Power transmission line out-of-phase point grounding fault positioning method and system, and storage medium

Abstract

The invention relates to a power transmission line out-of-phase point grounding fault positioning method and system and a storage medium, and the method comprises the following steps: obtaining and uploading the three-phase current data and traveling wave data of each node of a power transmission line to a main station when a grounding fault occurs; the master station analyzes the change of three-phase current to determine a fault section in combination with line topology information; and based on the fault section, the main station carries out traveling wave positioning distance measurement according to the traveling wave data and outputs the specific position of a ground fault point. According to the technical scheme of the invention, when a grounding fault occurs, the position of an out-of-phase grounding fault point is quickly and accurately calculated through traveling wave positioning and ranging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system fault diagnosis and positioning, and particularly relates to a power transmission line heterogeneous phase point grounding fault positioning method and system and a storage medium. BACKGROUND

[0002] Power transmission lines often face the challenge of inter-phase ground short-circuit faults during operation. Traditional positioning methods rely on short-circuit fault information monitored by terminal nodes and perform fault analysis based on amplitude and polarity, but these methods cannot accurately identify heterogeneous phase point grounding faults caused by two different grounding points. When this happens, traditional algorithms may only identify one fault location and miss the other, resulting in incomplete fault elimination. SUMMARY

[0003] The main purpose of the present application is to provide a power transmission line heterogeneous phase point grounding fault positioning method, which aims to solve the problem of missing reporting of heterogeneous phase point grounding fault location.

[0004] The first aspect of the present application provides a power transmission line heterogeneous phase point grounding fault positioning method, which comprises the following steps:

[0005] When a grounding fault occurs, the three-phase current data and traveling wave data of each node of the power transmission line are obtained and uploaded to a master station;

[0006] The master station analyzes the changes in three-phase current in combination with line topology information to determine the fault section;

[0007] Based on the fault section, the master station performs traveling wave positioning and distance measurement according to the traveling wave data and outputs the specific location of the grounding fault point;

[0008] The analysis of the changes in three-phase current to determine the fault section comprises:

[0009] The master station compares the polarity of the three-phase current between each pair of nodes on the power transmission line;

[0010] It is determined whether the polarity is consistent, if so, there are two fault points and they are located in the downstream area of the last node of the line, if not, there are two grounding fault points, and it is determined that the two grounding fault points are located in the sections with opposite polarity.

[0011] Optionally, the step of "obtaining three-phase current data and traveling wave data of each node of the power transmission line and uploading to the master station" further comprises:

[0012] Monitoring the three-phase current;

[0013] When the three-phase current is mutated, it is judged whether the mutation amount of any phase current in the three-phase current exceeds a preset threshold, if yes, the phase where the current mutation occurs is a short-circuit fault phase, otherwise it is a normal phase;

[0014] It is judged whether the fault current duration of the fault phase exceeds a preset time threshold, if yes, the short-circuit fault three-phase waveform is obtained and uploaded to the master station, if not, it is not obtained;

[0015] The master station analyzes the short-circuit fault three-phase waveform to determine the fault type as a ground fault.

[0016] Optionally, the step of "monitoring the three-phase current" includes: setting a non-contact induction traveling wave device at each measurement point of each section of the transmission line, and the non-contact induction traveling wave device is used to monitor the three-phase current data and the traveling wave data.

[0017] Optionally, the step of "determining that the two ground fault points are respectively located in the sections with opposite polarities" includes:

[0018] It is judged whether the mutation current polarities between adjacent two nodes on the first phase line are the same;

[0019] It is judged whether the mutation current polarities between adjacent two nodes on the second phase line are the same;

[0020] It is judged whether the mutation current polarities between adjacent two nodes on the third phase line are the same.

[0021] Optionally, the step of "based on the fault section, the master station performs traveling wave positioning and ranging according to the traveling wave data and outputs the specific position of the ground fault point" includes:

[0022] When there are two ground fault points, and it is determined that the two ground fault points are respectively located in the sections with opposite polarities, the traveling wave positioning and ranging are performed on the two ground fault points respectively, and the positioning and ranging results of each ground fault point are output respectively.

[0023] Optionally, the traveling wave data in the step of "obtaining and uploading the three-phase current data and the traveling wave data of each node of the transmission line to the master station" includes the time when the traveling wave reaches each non-contact induction traveling wave device.

