Zero-sequence current anomaly detection method, device and equipment based on double buses, medium and product

Abstract

The invention relates to a zero-sequence current anomaly detection method, device and equipment based on double buses, a medium and a product, and relates to the technical field of power system anomaly detection. The method comprises the steps of obtaining respective zero-sequence current of double buses of a to-be-detected power system, and obtaining a phase value sequence of the zero-sequence current of each bus according to the zero-sequence current; obtaining a phase value interval of each phase value sequence according to each phase value sequence; determining a plurality of quantized phase values of each bus and the confidence probability of each quantized phase value according to each phase value interval; and according to each quantized phase value of each bus, the confidence probability of each quantized phase value and the preset maximum phase difference of the zero-sequence current of the double buses, obtaining an alarm threshold of the to-be-detected power system, and performing abnormal early warning under the condition that the alarm threshold meets a preset condition. By adopting the method, the detection accuracy can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of power system anomaly detection, and particularly to a zero-sequence current anomaly detection method, device, equipment, medium, and product based on a double busbar. Background Art

[0002] In related technologies, the zero-sequence current phase method is a power system anomaly detection method that utilizes the steady-state characteristics of zero-sequence current. After a fault occurs in a power system, the zero-sequence current at the fault location exhibits abnormal phase and mutation. Based on this difference, the phase relationship of the zero-sequence current on both sides of the bus-coupling switch of the double busbar can be compared to determine whether the isolating switch is fully closed, and an alarm is given when an incomplete closing fault occurs. However, the hot busbar transfer process exacerbates the load imbalance and harmonic noise interference in the power system, affecting the credibility of the collected zero-sequence current data, resulting in a decrease in the accuracy of the calculated zero-sequence current phase, and further causing a decrease in the accuracy of the obtained detection results. Therefore, the zero-sequence current phase fault detection method in related technologies has the problem of low detection accuracy. Summary of the Invention

[0003] Based on this, it is necessary to provide a zero-sequence current anomaly detection method, device, computer equipment, computer-readable storage medium, and computer program product based on a double busbar that can improve the detection accuracy for the above technical problems.

[0004] In a first aspect, the present application provides a zero-sequence current anomaly detection method based on a double busbar, including:

[0005] Obtain the zero-sequence current of each of the double busbars of the power system to be detected, and based on the zero-sequence current, obtain a sequence of phase values of the zero-sequence current of each busbar;

[0006] Based on each sequence of phase values, obtain a phase value interval of each sequence of phase values;

[0007] Based on each phase value interval, determine a plurality of quantized phase values of each busbar and the confidence probability of each quantized phase value;

[0008] Based on each quantized phase value of each busbar, the confidence probability of each quantized phase value, and the maximum phase difference of the preset zero-sequence current of the double busbar, obtain an alarm threshold of the power system to be detected, and perform an anomaly warning when the alarm threshold meets a preset condition.

[0009] In one embodiment, the obtaining a phase value interval of each sequence of phase values based on each sequence of phase values includes:

[0010] For each of the phase value sequences, determine the maximum phase value and the minimum phase value in each of the phase value sequences;

[0011] Using the maximum phase value and the minimum phase value of each of the phase value sequences as the right endpoint and the left endpoint respectively, obtain the phase value interval of each of the phase value sequences.

[0012] In one embodiment, the determining of the multiple quantization phase values of each bus and the confidence probability of each quantization phase value according to each of the phase value intervals includes:

[0013] According to the maximum phase value, the minimum phase value in each of the phase value sequences, and the cumulative sum of the deviations of all phase values from the minimum phase, obtain the phase ambiguity of each of the phase value sequences;

[0014] Divide each of the phase value intervals into multiple sub - intervals, and use the endpoints of each of the sub - intervals as the quantization phase values to obtain the multiple quantization phase values corresponding to each bus;

[0015] According to each of the sub - intervals, determine the number of phase values in the neighborhood corresponding to each of the quantization phase values;

[0016] According to each of the phase ambiguities, the number of phase values in the neighborhood corresponding to each quantization phase value of each bus, and the maximum value of the number of phase values, obtain the confidence probability of each quantization phase value.

[0017] In one embodiment, wherein the determining method of the confidence probability of each quantization phase value includes:

[0018]

[0019] Wherein, norm() represents the sum normalization function, exp() represents the exponential function with the natural constant as the base, represents the phase ambiguity, represents the maximum value of the number of phase values, represents the number of phase values in the neighborhood corresponding to the k - th quantization phase value, represents the confidence probability of the k - th quantization phase value in the phase value interval.

[0020] In one embodiment, wherein the determining method of the alarm threshold includes:

[0021]

[0022] Wherein, K represents the number of quantization phase values in the phase value interval, and respectively represent the i-th quantization phase value and its confidence probability of the phase value interval of the first busbar described in the first item, and respectively represent the j-th quantization phase value and its confidence probability of the phase value interval of the second busbar described in the second item, represents the maximum phase difference of the preset zero-sequence current of the double busbars, and TH represents the alarm threshold of the power system to be detected.

[0023] In one embodiment, when the alarm threshold meets a preset condition, an abnormal warning is performed, including:

[0024] Determine the positive and negative value attributes of the alarm threshold according to the alarm threshold;

[0025] When the positive and negative value attributes of the alarm threshold are positive, it indicates that the alarm threshold meets the preset condition, and an abnormal alarm is performed.

