Power distribution network grounding fault positioning method, electronic equipment and medium

Abstract

The invention relates to a power distribution network grounding fault positioning method, electronic equipment and a medium, and the method comprises the steps: judging a fault type and a preliminary fault moment, and preliminarily determining a fault line according to the fault type; positioning a fault section: if the fault type is a grounding fault, performing wide area measurement on the preliminarily determined fault line, determining a fault phase and an accurate fault moment based on data of the wide area measurement, and calculating a differential offset degree and a current abrupt change rate to judge the fault section; accurate positioning of fault points: in the fault interval, determining accurate moments when fault initial traveling waves arrive at the detection points and accurate fault lines; and comparing and analyzing the polarity of the current initial traveling wave of each detection point, and calculating the final fault distance by using the corresponding time difference between the singular points in the fault current signals of the detection points with different polarities. Compared with the prior art, the method has the advantages of improving fault positioning precision and response speed and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution network fault location, and in particular to a power distribution network grounding fault location method, an electronic device and a medium. BACKGROUND

[0002] As the end of the power grid, the distribution network directly reflects the requirements of users in terms of power safety, economy and other aspects. On the other hand, distribution network faults are the main factors causing user power outages and personal injuries. With the development of mobile Internet, the public's attention to human and animal electric shock incidents has also increased, which is easy to turn a single production accident into a public event, causing harm to the company's brand image. Therefore, research on distribution network fault location and broken line fault identification technology considering personal safety can not only provide power supply reliability from a technical perspective, but also reduce the public opinion level of the company's public relations costs for sudden events such as human and animal electric shock, and better maintain the company's brand image.

[0003] Specifically, through accurate fault location, the fault recovery time can be significantly shortened, the power outage time can be reduced, and the user's satisfaction and trust can be improved. In addition, these technologies can also help power companies more effectively manage their assets, optimize operation and maintenance strategies, and reduce unnecessary maintenance costs. More importantly, when a fault occurs, timely and accurate location and handling can effectively avoid potential personal safety accidents and protect the safety of the public's life and property. Existing power distribution network fault location methods include traveling wave method, injected signal method and fault analysis method.

[0004] Traveling wave method: In distribution network faults, the traveling wave method locates faults by detecting transient current or voltage traveling wave signals generated when a fault occurs. When a fault occurs, the traveling wave signal propagates along the conductor at near the speed of light. High-precision sensors are installed at key nodes in the distribution network (such as substation outlets or branch points) to collect the traveling wave signal and identify the time it takes for the traveling wave front to reach the monitoring point. The distance from the fault point to the monitoring point is calculated using the traveling wave propagation speed and time difference. Furthermore, dual-end or multi-end monitoring can improve positioning accuracy, and techniques such as wavelet transform are used to extract features and reduce interference, thereby achieving fast and accurate fault location. However, traveling wave signals are easily affected by line structure during transmission. For example, branch lines, transformers, or load changes can cause signal reflection and refraction, making the traveling wave front characteristics complex and increasing the difficulty of accurate identification. In addition, traveling wave signals are sensitive to external interference. Lightning strikes, switching operations, or other electromagnetic interference may superimpose on the traveling wave signal, causing waveform distortion and affecting the accuracy of the positioning results. Meanwhile, traveling waves gradually attenuate during propagation due to conductor resistance and distributed parameters, especially over long distances, where this attenuation can lead to weak or undetectable signals at distant points. The traveling wave method places high demands on measurement equipment, requiring high-speed sampling and highly sensitive sensors. This not only increases system costs but may also introduce additional errors due to equipment performance limitations. The positioning accuracy of the traveling wave method depends on precise wave velocity settings, but the actual wave velocity in a given line may deviate from the theoretical value due to factors such as conductor type and insulation medium, further affecting the reliability of the positioning results.

