Electric power line fault distance measurement system and method

Abstract

The invention provides a power line fault distance measurement system and method, and belongs to the technical field of power line detection. The system comprises monitoring terminals deployed at two ends of a line and a background processing system, and each monitoring terminal comprises a sensor module used for detecting a traveling wave current signal related to a power line fault in the line; the data acquisition module is used for extracting the arrival time of a traveling wave head according to the detected traveling wave current signal; the GPS time synchronization module is used for adjusting the local clock of the data acquisition module, reducing the time synchronization error of the two monitoring terminals and correcting the arrival time of the traveling wave head; and the background processing system is used for calculating a traveling wave time difference and a junction wave velocity normalization processing result according to the corrected arrival time at the two ends of the line, and determining a fault position coordinate and a fault type. According to the invention, collaborative optimization of fault positioning precision and type identification in a hybrid power line environment is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power line detection, and specifically to a power line fault location system and method. Background Art

[0002] Power line fault location technology is one of the core technologies to ensure the safe operation of the power grid. Existing technologies mainly rely on the traveling wave propagation principle to locate faults by detecting the time difference of the transient traveling wave signals generated by faults reaching both ends of the line. A typical double - end traveling wave ranging system relies on high - precision time synchronization devices and line wave velocity parameters for distance calculation, and has achieved certain application effects in scenarios where the wave velocity is continuous, such as overhead lines. With the increase in the cable rate of urban power grids, transmission lines mostly show the characteristics of mixed overhead and cable erection. The difference in the propagation speed of traveling waves in different media can reach more than 30%, which poses new challenges to traditional ranging models.

[0003] The existing technologies have the following main defects: First, the discontinuous wave velocity of the mixed line causes systematic errors in traditional ranging models and cannot directly apply a single wave velocity parameter for calculation; second, the GPS time synchronization module is easily affected by environmental temperature changes, and the time synchronization error often exceeds 50 ns, directly affecting the time scale accuracy of micro - second - level traveling wave signals; third, the consistency of existing sensor components is insufficient, resulting in time - delay differences in signal acquisition at multiple monitoring points; finally, traditional methods lack the intelligent discrimination ability for fault types and are difficult to distinguish lightning over - voltage from real short - circuit faults, affecting the efficiency of operation and maintenance decision - making. Summary of the Invention

[0004] The present invention provides a power line fault location system and method to solve problems such as large errors and inability to identify fault types in the existing technologies.

[0005] To achieve the above object, an embodiment of the present invention provides a power line fault location system, including monitoring terminals deployed at both ends of the line and a background processing system. The monitoring terminal includes: a sensor module for detecting the traveling wave current signal related to the power line fault in the line; a data acquisition module for extracting the arrival time of the traveling wave head according to the detected traveling wave current signal; a GPS time synchronization module for adjusting the local clock of the data acquisition module, reducing the time synchronization error between the two monitoring terminals, and correcting the arrival time of the traveling wave head; the background processing system is used to calculate the traveling wave time difference according to the corrected arrival times at both ends of the line, and determine the fault location coordinates and fault type based on the wave velocity normalization processing result.

[0006] Optionally, the GPS time synchronization module is configured with a temperature-compensated crystal oscillator and a programmable logic device. The GPS time synchronization module is configured to: receive the second pulse signal sent by the GPS satellite through the programmable logic device, and synchronize the signal with the local clock of the data acquisition module to eliminate the phase deviation; when the absolute value of the time deviation between the local clock and the GPS second pulse exceeds a preset value, send a frequency adjustment instruction to the temperature-compensated crystal oscillator to reduce the time synchronization error between the two monitoring terminals.

[0007] Optionally, the background processing system includes: a data fusion unit, configured to receive the arrival times after the traveling wave heads at both ends of the line are corrected, verify the validity of the arrival times, and calculate the time difference; a wave velocity normalization calculation unit, configured to generate an equivalent wave velocity for the entire line according to the difference between the actual wave velocity of the cable section and the standard wave velocity of the overhead section; and a fault location unit, configured to calculate the fault distance based on the generated equivalent wave velocity for the entire line and the calculated time difference to locate the fault coordinates.

