Traveling wave fault location-based power grid fault location system and method

Abstract

The invention discloses a power grid fault positioning system and method based on traveling wave distance measurement, relates to the technical field of fault analysis, and solves the technical problems that traveling wave feature analysis, temperature compensation and high-precision synchronization technologies are not effectively integrated, and rapid and accurate fault positioning of a smart power grid is difficult to meet. Through the technical combination of dynamic temperature compensation, high-precision time synchronization and intelligent fault classification, the bottlenecks of traditional traveling wave distance measurement in the aspects of precision, reliability and intelligence are systematically solved, temperature sensors are deployed at key nodes of a cable, the temperature is monitored in real time, the wave speed is dynamically corrected through a formula, the overall error is reduced, and the fault location accuracy is improved. Meanwhile, an optical fiber two-way time transmission method is combined, transmission delay errors are reduced, synchronization reliability is improved, finally, a mapping library is constructed through laboratory simulation and field data, a Euclidean distance matching algorithm is combined, fault reasons are automatically recognized, and rapid positioning of the faults and accurate recognition of the fault reasons are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fault analysis, and in particular to a power grid fault location system and method based on traveling wave ranging. Background Art

[0002] The power grid fault location system is mainly used to identify and locate fault points in the power grid. It monitors the current and voltage changes of the power grid and analyzes the data to determine the specific location of the fault.

[0003] According to the patent application with publication number CN119510988A, a power grid fault location system and method based on traveling wave ranging is disclosed. By carefully tracking each instantaneous point of the signal, the fault location is made more accurate. By extracting the nonlinear eigenvalues ​​in the traveling wave signal and using data to analyze the dynamic characteristics of the fault signal, the actual impact of the fault on the stability of the power grid can be more comprehensively evaluated. The improvement of the reverse tracking signal propagation path makes the location of the fault point rely not only on theoretical data, but also on actual geographic data for verification, thereby greatly improving the accuracy of fault source location. The method of integrating signal analysis and geographic data provides a more systematic and comprehensive fault response mechanism, optimizes the maintenance operation of the power system, and significantly shortens the power supply interruption time caused by the fault.

[0004] Existing grid fault location technologies primarily rely on impedance and signal injection methods, which suffer from low positioning accuracy and significant influence from system operating modes. Traveling wave ranging technology, while already in use, faces challenges such as temperature-dependent wave velocity leading to positioning errors, insufficient multi-terminal time synchronization accuracy, and unclear mapping between complex fault types and traveling wave characteristics. Traditional solutions fail to effectively integrate traveling wave characteristic analysis, temperature compensation, and high-precision synchronization technologies, making them unable to meet the demands of smart grids for rapid and accurate fault location. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a power grid fault location system and method based on traveling wave ranging, which solves the problem that traveling wave feature analysis, temperature compensation and high-precision synchronization technology are not effectively integrated, making it difficult for smart grids to quickly and accurately locate faults.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a power grid fault location system based on traveling wave ranging, comprising: The traveling wave analysis and processing module is used to calculate the line wave velocity based on the power information transmitted by the power grid information acquisition module, analyze the impact of temperature on the line wave velocity, calculate the line wave velocity after temperature compensation, and synchronize the acquisition time using the two-way time transfer method to calculate the time deviation. Both are transmitted to the fault location analysis module; The fault location analysis module is used to calculate the fault distance based on the time deviation and line wave velocity, analyze the specific coordinates of the fault point based on the relationship between the reference point coordinates and the fault point using linear interpolation, and generate fault point information, which is then transmitted to the fault anomaly determination module and the fault location information output module. The fault anomaly determination module is used to determine the traveling wave characteristics based on the fault point information and establish a traveling wave characteristic-fault cause mapping library. The fault cause is determined by calculating the corresponding Euclidean distance between the two, and the fault cause information is generated and transmitted to the fault location information output module at the same time.

[0007] As a further solution of the present invention, it also includes a power grid information acquisition module and a fault location information output module; The power grid information acquisition module is used to collect power grid information and transmit it to the traveling wave analysis and processing module. The power grid information includes sensor information and cable material information. The fault location information output module is used to display the acquired fault point information and fault cause information to the corresponding management personnel.

