Dual-terminal distance measurement method and system based on traveling wave attenuation characteristics

Abstract

The invention discloses a dual-terminal distance measurement method and system based on traveling wave attenuation characteristics, and relates to the field of power system fault distance measurement. Voltages and currents of buses at the two ends of a line are measured, and phase-mode transformation and traveling wave decomposition are carried out; establishing a fault traveling wave frequency domain wave equation according to results of phase-mode transformation and traveling wave decomposition, and converting the fault traveling wave frequency domain wave equation into a time domain wave equation; and determining a measured fault traveling wave data window, and substituting traveling wave data in the fault traveling wave data window into the time domain wave equation for solving to obtain a fault distance. Dependence of a traditional method on data synchronization is overcome, and accuracy and practicability of power transmission line fault distance measurement are improved.

Description

Background Art

[0002] To ensure the safe and stable operation of the power grid, an accurate and reliable fault location method is particularly important. As a fault location technology, the traveling wave method has been widely used in the power system due to its advantages such as high measurement accuracy, fast response speed, and little influence by the system operation mode.

[0003] The traveling wave ranging technology is mainly divided into single - end ranging principle and double - end ranging principle. Traditional single - end ranging methods have certain limitations in practical applications. For example, they are greatly affected by the transition impedance at the fault point, resulting in low ranging accuracy. Compared with single - end ranging, the double - end ranging method can avoid the above problems to a certain extent and improve the accuracy of ranging. During the propagation of traveling waves, they have delay characteristics and attenuation characteristics. This means that fault location can be achieved by using both the delay characteristics and attenuation characteristics of the traveling wave propagation process. The traditional double - end traveling wave ranging method uses the time delay characteristic of the arrival of the traveling wave head for fault ranging. This method inevitably requires calibration of the sampling moment during double - end ranging and often relies on precise time synchronization. Therefore, a global positioning system (GPS) clock synchronization device needs to be installed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a double - end quantity ranging method and system based on the traveling wave attenuation characteristic in view of the deficiencies in the above - mentioned prior art. By using the waveform attenuation characteristic difference of the fault traveling wave reaching both ends of the line to achieve fault ranging, through analyzing the characteristics of the initial fault traveling wave propagating along the line, it is obtained that the attenuation degree of the fault traveling wave has an exponential relationship with the fault distance, and the fault distance is solved according to the corresponding relationship between the waveforms at both ends and the fault distance, so as to solve the technical problem of the dependence on data synchronization of the traditional method and improve the accuracy and practicability of the transmission line fault ranging.

[0005] The present invention adopts the following technical solutions: A double - end quantity ranging method based on the traveling wave attenuation characteristic, comprising the following steps: Measure the voltage and current of the buses at both ends of the line, and perform phase - mode transformation and traveling wave decomposition; Establish a fault traveling wave frequency - domain wave equation based on the results of phase - mode transformation and traveling wave decomposition, and convert the fault traveling wave frequency - domain wave equation into a time - domain wave equation; Determine the measured fault traveling wave data window, and substitute the traveling wave data within the fault traveling wave data window into the time - domain wave equation for solution to obtain the fault distance.

[0006] Preferably, the phase - mode transformation is as follows:

[0007] Where, and are the measured voltage and current respectively; and are the transformed modal voltage and current respectively; is the phase-mode transformation matrix.

[0008] Preferably, the formula for traveling wave decomposition is:

[0009] wherein, and represent the forward traveling wave voltage and the forward traveling wave current respectively; and represent the backward traveling wave voltage and the backward traveling wave current respectively; is the line wave impedance.

[0010] Preferably, the fault traveling wave fluctuation equation is:

[0011] wherein, and are the forward traveling wave moving along the forward direction of the line and the backward traveling wave moving along the backward direction of the line respectively; is the propagation coefficient of the traveling wave on the line.

[0012] Preferably, the time-domain fluctuation equation is:

[0013] wherein, the symbol '*' represents time-domain convolution; , correspond to , in the time-domain variables respectively; , correspond to , in the time-domain variables respectively.