[0005] Signal injection method: This method locates single-phase ground faults by injecting a specific frequency AC or DC signal into the distribution network and utilizing the signal's propagation characteristics in the faulty line. It effectively overcomes the limitations of traditional methods due to distributed capacitance and high-resistance grounding, and is particularly suitable for low-current grounding systems and complex branch lines. Currently, various improved techniques have been developed for this method, such as AC signal injection, DC signal injection, and pulse signal injection. Combined with modern signal processing technology and sensor equipment, it can achieve rapid live-line location. However, its practical application still faces problems such as signal attenuation and limited detection accuracy. Future research requires further optimization of signal source design and detector performance to improve reliability and adaptability. However, the injected signal may attenuate and distort during propagation due to impedance mismatch, branch nodes, or load changes, making accurate signal identification difficult, especially in complex network structures. Furthermore, this method has certain requirements on the power and frequency range of the injected signal source. If the signal strength is insufficient or the frequency selection is inappropriate, it may not effectively cover the entire line or be affected by background noise, impacting location accuracy. Meanwhile, the injection signal method usually requires the additional installation of signal generators and detection equipment, which increases system cost and maintenance complexity.

[0006] Fault analysis method: The fault analysis method mainly involves analyzing fault information in a faulty line and formulating equations to determine the fault distance. There are two main methods: single-end and double-end location. Single-end location involves collecting fault signals from monitoring equipment at one end of the distribution network line and calculating the fault location by utilizing the time or characteristic changes in signal propagation from the fault point to the monitoring point, combined with the signal propagation speed. Double-end location involves simultaneously collecting signals from monitoring equipment at both ends of the line and calculating the fault point by utilizing the time difference in signal arrival at both ends. This effectively reduces the impact of signal reflection and propagation errors, thereby improving location accuracy. However, the fault analysis method is highly dependent on line parameters; parameter deviations or distributed capacitance in actual lines can lead to calculation errors. The accuracy of this method is limited in complex network structures or multi-branch lines, making it difficult to accurately distinguish between faulty and non-faulty paths. Furthermore, high-resistance grounding faults or changes in transition resistance in low-current grounding systems further increase the analysis difficulty. The fault analysis method also relies on accurate synchronous measurement data; however, sampling errors or time asynchrony of equipment can significantly affect the location results, posing certain challenges in practical applications.

[0007] A search revealed Chinese invention patent application publication number CN104155582B, which discloses a method for locating fault sections in distribution network lines based on full waveform information. The method includes: 1. After a fault occurs, measuring the three-phase current and zero-sequence voltage of the busbar to determine the fault type and the faulty phase and time; 2. If the fault type is determined to be phase-to-phase, measuring the three-phase current at the beginning of each line from the time of the fault until the relay protection device operates, and selecting the faulty line; 3. If the fault type is determined to be a ground fault, measuring the zero-sequence current and zero-sequence voltage at the beginning of each line from the time of the fault until the arc suppression coil operates, and selecting the faulty line; 4. If the fault is determined to be phase-to-phase and the faulty line has been selected, measuring the faulty phase current at each detection point on the faulty line to determine the fault interval, thus achieving section location; 5. If the fault is determined to be phase-to-phase and the faulty line has been selected, measuring the zero-sequence current at each detection point on the faulty line, thus achieving section location; 6. If the fault is determined to be a ground fault and the faulty line has been selected, achieving section location. This existing patent application suffers from low location accuracy.

[0008] How to achieve rapid and accurate fault location in the power distribution network has become a technical problem that needs to be solved. Summary of the Invention

[0009] The purpose of this invention is to overcome the defects of the prior art by providing a method, electronic device and medium for locating grounding faults in power distribution networks.

[0010] The objective of this invention can be achieved through the following technical solutions: According to one aspect of the present invention, a method for locating ground faults in a distribution network is provided, the method comprising: Determine the fault type and initial fault time, and preliminarily identify the faulty line based on the fault type; Fault section location: If the fault type is a ground fault, a wide-area measurement is performed on the initially determined fault line, and the fault phase and precise fault time are determined based on the wide-area measurement data. The differential offset and current change rate are calculated based on the fault phase current waveform data within a set range before and after the precise fault time to determine the fault section. Precise fault location: Within the fault range, determine the precise time when the initial traveling wave of the fault arrives at each detection point and the precise fault line; compare and analyze the polarity of the initial traveling wave of the current at each detection point to find the detection point with the opposite polarity to the initial traveling wave of the current at other detection points; use the time difference between the corresponding singular points in the fault current signals of detection points with different polarities to calculate the final fault distance.