[0024] Optionally, the step of "performing the traveling wave positioning and ranging on the two ground fault points respectively" includes:

[0025] Suppose that the two non-contact induction traveling wave devices of the fault section where the ground fault point is located are respectively a first non-contact induction traveling wave device and a second non-contact induction traveling wave device;

[0026] calculating a time difference between the first non-contact induction traveling wave device and the second non-contact induction traveling wave device receiving the traveling wave generated by the grounding fault point;

[0027] calculating distances between the first non-contact induction traveling wave device and the grounding fault point and between the second non-contact induction traveling wave device and the grounding fault point according to the time difference and a wave speed of the traveling wave, wherein the wave speed is determined by medium characteristics of the traveling wave propagation.

[0028] Optionally, in the step of judging whether the mutation of each phase current in the three-phase current exceeds a preset threshold, the preset threshold is 500 A.

[0029] The application further provides a transmission line heterogeneous phase point grounding fault positioning system, which comprises:

[0030] a data acquisition unit configured to acquire and upload three-phase current data and traveling wave data of each node of the transmission line to a master station when a grounding fault occurs;

[0031] a positioning unit configured to analyze the three-phase current data to determine a fault section by the master station in combination with line topology information;

[0032] a calculation unit configured to perform traveling wave positioning and distance measurement according to the traveling wave data based on the fault section by the master station and output a specific position of the grounding fault point.

[0033] The application further provides a computer storage medium, wherein a computer program for implementing steps of the above transmission line heterogeneous phase point grounding fault positioning method is stored on the computer storage medium.

[0034] In the transmission line heterogeneous phase point grounding fault positioning method, when a grounding fault occurs, three-phase current data and traveling wave data of each node of the transmission line are acquired and uploaded to a master station; the master station analyzes the three-phase current data to determine a fault section in combination with existing line topology information; the master station performs traveling wave positioning and distance measurement on fault points in the fault section according to different fault sections, and determines whether the fault type is a heterogeneous phase point grounding fault by comparing the distance between the fault points, thereby calculating and outputting the accurate position of the heterogeneous phase point grounding fault, and solving the problem of missed reporting of the heterogeneous phase point grounding fault position. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in the drawings without any creative effort.

[0036] Figure 1 is a flow chart of one embodiment of the power transmission line out-of-phase point grounding fault locating method of the present application;

[0037] Figure 2 is a flow chart of one embodiment of determining a grounding fault in the power transmission line out-of-phase point grounding fault locating method of the present application;

[0038] Figure 3 is a flow chart of one specific embodiment of determining a fault section in the power transmission line out-of-phase point grounding fault locating method of the present application;

[0039] Figure 4 is a flow chart of one embodiment of performing traveling wave distance measurement in the power transmission line out-of-phase point grounding fault locating method of the present application;

[0040] Figure 5 is a schematic diagram of the power transmission line out-of-phase point grounding fault of the present application;

[0041] Figure 6 is a structural schematic diagram of one embodiment of the power transmission line out-of-phase point grounding fault locating system of the present application.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Reference Name Reference Name 1 Main transformer 7 Secondary main transformer 2 First terminal 8 First phase line 3 Second terminal 9 Second phase line 4 Third terminal 10 Third phase line 5 Fourth terminal 11 First ground fault point 6 Fifth terminal 12 Second ground fault point DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0045] Embodiment One

[0046] Referring to Figure 1 , the present application provides a power transmission line out-of-phase point grounding fault locating method, which comprises the following steps:

[0047] S1, when a grounding fault occurs, acquiring three-phase current data and traveling wave data of each node of the power transmission line and uploading to a master station;

[0048] S2, the master station analyzes the change of the three-phase current in combination with line topology information to determine a fault section;

[0049] S3, based on the fault section, the master station calculates and outputs the position of the grounding fault point according to the traveling wave data.

[0050] In the power transmission line non-phase point grounding fault positioning method of the application, when a grounding fault occurs, the three-phase current data and the traveling wave data of each node of the power transmission line are acquired and uploaded to the master station; the master station analyzes the change of the three-phase current in combination with the existing line topology information to determine the fault section; the master station performs traveling wave positioning and distance measurement on the fault points in the fault section according to different fault sections, compares the distance between the fault points to determine whether the fault type is a non-phase point grounding fault, and thus calculates and outputs the accurate position of the non-phase point grounding fault point, solving the problem of missing report of the non-phase point grounding fault position.