[0008] Optionally, the wave velocity normalization calculation unit is configured to: based on the preset calibration parameters of the cable section, convert the actual length of the cable section into an equivalent overhead line length according to the proportional relationship between the reference wave velocity and the actual wave velocity of the cable; merge the converted equivalent overhead line length with the original overhead line section to construct a line model with a continuous and consistent equivalent wave velocity; and generate the equivalent wave velocity for the entire line according to the line model.

[0009] Optionally, the sensor module is further configured to detect the zero-sequence current signal and the power frequency current signal in the line. The fault location unit includes: a lightning strike identification subunit, configured to detect the steep change characteristic of the traveling wave head according to the traveling wave current signal; a short-circuit identification subunit, configured to detect the consistency of the power frequency currents at both ends of the line according to the power frequency current signal; and a ground fault identification subunit, configured to detect the waveform characteristic of the zero-sequence current according to the zero-sequence current signal.

[0010] Optionally, the fault location unit is further configured to determine the fault type. The determination of the fault type includes: if it is detected that the voltage rises by more than a first preset value within a first preset time for the traveling wave head, determining that the fault type is a lightning strike fault; if the difference in the amplitudes of the power frequency currents at both ends of the line is greater than a second preset value and the duration exceeds a second preset time, determining that the fault type is a phase-to-phase short-circuit fault; and if the zero-sequence current shows an oscillating and decaying waveform and the duration exceeds a third preset time, determining that the fault type is a single-phase ground fault.

[0011] Optionally, the power line fault location system further includes a wireless communication module for transmitting the arrival time to the background processing system. The wireless communication module is configured to: establish a data transmission link with the background processing system through the GPRS network when the GPRS signal strength reaches a preset threshold; when the GPRS signal strength does not reach the preset threshold, adopt a wireless relay transmission mode in a specific frequency band and relay and forward data through adjacent monitoring terminals.

[0012] Optionally, the background processing system is further configured to: integrate the fault location coordinates, fault type, and fault time into a structured data packet and send a warning message.

[0013] On the other hand, a power line fault location method is also provided, which is applied to the background processing system in the above power line fault location system. The power line fault location method includes: obtaining the arrival times of the traveling wave heads at both ends of the line and calculating the time difference; calculating the equivalent overhead line length and the overall line equivalent wave velocity based on the preset cable section calibration parameters; determining the fault distance according to the calculated time difference, equivalent overhead line length, and overall line equivalent wave velocity.

[0014] Optionally, the power line fault location method further includes: determining the fault type according to the traveling wave steepness change rate, power frequency current amplitude difference, and zero-sequence waveform characteristics. The fault types include lightning strike faults, phase-to-phase short circuit faults, and single-phase ground faults.

[0015] A power line fault location system and method provided by the present invention. The present invention effectively eliminates the influence of the wave velocity difference between overhead lines and cable hybrid lines by establishing an equivalent line wave velocity normalization model; integrates a temperature-compensated crystal oscillator and an adaptive clock calibration technology, significantly reduces the sensitivity of the time synchronization system to environmental interference, and ensures the time scale accuracy of traveling wave signals; constructs a multi-dimensional fault feature criterion system by fusing traveling wave steepness features, power frequency current differential analysis, and zero-sequence current morphology recognition technology to achieve accurate classification of lightning strike, short circuit, and ground faults. The present invention significantly improves the fault location accuracy in complex line scenarios, while enhancing the fault type diagnosis ability and system environmental adaptability. Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings: Figure 1 is a structural diagram of a power line fault location system provided by an embodiment of the present invention; Figure 2 is the GPS time synchronization process provided by the embodiments of the present invention; Figure 3 is the fault type identification process provided by the embodiments of the present invention; Figure 4 is the flowchart of a method for fault location of power lines provided by the embodiments of the present invention; Figure 5 is the flowchart of a fault location system for power lines provided by the embodiments of the present invention. Detailed implementation manners

