein C i is the target capacitor value, I i is the first current data, ω i is the target angular velocity, and U i is the target voltage data.

[0121] Specifically, the first current data, the target voltage data, and the target angular velocities are substituted into the capacitive current calculation formula to calculate the actual capacitor value C i corresponding to the capacitor i, i.e., the target capacitor value.

[0122] To determine the predicted breaking current of each capacitor, in an optional implementation, the second determination unit includes:

[0123] a construction module, configured to construct a capacitor initial model based on MATLAB or PSPICE, the capacitor initial model being used to simulate the capacitor and circuit elements electrically connected with the capacitor;

[0124] Specifically, based on MATLAB or PSPICE software, a capacitor circuit model, i.e., the capacitor initial model, is constructed, which includes the capacitor itself and circuit elements electrically connected with the capacitor.

[0125] a second determination module, configured to configure parameters of the capacitor initial model according to a rated voltage of the capacitor and an initial capacitor value, and input at least the target voltage data into the capacitor initial model to determine an output current of the capacitor, to obtain sixth current data;

[0126] Specifically, initial conditions of the model are set according to the rated voltage and the capacity parameters of the capacitor. The simulation predicted current, i.e., the sixth current data, is determined based on the capacitor initial model and the current environment in which the capacitor is located.

[0127] an optimization module, configured to optimize the initial capacitor model by taking a difference between the sixth current data and the first current data as a loss function, to obtain the capacitor circuit model;

[0128] Specifically, the simulation deviation of the capacitor initial model is determined based on the sixth current data and the fifth current data, and the capacitor initial model is adjusted to obtain the capacitor circuit model.

[0129] a third determination module, configured to simulate the second current data initial current through the capacitor circuit model, and increase the current at a preset step size until the internal fuse is blown, to record an output current of the capacitor circuit model at a current time, to obtain third current data.

[0130] Specifically, the second current data is taken as an initial current value of the capacitor circuit model, and the current flowing through the capacitor is gradually increased in the simulation process, and the blowing process of the internal fuse of the capacitor is observed. By continuously adjusting the current value, until the fuse blowing condition is observed, the current value at this time is recorded, which is the internal fuse blowing current of the capacitor.

[0131] To accurately locate the fault, in an optional implementation, the third determination unit includes:

[0132] a second acquisition module, configured to acquire a factory capacitor value of the capacitor to obtain the initial capacitor value;

[0133] Specifically, the factory capacitor value of the capacitor is acquired to obtain the initial capacitor value C n .

[0134] The fourth computing module is configured to calculate a ratio of the target capacitance value to the initial capacitance value to obtain a first target value.

[0135] Specifically, the first target value is obtained by calculating a ratio of the target capacitance value to the initial capacitance value.

[0136] The fourth determining module is configured to determine that the capacitance has a capacitance lower limit fault when the first target value is less than a second threshold value, and determine that the capacitance has a capacitance upper limit fault when the first target value is greater than a third threshold value, the second threshold value being a lower limit value of the second preset range, and the third threshold value being an upper limit value of the second preset range.

[0137] Specifically, the second threshold value is 0.95, and the third threshold value is 1.05. When the first target value is less than the second threshold value, a capacitance value lower limit warning signal is sent, and when the first target value is greater than the third threshold value, a capacitance value upper limit warning signal is sent.

[0138] To accurately locate the fault, in an optional implementation, the third determining unit includes:

[0139] The fifth determining module is configured to determine that the capacitance has a capacitance lower limit fault when the difference between the fourth current data and the third current data is greater than a first threshold value and the third current data is less than the fourth current data.

[0140] Specifically, when the difference between the fourth current data and the third current data is greater than the first threshold value and the third current data is less than the fourth current data, the capacitance is determined to have a capacitance lower limit fault based on the correlation between the fourth current data and the capacitance value of the capacitance.

[0141] The sixth determining module is configured to determine that the capacitance has a capacitance upper limit fault when the difference between the fourth current data and the third current data is greater than the first threshold value and the third current data is greater than the fourth current data.

[0142] Specifically, when the difference between the fourth current data and the third current data is greater than the first threshold value and the third current data is greater than the fourth current data, the capacitance is determined to have a capacitance upper limit fault based on the correlation between the fourth current data and the capacitance value of the capacitance.