[0051] It should be noted that in step S1, when the transmission line occurs ground fault, first need to collect three-phase current data from each node of the line, which is the basis for determining the fault type and fault section; At the same time, it is also necessary to collect the traveling wave data, which is crucial for subsequent accurate positioning of the fault point. The collected three-phase current data and traveling wave data need to be uploaded to the master station in real time for further analysis and processing. In step S2, the master station will determine the possible fault section in combination with the existing line topology information and uploaded three-phase current data. By analyzing the current change of each node, the fault section can be preliminarily judged, which lays the foundation for accurate positioning in the next step. The line topology information refers to the connection relationship between each node in the power system and the main equipment such as transformer substation and power supply, including line transformer relationship, i.e. the connection relationship between power line and transformer, user transformer relationship, i.e. the connection relationship between user and transformer, and phase relationship, i.e. the relationship between voltage phases of each node, which is crucial for understanding the current flow direction and possible affected area under fault condition. For example, if the three-phase current of a node suddenly increases, and the node directly connected to it does not appear similar changes, the fault may be located on the line between the two nodes. In step S3, after determining the fault section, the master station will perform more accurate fault point positioning based on the traveling wave data. By analyzing the traveling wave data in the fault section and comparing the distance between fault points, the master station can determine whether the fault type is an out-of-phase point grounding fault. Once the fault type and specific location are determined, the master station will calculate and output the accurate position of the out-of-phase point grounding fault. When a fault occurs in the power system, a wave phenomenon called "traveling wave" will be generated at the fault point. This wave propagates along the transmission line and carries information about the fault nature. By analyzing the traveling wave data in the fault section, the master station can determine whether the fault type is an out-of-phase point grounding fault. Specifically, by using traveling wave data to locate and measure the distance of different fault points, the master station can compare the distance between different fault points. If the distance between two fault points is small, it can be determined that it is a short-circuit fault caused by the direct connection of two-phase conductors; If the distance is large, it can be determined that it is a grounding fault caused by the accidental connection of conductors of different phases with the ground. After determining the fault type, the time difference of the traveling wave propagating from the fault point to different non-inductive wave devices is calculated, and the distance between the fault point and different non-inductive wave devices is calculated by the time difference and the traveling wave propagation speed, thereby outputting the accurate position of the grounding fault point.

[0052] In general, when a grounding fault occurs in a power transmission line, the monitoring device on the line immediately starts collecting three-phase current data and traveling wave data of each node and transmits the data to the master station in real time through a high-speed communication network. After receiving the data, the master station first combines the internal line topology information and three-phase current data and quickly determines the possible fault section using a pre-set algorithm. Subsequently, the master station conducts in-depth analysis on the fault sections, uses the traveling wave data to accurately determine the fault type and calculate the specific location of the fault. Finally, the master station outputs the fault location information for reference by the operation and maintenance personnel to facilitate fault repair work as soon as possible.

[0053] Embodiment Two

[0054] As a further example, refer to Figure 2 , the step of acquiring and uploading three-phase current data and traveling wave data of each node of the power transmission line to the master station further includes:

[0055] S11, monitoring three-phase current;

[0056] S12, when the three-phase current is mutated, determining whether the mutation of any phase current in the three-phase current exceeds a pre-set threshold value;

[0057] S121, if yes, the phase in which the current mutation occurs has a short-circuit fault, which is the fault phase;

[0058] S122, if no, it is a normal phase;

[0059] S13, determining whether the fault current duration of the fault phase exceeds a pre-set time threshold value;

[0060] S131, if yes, acquiring the three-phase waveform of the short-circuit fault and uploading it to the master station;

[0061] S132, if no, not acquiring;

[0062] S14, the master station analyzes the three-phase waveform of the short-circuit fault to determine that the fault type is a grounding fault.

[0063] Among them, the step of "monitoring three-phase current" includes: setting a non-contact induction traveling wave device at the measurement point of each section of the power transmission line, and the non-contact induction traveling wave device is used to monitor three-phase current data and traveling wave data.