[0017] The following will describe in detail the specific implementation manners of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0018] It should be noted that the acquisition, transmission, storage, use, processing, etc. of data in the technical solutions of this application all comply with the relevant regulations of national laws and regulations. In the embodiments of this application, some industry-existing solutions such as certain software, components, models, etc. may be mentioned, and they should be regarded as exemplary. The purpose is only to illustrate the feasibility in the implementation of the technical solutions of this application, but it does not mean that the applicant has already or necessarily used this solution.

[0019] In the power industry, the stable operation of power lines is crucial. At present, power line faults occur frequently. Once a fault occurs, it will seriously affect the normal operation of key fields such as railway operations, causing huge economic losses and social impacts. There are many defects in traditional fault location technologies. For lines mixed with overhead lines and cables, due to the inconsistent wave impedances of cables and overhead lines, the wave velocity is discontinuous, making it difficult to accurately establish a unified model, resulting in large fault location errors and unable to meet actual needs. Therefore, it is particularly important to develop a more accurate power line fault location system.

[0020] In response to this problem, the present invention provides a power line fault location system and method. The present invention adopts the principle of double-ended traveling wave ranging technology. By coupling and injecting pulsed current on the cable and installing segmented calibration equipment along the line to achieve cable length calibration, and using the velocity normalization algorithm based on equivalent lines to optimize the problem of discontinuous wave velocity, the fault location accuracy is significantly improved. At the same time, it is equipped with a high-precision GPS clock time synchronization system to ensure accurate and timely signal detection.

[0021] The following will combine with Figures 1 - 5 Specifically describe the present invention.

[0022] Embodiment 1: As Figure 1As shown in the figure, an embodiment of the present invention provides a power line fault location system, which includes monitoring terminals deployed at both ends of the line and a background processing system. The monitoring terminal includes: a sensor module for detecting a traveling wave current signal related to a power line fault in the line; a data acquisition module for extracting the arrival time of the traveling wave head according to the detected traveling wave current signal; a GPS time synchronization module for adjusting the local clock of the data acquisition module, reducing the time synchronization error between the two monitoring terminals, and correcting the arrival time of the traveling wave head; the background processing system is used to calculate the traveling wave time difference according to the corrected arrival times at both ends of the line, and determine the fault location coordinates and fault type based on the wave velocity normalization processing result.

[0023] The power line fault location system provided by the present invention forms a closed-loop fault location logic through the cooperation of the monitoring terminals deployed at both ends of the line and the background system. Among them, the sensor module detects the traveling wave current signal, the data acquisition module extracts the arrival time of the wave head, the GPS time synchronization module realizes multi-terminal clock synchronization and timestamp correction, and the background system calculates the fault coordinates based on the corrected time difference and the wave velocity normalization model. Precise positioning of the fault point can be achieved.

[0024] As Figure 2 shown, preferably, the GPS time synchronization module is configured with a temperature-compensated crystal oscillator and a programmable logic device. The GPS time synchronization module is configured to: through the programmable logic device, receive the second pulse signal sent by the GPS satellite and synchronize the signal with the local clock of the data acquisition module to eliminate the phase deviation; when the absolute value of the time deviation between the local clock and the GPS second pulse exceeds a preset value, send a frequency adjustment instruction to the temperature-compensated crystal oscillator to reduce the time synchronization error between the two monitoring terminals.