[0026] In a second aspect, the present application further provides a zero-sequence current abnormal detection device based on a double busbar, including:

[0027] A sequence determination module, configured to obtain the zero-sequence current of each of the double busbars of the power system to be detected, and obtain the phase value sequence of the zero-sequence current of each busbar according to the zero-sequence current;

[0028] An interval determination module, configured to obtain the phase value interval of each phase value sequence according to each phase value sequence;

[0029] An interval processing module, configured to determine multiple quantization phase values of each busbar and the confidence probability of each quantization phase value according to each phase value interval;

[0030] An abnormal detection module, configured to obtain the alarm threshold of the power system to be detected according to each quantization phase value of each busbar, the confidence probability of each quantization phase value, and the maximum phase difference of the preset zero-sequence current of the double busbars, and perform an abnormal warning when the alarm threshold meets the preset condition.

[0031] In a third aspect, the present application further provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0032] Obtain the zero-sequence current of each of the double busbars of the power system to be detected, and obtain the phase value sequence of the zero-sequence current of each busbar according to the zero-sequence current;

[0033] Obtain the phase value interval of each phase value sequence according to each phase value sequence;

[0034] Determine multiple quantization phase values of each bus and the confidence probability of each quantization phase value according to each of the phase value intervals;

[0035] Obtain the alarm threshold of the power system to be detected according to each quantization phase value of each bus, the confidence probability of each quantization phase value, and the maximum phase difference of the preset zero-sequence current of the double bus, and perform an abnormal warning when the alarm threshold meets the preset conditions.

[0036] In a fourth aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0037] Obtain the zero-sequence current of each of the double buses of the power system to be detected, and obtain the phase value sequence of the zero-sequence current of each bus according to the zero-sequence current;

[0038] Obtain the phase value interval of each phase value sequence according to each of the phase value sequences;

[0039] Determine multiple quantization phase values of each bus and the confidence probability of each quantization phase value according to each of the phase value intervals;

[0040] Obtain the alarm threshold of the power system to be detected according to each quantization phase value of each bus, the confidence probability of each quantization phase value, and the maximum phase difference of the preset zero-sequence current of the double bus, and perform an abnormal warning when the alarm threshold meets the preset conditions.

[0041] In a fifth aspect, the present application further provides a computer program product, including a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0042] Obtain the zero-sequence current of each of the double buses of the power system to be detected, and obtain the phase value sequence of the zero-sequence current of each bus according to the zero-sequence current;

[0043] Obtain the phase value interval of each phase value sequence according to each of the phase value sequences;

[0044] Determine multiple quantization phase values of each bus and the confidence probability of each quantization phase value according to each of the phase value intervals;

[0045] Obtain the alarm threshold of the power system to be detected according to each quantization phase value of each bus, the confidence probability of each quantization phase value, and the maximum phase difference of the preset zero-sequence current of the double bus, and perform an abnormal warning when the alarm threshold meets the preset conditions.

[0046] The above zero-sequence current anomaly detection method, device, computer equipment, computer-readable storage medium, and computer program product based on double busbars obtain the zero-sequence currents of each of the double busbars of the power system to be detected, and based on the zero-sequence currents, obtain the phase value sequence of the zero-sequence current of each busbar as the data basis for anomaly detection. Then, based on each phase value sequence, obtain the phase value interval of each phase value sequence, and based on each phase value interval, determine multiple quantization phase values of each busbar and the confidence probability of each quantization phase value, so as to be able to provide more comprehensive data. According to each quantization phase value of each busbar, the confidence probability of each quantization phase value, and the maximum phase difference of the preset zero-sequence current of the double busbars, obtain the alarm threshold of the power system to be detected, and when the alarm threshold meets the preset conditions, perform anomaly early warning. By calculating the alarm threshold through multi-dimensional data of the double busbars, it can reflect the relative change situation between the two busbars, reduce the interference of the double busbar hot switching process on the power system load and harmonic noise, and thus improve the accuracy of anomaly detection. Brief Description of the Drawings

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments of the present application or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0048] Figure 1 It is a schematic flowchart of the zero-sequence current anomaly detection method based on double busbars in one embodiment;

[0049] Figure 2 It is a schematic flowchart of the steps of the time interval extraction schematic diagram of the zero-sequence current in one embodiment;

[0050] Figure 3 It is a structural block diagram of the zero-sequence current anomaly detection system based on double busbars in one embodiment;

[0051] Figure 4 It is a structural block diagram of the zero-sequence current anomaly detection device based on double busbars in one embodiment;

[0052] Figure 5 It is an internal structure diagram of the computer equipment in one embodiment. Detailed Embodiments