[0064] Specifically, in step S11 of the present embodiment, the monitoring of three-phase current is performed using a non-contact inductive traveling wave device, which is a key equipment in the power system for real-time monitoring and analysis of the state of the transmission line. By sensing the changes in current and voltage on the line wirelessly (such as magnetic coupling), there is no need for direct physical contact with the conductor, thereby reducing the complexity and cost of installation and maintenance. According to the layout and length of the transmission line, as well as the probability and impact of faults, the installation location of the non-contact inductive traveling wave device is selected. Typically, these devices are arranged at key nodes of the line, such as substation outlets, line branch points, or important crossing points, so as to be able to effectively cover and divide the transmission line into several monitoring sections. By installing non-contact inductive traveling wave devices at selected locations, the transmission line is logically divided into multiple independent monitoring sections. This division helps to quickly locate the specific section where the fault occurs when a fault occurs, thereby significantly improving the efficiency of fault detection and positioning. The non-contact inductive traveling wave device can monitor the three-phase current data of the transmission line in real time, which is crucial for monitoring the daily operating state and can help operators understand the line load and timely detect abnormal states such as overload; in addition to monitoring regular current data, these devices can also capture traveling wave data caused by faults. The traveling wave data contains detailed information about the nature of the fault, such as fault type, fault location, etc., and is an important basis for fault analysis and positioning. Non-contact inductive traveling wave devices usually transmit the collected data in real time to the main station or data center. After receiving the data, the main station uses advanced data processing and analysis algorithms to comprehensively analyze the three-phase current data and traveling wave data, and uses fault positioning technology based on the traveling wave principle to accurately locate the fault point. Once the non-contact inductive traveling wave device detects a fault and determines the fault type and location, the system will automatically trigger the fault response process. This may include isolating the fault section, adjusting the power supply line to bypass the fault area, and other emergency measures. After the fault is handled, the non-contact inductive traveling wave device continues to monitor the line state to ensure smooth recovery of power supply. At the same time, the fault data recorded by the device is of great significance for analyzing the causes of the fault and optimizing system design. In summary, by setting up several non-contact inductive traveling wave devices on the transmission line and dividing the transmission line into several sections for special monitoring, the response speed and processing efficiency of the power system to faults can be greatly improved, ensuring the stable operation and reliability of the power system.

[0065] In step S12, the non-contact inductive traveling wave device continuously monitors the three-phase current data on the transmission line and can capture even small current changes. When the current data changes abruptly, the device will immediately record this change. Current mutations usually mean that some abnormalities may have occurred on the line, such as short circuits or other types of faults.

[0066] The system sets a preset threshold of current change based on historical data and experience, which is 500A in this embodiment, to determine when the change in current is sufficient to indicate a fault. When the non-contact induction traveling wave device detects that the current change of any phase exceeds the preset threshold of 500A, it triggers an alarm indicating that a short-circuit fault may have occurred in that phase, and the phase is marked as a fault phase. This means that the phase may have a short-circuit fault and needs further processing and analysis. Conversely, if the current change of the other two phases does not exceed the preset threshold, these phases are identified as normal phases. They are not affected by the fault and can continue to operate normally. Once the fault phase is determined, the system uses traveling wave data for more accurate fault location to facilitate the dispatch of a repair team for on-site repair. During the fault handling process, the non-contact induction traveling wave device continues to monitor the line status to ensure that the fault is properly handled. Once the fault phase is repaired, the system will gradually return to normal operation.