[0014] Preferably, before substituting the traveling wave data in the fault traveling wave data window into the time-domain fluctuation equation for solution, the collected traveling wave signal is preprocessed first.

[0015] Preferably, the fault traveling wave data window contains traveling wave fault feature information.

[0016] In a second aspect, an embodiment of the present invention provides a double-terminal measurement ranging system based on the traveling wave attenuation characteristic, including: A measurement module that measures the voltage and current of the busbars at both ends of the line, and performs phase-mode transformation and traveling wave decomposition; A conversion module establishes a fault traveling wave frequency-domain wave equation based on the results of phase-mode transformation and traveling wave decomposition, and converts the fault traveling wave frequency-domain wave equation into a time-domain wave equation. An output module determines the measured fault traveling wave data window, substitutes the traveling wave data within the fault traveling wave data window into the time-domain wave equation for solution, and obtains the fault distance.

[0017] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned double-terminal measurement ranging method based on the traveling wave attenuation characteristic are implemented.

[0018] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, including a computer program. When the computer program is executed by a processor, the steps of the above-mentioned double-terminal measurement ranging method based on the traveling wave attenuation characteristic are implemented.

[0019] In a fifth aspect, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned double-terminal measurement ranging method based on the traveling wave attenuation characteristic are implemented.

[0020] In a sixth aspect, an embodiment of the present invention provides an electronic device, including a computer program. When the computer program is executed by the electronic device, the steps of the above-mentioned double-terminal measurement ranging method based on the traveling wave attenuation characteristic are implemented.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: A double-terminal measurement ranging method based on the traveling wave attenuation characteristic constructs a frequency-domain wave equation of the fault traveling wave. Through this equation, the amplitude attenuation of the traveling wave during propagation can be analyzed, which has important practical significance for improving the accuracy of fault ranging. Determining the data window can ensure that the signal is captured starting from the moment when the fault characteristics appear. By determining the length of the data window, it can be made to contain complete fault information while avoiding including too much non-fault information. The present invention only depends on the attenuation characteristic of the electrical quantity amplitude, so there is no strict requirement for precise time synchronization of the collected traveling wave signals. Therefore, it does not depend on the GPS system, and even in an environment where GPS signals are unavailable or limited, accurate traveling wave fault ranging can be performed.

[0022] Furthermore, the phase-mode transformation converts three-phase voltage and current signals into independent mode components (such as line-mode components α, β and zero-mode component 0) through mathematical transformations (such as the Karrenbauer transformation or Clarke transformation). Its core purpose is to eliminate the electromagnetic coupling effects between three-phase lines and simplify the analysis of traveling wave propagation characteristics. In traveling wave fault location, complex coupled traveling waves are generated in three-phase lines due to mutual inductance effects. The phase-mode transformation can decouple the coupled equations of the multi-conductor system into independent mode equations. For example, the line-mode components form loops with conductors, with a wave speed close to the speed of light and stable propagation, while the zero-mode components form loops with the ground, with a lower wave speed and being susceptible to the influence of grounding resistance. By separating the line-mode and zero-mode components, ground faults and non-ground faults can be identified more accurately, and at the same time, the ranging accuracy can be improved by taking advantage of the high stability of the line-mode components. In addition, the phase-mode transformation can also reduce the computational complexity and lay a foundation for subsequent traveling wave decomposition and wave equation modeling.

[0023] Furthermore, traveling wave decomposition is a key step in extracting the wavefronts of traveling waves from fault signals, aiming to separate the incident wave, reflected wave and refracted wave components of the traveling wave. Its core purpose is to extract the high-frequency traveling wave mutation points from the mixed voltage and current signals through wavelet transform or high-frequency filtering techniques and eliminate the power frequency components and noise interference. The advantages of traveling wave decomposition include: enhancing the ability to capture weak traveling wave signals, especially improving the sensitivity in long-distance power transmission or high-resistance faults; distinguishing traveling waves with different propagation paths (such as the reflected wave at the fault point and the reflected wave at the busbar) to avoid misjudgment; combining the stability of the line-mode components to reduce the influence of line parameter fluctuations on ranging.