[0025] In a preferred embodiment of the present invention, a cooperative control mechanism of a temperature-compensated crystal oscillator and a programmable logic device is integrated in the GPS time synchronization module: the programmable logic device receives the GPS satellite second pulse signal in real time, and aligns the local clock phase of the data acquisition module with the satellite clock at the nanosecond level; when it is detected that the cumulative deviation between the local clock and the satellite time exceeds a preset threshold, the frequency adjustment function of the temperature-compensated crystal oscillator is automatically triggered to dynamically compensate for the crystal oscillator frequency drift caused by environmental temperature changes, forming a double-closed-loop control structure of "satellite reference calibration - crystal oscillator dynamic compensation". Through the deep coupling of hardware and logical control, this solution greatly reduces the time synchronization error, breaks through the accuracy bottleneck of traditional single GPS time synchronization affected by temperature drift; establishes an active correction mechanism for abnormal deviations, avoids error accumulation caused by short-term signal loss, and improves the robustness of the system in complex environments (such as tunnels, mountains); provides a highly reliable time reference for accurately calibrating the arrival time of the traveling wave head, forms a technical collaboration with the wave velocity normalization model, jointly supports the sub-microsecond time difference calculation requirement, and greatly reduces the hybrid line positioning error.

[0026] For example, in the scenario of transmission line monitoring, when the environmental temperature suddenly rises by 15°C, causing a +8ppm frequency offset of the local crystal oscillator at the monitoring terminal A, its GPS time synchronization module activates the dynamic compensation mechanism: the programmable logic device detects in real time that the phase deviation between the local clock and the GPS second pulse reaches 60ns (exceeding the preset threshold, for example, 50ns), and immediately sends a frequency adjustment command to the temperature-compensated crystal oscillator, and adjusts the crystal oscillator control voltage to make its output frequency corrected from the initial 10MHz to 10.00008MHz. After 3 synchronous cycles (each cycle is 30 seconds) of iterative calibration, the time synchronization error between the monitoring terminals A and B is reduced from the initial 85ns to 18ns, effectively ensuring the detection accuracy of the arrival time difference of the traveling wave head (for example, Δt = 127μs), and making the subsequent fault location calculation error controlled within the 15-meter range required for the cable section, verifying the improvement effect of the temperature compensation and dynamic frequency adjustment mechanism on the reliability of the time reference in complex environments.

[0027] Preferably, the background processing system includes: a data fusion unit for receiving the corrected arrival times of the traveling wave heads at both ends of the line, verifying the validity of the arrival times and calculating the time difference; a wave velocity normalization calculation unit for generating an equivalent wave velocity for the entire line according to the difference between the actual wave velocity of the cable section and the standard wave velocity of the overhead section; a fault location unit for calculating the fault distance based on the generated equivalent wave velocity for the entire line and the calculated time difference to locate the fault coordinates.

[0028] Further preferably, the wave velocity normalization calculation unit is configured to: based on preset cable segment calibration parameters, convert the actual length of the cable segment into an equivalent overhead line length according to the proportional relationship between the reference wave velocity and the actual wave velocity of the cable; merge the converted equivalent overhead line length with the original overhead line segment to construct a line model with a continuous and consistent equivalent wave velocity; and generate the equivalent wave velocity of the entire line according to the line model.

[0029] In a preferred embodiment of the present invention, the equivalent overhead line length The equivalent expression is: (1) in, Indicates the standard wave speed of overhead lines, Indicates the measured wave velocity of the cable segment, Indicates the actual physical length of the cable. The coordinates of the fault location can be expressed as: (2) in, Indicates the equivalent overhead line distance from the fault point to the monitoring terminal, Indicates the total length of the equivalent overhead line (actual length of overhead line + equivalent overhead line length), It represents the arrival time difference of the traveling wave heads at both ends.

[0030] When the system locates the fault, the data fusion unit first verifies the validity of the arrival time of the traveling wave heads at both ends (such as eliminating abnormal timestamps caused by signal distortion). Then, the wave velocity normalization calculation unit converts the actual length of the cable segment into the equivalent overhead line length according to the proportional relationship between the reference wave velocity and the actual wave velocity based on the preset cable calibration parameters (for example, the actual cable length is 20 km and the wave velocity is 1.5×10 8 m / s, converted to an equivalent overhead line length of 37.33km), after merging the original overhead line segment, an equivalent model of the entire line with continuous wave velocity is formed. Finally, the fault location unit calculates the fault distance based on the total length of the equivalent model and the corrected time difference. The technical coupling between the two is reflected in the following aspects: the data fusion unit provides verified and reliable time difference data for wave velocity normalization, while the wave velocity normalization calculation unit eliminates the interference of the cable-overhead line wave velocity jump on the traditional two-end distance measurement formula by constructing an equivalent wave velocity continuous model, so that the calculation result of the fault location unit accurately corresponds to the actual position of the physical line.