[0143] The low-voltage distribution network reactive compensation capacitor bank fault positioning device based on the differential idea includes a processor and a memory, and the acquisition unit, the first determination unit, the first calculation unit, the second calculation unit, the second determination unit, the third determination unit and the like are stored in the memory as program units, and the corresponding functions are realized by the processor executing the program units stored in the memory. The modules are located in the same processor, or the modules are located in different processors in any combination.

[0144] The processor includes a core, and the core calls the corresponding program unit in the memory. The core can be one or more, and the prediction accuracy can be improved by adjusting the core parameters.

[0145] The memory can include a non-permanent memory in a computer readable medium, a random access memory (RAM) and / or a non-volatile memory such as a read-only memory (ROM) or a flash memory (flash RAM), and the memory includes at least one memory chip.

[0146] The embodiment of the application provides a computer readable storage medium, and the computer readable storage medium includes a stored program, wherein the program controls the device where the computer readable storage medium is located to execute the low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the differential idea when the program runs.

[0147] Specifically, the low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the differential idea includes:

[0148] In step S201, first current data is acquired, and the first current data is obtained by monitoring each capacitor current value;

[0149] Specifically, the current flowing through each capacitor of the running reactive compensation device is the same in theory, and the current flowing through each capacitor is the same, so the application judges the fault based on the current value deviation of the capacitor, and in the actual operation process, the current value flowing through each capacitor in the actual operation process is sampled to obtain the first current data.

[0150] In step S202, in the case that the first current data is 0, it is determined that the internal fuse of the corresponding capacitor has a fuse failure;

[0151] Specifically, whether the internal fuse of the capacitor has a fuse failure is determined by zero-crossing comparison, that is, in the case that the first current data is 0, the corresponding fault capacitor is positioned according to the number corresponding to the current signal, and the corresponding fault capacitor is determined.

[0152] Step S203, in the case that the first current data is not 0, the arithmetic mean of the current is calculated according to the difference idea based on each first current data, and the second current data is obtained;

[0153] Specifically, based on the collection period of the first current data, the continuous first current data is discretized, and then the difference calculation is performed based on the first current data collected at the current moment and the first current data collected at the last moment, and the arithmetic mean of the current of all capacitors at the current moment is obtained, and the second current data is obtained, which is used for comparison to determine the capacitors at risk of failure.

[0154] It can be understood that the starting point of capacitor bank fault location based on the difference idea is that the surrounding environment at different times will cause unpredictable errors in the measurement of the capacitor capacitance value, which is easy to cause misoperation and false alarm. At the same moment, the influence of each capacitor in the capacitor bank is the same, that is, the current value change trend flowing through different capacitors at different times should be almost consistent, that is, the deviation of each first current data and the second current data should be within the allowable range.

[0155] In specific implementation, when each capacitor is connected to the power grid, there is no first current data collected at the last moment, and the application sets the current value detected based on the factory of each capacitor as a reference value to perform difference calculation to determine the arithmetic mean of the current at the initial moment.

[0156] Step S204, in the case that the ratio of the first current data to the second current data is not within the first preset range, the actual capacitance value of the capacitor is calculated based on the first current data, and the target capacitance value is obtained;

[0157] Specifically, the ratio of the first current data to the second current data is between 0.945 and 0.964, if the ratio is within this interval, the next sampling is waited, and if the ratio is not within this interval, the actual capacitance value of the target capacitor is calculated based on the first current data.

[0158] Step S205, a corresponding capacitor circuit model is constructed according to each capacitor, a first target model is obtained, and the fusing current of each capacitor is determined according to the first target model, and third current data is obtained;

[0159] Specifically, a simulation model is constructed based on each capacitor, and then the environment parameters of each capacitor are configured, and the parameter optimization of the model is performed based on the first current data, and then the current is gradually increased based on the first current data until the internal fuse is fused, and the capacitor current jumps to 0, and the current at the moment when the fusing occurs is recorded, that is, the third current data is obtained.

[0160] Step S206, in the case that the target capacitance value is not in the second preset range or the difference between the fourth current data and the third current data is greater than the first threshold value, it is determined that the capacitor corresponding to the target capacitance value has a capacitor out-of-limit fault, and the fourth current data is the reference current of the capacitor.