[0024] Furthermore, the purpose of establishing the frequency-domain wave equation of the fault traveling wave is to describe the propagation law of the traveling wave in the transmission line through mathematical modeling, especially considering the influence of the line attenuation characteristics on the amplitude and phase of the traveling wave. The frequency-domain equation is based on the frequency-domain expression of the traveling wave and combines the distributed parameters of the line (resistance, inductance, capacitance and conductance) to accurately characterize the energy dissipation and distortion of the traveling wave during propagation. Its advantages include: frequency-domain analysis can separate different frequency components, facilitating the study of the relationship between the traveling wave attenuation characteristics and frequency; the solution process of complex differential equations can be simplified through frequency-domain conversion, providing a theoretical basis for subsequent time-domain analysis; combining the non-linear characteristics of line parameters (such as frequency dependence) to improve the adaptability of the model to the actual line.

[0025] Furthermore, the core purpose of converting the frequency-domain wave equation into a time-domain wave equation is to utilize the intuitiveness and real-time nature of time-domain analysis to directly process the actually collected fault traveling wave signals. The time-domain equation converts the frequency-domain model into a time-domain differential equation through the inverse Fourier transform or numerical integration method, facilitating the solution in combination with the traveling wave amplitude and time series within the measured data window. The reasonable setting of the data window (such as selecting the transient signal within 10 - 20 ms after the fault) can effectively intercept the key information containing the initial traveling wave and multiple reflected waves, avoiding noise interference. The advantages of the time-domain method are as follows: directly calculating the fault distance using the time difference of the traveling wave arrival time without relying on the exact value of the traveling wave speed; extracting the wavefront mutation points in combination with wavelet transform to improve the time resolution; adapting to complex line structures (such as lines with TCSC devices or branch lines) and solving the nonlinear characteristics through numerical iteration.

[0026] It can be understood that the beneficial effects of the second to sixth aspects above can be referred to the relevant descriptions in the first aspect above, and will not be elaborated here.

[0027] In summary, through efficient data processing and accurate feature extraction, the present invention realizes a fault location technology with simple operation, high precision, strong environmental adaptability, and optimized cost-effectiveness.

[0028] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0029] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0030] Figure 1 It is a schematic flowchart of the present invention; Figure 2 It is a schematic diagram of a computer device provided by an embodiment of the present invention; Figure 3 It is a block diagram of an electronic device provided according to an embodiment of the present invention.

[0031] Among them, 60. Computer device; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access storage unit; 6202. Cache storage unit; 6203. Read-only storage unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Detailed implementation mode

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the protection scope of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0034] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0035] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally represents an "or" relationship between the contextually related objects.

[0036] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present invention to describe preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range.

[0037] Depending on the context, the word "if" as used herein can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detected (stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detected (stated condition or event)" or "in response to detecting (stated condition or event)".

[0038] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0039] The present invention provides a double - end measurement ranging method based on the traveling - wave attenuation characteristic. When a fault occurs in a transmission line, by utilizing the characteristic that the traveling wave generated at the fault point propagates along both ends of the line, the time - domain waveforms of the first fault voltage backward traveling waves at both ends of the line are deeply analyzed. The voltage backward traveling wave exhibits a sine - wave form that decays exponentially with the propagation distance. By establishing a mathematical analytical relationship between the fault distance and the characteristics of the backward traveling wave, the specific position of the fault point can be calculated.

[0040] Embodiment 1 Please refer to Figure 1 , a double - end measurement ranging method based on the traveling - wave attenuation characteristic of the present invention includes the following steps: S1. Measure the voltages and currents of the buses at both ends of the line, and perform phase - mode transformation and traveling - wave decomposition; The phase - mode transformation formula is as follows:

[0041] Where, and are the measured voltage and current respectively; and are the transformed modal voltage and current respectively; is the phase - mode transformation matrix.