[0008] As a further solution of the present invention, the specific method of calculating the line wave velocity after temperature compensation by the traveling wave analysis and processing module is: According to the formula Calculate the line wave velocity v corresponding to the power grid, where c is the speed of light and c=3×10 8 m / s, is the relative dielectric constant of the medium and depends on the insulating material; Install temperature sensors at key cable nodes to monitor the line temperature T in real time and obtain the preset temperature coefficient k. The line wave velocity v1 after temperature compensation is calculated, and T0 is the reference temperature.

[0009] As a further solution of the present invention, the specific method for the traveling wave analysis and processing module to calculate the time deviation is: In the initial stage of time synchronization, the initiator A is at time t A 1 Send a synchronization pulse with a timestamp to the receiving end B, and the receiving end B records the local time t B 1, and at t B 2: Return response pulse; Get the two-way path delay and , then according to the formula Calculate the path delay , and delay the resulting path Substitute into the formula Calculate the corresponding time deviation .

[0010] As a further solution of the present invention, the fault location analysis module calculates the fault distance according to the time deviation and the line wave velocity in the following specific manner: The obtained line wave velocity v1 and time deviation Substitute into the formula The fault distance x is calculated and the specific location of the fault point is determined in combination with the corresponding geographic information system.

[0011] As a further solution of the present invention, the specific method for the fault location analysis module to determine the specific location of the fault point in combination with the corresponding geographic information system is: Get the first reference point a (x1, y1) and the second reference point b (x2, y2), get the distance d1 between the first reference point a and the fault point, and the distance d2 between the second reference point b and the fault point, then according to the formula Calculate the longitude coordinate x0 corresponding to the fault point, and according to the formula The latitude coordinate y0 corresponding to the fault point is calculated, and the fault point information is generated and transmitted to the fault anomaly determination module.

[0012] As a further solution of the present invention, the specific manner in which the fault anomaly determination module establishes a traveling wave feature-fault cause mapping library is as follows: Various types of power grid faults are simulated in the laboratory and traveling wave signals are collected. At the same time, fault traveling wave data is recorded in real time in the actual power grid. The traveling wave amplitude, frequency, polarity and other characteristics are extracted. After filtering and normalization, the cases are classified according to the fault mechanism, and the causes are annotated based on the field results. Based on the experience summary rules, a traveling wave feature-fault cause mapping library is generated.

[0013] As a further solution of the present invention, the specific manner in which the fault abnormality determination module generates fault cause information is as follows: The traveling wave characteristics of the fault point are matched with the traveling wave characteristics-fault cause mapping library, and the Euclidean distance between the traveling wave characteristic vector of the fault point and the characteristic vectors of each fault type in the mapping library is calculated. The fault type characteristic vector with the largest Euclidean distance is selected and used as the standard to determine the fault cause. The fault cause information is generated and then transmitted to the fault location information output module.

[0014] A method for locating a power grid fault based on traveling wave ranging, the method specifically comprising the following steps: Step 1: Acquire the collected information from the traveling wave collection device, calculate the line wave velocity according to the formula, analyze the influence of temperature on the line wave velocity, and calculate the line wave velocity after temperature compensation; Step 2: Use the two-way time transfer method to synchronize the acquisition time, calculate the time deviation, and calculate the fault distance based on the line wave velocity; Step 3: According to the relationship between the reference point coordinates and the fault point, the specific coordinates of the fault point are analyzed using the linear interpolation method, and the fault point information is generated; Step 4: Determine the traveling wave characteristics based on the fault point information, and establish a traveling wave characteristic-fault cause mapping library. Determine the fault cause by calculating the Euclidean distance between the two, and generate fault cause information.