[0067] In steps S13 and S14, once the faulty phase is determined, the system continues to monitor the fault current of that phase. This is to ensure a thorough understanding of the impact of the fault, including the strength and duration of the fault current. The system sets a pre-set time threshold for the duration of the fault current based on operational experience and equipment capacity. Exceeding this threshold may indicate a more serious fault that requires further analysis and handling. At the same time, it also avoids unnecessary troubleshooting due to temporary overload or small-scale disturbance. If the duration of the fault current exceeds the pre-set time threshold, the system will automatically trigger the acquisition of the three-phase current waveform at the time of the fault. After the main station receives the three-phase waveform data, the main station will first perform feature extraction on the uploaded three-phase waveform data. This includes identifying key information such as abnormal points, frequency changes, phase differences, etc. in the waveform. Then, using pattern recognition technology, the main station will analyze the extracted features and match them with known fault waveform patterns to identify possible fault types. Grounding faults are usually characterized by a sudden increase in current in one phase, while the other two phases remain normal or change slightly. At the same time, the fault phase voltage may decrease, and specific reflection and refraction phenomena may appear in the traveling wave data. By comparing real-time data with historical data during the fault, the main station can confirm whether there are characteristics of a grounding fault, thereby determining the fault type. After determining that the fault type is a grounding fault, the main station will further analyze the traveling wave data and use traveling wave positioning and ranging technology to accurately calculate the location of the fault. Based on the size, duration of the fault current, and fault location, the main station will assess the severity of the fault and the potential impact on the system. In order to ensure safety and prevent the spread of the fault, the main station will guide on-site personnel or automatically execute operations to isolate the fault area. Once the fault area is effectively isolated, the main station will coordinate other power supply lines or backup power sources to restore power to the affected area as soon as possible. The main station will record all relevant data and the handling process of this grounding fault in detail, providing a reference for future fault analysis and system optimization. Based on the cause of the fault and the handling results, the main station will also propose appropriate preventive measures, such as strengthening line inspection and improving grounding protection strategies, to reduce the occurrence of similar faults in the future. In summary, through the above process, the main station can effectively analyze the three-phase waveform data of the short-circuit fault and determine that the fault type is a grounding fault, thereby guiding subsequent fault handling and system recovery work. This series of operations helps to quickly respond to faults, reduces the impact of faults on the power system, and ensures the stable operation of the system and the reliability of power supply.

[0068] Example Three

[0069] As a further example, with reference to Figure 3 and 5 the step of determining the grounding fault section by the main station in combination with the line topology information and analyzing the changes in the three-phase current comprises:

[0070] S21, the main station compares the polarity of the three-phase current between each two nodes on the power transmission line;

[0071] Specifically, as an example, with reference to Figure 5 , the main station respectively compares the polarity of the first terminal and the second terminal, the second terminal and the third terminal, the third terminal and the fourth terminal, and the fourth terminal and the fifth terminal on the first phase line, the second phase line and the third phase line;

[0072] S22, determine whether the polarity is consistent;

[0073] S221, if yes, there are two fault points and they are located in the downstream area of the last node of the line;

[0074] S222, if not, there are two ground fault points, and it is determined that the two ground fault points are located in the opposite polarity section, including: judging whether the polarity of the sudden current between the adjacent two nodes on the first phase line is the same; judging whether the polarity of the sudden current between the adjacent two nodes on the second phase line is the same; judging whether the polarity of the sudden current between the adjacent two nodes on the third phase line is the same.

[0075] Specifically, in this embodiment, by comparing the polarity of the phase current sudden change at the fault time, whether the fault is in the same section is determined by the polarity comparison principle of the phase sudden current. When the polarity of the two-phase sudden current is consistent, the fault is located in the same section. Otherwise, the polarity is inconsistent, and the fault is located in different sections, which belongs to the ground fault of different phases. As an example, with reference to Figure 5 The schematic diagram of the ground fault of the different phase points of the power transmission line. When the polarity of the phase sudden current is inconsistent, it is determined that there are a first fault point 11 and a second fault point 12:

[0076] (1) When the first fault point 11 is grounded, the fault phase is the third phase line 10, the first terminal 2 and the second terminal 3 are between the main transformer 1 and the first ground fault point 11, and the polarity of the third phase line 10 sudden current of the first terminal 2 and the second terminal 3 is the same. The third terminal 4, the fourth terminal 5 and the fifth terminal 6 are between the secondary main transformer 7 and the first ground fault point 11, and the polarity of the third phase line 10 sudden current of the third terminal 4, the fourth terminal 5 and the fifth terminal 6 is the same. While the polarity of the sudden current of (the first terminal 2 and the second terminal 3) and (the third terminal 4, the fourth terminal 5 and the fifth terminal 6) is opposite, the polarity of the third phase line 10 sudden current of the second terminal 3 and the third terminal 4 is opposite, indicating that the fault is located between the second terminal 3 and the third terminal 4;