[0031] like Figure 3As shown, preferably, the sensor module is further configured to detect zero-sequence current signals and power-frequency current signals in the line. The fault location unit includes: a lightning strike identification subunit, configured to detect the steep change characteristics of the wavefront of the traveling wave current signal according to the traveling wave current signal; a short-circuit identification subunit, configured to detect the consistency of the power-frequency currents at both ends of the line according to the power-frequency current signal; and a ground fault identification subunit, configured to detect the waveform characteristics of the zero-sequence current according to the zero-sequence current signal.

[0032] More preferably, the fault location unit is further configured to determine the fault type. The determination of the fault type includes: if it is detected that the voltage rise of the wavefront of the traveling wave exceeds a first preset value within a first preset time, determining that the fault type is a lightning strike fault; if the difference in the magnitudes of the power-frequency currents at both ends of the line is greater than a second preset value and the duration exceeds a second preset time, determining that the fault type is an interphase short-circuit fault; if the zero-sequence current appears as an oscillating and decaying waveform and the duration exceeds a third preset time, determining that the fault type is a single-phase ground fault.

[0033] In a preferred embodiment of the present invention, the system separately sets up three dedicated identification subunits for lightning strike, short circuit, and ground fault, and respectively establishes independent analysis paths for the steep change characteristics of the traveling wavefront (lightning strike), the differential characteristics of the power-frequency current (short circuit), and the waveform pattern of the zero-sequence current (ground fault), forming a hierarchical determination framework. The traveling wave channel sets a voltage rise rate threshold and a time window, the power-frequency channel configures a current magnitude difference threshold and a duration condition, and the zero-sequence channel establishes a criterion based on the waveform oscillation frequency and the number of decay cycles. After each channel processes the signal characteristics in parallel, through sequential correlation analysis and spatial consistency verification, the final comprehensive fault type determination result is output. This design effectively distinguishes real faults from electromagnetic interference through the collaborative analysis of multiple physical quantities (traveling wave / power frequency / zero sequence) and multiple dimensions (magnitude / time / waveform).

[0034] For example, in a scenario where a hybrid transmission line is struck by lightning and a single-phase grounding fault occurs, the sensor module of the system detects the traveling wave current signal, zero-sequence current signal, and power frequency current signal in the line in real time. When a fault occurs, the lightning strike recognition sub-unit quickly analyzes the traveling wave current signal. If it is detected that the voltage of the traveling wave head rises sharply within an extremely short 0.001 seconds (the first preset time) and exceeds 1000 volts (the first preset value), the system immediately determines that the fault type is a lightning strike fault. At the same time, the short-circuit recognition sub-unit detects the power frequency current signals at both ends of the line. If it is found that the amplitude difference of the power frequency currents at both ends is as high as 50% (greater than the second preset value) and this difference lasts for 0.1 seconds (exceeds the second preset time), it is determined as an interphase short-circuit fault. When the grounding recognition sub-unit detects the zero-sequence current signal, if it observes that the zero-sequence current presents a typical oscillating and decaying waveform and this waveform lasts for 0.2 seconds (exceeds the third preset time), it accurately determines that this fault is a single-phase grounding fault, and then through the collaborative work of the entire system, the accurate positioning and handling of the fault point are achieved.

[0035] Preferably, the power line fault location system further includes a wireless communication module for transmitting the arrival time to the background processing system. The wireless communication module is configured as follows: when the GPRS signal strength reaches a preset threshold, a data transmission link is established with the background processing system through the GPRS network; when the GPRS signal strength does not reach the preset threshold, a wireless relay transmission mode of a specific frequency band is adopted, and data is relayed and forwarded by adjacent monitoring terminals.