[0011] Preferably, determining the fault phase and precise fault time based on wide-area measurement data specifically involves: after a ground fault is detected, selecting the fault phase according to the phase voltage change pattern, and determining the precise fault time tf based on the phase voltage change time or the arc suppression device power change time.

[0012] More preferably, the process of calculating differential offset and current mutation rate to determine the fault section includes performing the following operations for each line section until all fault sections are found, thereby achieving fault section location: The differential offset is calculated based on the phase current sampling sequence of adjacent detection points; Calculate the current change rate based on the phase current difference between adjacent detection points; If the differential offset is greater than the set differential offset threshold, the differential offset flag is set to 1; otherwise, it is set to 0. If the current mutation rate is greater than the set current mutation rate threshold, the current mutation rate flag is set to 1; otherwise, it is set to 0. Perform an OR operation on the differential offset flag and the current mutation rate flag. If the result is 1, the line section is determined to be a fault section; otherwise, the line section is determined to be a non-fault section.

[0013] Preferably, the process of determining the precise fault line includes: within the fault interval, comparing and analyzing the acquired initial traveling waves of the current, comparing the initial traveling waves of the three-phase current of the same outgoing line, if the polarity of the initial traveling waves of the three-phase current of each outgoing line is consistent, then the outgoing line with the opposite polarity to the other outgoing lines is determined to be the precise fault line; if the polarity of the initial traveling waves of the three-phase current of each outgoing line is not completely the same, selecting one line with a different polarity of the initial traveling waves of the three-phase current, determining the phase line with a different polarity from the other two phases of the initial traveling waves of the current as the fault phase, and then comparing the fault phase of each outgoing line, the outgoing line with the opposite polarity to the other outgoing lines is the precise fault line.

[0014] Preferably, determining the precise time when the initial traveling wave of the fault arrives at each detection point is specifically done as follows: after determining the fault interval, at least two detection points are selected on the non-faulty line closest to the fault interval; The singularities in the fault current signal at each detection point are decomposed using binary recursive SVD, and the precise time when the initial traveling wave of the fault arrives at each detection point is determined based on the singularities.

[0015] Preferably, the calculation of the final fault distance includes: assuming that each detection point is T1, T2...Tn, where n is greater than 1, if the detection point with the opposite polarity of the initial traveling wave of the current to other detection points is Tn, then the fault distance from the fault point to the detection point Tn is calculated based on the time difference obtained from the wide-area measurement of the detection point Tn and other detection points respectively, and the final fault distance is obtained by averaging all the calculated fault distances.

[0016] Preferably, the fault distance is calculated using the D-type traveling wave ranging method.

[0017] Preferably, the faulty line is initially determined based on the fault type, including: The fault type is determined based on the three-phase current and zero-sequence current of the busbar. If the fault type is a ground fault, and the zero-sequence current lags the zero-sequence voltage by 90° in the T1 period, and its magnitude is proportional to the sum of the capacitances to ground of the entire system excluding this line, where the T1 period is the transient or specific stage of the initial stage of the fault, then it is preliminarily determined that the line is a faulty line. If the fault type is phase-to-phase fault, the fault phase current of each outgoing line of the connecting bus is collected n cycles after the initial fault time, and the fault phase current is compared with the set current threshold. If the fault phase current of a certain line exceeds the set current threshold, it is determined that the line has an overcurrent and the line is a faulty line.

[0018] According to another aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement the method described thereon.

[0019] According to a third aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method described thereon.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1) In this invention, after determining that the fault type is a ground fault, a wide-area measurement is performed on the initially determined fault line, and the fault phase and precise fault time are determined based on the wide-area measurement data. The differential offset and current mutation rate are calculated by the fault phase current waveform data before and after the precise fault time to determine the fault interval. Based on the fault interval, the precise fault line is determined. Finally, the fault point in the precise fault line is accurately located by the time difference between the singular points in the fault current signal, thereby quickly achieving the positioning accuracy of the ground fault.