[0161] Specifically, according to the target capacitance value, it is judged whether to issue a capacitor out-of-limit early warning signal. When C i ≤0.95C n , a lower limit early warning signal of the capacitance value is issued, when C i ≥1.05C n , an upper limit early warning signal of the capacitance value is issued, when 0.95C n ≤C i ≤1.05C n , the capacitance value is in a reasonable range, and the monitoring continues, C n is the factory capacitance value of the capacitor, C i is the target capacitance value corresponding to the capacitor, and a capacitor out-of-limit early warning is issued.

[0162] In addition, the application also sets the capacitor out-of-limit judgment according to the simulation obtained fuse current. Generally, the fuse current is proportional to the capacitance value, that is, the larger the capacitance value, the larger the fuse current. Because the larger the capacitance value, the stronger the heat dissipation capacity of the fuse, which can withstand larger current, thereby improving the fusing capacity of the fuse. It should be noted that the relationship between the fuse current and the capacitance value is not linear, therefore, the application sets the first threshold value by experiment, and in the case that the difference between the fourth current data and the third current data is greater than the first threshold value, a capacitor out-of-limit alarm is issued.

[0163] The embodiment of the application provides a processor, which is used for running a program, wherein the low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the difference idea is executed when the program is running.

[0164] Specifically, the low-voltage distribution network reactive compensation capacitor bank fault positioning method based on the difference idea comprises the following steps.

[0165] Step S201, acquiring first current data, wherein the first current data is obtained by monitoring each capacitor current value;

[0166] Specifically, the current flowing through each capacitor of the running reactive compensation equipment is the same in theory, and the capacitance values of each capacitor are the same in theory, therefore, the application judges the fault based on the current value deviation of the capacitor, and in the actual operation process, the current value flowing through each capacitor in the actual operation process is sampled to obtain the first current data.

[0167] Step S202, in the case that the first current data is 0, it is determined that there is a fuse failure in the corresponding internal fuse of the capacitor;

[0168] Specifically, whether there is an internal fuse failure in the capacitor is determined by zero-crossing comparison, that is, in the case that the first current data is 0, the corresponding fault capacitor is located according to the number corresponding to the current signal, and the corresponding fault capacitor is determined.

[0169] Step S203, in the case that the first current data is not 0, the arithmetic mean of the current is calculated according to the first current data by the difference idea, and the second current data is obtained;

[0170] Specifically, based on the collection period of the first current data, the continuous first current data is discretized, and then based on the first current data collected at the current moment and the first current data collected at the last moment, the difference calculation is performed to obtain the arithmetic mean of the current of all capacitors at the current moment, and the second current data is obtained, which is used for comparison to determine the capacitors at risk of failure.

[0171] It can be understood that the starting point of capacitor bank fault location based on the difference idea is that the surrounding environment at different times will cause unpredictable errors in the measurement of the capacitor value, which is easy to cause misoperation and false alarm. At the same time, the influence of each capacitor in the capacitor bank is the same, that is, the trend of the current flowing through different capacitors at different times should be almost the same, that is, the deviation of the first current data and the second current data should be within the allowable range.

[0172] In specific implementation, when each capacitor is connected to the power grid, there is no first current data collected at the last moment, and the application sets the current value detected based on the factory of each capacitor as a reference value to perform difference calculation to determine the arithmetic mean of the current at the initial moment.

[0173] Step S204, in the case that the ratio of the first current data to the second current data is not within the first preset range, the actual capacitance value of the capacitor is calculated based on the first current data, and the target capacitance value is obtained;

[0174] Specifically, the first preset range is that the ratio of the first current data to the second current data is between 0.945 and 0.964. If the ratio is within this interval, the next sampling is waited, and if the ratio is not within this interval, the actual capacitance value of the target capacitor is calculated based on the first current data.

[0175] Step S205, a corresponding capacitor circuit model is constructed according to each of the capacitors to obtain a first target model, and a fuse current of each of the capacitors is determined according to the first target model to obtain third current data;

[0176] Specifically, a simulation model is constructed based on each of the capacitors, then the simulation model is configured based on environmental parameters of each of the capacitors, and the parameters of the simulation model are optimized based on the first current data, then the current is gradually increased based on the first current data until the internal fuse is fused and the capacitor current jumps to 0, and the current at the time of the fuse is recorded, that is, the third current data is obtained.

[0177] Step S206, in a case where the target capacitor value is not within a second preset range or a difference between fourth current data and the third current data is greater than a first threshold value, it is determined that the capacitor corresponding to the target capacitor value has a capacitor out-of-limit fault, and the fourth current data is a reference current of the capacitor.