[0036] In a preferred embodiment of the present invention, an adaptive wireless communication mechanism is provided. By integrating a multi-mode communication module (GPRS / wireless relay) in the monitoring terminal, the problem of data transmission in complex terrains is solved: when the monitoring terminal detects that the GPRS signal strength is lower than the preset threshold (for example, -90dBm), it automatically switches to the wireless relay mode of a specific frequency band (for example, 470MHz), searches for adjacent terminals and establishes a multi-hop transmission link, and relays and forwards the fault data through intermediate nodes to the area with GPRS signals and then uploads it to the background system. The technical advantage of this mechanism is that through dynamic signal strength perception and adaptive switching of the transmission mode, reliable data return in signal blind areas (such as tunnels and mountains) is ensured; it works in coordination with the GPS time synchronization module, and a timestamp check is embedded during the relay forwarding process to prevent the data transmission delay from affecting the fault location accuracy.

[0037] Preferably, the background processing system is further configured to: integrate the fault location coordinates, fault type, and fault time into a structured data packet and send a warning message.

[0038] In a preferred embodiment of the present invention, the system encapsulates the fault location coordinates, fault type, fault occurrence time, and associated waveform feature index values into a standardized data packet, and automatically selects the GPRS / CDMA or SMS channel to send a warning message based on the communication module status, significantly improving the emergency response efficiency for power grid faults.

[0039] As Figure 4 shown, an embodiment of the present invention also provides a power line fault location method, which is applied to the background processing system in the above-mentioned power line fault location system. The power line fault location method includes: S101: Obtain the arrival times of the traveling wave fronts at both ends of the line and calculate the time difference; S102: Calculate the equivalent overhead line length and the full-line equivalent wave velocity based on the preset cable section calibration parameters; S103: Determine the fault distance according to the calculated time difference, equivalent overhead line length, and full-line equivalent wave velocity.

[0040] Preferably, the power line fault location method further includes: determining the fault type according to the traveling wave steepness change rate, power frequency current amplitude difference, and zero-sequence waveform characteristics. The fault types include lightning strike faults, phase-to-phase short circuit faults, and single-phase ground faults.

[0041] The power line fault location method provided by the embodiment of the present invention realizes the efficient positioning of the hybrid line through a double-end collaborative data processing process: First, obtain the time difference of the arrival times of the traveling wave fronts at both ends of the line after time synchronization calibration, and combine the preset wave velocity parameters of the cable section to convert the actual length of the cable into the equivalent overhead line length according to the reference wave velocity. After constructing a continuous wave velocity model for the entire line, calculate the fault point coordinates based on the equivalent wave velocity and the time difference; at the same time, this method forms a three-level diagnostic logic for the fault type by synchronously analyzing the traveling wave steepness change rate, power frequency current amplitude difference, and zero-sequence current oscillation attenuation waveform through a multi-dimensional feature fusion mechanism.