[0021] 2) This invention quickly and accurately identifies the precise faulty line by comparing and analyzing the acquired initial traveling wave of the current. Then, it uses singularity detection to determine the precise time when the initial traveling wave of the fault arrives at each detection point. Finally, it uses the time difference between the singularities to accurately locate the fault point in the precise faulty line, thereby improving the accuracy and efficiency of the location.

[0022] 3) This invention uses the average fault distance as the final location result. Regardless of whether the calculated fault distance errors are positive or negative, or whether the multiple fault distance errors have the same sign, a more accurate location result can be obtained. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the principle of precise fault location in this invention. Figure 2 This is a flowchart illustrating the method for locating grounding faults in a power distribution network according to the present invention. Figure 3 This is a schematic diagram of the process for precise fault location in this invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] Example 1 This embodiment relates to a method for locating grounding faults in a distribution network. The method follows the principle of "selecting the line first, then locating the fault" and considers the compatibility of the location method with phase-to-phase faults. It makes full use of the waveform information of each detection point before and after the arc suppression device (or relay protection device) operates, and uses wide-area measurement data to accurately and quickly locate the fault section.

[0026] like Figure 2 The method includes the following steps: Step S1: Determine the fault type and the initial fault time.

[0027] Although single-phase ground faults occur frequently in distribution networks, it is still necessary to identify the fault type and the faulty phase before locating the ground fault section. Furthermore, determining the time of the fault occurrence will provide essential information for further analysis of the fault section.

[0028] The fault type and initial fault time are determined based on the three-phase current and zero-sequence voltage of the busbar. If overcurrent occurs in the three-phase current of the busbar, it is a phase-to-phase fault, and the phase with overcurrent is identified as the faulty phase. If the zero-sequence voltage increases, it is a ground fault, and the phase with the sudden decrease in phase voltage is recorded as the faulty phase. The moment when the phase current or zero-sequence voltage changes abruptly is recorded and defined as the initial fault time. If it is determined to be a ground fault, for non-faulty lines, the zero-sequence current at the beginning of line i during time intervals P1 and P2 is used. satisfy: (1) in, Let be the capacitance to ground of the i-th line. P1 represents the neutral point zero-sequence voltage, P2 represents the normal state period when no fault has occurred, and P2 represents the period when the fault has occurred and is stable.

[0029] For the faulty line (let's call it line n), its zero-sequence current... It equals the vector sum of the line capacitive current and the residual current at the fault point, i.e. (2) in, Let be the capacitance to ground of the nth faulty line. The neutral point zero-sequence voltage, This is the residual current at the grounding fault point.

[0030] During time period T1, due to the small zero-sequence voltage and large impedance of the arc suppression coil, the compensation effect of the arc suppression coil can be ignored. The residual current at the grounding point is mainly composed of the capacitive current of the entire system, and equation (2) can be simplified to... (3) in, This represents the sum of the ground capacitance currents of the entire system. This is the total capacitance of the three phases to ground of the entire system.

[0031] It can be seen that, theoretically, the zero-sequence current of the faulty line lags behind the zero-sequence voltage by 90° during the T1 period, and its magnitude is proportional to the sum of the capacitances to ground of the entire system excluding this line.

[0032] The phase of the zero-sequence current in time period T2 is related to the compensation degree of the arc suppression coil and there is no definite phase relationship. Therefore, the faulty line can be selected based on the zero-sequence voltage and zero-sequence current sampling sequences in time period T1. Let the phase difference between the zero-sequence voltage and zero-sequence current be represented by the subscript of the sequence corresponding to the maximum value of the cross-correlation function. Let N be the sampling points per cycle at power frequency, and the zero-sequence voltage and zero-sequence current sampling sequences be respectively... I 0( n )and U 0( n) The cross-correlation function is defined as: (4) in, It reflects the degree of similarity between zero-sequence voltage and zero-sequence current at different relative positions.