[0053] In order to make the purpose, technical solutions, and advantages of the present application clearer, the following further details the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0054] As described in the background art, in the zero-sequence current abnormal detection method of the related art, there is a problem of low detection accuracy. After research by the inventor, it is found that the reason for this problem is that the double-busbar connection method is widely used in substations of various voltage levels because of its characteristics of both reliability and flexibility. In this connection method, lines or components can be flexibly switched between the two busbars according to the operation needs. Among them, the switching operation carried out under the condition that the line or component is not powered off is called "hot switching", and vice versa, the switching operation carried out under the power-off condition is called "cold switching". Restricted by the requirements of power supply reliability, hot switching is adopted more frequently. During the double-busbar hot switching process, it is necessary to detect the state of the power system in real time and give an alarm in time when the isolating switch has an incomplete closing fault to avoid affecting the stable operation of the power system during the double-busbar hot switching process. The zero-sequence current phase method is a power system abnormal detection method that utilizes the steady-state characteristics of the zero-sequence current. After a fault occurs in the power system, the zero-sequence current at the fault point shows abnormal phase and mutation. Based on this difference, it is possible to judge whether the isolating switch is fully closed by comparing the phase relationship of the zero-sequence current on both sides of the double-busbar bus-coupling switch, and give an alarm when an incomplete closing fault occurs. The double-busbar hot switching process exacerbates the load imbalance and harmonic noise interference of the power system, affects the credibility of the collected zero-sequence current data, causes the accuracy of the calculated zero-sequence current phase to decrease, and further causes the accuracy of the obtained detection result to decrease. In the related art, by comparing the current amplitude and active power of the busbar, it is judged whether the busbar isolating switch is closed in place during the hot busbar transfer process. Considering that incomplete closing usually occurs only in one phase of the three-phase circuit, and when there is an incomplete closing in one-phase circuit of the power system, the fluctuations of the current amplitude and active power are small, so the sensitivity of judging the abnormal state during the hot busbar transfer process is low, and its detection ability needs to be improved. Or judge whether the closing operation is successful by calculating the current ratio, without considering the influence of the harmonic noise generated by the hot busbar closing operation on the power system, and it is easy to cause false alarms of faults during normal current fluctuations.

[0055] For the above reasons, the present application provides a zero-sequence current abnormal detection method based on a double busbar, aiming to improve the accuracy of abnormal detection.

[0056] In one embodiment, as Figure 1 shown, a zero-sequence current abnormal detection method based on a double busbar is provided. In this embodiment, taking the application of this method in a server system as an example, it can be understood that this method can also be applied to a server, and can also be applied to a system including a terminal, and is realized through the interaction between the terminal and the server. In this embodiment, the method includes the following steps S102 to step S108. Among them:

[0057] Step S102: Obtain the zero-sequence current of each of the double buses in the power system to be detected, and based on the zero-sequence current, obtain the sequence of phase values of the zero-sequence current of each bus.

[0058] Among them, the double bus can be a bus arrangement method in a power system where, to improve power supply reliability, two buses of the same voltage level (i.e., conductors with the same neutral point or ground potential) are used in parallel. In this arrangement, one bus serves as the working bus and the other as the standby bus. When the working bus needs to be taken out of service due to a fault or maintenance, it can be quickly switched to the standby bus through the lateral disconnect switch, thus achieving uninterrupted power supply.

[0059] Among them, the power system to be detected can be a power system that needs to perform anomaly detection.

[0060] Among them, the zero-sequence current can be a specific current component mainly used to analyze the unbalance in a three-phase power system and is composed of the same components of the three-phase currents.

[0061] Among them, the sequence of phase values can be a sequence composed of the phase values of the zero-sequence currents of multiple buses. The phase value of the zero-sequence current is usually the same as the phase of the three-phase current because it is based on the common component of the three-phase currents.

[0062] Optionally, the system obtains the three-phase currents on both sides of the bus coupler switch of the double buses in the power system to be detected, and uses the three-phase current synthesis method to obtain the zero-sequence current of each bus on both sides of the bus coupler switch during the hot bus transfer process. The system further processes the zero-sequence current to obtain the sequence of phase values of the zero-sequence current of each bus, which serves as a data reference for subsequent anomaly detection.

[0063] It should be noted that to ensure the synchronization of the extraction of the phase values of the zero-sequence currents on both sides of the bus coupler switch of the double buses, the phase value of the zero-sequence current is calculated through the second pulse provided by the system. The single-chip microcomputer timer of the system starts timing at the rising edge of the second pulse signal and ends timing at the rising edge of the zero-sequence current to obtain the time interval , as Figure 2 shown, provides a schematic diagram for extracting the time interval of the zero-sequence current. According to the relationship between the period T of the zero-sequence current and the phase value , calculate the phase value of the zero-sequence current:

[0064]

[0065] The system takes the phase value calculated and obtained by the second pulse signal at the current moment as the end data, and sequentially takes N - 1 extracted phase values from the historical moment to jointly form a sequence of phase values with a length of N, where N is an integer.

[0066] Step S104: Obtain the phase value interval of each phase value sequence according to each phase value sequence.

[0067] Among them, the phase value interval can be the interval range composed of the minimum value and the maximum value in the phase value sequence.

[0068] Optionally, the system sorts each phase value sequence respectively, determines the minimum value and the maximum value therein, so as to obtain the phase value interval of the phase value sequence.

[0069] Step S106: Determine multiple quantized phase values of each bus and the confidence probability of each quantized phase value according to each phase value interval.

[0070] Among them, the quantized phase value can be the phase value corresponding to a finite number (or a smaller number) of discrete values obtained after quantizing the continuous values of the phase value sequence.

[0071] Among them, the confidence probability can be used in statistics and machine learning to describe the reliability of a certain parameter or prediction. The confidence probability reflects the probability that the parameter estimation falls into a certain interval under a certain sample data.

[0072] Optionally, the system performs quantization processing on each phase value interval respectively to obtain multiple quantized phase values corresponding to each bus. In addition, the system performs further calculation processing according to the quantized phase values to obtain the confidence probability of each quantized phase value.