[0042] Embodiment 2: As Figure 5 shown, based on the same inventive concept, when a power line fault location and method provided by the present invention is applied to a certain hybrid transmission line, the complete operation process of the system is as follows: The fault point is located at a cable 15.2 km away from the monitoring terminal at end A. The traveling wave current generated instantaneously during the fault is at 1.5×10 8The m / s wave velocity propagates towards both ends. The sensor module at end A captures the traveling wave signal at 10:05:23.000150 (UTC). Due to electromagnetic environment interference at end B, there is a 120 ns deviation in the initial detection time. The GPS time synchronization module corrects the clock error at end B to 18 ns through dynamic compensation of the temperature-compensated crystal oscillator. After correction, the arrival times of the wavefronts at ends A and B are 10:05:23.000152 and 10:05:23.000372 respectively. After the background system verifies the time validity, it calculates the time difference Δt = 220 μs. The wave velocity normalization unit converts the cable section to an equivalent overhead line length of 37.3 km according to the reference wave velocity of 2.8×10 8 m / s, constructs a continuous wave velocity model with an equivalent total length of 117.3 km, and substitutes it into the formula to calculate the equivalent fault location of 34.8 km. Since this value exceeds the overhead line segment (80 km), the actual cable location is inverted to be (34.8 - 80)×(20 / 37.3) = 14.9 km, and the positioning error is only 0.3 km (<15 m requirement). Synchronously, the fault identification module detects that the zero-sequence current shows a 58 Hz decaying oscillation (lasting for 6 cycles), the power frequency differential value is 12% (not reaching the short-circuit threshold), and the traveling wave steepness rate is 4.8 kV / μs (lower than the lightning strike threshold). It is comprehensively determined to be a pure single-phase ground fault. Finally, the positioning coordinates (cable 14.9 km), fault type code (F02), and UTC timestamp are encapsulated into a 2 KB compressed message and transmitted redundantly through GPRS (signal strength at end B - 88 dBm) and satellite dual channels. The operation and maintenance personnel receive the warning message 1.2 seconds after the fault. After verification by drone inspection, the actual fault point is located at 15.1 km of the cable, verifying the reliability of the entire process from signal acquisition, clock synchronization, wave velocity conversion to intelligent diagnosis.

[0043] In summary, a power line fault location and method provided by the present invention effectively solves the problem of discontinuous wave velocity of the overhead line and cable hybrid line by constructing an equivalent line wave velocity normalization model. Combining a high-precision temperature compensation clock synchronization system and a multi-dimensional fault feature fusion criterion, it realizes the collaborative optimization of fault location accuracy and type recognition ability in a complex line environment. At the same time, the innovative intelligent hierarchical communication mechanism dynamically adapts to different network conditions to ensure reliable data transmission, and the structured warning output and historical data archiving functions form a closed-loop management from fault perception, analysis to response, comprehensively improving the environmental adaptability, positioning reliability and operation and maintenance decision-making efficiency of the power line fault monitoring system.

[0044] It should be understood that in various embodiments of the present invention, the magnitude of the sequence numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0045] In addition, the terms "system" and "network" in this document are often used interchangeably herein. The term "and / or" in this document is merely a description of the associated relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally represents an "or" relationship between the associated objects before and after.

[0046] It should be understood that in the embodiments of the present invention, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0047] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this document can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0048] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0049] In several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or communication connection to each other can be an indirect coupling or communication connection through some interfaces, devices, or units, and can also be an electrical, mechanical, or other form of connection.

[0050] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present invention.

[0051] In addition, in each embodiment of the present invention, each functional unit can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0052] Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or by firmware, or by a combination thereof. When implemented in software, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. A computer-readable medium includes a computer storage medium and a communication medium, where the communication medium includes any medium that facilitates the transfer of a computer program from one place to another. The storage medium can be any available medium that can be accessed by a computer. By way of example but not limitation: a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection can be appropriately made a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, wireless and microwave are included in the definition of the medium. As used in the present invention, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disk generally magnetically replicates data, while disc optically replicates data using a laser. The above combinations should also be included within the scope of protection of computer-readable media.

[0053] In summary, the above description is only a preferred embodiment of the technical solution of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A power line fault location system, characterized in that, It includes monitoring terminals deployed at both ends of the line and a background processing system. The monitoring terminal includes: A sensor module for detecting the traveling wave current signal related to the power line fault in the line; A data acquisition module for extracting the arrival time of the traveling wave head according to the detected traveling wave current signal; A GPS time synchronization module for adjusting the local clock of the data acquisition module, reducing the time synchronization error between the two monitoring terminals, and correcting the arrival time of the traveling wave head; The background processing system is used to calculate the traveling wave time difference according to the corrected arrival times at both ends of the line, and determine the fault location coordinates and fault type based on the wave velocity normalization processing result.