[0033] set up Then τ is U 0( n )relatively I 0( n The time delay is calculated as follows: τ = 0 to N / 2 for non-faulty lines and N / 2 to N for faulty lines. If all lines are fault-free, then the fault is on the bus.

[0034] If the fault type is phase-to-phase fault, the fault phase current of each outgoing line of the connecting bus is collected several cycles after the initial fault time (i.e., 2-5 cycles before the relay protection device operates), and the fault phase current is compared with the set current threshold. If the fault phase current of a certain line exceeds the set current threshold, it is determined that there is an overcurrent in that line, and that line is the initial fault line.

[0035] Step S2: Locate the faulty area.

[0036] set up , Given the phase current sampling sequence of adjacent detection points, with the index of the data point at the time of the fault occurrence set to zero, the phase current changes of two adjacent detection points are defined as follows: (5) In the formula, N The sampling point for one period is 0.02fs; n Negative integer values ​​indicate the state before the fault occurred. n A positive integer is used to represent the value after the fault occurs. To reduce the impact of fault transition resistance on the sensitivity of the location method, the sum of the squares of the current changes at the two points is used as the braking amount. Therefore, the differential offset is defined as a measure of the difference in phase current changes, specifically: (6) Based on the analysis in the previous section, it is easy to determine the differential offset in the non-faulty region.diff The differential offset within the fault range is close to 0. diff It is a positive number greater than 0.

[0037] Define the phase current difference between adjacent detection points: (7) Define the effective values ​​of the phase current difference before and after the fault as follows: (8) (9) Define the current mutation rate as: (10) Based on the analysis, it is easy to determine the section current change rate in the non-faulty section. A I Less than or equal to 1, the section current change rate in the fault region A I Greater than 1.

[0038] In step S2, the specific positioning steps are as follows: S21, after the system detects a ground fault, it selects the faulty phase (grounded phase) according to the phase voltage change pattern, and determines the precise fault time tf based on the phase voltage change time (or the arc suppression device power change time). S22, select fault phase current waveform data from 2N points within the interval [tf-N, tf+N] (N=0.02fs, where fs is the sampling frequency) of the detection device (assuming the index of the data point at the time of fault occurrence is zero), and calculate the differential offset according to the definition of differential offset. diff Calculate the current mutation rate according to the definition of current mutation rate. A I ; S23, if diff > diff set Set the differential offset flag to 1 if necessary, otherwise set it to 0. A I > A Iset Set the current mutation rate flag to 1, otherwise set it to 0; where diff set The set differential offset threshold, A Iset The threshold for the current mutation rate is set. S24. Perform an OR operation on the two flag bits. If the result is 1, it means that the judgment condition of at least one fault section is met, and the corresponding line section is judged as a fault section. Otherwise, the corresponding line section is judged as a non-fault section. S25. Based on the network topology and the distribution of detection points on the line, traverse sequentially until all fault intervals are found, thereby achieving fault interval location.

[0039] Step S3: Accurately locate the fault point.

[0040] The initial traveling waves of the acquired current are compared and analyzed. If the polarity of the initial traveling waves of the three-phase currents of the same outgoing line is consistent, the outgoing line with the opposite polarity to the other two outgoing lines can be identified as the precise fault line. If the polarity of the initial traveling waves of the three-phase currents of each outgoing line is not completely the same, one line with a different polarity is selected, and the phase line with a different polarity from the other two phases is identified as the fault phase. Then, the fault phase of each outgoing line is compared, and the outgoing line with the opposite polarity to the other two outgoing lines is identified as the precise fault line.