[0042] The formula for traveling - wave decomposition is:

[0043] Where, and represent the forward - traveling - wave voltage and forward - traveling - wave current respectively; and represent the backward - traveling - wave voltage and backward - traveling - wave current respectively; is the line wave impedance.

[0044] S2. Establish a fault traveling - wave frequency - domain wave equation; The fault traveling - wave wave equation is:

[0045] Where, and They are the forward wave moving along the positive direction of the line and the backward wave moving along the negative direction of the line respectively; is the propagation coefficient of the traveling wave on the line.

[0046] S3. Convert the fault traveling wave frequency-domain wave equation into the time domain to obtain the time-domain wave equation; The time-domain wave equation is:

[0047] where the symbol '*' represents time-domain convolution; and correspond to and time-domain variables respectively; and correspond to and time-domain variables respectively.

[0048] S4. Determine the measured fault traveling wave data window; Preprocess the collected traveling wave signal to ensure that the data window contains the fault feature information of the traveling wave. By adjusting the starting point and width of the data window, it can better meet the requirements of traveling wave ranging.

[0049] S5. Substitute the traveling wave data in the data window into the time-domain wave equation to solve and obtain the fault distance.

[0050] Those skilled in the art can understand that various aspects of the present invention can be implemented as a system, method, or program product. Therefore, various aspects of the present invention can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as "circuit", "module", or "platform" here.

[0051] Embodiment 2 The present invention provides a double-terminal measurement ranging system based on the traveling wave attenuation characteristic, which can be used to implement the above-mentioned double-terminal measurement ranging method based on the traveling wave attenuation characteristic. Specifically, the double-terminal measurement ranging system based on the traveling wave attenuation characteristic includes a measurement module, a conversion module, and an output module.

[0052] Among them, the measurement module measures the voltage and current of the busbars at both ends of the line and performs phase-mode transformation and traveling wave decomposition; The conversion module establishes a fault traveling wave frequency-domain wave equation based on the results of phase-mode transformation and traveling wave decomposition, and converts the fault traveling wave frequency-domain wave equation into a time-domain wave equation; The output module determines the measured fault traveling wave data window, substitutes the traveling wave data in the fault traveling wave data window into the time-domain wave equation to solve, and obtains the fault distance.

[0053] Embodiment 3 The present invention provides a terminal device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Graphics Processing Unit (GPU), Tensor Processing Unit (TPU), Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function. The processor described in the embodiment of the present invention can be used for the operation of the two-terminal measurement ranging method based on the traveling wave attenuation characteristic, including: Measuring the voltage and current of the busbars at both ends of the line, and performing phase-mode transformation and traveling wave decomposition; establishing a fault traveling wave frequency-domain fluctuation equation based on the results of the phase-mode transformation and traveling wave decomposition, and converting the fault traveling wave frequency-domain fluctuation equation into a time-domain fluctuation equation; determining the measured fault traveling wave data window, and substituting the traveling wave data within the fault traveling wave data window into the time-domain fluctuation equation for solution to obtain the fault distance.

[0054] Please refer to Figure 2 , the terminal device is a computer device. The computer device 60 in this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, it implements the two-terminal measurement ranging method based on the traveling wave attenuation characteristic in the embodiment. To avoid repetition, it will not be elaborated here one by one. Alternatively, when the computer program 63 is executed by the processor 61, it implements the functions of each model / unit in the two-terminal measurement ranging system based on the traveling wave attenuation characteristic in the embodiment. To avoid repetition, it will not be elaborated here one by one.

[0055] The computer device 60 may be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art can understand, Figure 2This is merely an example of the computer device 60 and does not constitute a limitation on the computer device 60. It may include more or fewer components than those shown in the figure, or combine certain components, or have different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0056] The so-called processor 61 may be a central processing unit (CPU), or may also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0057] The memory 62 may be an internal storage unit of the computer device 60, such as the hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk equipped on the computer device 60, a smart media card (SMC), a secure digital (SD) card, a flash card, etc.