[0073] Step S108: Obtain the alarm threshold of the power system to be detected according to each quantized phase value of each bus, the confidence probability of each quantized phase value, and the maximum phase difference of the preset zero-sequence current of the double bus, and perform abnormal warning when the alarm threshold meets the preset conditions.

[0074] Among them, the maximum phase difference of the preset zero-sequence current of the double bus can be the maximum phase difference of the zero-sequence currents of the two buses during the hot transfer of the double bus under the normal operating state of the power system.

[0075] Among them, the alarm threshold can be an index used to judge whether there is an abnormality in the power system.

[0076] Among them, the preset condition can be a threshold condition obtained through a large number of experiments according to the operating conditions of the power system and the abnormal detection requirements, and is used to match the alarm threshold.

[0077] Optionally, the system calculates based on the respective quantized phase values of each bus, the confidence probability of each quantized phase value, and the maximum phase difference of the preset zero-sequence current of the double bus, to obtain the alarm threshold of the power system to be detected. The alarm threshold is matched with the preset conditions. When the alarm threshold meets the preset conditions, an abnormal warning is given according to the preset warning method. For example, an audible and visual warning, a pop-up warning, and sending a text message or an email warning are carried out, etc.

[0078] In the above zero-sequence current abnormal detection method based on a double bus, the method obtains the zero-sequence current of each of the double buses of the power system to be detected, and based on the zero-sequence current, obtains the phase value sequence of the zero-sequence current of each bus as the data basis for abnormal detection. And based on each phase value sequence, obtains the phase value interval of each phase value sequence, and based on each phase value interval, determines multiple quantized phase values of each bus and the confidence probability of each quantized phase value, so as to be able to provide more comprehensive data. Based on the respective quantized phase values of each bus, the confidence probability of each quantized phase value, and the maximum phase difference of the preset zero-sequence current of the double bus, the alarm threshold of the power system to be detected is obtained, and when the alarm threshold meets the preset conditions, an abnormal warning is given. By calculating the alarm threshold through multi-dimensional data of the double bus, the relative change situation between the two buses can be reflected, and the interference of the power system load and harmonic noise during the hot bus transfer process of the double bus can be reduced, thereby improving the accuracy of abnormal detection.

[0079] In an exemplary embodiment, step S104 obtaining the phase value interval of each phase value sequence based on each phase value sequence includes:

[0080] Based on each phase value sequence, determine the maximum phase value and the minimum phase value in each phase value sequence; use the maximum phase value and the minimum phase value of each phase value sequence as the right endpoint and the left endpoint respectively, to obtain the phase value interval of each phase value sequence.

[0081] Optionally, the system determines the maximum phase value and the minimum phase value in each phase value sequence according to each phase value sequence corresponding to each bus, and uses the maximum phase value and the minimum phase value of each phase value sequence as the right endpoint and the left endpoint respectively to form a continuous signal, which serves as the basis for subsequent phase value quantization.

[0082] In this embodiment, by constructing a unified signal interval, the phase performance between different buses can be more conveniently compared, which helps to identify the abnormal differences in the operation of each bus in the system and promotes timely intervention. The maximum and minimum points of the phase value sequence can reduce the noise interference in a short time to a certain extent, because these extreme values are usually representative values that are stable for a period of time, making the subsequently extracted signal more reliable. The continuous signal constructed by the maximum phase value and the minimum phase value provides a necessary basis for subsequent phase value quantization.

[0083] In an exemplary embodiment, step S106 determines multiple quantization phase values of each bus and the confidence probability of each quantization phase value according to each phase value interval, including:

[0084] Obtain the phase ambiguity of each phase value sequence according to the maximum phase value, the minimum phase value in each phase value sequence, and the sum of the deviations of all phase values from the minimum phase; divide each phase value interval into multiple sub-intervals, and use the endpoints of each sub-interval as the quantization phase values to obtain multiple quantization phase values corresponding to each bus; determine the number of phase values within the neighborhood corresponding to each quantization phase value according to each sub-interval; and obtain the confidence probability of each quantization phase value according to each phase ambiguity, the number of phase values within the neighborhood corresponding to each quantization phase value of each bus, and the maximum value of the number of phase values.

[0085] Among them, the phase ambiguity can be used to reflect the uncertainty degree of the phase extraction of the zero-sequence current. Among them, the determination method of the phase ambiguity includes:

[0086]

[0087] Among them, and respectively represent the maximum phase value and the minimum phase value in the phase value sequence, F represents the phase ambiguity, and sum represents the sum of the deviations of all phase values from the minimum phase.

[0088] Among them, the determination method of the confidence probability of each quantization phase value includes:

[0089]

[0090] Among them, () represents the sum normalization function, () represents the exponential function with the natural constant as the base, represents the phase ambiguity, represents the maximum value of the number of phase values, represents the number of phase values within the neighborhood corresponding to the k-th quantization phase value, represents the confidence probability of the k-th quantization phase value within the phase value interval.