[0077] (2) When the second fault point 12 is grounded, the fault phase is the first phase line 8, the first terminal 2, the second terminal 3 and the third terminal 4 are between the main transformer 1 and the second ground fault point 12, the first phase line 8 of the first terminal 2, the second terminal 3 and the third terminal 4 has the same sudden current polarity; the fourth terminal 5 and the fifth terminal 6 are between the secondary main transformer 7 and the second ground fault point 12, the first phase line 8 of the fourth terminal 5 and the fifth terminal 6 has the same sudden current polarity; and the sudden current polarity of the first phase line 8 of (the first terminal 2, the second terminal 3 and the third terminal 4) and (the fourth terminal 5 and the fifth terminal 6) is opposite, then the sudden current polarity of the first phase line 8 of the third terminal 4 and the fourth terminal 5 is opposite, indicating that the fault is located between the third terminal 4 and the fourth terminal 5;

[0078] (3) Separate phase and research, the trigger phase is the third phase line 10 and the first phase line 8, research the sudden current polarity section of the third phase line 10 opposite in the second terminal 3 and the third terminal 4 at the same time, if the second terminal 3 and the third terminal 4 judge the sudden current polarity section of the first phase line 8 is the same, then the section of the second terminal 3 and the third terminal 4 of the third phase line 10 exists an opposite point ground fault, and the section of the second terminal 3 and the third terminal 4 of the first phase line 8 does not exist an opposite point ground fault; the sudden current polarity section of the first phase line 8 between the third terminal 4 and the fourth terminal 5 is opposite, while the third terminal 4 and the fourth terminal 5 have the same sudden current polarity section of the third phase line 10, then the section of the third terminal 4 and the fourth terminal 5 of the first phase line 8 exists an opposite point ground fault, and the section of the third terminal 4 and the fourth terminal 5 of the third phase line 10 does not exist an opposite point ground fault. In combination with the foregoing, it is judged that the two opposite point ground fault sections are respectively on the third phase line 10 of the second terminal 3 and the third terminal 4, and on the first phase line 8 of the third terminal 4 and the fourth terminal 5.

[0079] Embodiment four

[0080] As a further embodiment, based on the fault section, the main station performs traveling wave positioning and ranging according to the traveling wave data and outputs the specific position of the ground fault point, which includes the following steps:

[0081] When the two fault points are located in the downstream area of the last node of the line, the traveling wave positioning and ranging of the two fault points are performed respectively, the distance between the two fault points is judged, and the distance is judged based on the artificially preset interval or reference value, if the distance is small, it is an opposite point short circuit fault, and the positioning and ranging result of one of the fault points is taken; if the distance is large, it is an opposite point ground fault, and the positioning and ranging result of each fault point is output respectively;

[0082] When there are two ground fault points, it is determined that the two ground fault points are respectively located in the sections with opposite polarities, the traveling wave positioning and ranging of the two ground fault points are performed respectively, and the positioning and ranging result of each ground fault point is output respectively.

[0083] In particular, with reference to Figure 5 The schematic diagram of the transmission line out-of-phase grounding fault, when there are two grounding fault points, the first fault point 11 is located between the second terminal 3 and the third terminal 4, the traveling wave of the third phase line 10 of the second terminal 3 and the third terminal 4 is used for positioning and distance measurement, and the accurate ranging point of the first fault point 11 is output; the second fault point 12 is located between the third terminal 4 and the fourth terminal 5, the traveling wave of the first phase line 8 of the third terminal 4 and the fourth terminal 5 is used for positioning and distance measurement, and the accurate ranging point of the second fault point 12 is output.

[0084] Example five

[0085] As a further example, please refer to Figure 4 When the grounding fault occurs, the three-phase current data and the traveling wave data of each node of the transmission line are acquired and uploaded to the main station, the traveling wave data in the step of uploading the traveling wave data to the main station includes the time of the traveling wave reaching each non-inductive traveling wave device, and the steps of respectively performing traveling wave positioning and distance measurement on the two grounding fault points include:

[0086] S31, the two non-inductive traveling wave devices of the fault section where a grounding fault point is located are respectively a first non-inductive traveling wave device and a second non-inductive traveling wave device;

[0087] S32, the time difference of the first non-inductive traveling wave device and the second non-inductive traveling wave device receiving the traveling wave generated by a grounding fault point is calculated;

[0088] S33, the distance between the first non-inductive traveling wave device and a grounding fault point and the distance between the second non-inductive traveling wave device and a grounding fault point are calculated according to the time difference and the wave speed of the traveling wave; the wave speed is determined by the medium characteristics of the traveling wave propagation.