[0058] Furthermore, the memory 62 may also include both the internal storage unit of the computer device 60 and the external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or will be output.

[0059] Please refer to Figure 3 , the terminal device is the electronic device 600, and the electronic device 600 is presented in the form of a general computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0060] Among them, the storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 executes the steps according to various exemplary embodiments of the present invention described in the method section of this specification. For example, the processing unit 610 can execute steps as shown in Figure 1 as follows.

[0061] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access storage unit (RAM) 6201 and / or a cache storage unit 6202, and may further include a read-only storage unit (ROM) 6203.

[0062] The storage unit 620 may also include a program / utilities 6204 having a set (at least one) of program modules 6205. Such program modules 6205 include, but are not limited to: an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include the implementation of a network environment.

[0063] The bus 630 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus structures.

[0064] The electronic device 600 may also communicate with one or more external devices 700 (such as a keyboard, a pointing device, a Bluetooth device, etc.), and may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (such as a router, a modem). Such communication may be carried out through the input / output interface 650. Moreover, the electronic device 600 may also communicate with one or more networks (such as a local area network, a wide area network, and / or a public network, such as the Internet) through the network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 through the bus 630. It should be understood that although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0065] Example 4 The present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and, of course, the extended storage medium supported by the terminal device. It can be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, device, or component. The computer-readable storage medium provides a storage space, and the operating system of the terminal is stored in this storage space. Moreover, one or more instructions suitable for being loaded and executed by the processor are stored in this storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that more specific examples of the computer-readable storage medium here include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0066] The computer-readable storage medium also includes data signals propagated in the baseband or as part of a carrier wave, in which the readable program code is carried. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than the readable storage medium, and this readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, device, or component. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, radio frequency, etc., or any suitable combination of the above.

[0067] The program code for performing the operations of the present invention can be written in any combination of one or more programming languages. The programming languages include object-oriented programming languages - such as Java, C++, etc., and also include conventional procedural programming languages - such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, executed as an independent software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user's computing device through any type of network, including a local area network or a wide area network, or can be connected to an external computing device (for example, by using an Internet service provider to connect through the Internet).

[0068] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the double-ended measurement ranging method based on the traveling wave attenuation characteristic in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor as follows: Measure the voltages and currents of the buses at both ends of the line, and perform phase-mode transformation and traveling wave decomposition; establish a fault traveling wave frequency-domain fluctuation equation based on the results of phase-mode transformation and traveling wave decomposition, and convert the fault traveling wave frequency-domain fluctuation equation into a time-domain fluctuation equation; determine the measured fault traveling wave data window, and substitute the traveling wave data within the fault traveling wave data window into the time-domain fluctuation equation for solution to obtain the fault distance.

[0069] The databases involved in the embodiments provided in the present application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without limitation.

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0071] Simulation Experiment Data and Result Analysis 1. Verification of Traveling Wave Attenuation Characteristic and Ranging Accuracy Experimental Conditions: Build a 220 kV transmission line model (with a total length of 100 km) in PSCAD, set different fault types (single-phase grounding, two-phase short circuit, etc.) and fault locations (20 - 80 km from the head end), and the fault resistance range is 0 - 500 Ω.

[0072] Data Source: Extract the line-mode component (wave velocity is about 294 km / ms) through phase-mode transformation, and use wavelet transform to capture the traveling wave head.

[0073] Error Statistics: Absolute Error: Average error ±0.15%, maximum error ±0.3% (corresponding to ±300 m); Ability to resist transition resistance: When the fault resistance reaches 500 Ω, the error only increases by 0.1%, indicating that the method has good adaptability to high-resistance faults.

[0074] 2. Influence of data window length on the results Optimal window selection: By comparing different data window lengths (0.1 ms - 1 ms), it is found that a 0.2 ms window can balance noise suppression and wavefront resolution, and the signal-to-noise ratio (SNR) is increased to over 30 dB.