[0091] Optionally, the system calculates the phase ambiguity of each phase value sequence by multiplying the difference between the maximum phase value and the minimum phase value in each phase value sequence by the sum of the accumulations of the difference and the deviations of all phase values from the minimum phase. Further, the system divides each phase value interval into multiple sub-intervals in an equal division manner, numbers them in the order of the size of each sub-interval, and takes the endpoints of each sub-interval as the quantized phase values to obtain multiple quantized phase values corresponding to each bus. Further, the system determines the number of phase values within the neighborhood of each quantized phase value with the quantized phase value of each sub-interval as the center and the sub-intervals on the left and right sides of the center jointly constituting the neighborhood of the quantized phase value, and then calculates the confidence probability of each quantized phase value according to the calculation method of the above formula based on each phase ambiguity, the number of phase values within the neighborhood corresponding to each quantized phase value of each bus, and the maximum value of the number of phase values.

[0092] It should be noted that since the number of phase values within the neighborhood of the quantized phase value is positively correlated with its confidence probability. The more phase values there are within the neighborhood of the quantized phase value, the smaller the deviation from the actual phase value of the zero-sequence current, and the greater the calculated confidence probability. In addition, considering that the higher the phase ambiguity, the more evenly distributed the confidence probabilities of different quantized phase values; the smaller the phase ambiguity, the greater the difference in confidence probabilities. Therefore, the confidence probabilities of different quantized phase values are adjusted by the phase ambiguity to further reduce the interference of noise during the hot switching process.

[0093] In this embodiment, by calculating the difference between the maximum phase value and the minimum phase value and combining the cumulative sum of deviations, the system can more accurately reflect the volatility and uncertainty of the phase value sequence. The quantization of the phase ambiguity provides a basis for subsequent data processing and analysis, enabling the system to effectively identify the distribution characteristics of the phase values. Incorporating the number of phase values within the neighborhood of the quantized phase value into the calculation, the system can take into account the influence of the surrounding environment on a specific phase value. Calculating the confidence probability based on the phase ambiguity and the maximum value of the number of phase values can provide a reliability assessment of the phase value. This method can not only reflect the characteristics of the phase value itself but also evaluate its importance in the overall sequence, contributing to the improvement of the accuracy of subsequent decisions.

[0094] In an exemplary embodiment, the content of performing abnormal early warning when the alarm threshold meets the preset conditions in step S108 includes:

[0095] According to the alarm threshold, determine the positive and negative value attributes of the alarm threshold; when the positive and negative value attributes of the alarm threshold are positive, it indicates that the alarm threshold meets the preset conditions, and abnormal alarm is performed.

[0096] Among them, the positive and negative value attributes can be whether the data of the alarm threshold is positive or negative. On the number axis, positive values usually represent numbers greater than zero, while negative values represent numbers less than zero.

[0097] Among them, the determination methods of the alarm threshold include:

[0098]

[0099] Among them, K represents the number of quantized phase values within the phase value range, and respectively represent the i-th quantized phase value and its confidence probability in the phase value range of the first bus, and respectively represent the j-th quantized phase value and its confidence probability in the phase value range of the second bus, represents the maximum phase difference of the preset zero-sequence current of the double bus, and TH represents the alarm threshold of the power system to be detected. It should be noted that the quantized phase values of the zero-sequence current obtained on both sides of the bus-coupling switch are independent of each other, and the joint confidence probability of the two is equal to the product of their respective confidence probabilities, which is used as the weight to adjust the calculation of the alarm threshold for different phase differences, reducing the influence of zero-sequence current phase ambiguity and the fluctuation of the zero-sequence current phase difference of the double bus.

[0100] Optionally, the system determines the positive and negative value attributes of the alarm threshold according to the alarm threshold. When the positive and negative value attributes of the alarm threshold are positive, it indicates that the alarm threshold meets the preset conditions and an abnormal alarm is issued. It should be noted that during the hot bus transfer process of the double bus, when a line or component is newly connected to the power system, the load imbalance causes a certain degree of fluctuation in the zero-sequence current phase difference on both sides of the bus-coupling switch. To prevent false alarms, it is necessary to dynamically calculate the alarm threshold. According to the above steps, K quantized phase values and their confidence probabilities of the zero-sequence current on both sides of the bus-coupling switch of the double bus are calculated. The greater the difference between the two quantized phase values of the zero-sequence current and the greater their confidence probabilities, the greater the risk of zero-sequence current abnormality in the power system. When the calculated phase difference of the zero-sequence current on both sides of the bus-coupling switch exceeds the maximum phase difference of the zero-sequence current of the two buses during normal hot bus transfer, it indicates that there is a fault of incomplete closing in the power system to be detected, and an alarm needs to be issued in a timely manner.

[0101] In this embodiment, the system can adapt to the load changes during the hot bus transfer process of the power system by dynamically calculating the alarm threshold. This adaptability improves the accuracy of the alarm mechanism and helps to reduce false alarms. By judging the positive and negative value attributes of the alarm threshold, it can quickly identify whether the system meets the preset conditions. The binary judgment can improve the response time, enabling abnormal situations to be detected and alarmed immediately when they occur.

[0102] In an exemplary embodiment, another zero-sequence current abnormality detection method based on a double bus is provided, which is applied to a zero-sequence current abnormality detection system based on a double bus as Figure 3 shown. Among them:

[0103] The zero-sequence current abnormal detection system based on a double busbar includes: a line measurement unit, a phase extraction unit, and an abnormal warning unit.