[0041] Assume the fault occurs at some point on the faulty line, such as... Figure 1 Point F is shown, T1~T3 are detection points, and S1~S10 are terminals. Using the fault traveling wave initial wave head detection device installed at each terminal and the algorithm described above, the precise times when the initial fault traveling wave arrives at each detection point T1, T2, and T3 can be measured. , , According to the D-type traveling wave ranging method, the fault distance can be obtained as follows: (11) in, and The average value is the final fault distance. d T1-T3 To calculate the fault distance from the fault point to the detection point T3 based on the wide-area measurement data of detection points T1 and T3, d T2-T3 The fault distance from the fault point to the detection point T3 is calculated based on the wide-area measurement data of detection points T2 and T3. l T1-T3 This is the total length of the transmission line between the two detection points T1 and T3; l T2-T3 This refers to the total length of the transmission line between the two detection points T2 and T3; v This represents the propagation speed of the traveling wave on the transmission line.

[0042] The purpose of using the average fault distance as the final result is that when multiple calculated fault distance errors are both positive and negative, the positive and negative errors can cancel each other out, thus obtaining a more accurate positioning result. At the same time, when the calculated fault distance errors have the same sign, taking the average can also yield a compromise positioning result, preventing the error from becoming too large.

[0043] The steps for precise positioning are as follows Figure 3 ,include: S31. After confirming the faulty section, select at least two detection points on the non-faulty line closest to the faulty section. In this embodiment, three detection points T1, T2, and T3 are selected to improve positioning accuracy and redundancy.

[0044] S32 uses binary recursive SVD to decompose and detect singularities in the fault current signals at the three detection points, and determines the precise time when the initial traveling wave of the fault arrives at each detection point based on the singularities.

[0045] S33, compare and analyze the polarity of the initial traveling current waves at the three detection points to find the detection point with the opposite polarity to the initial traveling current waves at the other detection points, thereby determining the precise faulty circuit. For example... Figure 1 As shown, if the fault occurs between terminals S2 and S5, then the initial traveling wave polarity of the three-phase currents in all outgoing lines from terminal S2 on the faulty line is the same. Similarly, the initial traveling wave polarity of the three-phase currents in all outgoing lines from terminal S5 on the faulty line is the same; however, the polarity of the initial traveling wave polarity of the three-phase currents in the outgoing lines from terminal S2 is opposite to that of the outgoing lines from terminal S5. That is... Figure 1 The initial traveling wave polarities of the currents in T1 and T2 are the same, while the initial traveling wave polarities of the currents in T3 are opposite to those in T1, and the initial traveling wave polarities of the currents in T3 are opposite to those in T2.

[0046] S34. The fault distance can be calculated by using the time difference between singular points in the fault current signals of different polarities. The distance to the fault point can be calculated by using the time difference between detection points T1 and T3, and T2 and T3 respectively, and the average of these two fault distances is taken as the final fault distance.

[0047] The fault location method of this invention significantly improves fault location accuracy: through high-precision sensors, high-speed sampling, and advanced data analysis algorithms, the system can monitor and quickly and accurately identify the fault location in real time, achieving sub-meter level precision. Compared to traditional methods, this system drastically shortens fault response time from hours to minutes or even seconds, enabling maintenance personnel to more quickly isolate fault areas and reduce power outage time and user impact. It also improves the safety and intelligence level of the distribution network; the system not only accurately locates faults but also records detailed waveform data before and after the fault, providing support for subsequent analysis and prevention. Furthermore, this system facilitates the safe grid connection of distributed power sources, promoting the development of smart grids. Combined with distribution automation systems, it can achieve automatic fault isolation and load transfer, further enhancing the flexibility and reliability of the distribution network and ensuring power supply continuity and stability.

[0048] Example 2 The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0049] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0050] The processing unit performs the various methods and processes described above. For example, in some embodiments, the methods may be implemented as computer software programs tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of the methods described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute the methods by any other suitable means (e.g., by means of firmware).

[0051] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0052] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0053] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for locating grounding faults in a distribution network, characterized in that, The method includes: Determine the fault type and initial fault time, and preliminarily identify the faulty line based on the fault type; Fault section location: If the fault type is a ground fault, a wide-area measurement is performed on the initially determined fault line, and the fault phase and precise fault time are determined based on the wide-area measurement data. The differential offset and current change rate are calculated based on the fault phase current waveform data within a set range before and after the precise fault time to determine the fault section. Precise fault location: Within the fault range, determine the precise time when the initial traveling wave of the fault arrives at each detection point and the precise fault line; compare and analyze the polarity of the initial traveling wave of the current at each detection point to find the detection point with the opposite polarity to the initial traveling wave of the current at other detection points; use the time difference between the corresponding singular points in the fault current signals of detection points with different polarities to calculate the final fault distance.