[0178] Specifically, whether a capacitor out-of-limit early warning signal is sent is determined according to the target capacitor value, when C i ≤0.95C n , a lower limit of the capacitor value early warning signal is sent, when C i ≥1.05C n , an upper limit of the capacitor value early warning signal is sent, when 0.95C n ≤C i ≤1.05C n , the capacitor value is within a reasonable range, and monitoring is continued, C n is a factory capacitor value of the capacitor, C i is the target capacitor value corresponding to the capacitor, and a capacitor out-of-limit early warning is sent.

[0179] In addition, the application also sets the capacitor out-of-limit judgment according to the fuse current obtained through simulation. Generally, the fuse current is proportional to the capacitor value, that is, the larger the capacitor value, the larger the fuse current. This is because the larger the capacitor value, the stronger the heat dissipation capacity of the fuse, which can withstand larger current, thereby improving the fusing capacity of the fuse. It should be noted that the relationship between the fuse current and the capacitor value is not linear, therefore, the application sets the first threshold value through experiments, and in a case where the difference between the fourth current data and the third current data is greater than the first threshold value, a capacitor out-of-limit alarm is sent.

[0180] The embodiment of the application provides a monitoring system, the monitoring system comprises a processor, a memory and a program stored on the memory and executable on the processor, and at least the following steps are implemented when the processor executes the program:

[0181] Step S201, obtaining first current data, the first current data being obtained by monitoring each capacitor current value;

[0182] Step S202, in the case that the first current data is 0, determining that the internal fuse of the corresponding capacitor has a fuse failure;

[0183] Step S203, in the case that the first current data is not 0, calculating an arithmetic mean of the current according to each first current data by a difference idea to obtain second current data;

[0184] Step S204, in the case that the ratio of the first current data to the second current data is not within a first preset range, calculating an actual capacitance value of the capacitor based on the first current data to obtain a target capacitance value;

[0185] Step S205, constructing a corresponding capacitor circuit model according to each capacitor to obtain a first target model, and determining a fuse current of each capacitor according to the first target model to obtain third current data;

[0186] Step S206, in the case that the target capacitance value is not within a second preset range or the difference between fourth current data and the third current data is greater than a first threshold value, determining that the capacitor corresponding to the target capacitance value has a capacitor out-of-limit fault, the fourth current data being a reference current of the capacitor.

[0187] The application also provides a computer program product adapted to execute a program having at least the following method steps when executed on a data processing device:

[0188] Step S201, obtaining first current data, the first current data being obtained by monitoring each capacitor current value;

[0189] Step S202, in the case that the first current data is 0, determining that the internal fuse of the corresponding capacitor has a fuse failure;

[0190] Step S203, in the case that the first current data is not 0, calculating an arithmetic mean of the current according to each first current data by a difference idea to obtain second current data;

[0191] Step S204, in the case that the ratio of the first current data to the second current data is not within a first preset range, calculating an actual capacitance value of the capacitor based on the first current data to obtain a target capacitance value;

[0192] Step S205, a corresponding capacitor circuit model is constructed according to each of the capacitors to obtain a first target model, and a fuse current of each of the capacitors is determined according to the first target model to obtain third current data;

[0193] Step S206, in a case that the target capacitor value is not within a second preset range or a difference between fourth current data and the third current data is greater than a first threshold, it is determined that the capacitor corresponding to the target capacitor value has a capacitor out-of-limit fault, and the fourth current data is a reference current of the capacitor.

[0194] Obviously, those skilled in the art should understand that each module or each step of the present application can be realized by a general computing device, which can be concentrated on a single computing device or distributed on a network composed of multiple computing devices, which can be realized by program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in different order, or they can be manufactured into individual integrated circuit modules, or multiple modules or steps can be manufactured into a single integrated circuit module. Thus, the present application is not limited to any specific combination of hardware and software.

[0195] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product in the form of one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0196] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The devices that realize the functions specified in one block or multiple blocks.

[0197] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0198] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0199] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0200] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, or a combination of non-volatile memories in different forms. The memory is an example of computer readable storage media.