[0015] The present invention provides a system and method for locating power grid faults based on traveling wave ranging. Compared with the existing technology, it has the following advantages: The present invention systematically solves the bottlenecks of traditional traveling wave ranging in terms of accuracy, reliability and intelligence through the technical combination of dynamic temperature compensation + high-precision time synchronization + intelligent fault classification. Specifically, by deploying temperature sensors at key nodes of the cable, the temperature is monitored in real time, and the wave velocity is dynamically corrected through a formula to reduce the overall error. At the same time, the optical fiber bidirectional time transfer method is combined to reduce the transmission delay error and improve the synchronization reliability. Finally, a mapping library is constructed through laboratory simulation and field data, combined with the Euclidean distance matching algorithm, the cause of the fault is automatically identified, which not only achieves accurate identification of the cause of the fault, but also achieves rapid location of the fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a block diagram of the system principle of the present invention; Figure 2 It is a diagram of the steps of the present invention. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] Example 1 See also Figure 1 The present application provides a power grid fault location system based on traveling wave ranging, comprising: a power grid information acquisition module, a traveling wave analysis and processing module, a fault location analysis module, a fault abnormality determination module and a fault location information output module, and in combination with Figure 1 It can be known that the functional modules are electrically connected in a unidirectional manner.

[0019] The power grid information acquisition module is used to collect power grid information, where the power information includes sensor information and cable material information, and transmit the acquired power information to the traveling wave analysis and processing module.

[0020] The traveling wave analysis and processing module is used to locate and analyze the fault point of the power grid based on the obtained power information. The specific analysis method is as follows: Install high-precision traveling wave acquisition devices at both ends of the transmission line (or in the middle nodes) to record the arrival time and waveform characteristics of the traveling wave. Calculate the line wave velocity v corresponding to the power grid, where c is the speed of light and c=3×10 8 m / s, is the relative dielectric constant of the medium and depends on the insulation material, such as oil-paper insulation material The value is 3-5, and the XLPE insulation material The value is 2.3-2.5; For example, oil-paper insulation The value range is 3-5, and the value of XLPE insulation material is The value range is 2.3-2.5. Taking XLPE insulation material as an example, if Taking the value as 2.3, the line wave velocity can be obtained according to the formula = 1.98×10 8 m / s.

[0021] Next, we analyze the effect of temperature on the line wave velocity v, and use the temperature compensation algorithm to correct the line wave velocity v. The specific processing method is as follows: Temperature sensors (such as thermocouples, fiber Bragg grating sensors) are installed at key cable nodes (such as substation outlets, cable joints, and large spans) to monitor the line temperature T in real time and obtain the preset temperature coefficient k. The specific value is set by the operator and then calculated according to the formula The line wave velocity v1 after temperature compensation is calculated, and T0 is the reference temperature; For example, after testing and analysis, a certain cable line is set to have a temperature coefficient k = 0.002°C. -1 , the reference temperature T0 is 20℃, and the wave velocity v0 at the reference temperature is 1.8×10 8 m / s, when the line temperature T is 30℃ in real time monitoring, according to the formula =1.8×10 8 ×[1+0.002×(30-20)]=1.8×10 8 m / s.

[0022] At the same time, the two-way time transfer method is used to synchronize the traveling wave acquisition time, and the specific processing method is as follows: The time initiator and receiver are denoted as A and B respectively. In the initial stage of time synchronization, at a specific time t A1 sends a synchronization pulse containing a timestamp to the B end, and this timestamp accurately records the moment the pulse is sent. It is the starting mark of the entire time transfer process. The specific function of this synchronization pulse is to provide a time reference starting point for the B end so that the B end can perform time response and return operations based on this. The synchronization pulse sent by the A end needs to have certain characteristics. For example, the strength of the pulse signal must be able to resist a certain degree of attenuation and noise interference during the transmission process to ensure that the B end can accurately receive the signal and identify the timestamp information. When the B end receives the synchronization pulse sent by the A end, it will B 1 moment accurately records the local time, and the local time here reflects the state of the clock at the moment when the B end receives the signal from the A end. After that, the B end immediately records the local time at t B 2. The response pulse is sent back at the same time, and the response process of the B side requires it to have the ability to quickly and accurately record time and send back signals. To achieve this, the hardware equipment of the B side needs to have a high-precision clock module and a fast signal processing circuit. The high-precision clock module can ensure that the recorded local time is extremely accurate, while the fast signal processing circuit can ensure that the signal is processed quickly after receiving it and the response pulse is sent back, reducing the time delay error introduced during the processing process. A end at t A After receiving the response pulse from the B end at time 2, the corresponding delay calculation steps are started, assuming that the bidirectional path delay is equal. = = , and this is based on the assumption that the communication line is ideal, then according to the formula Calculate the path delay , and delay the resulting path Substitute into the formula Calculate the corresponding time deviation .