2. The method for locating grounding faults in a distribution network according to claim 1, characterized in that, The specific steps for determining the fault phase and precise fault time based on wide-area measurement data are as follows: after a ground fault is detected, the fault phase is selected according to the phase voltage change pattern, and the precise fault time tf is determined according to the phase voltage change time or the arc suppression device power change time.

3. The method for locating grounding faults in a distribution network according to claim 2, characterized in that, The process of calculating differential offset and current mutation rate to determine fault sections includes performing the following operations for each line section until all fault sections are found, thereby achieving fault section location: The differential offset is calculated based on the phase current sampling sequence of adjacent detection points; Calculate the current change rate based on the phase current difference between adjacent detection points; If the differential offset is greater than the set differential offset threshold, the differential offset flag is set to 1; otherwise, it is set to 0. If the current mutation rate is greater than the set current mutation rate threshold, the current mutation rate flag is set to 1; otherwise, it is set to 0. Perform an OR operation on the differential offset flag and the current mutation rate flag. If the result is 1, the line section is determined to be a fault section; otherwise, the line section is determined to be a non-fault section.

4. The method for locating grounding faults in a distribution network according to claim 1, characterized in that, The process of accurately determining the faulty line includes: within the faulty section, comparing and analyzing the acquired initial traveling waves of the current; comparing the initial traveling waves of the three-phase current of the same outgoing line; if the polarity of the initial traveling waves of the three-phase current of each outgoing line is consistent, then the outgoing line with the opposite polarity to the other outgoing lines is determined to be the accurately faulty line; if the polarity of the initial traveling waves of the three-phase current of each outgoing line is not completely the same, selecting one line with a different initial traveling wave polarity, determining the phase line with a different polarity from the other two phases as the faulty phase, and then comparing the faulty phase of each outgoing line, the outgoing line with the opposite polarity to the other outgoing lines is the accurately faulty line.

5. The method for locating grounding faults in a distribution network according to claim 1, characterized in that, The precise time when the initial traveling wave of the fault arrives at each detection point is determined as follows: After determining the fault section, at least two detection points are selected on the non-faulty line closest to the fault section; The singularities in the fault current signal at each detection point are decomposed using binary recursive SVD, and the precise time when the initial traveling wave of the fault arrives at each detection point is determined based on the singularities.

6. The method for locating grounding faults in a distribution network according to claim 1, characterized in that, The calculation of the final fault distance includes: assuming that each detection point is T1, T2...Tn, where n is greater than 1, if the detection point with the opposite polarity of the initial traveling wave of the current to other detection points is Tn, then the fault distance from the fault point to the detection point Tn is calculated based on the time difference obtained from the wide-area measurement of the detection point Tn and other detection points respectively, and the final fault distance is obtained by averaging all the calculated fault distances.

7. The method for locating grounding faults in a distribution network according to claim 1, characterized in that, The fault distance was calculated using the D-type traveling wave ranging method.

8. The method for locating grounding faults in a distribution network according to claim 1, characterized in that, Based on the type of fault, the faulty lines have been preliminarily identified as including: The fault type is determined based on the three-phase current and zero-sequence current of the busbar. If the fault type is a ground fault, and the zero-sequence current lags the zero-sequence voltage by 90° in the T1 period, and its magnitude is proportional to the sum of the capacitances to ground of the entire system excluding this line, where the T1 period is the transient or specific stage of the initial stage of the fault, then it is preliminarily determined that the line is a faulty line. If the fault type is phase-to-phase fault, the fault phase current of each outgoing line of the connecting bus is collected n cycles after the initial fault time, and the fault phase current is compared with the set current threshold. If the fault phase current of a certain line exceeds the set current threshold, it is determined that the line has an overcurrent and the line is a faulty line.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 8.

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