[0201] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassettes, magnetic disks storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0202] It is also to be noted that the terms "comprising", "including", and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0203] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0204] 1) In the low-voltage distribution network reactive power compensation capacitor bank fault positioning method based on the difference idea of the present application, first, the first current data is obtained, which is obtained by monitoring each capacitor current value; Then, in the case that the first current data is 0, it is determined that the corresponding internal fuse of the capacitor has a fuse failure; After that, in the case that the first current data is not 0, the arithmetic mean of the current is calculated according to each first current data by the difference idea, and the second current data is obtained; After that, in the case that the ratio of the first current data to the second current data is not within the first preset range, the actual capacitance value of the capacitor is calculated based on the first current data, and the target capacitance value is obtained; After that, the corresponding capacitor circuit model is constructed according to each capacitor, and the first target model is obtained, and the fuse current of each capacitor is determined according to the first target model, and the third current data is obtained; Finally, in the case that the target capacitance value is not within the second preset range or the fourth current data and the third current data difference is greater than the first threshold value, it is determined that the capacitor corresponding to the target capacitance value has a capacitor out-of-limit fault, and the fourth current data is the reference current of the capacitor. The method is based on the early fault characteristics of the reactive power compensation device as the judgment basis, and based on the difference idea, the fault capacitor is positioned according to the current value, which solves the problem that the existing technology uses endpoint network detection for fault detection of the capacitor group of the reactive power compensation device, and cannot perform early warning according to the actual operation state of the reactive power compensation device.

[0205] 2) The low-voltage distribution network reactive power compensation capacitor bank fault location device based on the difference idea of the application, the acquisition unit acquires the first current data, the first current data is obtained by monitoring each capacitor current value; the first determination unit determines that the internal fuse of the corresponding capacitor exists a fuse failure in the case that the first current data is 0; the first calculation unit calculates the current arithmetic mean value according to each first current data through the difference idea in the case that the first current data is not 0, and obtains the second current data; the second calculation unit calculates the actual capacitance value of the capacitor based on the first current data in the case that the ratio of the first current data to the second current data is not in the first preset range, and obtains the target capacitance value; the second determination unit constructs the corresponding capacitor circuit model according to each capacitor, obtains the first target model, and determines the fuse current of each capacitor according to the first target model, and obtains the third current data; the third determination unit determines that the capacitor corresponding to the target capacitance value exists a capacitor out-of-limit fault in the case that the target capacitance value is not in the second preset range or the fourth current data and the third current data difference is greater than the first threshold value, and the fourth current data is the reference current of the capacitor. The device takes the early fault characteristics of the reactive power compensation device as the basis for judgment, and uses the difference idea to locate the initial fault of the capacitor according to the current value, which solves the problem that the existing technology uses endpoint network detection to detect the fault of the capacitor group of the reactive power compensation device, and cannot perform early warning according to the actual operation state of the reactive power compensation device.

[0206] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A fault location method for low-voltage distribution network reactive power compensation capacitor banks based on differential principles, characterized in that, The reactive power compensation capacitor bank includes multiple capacitors, and the method includes: Acquire first current data, which is obtained by monitoring the current value of each capacitor; If the first current data is 0, it is determined that the internal fuse of the corresponding capacitor has a blown fault. If the first current data is not zero, the second current data is obtained by calculating the arithmetic average of the currents based on the difference method according to each of the first current data. If the ratio of the first current data to the second current data is not within a first preset range, the actual capacitance value of the capacitor is calculated based on the first current data to obtain the target capacitance value. Construct a corresponding capacitor circuit model based on each capacitor to obtain a first target model, and determine the fusing current of each capacitor based on the first target model to obtain third current data; If the target capacitance value is not within the second preset range or the difference between the fourth current data and the third current data is greater than the first threshold, it is determined that the capacitor corresponding to the target capacitance value has a capacitance over-limit fault, and the fourth current data is the reference current of the capacitor. Based on the first current data, the corresponding arithmetic average of the currents is calculated using the differential method to obtain the second current data, including: The fifth current data is determined based on the first current data and the historical current data. The fifth current data is the historical current data whose acquisition time differs from the acquisition time of the first current data by a preset time. The historical current data is the first current data acquired before the current time. Calculate the difference between each of the first current data and the corresponding fifth current data to obtain the difference value; The target quantity is obtained by acquiring the number of capacitors, and the second current data is obtained by calculating the ratio of the sum of the differential values ​​to the target quantity.