[0023] At the same time, the obtained line wave velocity v1 and time deviation Transmitted to the fault location analysis module.

[0024] Fault location analysis module, which is used to locate the fault according to the line wave speed v1 and time deviation Calculate the distance to the fault point, and the specific calculation method is as follows: The obtained line wave velocity v1 and time deviation Substitute into the formula The fault distance x is calculated, where x represents the distance from the fault point to the measurement end (usually the end on which the calculation is based). The specific location of the fault point is determined in conjunction with the corresponding geographic information system, and here the corresponding longitude and latitude coordinates are generated. The specific determination method is as follows: Get the first reference point a (x1, y1) and the second reference point b (x2, y2), and analyze the relationship between the two and the fault point. Then use the linear interpolation method to analyze the specific coordinates of the fault point, and get the distance d1 between the first reference point a and the fault point, and the distance d2 between the second reference point b and the fault point. Then according to the formula Calculate the longitude coordinate x0 corresponding to the fault point, and according to the formula The latitude coordinate y0 corresponding to the fault point is calculated, and the longitude and latitude coordinates (x0, y0) corresponding to the fault point are further obtained, and the fault point information is generated. At the same time, the generated fault point information is transmitted to the fault anomaly determination module.

[0025] For example, suppose that after temperature compensation, the wave velocity of a cable line is v1=1.8×10 8 m / s, and the time difference t at which the traveling wave reaches both ends is determined by the two-way time transfer method. B -t A =0.0001s, synchronization error compensation value 0.00001s, signal transmission delay (path delay) The fault distance x is 0.00002s. Substituting the above parameters into the formula, the fault distance x is 11700m. The longitude and latitude coordinates of the first reference point a are known to be (116.38, 39.90), and the longitude and latitude coordinates of the second reference point b are known to be (116.40, 39.92). Using traveling wave ranging and other methods, the distance between the first reference point a and the fault point is determined to be d1 = 200m, and the distance between the second reference point b and the fault point is d2 = 300m. The longitude coordinate of the fault point is calculated according to the formula, and the result is x0 = 116.388. Similarly, the latitude coordinate y0 = 39.908 is calculated. Therefore, the longitude and latitude coordinates corresponding to the fault point are (116.388, 39.908).