[0089] It should be noted that the two grounding fault points in this embodiment are respectively located by the double-ended distance measurement method, which is a fault location technology based on the principle of traveling wave. The position of the fault point is calculated by recording the time difference of the arrival of the fault traveling wave at both ends of the line. In the power system, when a fault occurs, an electromagnetic wave called traveling wave will be generated. This traveling wave will propagate along the conductor and produce reflection and refraction at the fault point. The double-ended distance measurement method makes use of this phenomenon. By detecting the arrival time of the traveling wave at both ends of the line and calculating the time difference, and combining the propagation speed of the traveling wave, the accurate position of the fault point can be calculated. Specifically, when a fault occurs in the transmission line, a voltage and current traveling wave close to the speed of light will be generated at the fault point. These traveling waves propagate bidirectionally along the conductor until they encounter impedance discontinuities such as the end of the line or the fault point and are reflected. The detection devices at both ends of the line will record the exact time of arrival of the fault traveling wave. Let the time of arrival of the fault traveling wave at one end of the line be t1, and the time of arrival at the other end be t2. The time difference Δt is |t1-t2|. This time difference reflects the time required for the fault traveling wave to travel from one end to the other. The propagation speed v of the traveling wave in the conductor depends on the physical characteristics of the line and is usually close to the speed of light. The specific propagation speed needs to be determined according to the actual material and structure of the line. Let the total length of the line be L, and the distance from the fault point to one end be x. According to the time difference Δt and the propagation speed v of the traveling wave, the formula x=v×Δt can be used to calculate the position of the fault point.

[0090] In addition to the double-ended distance measurement method, the single-ended distance measurement method can also be used. The principle is to use the voltage and current traveling waves generated when a fault occurs, and the time difference between the initial traveling wave and the reflected wave from the fault point is detected, combined with the propagation speed of the traveling wave, to calculate the position of the fault point.

[0091] Specific calculation process: By recording the time of arrival of the initial traveling wave at the detection busbar, i.e. the measurement point, and the time of arrival of the reflected traveling wave from the fault point at the detection busbar, the propagation time difference of the traveling wave between the fault point and the measurement point can be calculated. Let the total length of the line be L, the distance from the fault point to the measurement point be x, the propagation speed of the traveling wave be v, the arrival time of the initial traveling wave be tm1, and the arrival time of the reflected traveling wave be tm2. The time difference Δt is tm2-tm1.

[0092] Fault distance calculation: According to the time difference Δt and the propagation speed v of the traveling wave, the formula x=v×Δt can be used to calculate the position of the fault point. This method can provide relatively accurate fault location, with an error usually not exceeding 10% of the total length of the line.

[0093] Example six

[0094] Reference Figure 6 , Figure 6 is a structural schematic diagram of an embodiment of the transmission line asynchronous point grounding fault location system of the present application, as an embodiment of theFigure 1 In order to achieve the power transmission line phase point grounding fault positioning method, the embodiment provides a power transmission line phase point grounding fault positioning system 100, and the system embodiment is used for Figure 1 The power transmission line phase point grounding fault positioning system 100 corresponding to the method embodiment comprises:

[0095] A data acquisition unit 110 is configured to acquire and upload three-phase current data and traveling wave data of each node of the power transmission line to a master station when a grounding fault occurs.

[0096] A positioning unit 120 is configured to analyze the change of the three-phase current to determine a fault section by the master station in combination with line topology information.

[0097] A calculation unit 130 is configured to perform traveling wave positioning and distance measurement according to the traveling wave data based on the fault section by the master station, and output a specific position of the grounding fault point.

[0098] The power transmission line phase point grounding fault positioning system 100 of the embodiment has the same beneficial effects as the power transmission line phase point grounding fault positioning method, which will not be repeated here.

[0099] Embodiment seven

[0100] The application further provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the program is used for implementing the steps of the power transmission line phase point grounding fault positioning method.

[0101] The computer readable storage medium has the same beneficial effects as the power transmission line phase point grounding fault positioning method, which will not be repeated here.

[0102] The above is only used for describing the embodiments of the application, and is not used for limiting the application, and any modification, equivalent replacement, improvement and the like within the spirit and principle of the application without creative labor should be included in the protection scope of the application.