[0104] Among them, the line measurement unit includes a current sensor, a filter, and a Bluetooth module; the phase extraction unit includes a Bluetooth module, a single-chip microcomputer, and a GPS module circuit; the abnormal warning unit includes a host computer. The line measurement module is connected to the phase extraction unit through Bluetooth, and the phase extraction unit is connected to the abnormal warning unit through the GPRS network. The current sensor uses a CS1000EK2 type open-loop Hall current sensor to respectively collect the three-phase currents on both sides of the double busbar sectionalizing switch, and uses the three-phase current synthesis method to obtain the zero-sequence current on both sides of the double busbar sectionalizing switch during the hot bus transfer process. The C8051F310 single-chip microcomputer is used to complete the AD conversion and phase calculation of the zero-sequence current, and the sampling frequency of the AD conversion is set to 10 kHz.

[0105] The method includes:

[0106] Step 1, the line measurement unit collects the zero-sequence current and filters and amplifies it. During the hot bus transfer process of the double busbar, the transient impact caused by the load switching increases the harmonic noise in the power system. The harmonic noise is superimposed on the normal current signal, causing the measured value of the zero-sequence current to deviate from the true value. The present invention uses a UAF42 active filter to filter and amplify the obtained zero-sequence current, extract the useful signal, and retain the phase information, making the amplitude of the signal convenient for subsequent phase extraction. Thus, the pretreatment of the zero-sequence current is completed.

[0107] Step 2: The phase extraction unit obtains the quantized phase value of the zero-sequence current. During the hot transfer process of the double busbars, the isolating switch of the target busbar in the double busbars needs to be closed, so that the target busbar and the original busbar are both connected to the line at the same time, and finally the isolating switch of the original busbar is disconnected. To ensure the normal operation of the power system, before disconnecting the isolating switch of the original busbar, it is necessary to ensure that the isolating switch of the target busbar is fully closed, and an alarm is issued when an abnormal situation of incomplete closing is detected, and a further inspection of the power system is carried out. Considering that incomplete closing usually occurs only in a certain phase of the three-phase circuit, and when there is incomplete closing in one-phase circuit of the power system, the fluctuations of the current amplitude and active power are small, while the phase of the zero-sequence current will mutate due to a contact problem in one-phase circuit. Therefore, the present invention adopts the zero-sequence current phase method to detect the abnormal state during the hot transfer process of the double busbars, and improves the detection ability of the abnormal zero-sequence current caused by incomplete closing of one-phase circuit. To ensure the synchronization of the extraction of the zero-sequence current phase values on both sides of the double-busbar sectionalizing switch, the present invention calculates the phase value of the zero-sequence current through the second pulse provided by the GPS module circuit. The single-chip microcomputer timer starts timing at the rising edge of the GPS second pulse and ends timing at the rising edge of the zero-sequence current to obtain the time interval. According to the relationship between the zero-sequence current period T and the phase value, the zero-sequence current phase value is calculated. Considering that during the hot transfer process of the double busbars, in addition to the harmonic components of the zero-sequence current itself, there are also noise interferences of other frequencies generated by the load access, and there are deviations in the zero-sequence current phase values calculated at different times, resulting in phase ambiguity and a decrease in the accuracy of the extracted zero-sequence current phase value. To improve the credibility of the extracted phase value of the zero-sequence current, the present invention analyzes the distribution of the phase values calculated from multiple GPS second pulses, calculates and obtains the quantized phase value and its confidence probability to reduce the zero-sequence current phase ambiguity existing during the hot transfer process of the double busbars. Taking the phase value calculated from the current GPS second pulse as the end data, N-1 previously extracted phase values are taken forward in sequence to jointly form a phase value sequence with a length of N, and they are numbered in the order of extraction time. In the present invention, N is taken as 30. The phase value with the smallest difference from each phase value in the phase value sequence is obtained, and the absolute value of the difference between the two is recorded as the minimum phase deviation of the phase value. On the one hand, the larger the difference between the maximum phase value and the minimum phase value in the phase value sequence, the greater the uncertainty of the zero-sequence current phase extraction caused by noise. On the other hand, the smaller the cumulative sum of the minimum phase deviations of the phase values in the phase value sequence, the more concentrated the distribution of the phase values calculated from the GPS second pulses, the smaller the influence of noise on the zero-sequence current phase extraction, and the smaller the uncertainty of the phase extraction. According to the size distribution of the phase values in the phase value sequence, the phase ambiguity of the phase value sequence is calculated. To further quantify the phase value of the zero-sequence current, the maximum phase value of the phase value sequence is used as the right endpoint, and its minimum phase value is used as the left endpoint to construct a closed interval, which is recorded as the phase value interval of the phase value sequence.Meanwhile, divide the phase value interval equally into K-1 sub-intervals, denote the endpoints of the K-1 sub-intervals as quantization phase values, and number them in ascending order. In the present invention, K takes the value of 10. Since the deviations between different quantization phase values and the actual zero-sequence current phase are different, there are differences in their confidence probabilities as the zero-sequence current phase value. Therefore, according to the distribution of phase values in the phase value interval, calculate the confidence probabilities of different quantization phase values. First, with the quantization phase value as the center, the sub-intervals on its left and right together form its neighborhood. In particular, for the minimum phase value, its neighborhood is the sub-interval on its right; for the maximum phase value, its neighborhood is the sub-interval on its left. Second, obtain the number of phase values located within the neighborhood of each quantization phase value. Finally, since the number of phase values within the neighborhood of the quantization phase value is positively correlated with its confidence probability. The more phase values there are in the neighborhood of the quantization phase value, the smaller the deviation between it and the actual zero-sequence current phase value, and the greater the calculated confidence probability. In addition, considering that the higher the phase ambiguity, the more evenly distributed the confidence probabilities of different quantization phase values; the smaller the phase ambiguity, the greater the difference in confidence probabilities. Therefore, adjust the confidence probabilities of different quantization phase values according to the phase ambiguity to further reduce the interference of noise during the hot switching process. Calculate the confidence probability of the quantization phase value according to the phase ambiguity and the distribution of phase values within the neighborhood of the quantization phase value.