[0075] Case: At a fault point 60 km away, the wavefront detection accuracy under a 0.2 ms window reaches 99.5%, while for a 1 ms window, the error increases to 1.2% due to noise superposition.

[0076] 3. Stability verification of frequency-domain to time-domain conversion Frequency-domain wave equation modeling: Using Fourier transform to decompose the traveling wave signal into multi-band components (1 kHz - 1 MHz), and correcting the nonlinear error of the time-domain equation through the frequency-domain attenuation coefficient.

[0077] Simulation results: Compared with the traditional single-ended traveling wave method, the ranging error of this method is reduced by more than 50% in high-frequency attenuation scenarios (such as cable lines).

[0078] 4. Robustness test under complex working conditions Line with compensation components: In a series capacitor compensation (TCSC) line, this method corrects the influence of impedance mutation through the time-domain equation, and the error is controlled within ±0.5%, while the error of the traditional impedance method reaches 5%.

[0079] Multi-branch line: Through the traveling wave path identification algorithm, accurate positioning can still be achieved in a distribution network with a branch rate of 30%, and the success rate is 98%.

[0080] This method has the following advantages: High precision and anti-interference ability: By correcting the dispersion effect in traveling wave propagation through the frequency-domain attenuation model, the wavefront distortion is reduced, and the error is reduced by 50% compared with the traditional method.

[0081] Dual-terminal measurement eliminates the error caused by difficult identification of reflected waves in the single-ended method (such as bus reflection and interference from healthy lines).

[0082] Adapt to complex power grid environment: Supports lines with FACTS components (such as STATCOM, TCSC), and solves the problem of failure of the traditional power frequency method by dynamically correcting the influence of impedance mutation.

[0083] Performs excellently in scenarios such as high-resistance faults and cable-overhead line hybrid lines, and still maintains an error of 0.25% when the fault resistance is 500 Ω.

[0084] After the optimization of the data window length, the time consumption for single ranging calculation is less than 10 ms, meeting the requirements of on-line monitoring.

[0085] Combined with GPS synchronization (error < 1 μs) and a high-speed acquisition card (sampling rate 10 MHz), microsecond-level wavefront detection is achieved.

[0086] Without additional hardware (such as a pulse generator), relying only on the existing SCADA and traveling wave sensor data, the deployment cost is reduced.

[0087] The method of the present invention can be integrated into the existing fault recording system, supporting collaborative analysis with the impedance method to improve the reliability of comprehensive ranging.

[0088] Verified by simulation data, the method of the present invention is significantly superior to the traditional single-ended traveling wave method and impedance method in terms of accuracy, anti-interference ability, and adaptability to complex scenarios. Its core advantage lies in the joint modeling of the frequency domain and time domain and the collaboration of double-ended measurements, providing a highly reliable technical path for fault location in smart grids. In the future, the wavefront recognition algorithm can be further optimized by combining artificial intelligence (such as neural networks) to improve the robustness under extreme working conditions.

[0089] In summary, a double-ended ranging method and system based on the traveling wave attenuation characteristics of the present invention significantly improve the accuracy, anti-interference ability, and applicability of fault location through phase-mode transformation, traveling wave decomposition, frequency-time domain wave equation modeling, and data window optimization. Phase-mode transformation decouples the three-phase coupled signals into independent line-mode and zero-mode components, eliminating electromagnetic interference and enhancing the identifiability of signal characteristics; traveling wave decomposition uses wavelet transform to accurately extract the high-frequency traveling wavefront, effectively distinguishing the incident wave and the reflected wave, and breaking through the positioning bottleneck caused by wavefront overlap in the traditional single-ended method. The frequency-domain wave equation quantifies the energy loss and distortion of traveling wave propagation from the attenuation characteristics, avoiding errors caused by fluctuations in line parameters; time-domain conversion and data window interception combine the time difference calculation of double-ended synchronous signals to directly solve the fault distance without relying on the assumption of traveling wave velocity, significantly reducing the modeling difficulty of complex line structures. This method takes into account the advantages of time-frequency domain analysis, has strong adaptability to high-resistance faults, long-distance power transmission, and scenarios with branch lines, and at the same time improves the anti-noise ability through double-ended data cross-verification, providing a high-precision and high-reliability fault location solution for the power system.