Claims

1. A method for locating a ground fault at a point of discontinuity of a power transmission line, the method comprising: The method comprises the following steps: When a ground fault occurs, three-phase current data and traveling wave data of each node of the transmission line are acquired and uploaded to a master station; The master station analyzes the change of the three-phase current to determine the fault section in combination with the line topology information; Based on the fault section, the master station performs traveling wave positioning and distance measurement according to the traveling wave data and outputs the specific position of the ground fault point; The analysis of the change of the three-phase current to determine the fault section comprises: The master station compares the polarity of the three-phase current between each two nodes on the transmission line one by one; It is judged whether the polarity is consistent, if yes, there are two fault points and they are located in the downstream area of the last node of the line, if not, there are two ground fault points, and it is determined that the two ground fault points are located in the sections with opposite polarity respectively.

2. The method of claim 1, wherein, The step of "acquiring and uploading the three-phase current data and traveling wave data of each node of the transmission line to the master station" further comprises: Monitoring the three-phase current; When the three-phase current suddenly changes, it is judged whether the sudden change of any phase current in the three-phase current exceeds a preset threshold, if yes, the phase in which the current suddenly changes has a short-circuit fault, which is a fault phase, otherwise, it is a normal phase; It is judged whether the fault current duration of the fault phase exceeds a preset time threshold, if yes, the short-circuit fault three-phase waveform is acquired and uploaded to the master station, if not, it is not acquired; The master station analyzes the short-circuit fault three-phase waveform to determine that the fault type is a ground fault.

3. The method of claim 2, wherein, The step of "monitoring the three-phase current" comprises: setting a non-contact induction traveling wave device at a measuring point of each section of the transmission line, and the non-contact induction traveling wave device is used for monitoring the three-phase current data and the traveling wave data.

4. The method of claim 1, wherein, The step of "determining that the two ground fault points are located in the sections with opposite polarity respectively" comprises: It is judged whether the sudden change current polarity between the adjacent two nodes on the first phase line is the same; It is judged whether the sudden change current polarity between the adjacent two nodes on the second phase line is the same; It is judged whether the sudden change current polarity between the adjacent two nodes on the third phase line is the same.

5. The method of claim 4, wherein, The step of "based on the fault section, the master station performs traveling wave positioning and distance measurement according to the traveling wave data and outputs the specific position of the ground fault point" comprises: When there are two ground fault points and it is determined that the two ground fault points are located in the sections with opposite polarity respectively, the traveling wave positioning and distance measurement are performed on the two ground fault points respectively, and the positioning and distance measurement results of each ground fault point are output respectively.

6. The method of claim 5, wherein, The traveling wave data in the step of "acquiring and uploading the three-phase current data and traveling wave data of each node of the transmission line to the master station" comprises the time when the traveling wave reaches each non-contact induction traveling wave device.

7. The method of claim 6, wherein, The step of "performing the traveling wave positioning and distance measurement on the two ground fault points respectively" comprises: Supposing that the two non-contact induction traveling wave devices of the fault section where a ground fault point is located are a first non-contact induction traveling wave device and a second non-contact induction traveling wave device respectively; The time difference between the time when the first non-contact induction traveling wave device receives the traveling wave generated by the ground fault point and the time when the second non-contact induction traveling wave device receives the traveling wave is calculated; The distance between the first non-contact induction traveling wave device and the grounding fault point and the distance between the second non-contact induction traveling wave device and the grounding fault point are calculated according to the time difference and the wave speed of the traveling wave, wherein the wave speed is determined by the medium characteristics of the traveling wave propagation.

8. The method of claim 2, wherein, In the step of judging whether the mutation quantity of each phase current in the three-phase current exceeds a preset threshold, the preset threshold is 500 A.

9. A system for locating a ground fault at a point of discontinuity in a power transmission line, the system comprising: The system comprises: A data acquisition unit is configured to acquire and upload three-phase current data and traveling wave data of each node of a power transmission line to a master station when a grounding fault occurs; A positioning unit is configured to analyze the change of the three-phase current to determine a fault section by the master station in combination with line topology information; A calculation unit is configured to perform traveling wave positioning and distance measurement according to the traveling wave data and output a specific position of the grounding fault point by the master station based on the fault section.

10. A computer storage medium, characterized in that The computer storage medium stores a computer program for implementing the steps of the method in any one of claims 1 to 8.

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