[0108] Step 3: The abnormal warning unit calculates the alarm threshold and issues an abnormal alarm when the alarm threshold is positive. The abnormal warning unit consists of a host computer. During the hot switching process of the double busbar, when a line or component is just connected to the power system, the load imbalance causes a certain degree of fluctuation in the phase difference of the zero-sequence current on both sides of the bus-coupling switch. To prevent false alarms, it is necessary to dynamically calculate the alarm threshold. According to the above steps, calculate and obtain the K quantization phase values and their confidence probabilities of the zero-sequence currents on both sides of the double busbar bus-coupling switch respectively. When the difference between the two zero-sequence current quantization phase values is larger and the confidence probabilities of both are greater, the risk of abnormal zero-sequence current in the power system is greater. When the calculated phase difference of the zero-sequence currents on both sides of the bus-coupling switch exceeds the maximum phase difference of the zero-sequence currents of the two busbars during normal hot switching, it indicates that there is a fault of incomplete closing in the power system at this time, and an alarm needs to be issued in time. Calculate the alarm threshold according to the quantization phase values and their confidence probabilities of the zero-sequence currents on both sides of the bus-coupling switch. It should be noted that the quantization phase values of the zero-sequence currents obtained on both sides of the bus-coupling switch are independent of each other, and the joint confidence probability of the two is equal to the product of their respective confidence probabilities, which is used as the weight to adjust the calculation of the alarm threshold for different phase differences, reducing the influence of zero-sequence current phase ambiguity and the fluctuation of the zero-sequence current phase difference of the double busbar.

[0109] In this embodiment, by extracting the zero-sequence current phase values on both sides of the bus-tie switch multiple times, the deviation caused by single-phase difference calculation is reduced. Taking the confidence probability of the zero-sequence current quantization phase value on both sides of the bus-tie switch as the weight of the zero-sequence current phase difference further reduces the influence of phase ambiguity on anomaly detection. While ensuring the sensitivity of anomaly detection, false alarms within the normal fluctuation range of the zero-sequence current phase value are avoided. When the weighted phase difference of the zero-sequence current on both sides of the bus-tie switch exceeds the maximum phase difference of the zero-sequence current of the two busbars during normal thermal switching, the alarm threshold is a positive number, indicating a fault of incomplete closing during the double-busbar thermal switching process. The system issues an alarm and further checks the power system.

[0110] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or steps in other steps.

[0111] Based on the same inventive concept, an embodiment of the present application also provides a zero-sequence current anomaly detection device based on a double busbar for implementing the above-mentioned zero-sequence current anomaly detection method based on a double busbar. The implementation solutions provided by this device to solve problems are similar to the implementation solutions described in the above method. Therefore, the specific limitations in one or more embodiments of the zero-sequence current anomaly detection device based on a double busbar provided below can refer to the limitations on the zero-sequence current anomaly detection method based on a double busbar in the above text, and will not be repeated here.

[0112] In an exemplary embodiment, as Figure 4 shown, a zero-sequence current anomaly detection device 400 based on a double busbar is provided, including: a sequence determination module 402, an interval determination module 404, an interval processing module 406, and an anomaly detection module 408, where:

[0113] The sequence determination module 402 is configured to obtain the zero-sequence current of each of the double busbars of the power system to be detected, and obtain the phase value sequence of the zero-sequence current of each busbar according to the zero-sequence current.

[0114] The interval determination module 404 is configured to obtain the phase value interval of each phase value sequence according to each phase value sequence.

[0115] The interval processing module 406 is configured to determine multiple quantization phase values of each bus and the confidence probability of each quantization phase value according to each phase value interval.

[0116] The anomaly detection module 408 is configured to obtain an alarm threshold of the power system to be detected according to each quantization phase value of each bus, the confidence probability of each quantization phase value, and a maximum phase difference of a preset zero-sequence current of a dual bus, and perform anomaly early warning when the alarm threshold meets a preset condition.

[0117] Further, in one embodiment, the interval determination module 404 is further configured to determine a maximum phase value and a minimum phase value in each phase value sequence according to each phase value sequence; use the maximum phase value and the minimum phase value of each phase value sequence as the right endpoint and the left endpoint respectively to obtain a phase value interval of each phase value sequence.

[0118] Further, in one embodiment, the interval processing module 406 is further configured to obtain a phase ambiguity of each phase value sequence according to the maximum phase value, the minimum phase value, and the cumulative sum of the deviations of all phase values from the minimum phase value in each phase value sequence; divide each phase value interval into multiple sub-intervals, and use the endpoints of each sub-interval as quantization phase values to obtain multiple quantization phase values corresponding to each bus; determine the number of phase values in the neighborhood corresponding to each quantization phase value according to each sub-interval; obtain the confidence probability of each quantization phase value according to each phase ambiguity, the number of phase values in the neighborhood corresponding to each quantization phase value of each bus, and the maximum value of the number of phase values.