[0026] The fault anomaly determination module is used to analyze the acquired fault point information, obtain the traveling wave characteristics corresponding to the fault point, and the traveling wave characteristics specifically refer to the amplitude, frequency, and polarity characteristics of the corresponding traveling wave, and establish the corresponding traveling wave characteristic-fault cause mapping library. The specific establishment method is as follows: A power system simulation platform was built in the laboratory to simulate various grid faults, such as single-phase grounding, phase-to-phase short circuits, and line breaks. Different fault conditions, including fault location, transition resistance, and fault time, were set to collect traveling wave signals on the line when the fault occurred. For example, the transition resistance value of a short-circuit fault was changed (from low resistance to high resistance), and the corresponding characteristic data such as the traveling wave amplitude, frequency, and polarity were recorded. Simultaneously, in the actual power grid, traveling wave monitoring devices installed at key nodes of substations and transmission lines were used to record traveling wave data in real time when the fault occurred. Then, the maximum amplitude and amplitude change rate of the traveling wave are extracted, and the spectrum of the traveling wave signal is obtained through methods such as Fourier transform and wavelet transform. The main frequency components and the proportion of high-frequency components are determined, and the polarity of the initial wave head of the traveling wave and the change of the polarity of the traveling wave during propagation are recorded. The collected traveling wave data is filtered to remove noise interference, and methods such as wavelet noise reduction and median filtering can be used. At the same time, the data is normalized. The collected fault cases are classified according to the physical process and mechanism of the fault, such as insulation faults (including faults caused by equipment insulation aging and moisture), overcurrent faults (caused by short circuits and overloads), lightning strike faults, and external force damage faults (such as trees falling on power lines). For each set of traveling wave data, the corresponding fault cause is accurately labeled based on the fault site inspection results and relay protection action information. Based on existing power system knowledge and experience, the rules between traveling wave characteristics and fault causes are summarized to generate a traveling wave feature-fault cause mapping library. The traveling wave characteristics of the fault point are matched with the traveling wave characteristics-fault cause mapping library, and the matching here is achieved by calculating the Euclidean distance between the traveling wave characteristic vector of the fault point and the characteristic vector of each fault type in the mapping library. The closer the distance, the higher the similarity. For example, assuming that the traveling wave characteristic vector of the fault point is A = [a1, a2, ..., a n ], the characteristic vector of a certain fault type in the mapping library is A = [b1, b2, ..., b n ], then the Euclidean distance , and screen and determine the fault cause according to the obtained Euclidean distance d, determine the fault cause corresponding to the fault point, and generate fault cause information at the same time, and transmit it to the fault location information output module.

[0027] The fault location information output module is used to display the acquired fault point information and fault cause information to the corresponding management personnel.

[0028] Example 2 Refer to 2. This application provides a power grid fault location method based on traveling wave ranging, which specifically includes the following steps: Step 1: Acquire the collected information from the traveling wave collection device, calculate the line wave velocity according to the formula, analyze the influence of temperature on the line wave velocity, and calculate the line wave velocity after temperature compensation. The specific processing method is the same as that of the traveling wave analysis and processing module in Example 1; Step 2: Synchronize the acquisition time using a two-way time transfer method to calculate the time deviation, and calculate the fault distance based on the line wave velocity. The specific processing method is the same as that of the traveling wave analysis and processing module in Example 1. Step 3: According to the relationship between the reference point coordinates and the fault point, the specific coordinates of the fault point are analyzed using linear interpolation, and the fault point information is generated. The specific processing method is the same as that of the fault location analysis module in Example 1. Step 4: Determine the traveling wave characteristics based on the fault point information, and establish a traveling wave characteristic-fault cause mapping library. Determine the fault cause by calculating the corresponding Euclidean distance between the two, and generate fault cause information. The processing method here is similar to the fault abnormality determination module in Example 1.

[0029] Some of the data in the above formulas are calculated based on their numerical values ​​and are not substituted into parameter units for calculation. At the same time, the contents not described in detail in this specification belong to the existing technology known to those skilled in the art.

[0030] The above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A power grid fault location system based on traveling wave ranging, characterized in that: include: The traveling wave analysis and processing module is used to calculate the line wave velocity based on the power information transmitted by the power grid information acquisition module, analyze the impact of temperature on the line wave velocity, calculate the line wave velocity after temperature compensation, and synchronize the acquisition time using the two-way time transfer method to calculate the time deviation. Both are transmitted to the fault location analysis module; The fault location analysis module is used to calculate the fault distance based on the time deviation and line wave velocity, analyze the specific coordinates of the fault point based on the relationship between the reference point coordinates and the fault point using linear interpolation, and generate fault point information, which is then transmitted to the fault anomaly determination module and the fault location information output module. The fault anomaly determination module is used to determine the traveling wave characteristics based on the fault point information and establish a traveling wave characteristic-fault cause mapping library. The fault cause is determined by calculating the corresponding Euclidean distance between the two, and the fault cause information is generated and transmitted to the fault location information output module at the same time.

2. A power grid fault location system based on traveling wave ranging according to claim 1, characterized in that: It also includes a power grid information acquisition module and a fault location information output module; The power grid information acquisition module is used to collect power grid information and transmit it to the traveling wave analysis and processing module. The power grid information includes sensor information and cable material information. The fault location information output module is used to display the acquired fault point information and fault cause information to the corresponding management personnel.