2. The method according to claim 1, characterized in that, The actual capacitance value of the capacitor is calculated based on the first current data to obtain the target capacitance value, including: Obtain the voltage value of each capacitor to get the target voltage data; obtain the angular velocity of each capacitor to get the target angular velocity. The target capacitance value is calculated based on the first current data, the target voltage data, and the target angular velocity.

3. The method according to claim 2, characterized in that, The target capacitance value is calculated based on the first current data, the target voltage data, and the target angular velocity, including: Substituting the first current data, the target voltage data, and the target angular velocity into the first target formula, we obtain the target capacitance value: ； Among them, C i For the target capacitance value, I i For the first current data, ω i U is the target angular velocity. i The target voltage data.

4. The method according to claim 2, characterized in that, Based on each capacitor, a corresponding capacitor circuit model is constructed to obtain a first target model. Then, based on the first target model, the fusing current of each capacitor is determined to obtain third current data, including: An initial model of the capacitor is constructed based on MATLAB or PSPICE. The initial model of the capacitor is used to simulate the capacitor and the circuit elements electrically connected to the capacitor. Configure the parameters of the initial capacitor model according to the rated voltage and initial capacitance value of the capacitor, and at least input the target voltage data into the initial capacitor model to determine the capacitor output current, thereby obtaining the sixth current data; The difference between the sixth current data and the first current data is used as a loss function to optimize the initial capacitor model, thereby obtaining the capacitor circuit model. The second current data is used as the initial current to simulate the capacitor circuit model, and the current is increased in a preset step size until the internal fuse blows. The output current of the capacitor circuit model at the current moment is recorded to obtain the third current data.

5. The method according to claim 1, characterized in that, If the target capacitance value is not within a second preset range, determining that the capacitor corresponding to the target capacitance value has a capacitance over-limit fault includes: Obtain the factory capacitance value of the capacitor to obtain the initial capacitance value; Calculate the ratio of the target capacitance value to the initial capacitance value to obtain the first target value; If the first target value is less than the second threshold, it is determined that the capacitor has a capacitance lower limit fault. If the first target value is greater than the third threshold, it is determined that the capacitor has a capacitance upper limit fault. The second threshold is the lower limit of the second preset range, and the third threshold is the upper limit of the second preset range.

6. The method according to claim 1, characterized in that, If the difference between the fourth current data and the third current data is greater than a first threshold, it is determined that the capacitor corresponding to the target capacitance value has a capacitance over-limit fault, including: If the difference between the fourth current data and the third current data is greater than a first threshold and the third current data is less than the fourth current data, it is determined that the capacitor has a capacitance lower limit fault. If the difference between the fourth current data and the third current data is greater than a first threshold and the third current data is greater than the fourth current data, it is determined that the capacitor has a capacitance exceeding the upper limit fault.

7. A fault location device for a low-voltage distribution network reactive power compensation capacitor bank based on differential principles, wherein the reactive power compensation capacitor bank comprises multiple capacitors, characterized in that... The device includes: The acquisition unit is used to acquire first current data, which is obtained by monitoring the current value of each capacitor. The first determining unit is used to determine that the internal fuse of the corresponding capacitor has a blown fault when the first current data is 0. The first calculation unit is used to calculate the arithmetic average of the current based on each of the first current data using the differential method when the first current data is not 0, so as to obtain the second current data. The second calculation unit is used to calculate the actual capacitance value of the capacitor based on the first current data and obtain the target capacitance value when the ratio of the first current data to the second current data is not within a first preset range. The second determining unit is used to construct a corresponding capacitor circuit model based on each capacitor to obtain a first target model, and to determine the fusing current of each capacitor based on the first target model to obtain third current data. The third determining unit is used to determine that the capacitor corresponding to the target capacitance value has a capacitance over-limit fault when the target capacitance value is not within the second preset range or the difference between the fourth current data and the third current data is greater than the first threshold. The fourth current data is the reference current of the capacitor. The first computing unit includes: The first determining module is used to determine the fifth current data based on the first current data and the historical current data. The fifth current data is the historical current data whose acquisition time differs from the acquisition time of the first current data by a preset time. The historical current data is the first current data acquired before the current time. The first calculation module is used to calculate the difference between each of the first current data and the corresponding fifth current data to obtain a difference value. The second calculation module is used to obtain the number of capacitors to get the target number, and to calculate the ratio of the sum of the difference values ​​to the target number to obtain the second current data.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 6.

9. A monitoring system, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising methods for performing any one of claims 1 to 6.

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