[0119] Further, in one embodiment, the anomaly detection module 408 is further configured to determine the positive / negative value attribute of the alarm threshold according to the alarm threshold; when the positive / negative value attribute of the alarm threshold is positive, it indicates that the alarm threshold meets the preset condition, and perform anomaly alarm.

[0120] Each module in the above zero-sequence current anomaly detection device 400 based on a dual bus can be implemented in whole or in part by software, hardware, and their combination. The above modules can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to the above modules.

[0121] In an exemplary embodiment, a computer device is provided. The computer device can be a server, and its internal structure diagram can be as Figure 5As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data such as zero-sequence current, phase value sequence, quantized phase value, confidence probability, and alarm threshold. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a method for detecting abnormal zero-sequence current based on a double busbar.

[0122] Those skilled in the art can understand that Figure 5 the structure shown in is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0123] In one embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0124] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0125] In one embodiment, a computer program product is provided, including a computer program. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0126] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, artificial intelligence (AI) processors, etc., without limitation.

[0127] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope recorded in the present application.

[0128] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A method for detecting zero-sequence current anomaly based on double busbars, characterized in that: The method comprises: Obtaining the zero-sequence current of each of the double buses of the power system to be detected, and obtaining a phase value sequence of the zero-sequence current of each bus according to the zero-sequence current; According to each of the phase value sequences, a phase value interval of each of the phase value sequences is obtained; Determine, according to each phase value interval, a plurality of quantized phase values ​​of each of the busbars and a confidence probability of each of the quantized phase values; According to each quantized phase value of each bus, the confidence probability of each quantized phase value and the preset maximum phase difference of the double bus zero-sequence current, the alarm threshold of the power system to be detected is obtained, and an abnormal warning is issued when the alarm threshold meets the preset conditions.

2. The method according to claim 1, characterized in that The obtaining, according to each of the phase value sequences, a phase value interval of each of the phase value sequences comprises: According to each of the phase value sequences, determining the maximum phase value and the minimum phase value in each of the phase value sequences; The maximum phase value and the minimum phase value of each phase value sequence are taken as the right endpoint and the left endpoint respectively, to obtain the phase value interval of each phase value sequence.

3. The method according to claim 2, characterized in that Determining a plurality of quantized phase values ​​of each of the bus bars and a confidence probability of each of the quantized phase values ​​according to each of the phase value intervals includes: Obtaining a phase ambiguity of each phase value sequence according to the maximum phase value, the minimum phase value and the cumulative sum of deviations of all phase values ​​from the minimum phase in each phase value sequence; Dividing each phase value interval into a plurality of sub-intervals, and taking the endpoints of each sub-interval as quantized phase values, to obtain a plurality of quantized phase values ​​corresponding to each bus; Determine, according to each of the subintervals, the number of phase values ​​in a neighborhood corresponding to each of the quantized phase values; The confidence probability of each of the quantized phase values ​​is obtained according to each of the phase ambiguities, the number of phase values ​​in a neighborhood corresponding to each of the quantized phase values ​​of each of the bus lines, and the maximum value of the number of phase values.

4. The method according to claim 3, characterized in that in, The method for determining the confidence probability of each of the quantized phase values ​​includes: Wherein, norm() represents the sum normalization function, exp() represents the exponential function with the natural constant as the base, F represents the phase ambiguity, M represents the maximum value of the phase value number, M K represents the number of phase values ​​in the neighborhood corresponding to the kth quantized phase value, P K Represents the confidence probability of the kth quantized phase value in the phase value interval.

5. The method according to claim 1, characterized in that: in, The method for determining the alarm threshold includes: Wherein, K represents the number of the quantized phase values ​​in the phase value interval, and respectively represent the i-th quantized phase value and its confidence probability in the phase value interval of the first bus, and represent the j-th quantized phase value and its confidence probability in the phase value interval of the second busbar, respectively, represents the maximum phase difference of the preset double bus zero-sequence current, and TH represents the alarm threshold of the power system to be detected.

6. The method according to claim 1, characterized in that When the alarm threshold meets the preset condition, an abnormal warning is performed, including: According to the alarm threshold, determining the positive and negative value attributes of the alarm threshold; When the positive and negative value attribute of the alarm threshold is positive, it indicates that the alarm threshold meets the preset condition and an abnormal alarm is issued.

7. A zero-sequence current anomaly detection device based on double busbars, characterized in that: The device comprises: A sequence determination module, used to obtain the zero-sequence current of each of the double buses of the power system to be detected, and obtain a phase value sequence of the zero-sequence current of each bus according to the zero-sequence current; An interval determination module, used for obtaining a phase value interval of each phase value sequence according to each phase value sequence; An interval processing module, used for determining a plurality of quantized phase values ​​of each of the bus bars and a confidence probability of each of the quantized phase values ​​according to each of the phase value intervals; The abnormality detection module is used to obtain the alarm threshold of the power system to be detected based on the quantized phase values ​​of each bus, the confidence probability of each quantized phase value and the preset maximum phase difference of the double bus zero-sequence current, and to issue an abnormality warning when the alarm threshold meets the preset conditions.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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