3. The power grid fault location system based on traveling wave ranging according to claim 1, characterized in that: The specific method for the traveling wave analysis and processing module to calculate the line wave velocity after temperature compensation is: According to the formula Calculate the line wave velocity v corresponding to the power grid, where c is the speed of light and c=3×10 8 m / s, is the relative dielectric constant of the medium and depends on the insulating material; Install temperature sensors at key cable nodes to monitor the line temperature T in real time and obtain the preset temperature coefficient k. The line wave velocity v1 after temperature compensation is calculated, and T0 is the reference temperature.

4. The power grid fault location system based on traveling wave ranging according to claim 1, characterized in that: The specific method for the traveling wave analysis and processing module to calculate the time deviation is: In the initial stage of time synchronization, the initiator A is at time t A 1 Send a synchronization pulse with a timestamp to the receiving end B, and the receiving end B records the local time t B 1, and at t B 2: Return response pulse; Get the two-way path delay and , then according to the formula Calculate the path delay , and delay the resulting path Substitute into the formula Calculate the corresponding time deviation .

5. The power grid fault location system based on traveling wave ranging according to claim 1, characterized in that: The specific method in which the fault location analysis module calculates the fault distance based on the time deviation and the line wave velocity is: The obtained line wave velocity v1 and time deviation Substitute into the formula The fault distance x is calculated and the specific location of the fault point is determined in combination with the corresponding geographic information system.

6. A power grid fault location system based on traveling wave ranging according to claim 5, characterized in that: The specific method for the fault location analysis module to determine the specific location of the fault point in combination with the corresponding geographic information system is: Get the first reference point a (x1, y1) and the second reference point b (x2, y2), get the distance d1 between the first reference point a and the fault point, and the distance d2 between the second reference point b and the fault point, then according to the formula Calculate the longitude coordinate x0 corresponding to the fault point, and according to the formula The latitude coordinate y0 corresponding to the fault point is calculated, and the fault point information is generated and transmitted to the fault anomaly determination module.

7. The power grid fault location system based on traveling wave ranging according to claim 1, characterized in that: The specific method for the fault anomaly determination module to establish the traveling wave feature-fault cause mapping library is as follows: Various types of power grid faults are simulated in the laboratory and traveling wave signals are collected. At the same time, fault traveling wave data is recorded in real time in the actual power grid. The traveling wave amplitude, frequency, polarity and other characteristics are extracted. After filtering and normalization, the cases are classified according to the fault mechanism, and the causes are annotated based on the field results. Based on the experience summary rules, a traveling wave feature-fault cause mapping library is generated.

8. The power grid fault location system based on traveling wave ranging according to claim 1, characterized in that: The specific method for the fault abnormality determination module to generate fault cause information is as follows: The traveling wave characteristics of the fault point are matched with the traveling wave characteristics-fault cause mapping library, and the Euclidean distance between the traveling wave characteristic vector of the fault point and the characteristic vectors of each fault type in the mapping library is calculated. The fault type characteristic vector with the largest Euclidean distance is selected and used as the standard to determine the fault cause. The fault cause information is generated and then transmitted to the fault location information output module.

9. A method for locating a power grid fault based on traveling wave ranging, performed by the power grid fault locating system according to any one of claims 1 to 8, characterized in that: The method specifically comprises the following steps: Step 1: Acquire the collected information from the traveling wave collection device, calculate the line wave velocity according to the formula, analyze the influence of temperature on the line wave velocity, and calculate the line wave velocity after temperature compensation; Step 2: Use the two-way time transfer method to synchronize the acquisition time, calculate the time deviation, and calculate the fault distance based on the line wave velocity; Step 3: According to the relationship between the reference point coordinates and the fault point, the specific coordinates of the fault point are analyzed using the linear interpolation method, and the fault point information is generated; Step 4: Determine the traveling wave characteristics based on the fault point information, and establish a traveling wave characteristic-fault cause mapping library. Determine the fault cause by calculating the Euclidean distance between the two, and generate fault cause information.

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