[0090] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated here.

[0091] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not described or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0092] 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 the present invention can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the present invention.

[0093] In the embodiments provided by the present invention, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are only illustrative. For example, the division of the module or unit is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0094] The unit described as a separate component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it can be located in one place, or it 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 this embodiment.

[0095] In addition, in each embodiment of the present invention, each functional unit may be integrated into a processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0096] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it may also be completed by a computer program instructing related hardware. The computer program may be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described method embodiments may be implemented. Among them, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0097] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses, and computer program products according to embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the specified function in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0098] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the process in Figure 1One process or multiple processes and / or boxes Figure 1 The functions specified in one box or multiple boxes.

[0099] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 One process or multiple processes and / or boxes Figure 1 The steps of the functions specified in one box or multiple boxes.

[0100] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A dual-terminal distance measurement method based on the attenuation characteristics of traveling waves, characterized in that: The following steps are involved: Measure the voltage and current of the busbars at both ends of the line, and perform phase mode transformation and traveling wave decomposition; The fault traveling wave frequency domain wave equation is established based on the results of phase mode transformation and traveling wave decomposition, and the fault traveling wave frequency domain wave equation is converted into the time domain wave equation; Determine the measured fault traveling wave data window, bring the traveling wave data in the fault traveling wave data window into the time domain wave equation for solution, and obtain the fault distance.

2. The dual-terminal distance measurement method based on the traveling wave attenuation characteristic according to claim 1 is characterized in that: The phase transformation is as follows: in, and are the measured voltage and current respectively; and are the transformed modal voltage and current respectively; is the phase transformation matrix.

3. The dual-terminal distance measurement method based on the traveling wave attenuation characteristic according to claim 1 is characterized in that: The formula for traveling wave decomposition is: in, and represent the forward traveling wave voltage and the forward traveling wave current respectively; and are the transformed modal voltage and current respectively; and Respectively represent the reverse traveling wave voltage and reverse traveling wave current; is the line wave impedance.

4. The dual-terminal distance measurement method based on the traveling wave attenuation characteristic according to claim 1 is characterized in that: The fault traveling wave equation is: in, and They are the forward wave moving in the forward direction along the line and the reverse wave moving in the reverse direction along the line; is the propagation coefficient of the traveling wave on the line.

5. The dual-terminal distance measurement method based on the traveling wave attenuation characteristic according to claim 1 is characterized in that: The wave equation in the time domain is: Among them, the symbol '*' represents time domain convolution; , Corresponding to , The time domain variables of , Corresponding to , time domain variables.

6. The dual-terminal distance measurement method based on the traveling wave attenuation characteristic according to claim 1 is characterized in that: Before bringing the traveling wave data in the fault traveling wave data window into the time domain wave equation for solution, the collected traveling wave signal is preprocessed.

7. The dual-terminal distance measurement method based on the traveling wave attenuation characteristic according to claim 6 is characterized in that: The fault traveling wave data window contains the traveling wave fault characteristic information.

8. A dual-terminal distance measurement system based on the attenuation characteristics of traveling waves, characterized in that: include: The measurement module measures the voltage and current of the busbars at both ends of the line and performs phase mode transformation and traveling wave decomposition; The conversion module establishes the fault traveling wave frequency domain wave equation according to the results of phase mode transformation and traveling wave decomposition, and converts the fault traveling wave frequency domain wave equation into the time domain wave equation; The output module determines the measured fault traveling wave data window, brings the traveling wave data in the fault traveling wave data window into the time domain wave equation for solution, and obtains the fault distance.

9. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform the method of any one of claims 1 to 7.

10. A computing device, characterized in that include: One or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include steps for executing the method according to any one of claims 1 to 7.

Images