2. The power line fault location system according to claim 1, wherein The GPS time synchronization module is configured with a temperature-compensated crystal oscillator and a programmable logic device, and the GPS time synchronization module is configured as: Receiving the second pulse signal sent by the GPS satellite through the programmable logic device and synchronizing the signal with the local clock of the data acquisition module to eliminate the phase deviation; When the absolute value of the time deviation between the local clock and the GPS second pulse exceeds a preset value, sending a frequency adjustment instruction to the temperature-compensated crystal oscillator to reduce the time synchronization error between the two monitoring terminals.

3. The power line fault location system according to claim 1, characterized in that, The background processing system includes: A data fusion unit for receiving the corrected arrival times of the traveling wave heads at both ends of the line, verifying the validity of the arrival times and calculating the time difference; A wave velocity normalization calculation unit for generating the equivalent wave velocity of the entire line according to the difference between the actual wave velocity of the cable section and the standard wave velocity of the overhead section; A fault location unit for calculating the fault distance according to the generated equivalent wave velocity of the entire line and the calculated time difference to locate the fault coordinates.

4. The power line fault location system according to claim 3, characterized in that The wave velocity normalization calculation unit is configured as: Based on the preset calibration parameters of the cable section, converting the actual length of the cable section into the equivalent overhead line length according to the ratio of the reference wave velocity to the actual wave velocity of the cable; Merging the converted equivalent overhead line length with the original overhead line section to construct a line model with continuous and consistent equivalent wave velocity; Generating the equivalent wave velocity of the entire line according to the line model.

5. The power line fault location system according to claim 3, characterized in that, The sensor module is also used to detect the zero-sequence current signal and the power frequency current signal in the line. The fault location unit includes: A lightning strike identification sub-unit for detecting the steep change characteristics of the traveling wave head according to the traveling wave current signal; A short-circuit identification sub-unit for detecting the consistency of the power frequency currents at both ends of the line according to the power frequency current signal; A grounding identification sub-unit for detecting the waveform characteristics of the zero-sequence current according to the zero-sequence current signal.

6. The power line fault location system according to claim 3, wherein The fault location unit is also used to determine the fault type. The determination of the fault type includes: If it is detected that the voltage of the traveling wave head rises by more than the first preset value within the first preset time, determining that the fault type is a lightning strike fault; If the difference in the magnitudes of the power frequency currents at both ends of the line is greater than the second preset value and the duration exceeds the second preset time, determining that the fault type is an interphase short-circuit fault; If the zero-sequence current shows an oscillating and decaying waveform and the duration exceeds the third preset time, determining that the fault type is a single-phase grounding fault.

7. The power line fault location system according to claim 6, wherein The power line fault location system further includes a wireless communication module for transmitting the arrival time to the background processing system, and the wireless communication module is configured as follows: When the GPRS signal strength reaches a preset threshold, establish a data transmission link with the background processing system through the GPRS network; When the GPRS signal strength does not reach the preset threshold, adopt a wireless relay transmission mode in a specific frequency band to relay and forward data through adjacent monitoring terminals.

8. The power line fault location system according to claim 1, characterized in that, The background processing system is further configured to: Integrate the fault location coordinates, fault type, and fault time into a structured data packet and send a warning message.

9. A power line fault location method, characterized in that, A background processing system applied to the power line fault location system according to any one of claims 1-8, the power line fault location method includes: Obtain the arrival times of the traveling wave wavefronts at both ends of the line and calculate the time difference; Based on the preset cable section calibration parameters, calculate the equivalent overhead line length and the equivalent wave velocity of the whole line; Determine the fault distance according to the calculated time difference, equivalent overhead line length, and equivalent wave velocity of the whole line.

10. The power line fault location method according to claim 9, characterized in that, The power line fault location method further includes: Determine the fault type according to the traveling wave steepness change rate, power frequency current amplitude difference, and zero-sequence waveform characteristics, and the fault types include lightning strike faults, phase-to-phase short circuit faults, and single-phase ground fault.

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